Inverter Training Manual

7/21/2019 Inverter Training Manual

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Renewable Energy Technologies in Asia:

A Regional Research and Dissemination Programme

PHASE II

For Photovoltaic Applications

Training Manual

Prepared by

Solar Laboratory

01 Mac Dinh Chi St., 1 District

Ho Chi Minh City

SR Vietnam



C C C O O O N N N T T T E E E N N N T T T S S S

Page

Lesson 1 Overview of Development of Inverter. 01 By Phys. Trinh Quang Dung

Lesson 2 Renewable Hybrid Power Supply Unit Smart 1000 09

a combination of Charger - Inverter UPS Unit By Phys.Trinh Quang Dung Eng. Nguyen Truong Duc Eng. Le Sy Thang

Lesson 3 Sine-Square and Sine-Modification Inverter 26By Eng. Tran Phi Cong

Lesson 4 High Frequency Inverter. 35 By Eng. Nguyen Truong Duc

Eng. Tran Phi Cong

Lesson 5 True Sine Inverter. 42 By Eng. Le Si Thang

Lesson 6 Computer Designing of Inverter. 50 By Eng. Nguyen Truong Duc



1

LESSON 1

OVERVIEW OF DEVELOPMENT OF INVETER

I. BRIEF HISTORY AND TECHNICAL DEVELOPMENT

1.1 Motor Generator Inverter:

Since 1940 inverter has appeared and the first uses were in the Second World War.This time together with a development of electronic lamps, the need of high DC

voltage had been requested. During the time of world war’s II when Navy Ships ranon DC power only then DC source was urgently needed. That time, the Invertor was Rotary Inverter. In fact this was a motor generator,which could convert 12 VDC, 27 VDC, into110 VAC, 220 VAC and it was only way toconvert DC voltage into AC voltage.The most popular brand of that era wasRedi – Line. Over half of century passed butRedi – Lines still appear in use in the country- side around us. These rugged units were

quite reliable, strong enough and producedAC voltage with a low efficiency about 50%.The Rotary Inverter had many disadvantagesas very high start current of 20A – 30A and nostable out put voltage. It also could not havestart up surge capacity, which limited applications of inductive loads as fan, pump,compressor etc… Because of their quite high reliability, Blue Bird Rotary Inverter still had been produced until the late of 1970’s and early 1980’s.

1.2 Electronic Sine Square Inverter.

Trip-lite company founded in 1992 was the first produced a unique automobileheadlight, which has been Invented by Graham Tripped. Later, the product lineexpanded to include Electronic Inverter. In that era, the early units used mechanicalvibrator to oscillate DC power into square waveform AC, the mechanic vibrator when it oscillates which turning on and off continuously contact-points to makesquare wave current. This kind of Inverter could response only one defined load andshort lifetime because of contact points easy damaged. Solid-state semiconductor devices were born in middle of 20 century, which

supported to new generations of Inverte: Full –

Electronic Inverter in the early 1960’s. The solid-state transistors replaced the mechanical vibrator,which maintains longer lifetime of the unit. This

REGIONAL TRAINING COURSE ON ‘INVERTER TECHNOLOGY” 16 -20 October, 2000 HCM City Vietnam



2

event declared a termination of Rotary Inverter Technology as well as mechanicvibration system. Since this point, the motor – generators no longer producedanywhere. Although that, unregulated square wave design of this kind Inverter couldnot go over and many technical problems were still open as unstable output voltage,no surge power, no frequency control etc… This time Inverter could response only for resistive loads but they was not possibleto run reactive loads as motor, Ice – creamaker, pump, microware oven etc… Theseweak points limited applications of Inverter and they had almost fallen in forgettingof people. Later on a design of frequency control was applied to allow a steady draw, whichhad improved the time-by-time and formed modified sine wave, which is still very

popular for today. On basic of this technology, Tripp lite has produced power Inverter, UPS devices(Uninterruptible Power Supply). The company provides products in worldwidemarket. In 1979 Vanner inc. introduced the first 1000W sine modified wave Inverter thanks to it’s parented power transistor drive technique. That time it was a bigachievement and subrising, because of an unheard efficiency of 87%. The firstapplication of this Inverter was used in ambulances. Few years later, the applicationwas expanded into various types of vehicles including remote television vans. After that following the market request, product line expanded with 2200W and 3000WInverter. After the world energy crisis in 1973, Renewable Energy Sources have beenmentioned and attracted energy policy markers. One of the urgent request was howto produce high quality AC electricity from RE and one again the companies,researchers, engineers have jumped in a competition of Inverter Technology. During 1980’s there were two companies manufacturing Inverter in USA for theworld market: Heart interface and GTO Electronics. There were some others inEurope and Asia but they were small. In 1986 Heart split off to form TraceEngineering, which later became a famous Inverter manufacture in the world. TheHeart Inverter had a battery charger /converter built in and was the pioneer reachedhighest efficiency that time over 90%. Another strong point of it’s specification wasthe surge power had got three times. In 1986 one of the Inverter models included a microprocessor control wasmentioned. On the technical point of view, we could classify that the first generationInverters used Metered Darlington Technology. This special circuit metered basecurrent to power a transistor proportional to load. The magnetic design increasedefficiency. Second – generation Inverters used FETs (Field Effect Transistors), sinceFETs have almost no switching losses, efficiency was markedly improved. In the last decade of 20th century, the Inverter Technology has strongly developedwith a big worldwide competition. In 1987 Exeltech was founded and manufacturedHigh Frequency Sin Ware Inverter. It claims the first redundant Inverter system,“hot” swappable capability and modular design. This kind of Inverter do not used bigtransformator that why they have quite small size, much lighter and convenience for mobile application.

Stat-power Technologies Corporation head quartered in British, Columbia,Canada was founded in 1988 also manufactured M.S.W Inverters using HighFrequency design. The company provided portable power for remote regions.



3

In 1990 IC (Integrated circuits) were applied which allowed the creation of energy management system and microprocessor in Inverter Technology. The firstmicroprocessor controlled Inverter/Charger was introduced in 1993. The advantagesof M.S.W Technology are efficiency and relatively economical cost although that theM. S. W Inverter however, still cannot run all kinds of loads because of poor peak voltage regulation and the fact that the AC output is not a pure sin wave. Beside this,M. S. wave Inverter also makes interference to loads in some cases. Trace Engineering developed and patented improvements to the modified sinewave technology in their sine wave series Inverter. While not a true sine wave, theoutput is a multi – step approximation thatresults in fewer load incompatibilities. Thecharger is more efficient and results lower AC. This sine wave series Inverter still hasseveral other features as including anautomatic generator start/stop, a batterytemperature sensor and three independencyset voltage relays. Trace Engineering hascovered big part of the global market thatwhy in South Africa the name “Trace” itmeans “Inverter” In 1995 Stat-power introduced a pure sinewave Inverter/Charger using highFrequency Switching Techniques, they were successful in producing a high outputcharger with a power factor approaching “1”. This is almost not distortion at the DC

port in both Inverter and charger mode which could be viewed as a technologicalmilestone. Pure Sine Wave Inverter opens a new era and any limitation of use isremained. Although that Pure Sine Wave Technology just in start, we expect a quick development to sweep out some barriers as high cost, difficult to maintained etc…and catching a potential world market. The Pure Sine Wave Inverters have givengood chance for grid – connected design as well as synchronous of several Pure SineWave Inverter to increase power. We could say that since 1995 a “boom” of competition for Inverter manufacturing. Millions solar roofs, thousands of windfarms, micro-hydro projects which have requested big amount of Inverters. Thanksto the revolution of Renewable Energy in world wide together with bigmanufactures, a lot of new electronic companies as Steca, Leomics, AST, Zenit have

jumped in the exciting market. Nowadays appearing a variable service of Invertersas Inverter for solar pump, for AC solar module for grid – connected use etc…

The smallest Inverter is one supplying for ACmodule which size is only108 x108 x30mm or 220x70x20mm. Output

power only 80W – 100W and catching anefficiency of 94%. They are introduced by TraceEngineering USA and OK service company of

Neither Land.

PV Series Inverter



4

The larger pure sine Inverter has already built up to a of power of 20 KVA andsurge power 200% . It runs big advanced micro processor control with soft start. Theefficiency gets over 90%. Stable output voltage and frequency, full protection for overload and short circuit, current mode control, automatic low battery shutdown to

protect battery, variable speed fan cooling. It’sweight is 250 kg and could operates in poor

condition up to 450C and relativehumidity 95%.

II. DEVELOPMENT INVERTER IN VIETNAM

During 1985 –1990 Vietnam had not enough Electricityon network and three nights per week were black out inall main cities. An urgent of Market request was given: AC

power from battery or an Inverter. During 1987 – 1990 anelectronic company Divu HCM City jumped in product – line

and introduced Divu Inverter. It was sin square Inverter with a max power of 300w. The quality was poor, nosurge power and responded only for resistive loads.

SPECIFICATIONS OF LEONICS TRUE SINE INVERTER

The efficiency was low about 60%. Later on in short time the imported Inverters from TaiwanAND South East Asia and Copy imported – Inverter covered quite small and poor market thattime there for Divu company also stopped their product.

AC Module Inverter



5

A serious research and good design of Inverter has been done by AST Company during 1986 – 1989. In 1990 AST Company put it’s products in local market with two ranges: 300W and600W sin modified wave Inverter with stabilizes output voltage220V ± 5% and full – protection system. Since 1995 thanks to open – door policy, the economic of

Vietnam going on fastly and Renewable Energy Sources as solar,wind, micro hydro have strongly developed. One again Inverter has become “hot” request for remote, mountainous regions as well as on Island and country side A lot of electronic companies have put in market their Inverters as RoBo, Solar, Hansinetc…. The common disadvantages of the Market – Inverter are poor quality, high stand bycurrent or low efficiency. AST company is still pioneer among them for quality and thecompany has continuously done research and improved design and quality. AST is also leadingahead in manufacturing UPS devices and Auto Stabilizations. The company networks havedistributors and agencies along the country and sell out 5000 products/month approximately. Solarlab is a National Laboratory belongs to Vietnam National Center for Sciences andTechnologies. It is a pioneer and leader of PV development of Vietnam. To serve own activities,

Solarlab has researched on Inverter – Technology since 1990 and has Introduced the first “SOLARSTAT” equipment in the Solar Station and Cultural House at Tam Thon Hiep DistrictHCM City in Vietnam end of 1990.The SOLARSTAT kept “Industrial Model and Design” issued by Department of Invention and

Properties of Vietnam during 1992 – 1998. The SOLARSTAT is aheart of Battery Charging Center and Cultural House, It consists of four Charging Channels by solar modules and a built in sin squareInverter of 300W. Later on,Solarlab has continuouslydeveloped and improved quality of it’s Inverters with 500W and1000W. The Inverters of Solar labmanufactured specially for PV.Applications that why the qualityand energy saving are priorities. The stand by current of Solarlab’sInverter usually was 2/3 of the market Inverter and high surge

power. During last 10 years. Solar lab put in operation about 60SOLARSTAT along the country. In 1993 nine SOLARSTATswere exported to Republic of Mali in Africa according cooperation

with FONDEM France and one SOLARSTAT was exported to Lao P.D.R in order of MOSTEVietnam in 1997. The SOLARSTATs provide electrical power for various PV. Applications asTelecommunication repeaters, Satellite – Para ball Receiver – Transmitter Cultural Houses, Solar House, and Local Radio Broadcasting Center etc… In 1996 Solar lab designed a first High Frequency Inverter in Vietnam following a research

program funded by Sida Sweden. The productwas 50W only but it could not become a real

product because of lacking imported FETs Since 1997, AST Company and TectransViet Enterprise has joined to design andmanufactured Smart product with the range of

300W, 500W and 1000W. For short time of 2years, Smart 300, 500 and 1000 wereimproved much good design and quality. It is

Certification of Solar start

SOLAR START

front of Smart back of Smart



6

a Hybrid Power Supplied unit built in a power - full good sine modified Inverter. Surge power gets 200% and unheard efficiency of 90% Full protection as well as UPS function guaranteed.Frequency controlled, stabilized AC output voltage ± 5%, Hybrid Charging Control process andBattery Metter System are very competitive advantages of the Smart product – line. Smart 1000run all kinds of load as: water pump, photocopy machine, glass cutter etc… Especially itresponse also fun, refregenerator too. 2000’s is a good start of the product -line of smart with 14

units were exported to Thailand, Philippine and Germany.

APPENDIX: SMART SYSTEM



7



8

Grid-connected Inverter



9

LESSON 2

RENEWABLE HYBRID POWER SUPPLY UNIT SMART 1000

I. INTRODUCTION:

Smart 1000 is a Renewable Hybrid Power Supply Unit, which has manufactured byAST electronic CO. & TECTRANS VIET Enterprise. It is an intelligent equipment, whichhas many advantages and conveniences for Use.

The UPS function allows Smart 1000 can operates everywhere catching network.Especially in the domain of communication and informatics applications the continuous power all of time is very important fact. Which guarantee dropping out communicationsignal and losing database.

On input source, Smart has a wide range of choice whatever: grid reconnected, Solar module, Wind, micro hydro generator as well as Diesel generator… which makes Smart becomes a power source everywhere and every time.

You know, solar radiating is everywhere in Vietnam and almost everywhere in theworld. Furthermore, Solar power is a renewable and infinite power. Therefore Producers of Smart has designed Smart 1000 use solar power is a basic power source. Besides, othersrenewable are Wind power, hydroelectric power has been used too.

Smart 1000 can use in mountainous, remote area as well as in island... In mountainouswhere has much solar radiating and waterfalls you can use solar power and hydroelectric power to charge battery and use other applications. In coastal region or island where havemuch solar radiating and wind you can use solar power and wind power. With countrysideyou can use solar power and diesel generator…

Now, in Vietnam Smart 1000 has used on cultural boats and health service boats.Smart 1000 has been exported to some countries in ASIA. For example: Thailand,

Philippine … and it’s going to export to Germany on next time. It expect a big marketfuture thanks its advantage

II. DESIGN AND OPERATION

2.1 Description

Mobile independent hybrid power station for 12V DC and 110/230V AC, 50 Hz, built-in mains charge (AC 230 V) and solar charger regulator (DC 12V) for solar modules

up to 500Wp (40A) charging capacity, DC/AC inverter (modified sine wave) with rated

REGIONAL TRAINING COURSE ON “INVERTER TECHNOLOGY” 16-20 OCTOBER, 2000 HCMC



10

power capacity: 1000 W (surge power capacity = 2000 W), built-in uninterrupted power supply (UPS) device for safe supply during power cuts, multiple connections for 12V DC power charging systems (wind, hydro, generator), main and battery voltage indicator,

charging current indicator, system protection for low and overload, 12V DC mainsadaptor, switch-able 1.5–3–4.5–6 –7.5–9–12V, 1 cigarette lighter socket for 12V DC and 4AC safety sockets for 110/230V, system mounted in a roller rack in ready-to-use performance for direct connection of 12V DC battery bank (180Ah – 400Ah); weightwithout battery bank ≈ 30 Kg.

Smart 1000 is a mobile intelligent hybrid power supply and control unit for AC and DCappliances in home, offices and remote dwellings. It’s an AC power source for anytimeand everywhere

Smart 1000 is an ideal and unique equipment for reliable energy supply in isolated areawith selected and approved components, guaranteeing: high power quality, high reliability,quiet operation, multiple possibilities.

Smart 1000 is a ready-to-connect unit, simple to install, easy to use and requires nomaintenance. Charging power sources for Smart 1000 are besides grid or generator - a setof two qualities certified solar modules in combination with a sophisticated and highlyefficient wind generator.

Smart 1000 is capable of supplying power for: Lighting, Refrigeration, Air Conditioning, House hold Appliances, Tools, Communication Equipment, Radio, TV,Video, Computer, Charging Facility for DC source, etc.

Smart 1000 is used with Power sources Renewable Energies: Solar Module 100Wp-300Wp, Wind power Air 403, Micro Hydro Gurgler PT02 (150W-300W), Grid 220V, andGenerator 500W-3000W.

Hybrid Power Station is a hybrid power supply uses different sources of renewableenergies. The equipment consists of three parts as following:

Figure 1: The Block Scheme of Hybrid Power Station

Storage SystemU.P.S / Inverter 12V / 220 VAC

Charger Regulator

* Solar & Grid * Power

For Loading:- TV- Lighting- Computer - House appliances

12 VDC 220V 50Hz(60Hz)



11

The charging process of Charger Regulator for Solar and Grid is built in. And theGenerator, Micro Hydro, Wind had the control charging regulator themselves.

The full protection system allows the equipment auto-operates to against most of

troubles keeping high reliability of the equipment.§Energy charging

The charging of Hybrid Power Station can be applied with many variable kinds up tolocal conditions such as Grid, Diesel Engine, Micro Hydro, Wind or Solar Generator. Wecan use single or Hybrid Energy Power at the same time for charging. However, the mostimportant charging principle is a total charging current must not to be over a limit of:30Amax for H.P.S Smart 1000

The user should read carefully the catalogues when charging with Wind, Micro Hydro before connecting into H.P.S Smart 1000.

TECTRANS-VIET is willing supply Synchronous Renewable Energy Sources such asSolar, Wind, Micro Hydro sources that are suitable with the equipment Smart

For charging we must connect in exactly positions. Grid connects to AC-in, Solar intoSolar-in, Wind or Micro Hydro into Wind/ Hydro-in, Generator into Generator in. Theimportant note is a right connection to ⊕ and of DC sources. For Grid charging, turn onAC power contact to Charger.

§ Use DC power:

To use DC power, turning on the contact DC power ON, lighting indicator indicates

12V DC is on DC-out. When Battery voltage gets lower than 10.5V, empty indicator lighting on and DC source auto cutting off to protect Battery Bank. When the Battery Bank is full charged, DC source will auto Reset (or press Reset button).

DC source can also supply from contact cigarette in the backside, note follow correct pole ⊕ and printed in equipment.

§ Use AC power:

The UPS/ Inverter provides a continuing power of 500W or 1000W with voltage220V AC ± 5% 50Hz (or 60Hz) for: TV, Video, Lighting, Computer use. Surge power is

1000Wmax with and 1500Wmax with Smart 1000 SS in 5 seconds. Inverter supplies AC110V - 220V with Sine modification waveform. So, when use H.P.S for running motorswhich have high inductive characteristic, please carefully ask expert about the equipment.

When the Smart connects to a Grid power, AC source connected directly withnetwork. If the AC source suddenly interrupts the UPS function will be auto-change toInverter within 1 second.

When AC source disconnect by overload or short circuit, please check carefully andrepair to be sure troubles overcame, and turn off AC contact then turn on, AC source will be reset.

When using with invertors, the loading must turning on slowly to avoid suddenly

heavy loading for Smart.



12

220V ACINPUT

V DCINPUT

Solar Regular

Diesel source

Wind/M. hydro

Rectifier

DCAmpereMeter

OverchargeProtection

Store batteryBank 12V DC100/200 Ah

Charging indicator system

Battery state Indicator system

DCVoltageMeter

Transformer inverter

Oscillator 50 Hz

Ejectioncontroller protection

block

Low voltagedisconnection

Driver andTower

ACAmper

e

UPScontroller

ACAmpereMeter

ACVoltageMeter

12V DC

220V AC

110V ACOUTPUT

§ Indication systems:

AC Power: lighting at ON position and AC voltage. DC Power: lighting at ON position and DC voltage. Charger: ° Grid Power Led will be lighting if charges by Grid on AC - in 220V AC.

° Solar Power Led will be lighting if charging by Solar Modules on Solar in12 V DC.

° Diesel Power Led will be lighting if charging by Generator 12VDC onDiesel input.

° Wind / M. Hydro Led will be lighting if charging by Wind or Micro Hydro,Generator ON Wind / M.Hydro in 12VDC

Battery: ° Full Led (100%) will be lighting if the voltage of Battery Bank is 12.5V.° Normal Led (60%) will be lighting if the voltage of Battery Bank is 12V.° Low Led (30%) will be lighting if the voltage of Battery Bank is 11V.° Empty Led (10%) will be lighting if the voltage of Battery Bank under 10.5V and cut off DC-out.

Ammeter: showing charge – current into Battery Bank if equipment is charging by anyenergy sources: 50Amax for Smart 1000

VDC meter: show voltage in the two pales of Battery Bank from Storage Systemscapacity 200 AH / 300 AH.

VAC meter: show voltage 220V AC ± 5%, 50 Hz or 60 Hz. This voltage will appear when inverter is using or the Smart connecting to Grid.

§ Protection systems:

Smart 1000 is high reliability with full protection systems, includes: > Against overload and short circuit on outside. > Against inverse charging on Solar in. > Against overcharge. > Against exhausted Battery Bank.

2.2 Design

2.2.1 Block Scheme



13

2.2.2 Block function

• Solar regular, Diesel source, Wind / M-hydro block: there are energy charging sources,the charging of Hybrid power station can be applied with many variable kinds up to localconditions such as Solar, Diesel, win and Micro Hydro.• Charging indicator system block: include Leds such as Solar Power Led, Generator power Led… to indicate energy charging and charging state. For example: Solar Power Led lighting if charging by Solar Modules, Generator power Led lighting if charging byDiesel generator…• DC Ampere meter block: show current charge for battery.• Overcharge Protection block: Overcharge Protection.•

Battery state indicator system: include Leds to indicate Battery state. When battery isfull, the FULL LED will be lighting. When voltage of battery is low the LOW LED will belighting…• DC voltage meter: display battery voltage.• Store battery bank block: Battery bank from storage systems capacity 100/200Ah• Low voltage disconnection block: disconnect to load when battery is Low voltage• Oscillator 50 Hz block: change DC voltage input to 50Hz potential pulse.• Ejection controller protection block: against overload and short circuit on outside• Driver and power amplifier block: control power amplifier to amplify 50Hz potential pulse before it goes into transformer. To intensify output capacity

• Transformer Inverter block: change 50Hz potential pulse to 110/220V AC output• AC voltage meter: display AC voltage output.• UPS controller block: control UPS mode. When the Smart connects to a grid power, ACsource connect directly with network. If AC source suddenly interrupts the UPS functionwill be auto-change to Inverter within 1 second.

2.3 Principle Circuit

2.3.1 Main circuit

1 5 v

A C OPTO

2 2 0 / 5 0 v

1K

5 k 6

1 k

C1815

470/0.5w

1 k

Gate

2 2 0 V A C

I N

TRANS

Gate

AK

TRANS

RELAY 1

RELAY 2

Vcc

Vcc

IN

OUT



14

+B

SW

3.3/1W 10/5W 10/5W

6k8

6k8

6k8

A1013

6k8

6k8

4 7 0 k

1 5 k

3v

1MF

18v

9v

D613

2 k 2

10

15k

2 2 0 / 5 0 v

C1815

560

2 k 2

5 k103

103

220/50v

LM317

Vcc

T S

1 0 0 / 1 0 0 v

1 M F

Vin3

A D J

1

+Vout 2

MAIN CIRC

4007

2k2

C1815

A1015

100MF 100

6v

2k2C1815

A1015

6V

100

100MF 1K

1K

10MF103

15V

Text Text

( 6 0 N 0 6 * 6 )

( 6 0 N 0 6 * 6 )

10

4054

4054

4054

4054

4M/250v

10/5W+B

R1

R6

10

R1

R6

Main circuit contains Power supply circuit and associate circuits to apply power andassociate other circuit together.

Power supply circuit: In Principle of Inverter changes DC to AC voltage. To do that,it needs a stable oscillator 50 Hz. So that, request for power supply is voltage and currentsupply must is very stable. Therefore in Power supply circuit must have Voltage stabilizer and current stabilizer. In circuit, power supply on B+ through A1013, C1815 and D613 transistor to pin 1 of LM317 will create a voltage and current stable on output pin 3

2.3.2 Oscillatory circuit



15

An oscillation at 12800 Hz was created IC 555 on pin 3 and conducted to pin 1 of IC4520. After that, it will be divided to have a signal with 800 Hz frequency. This signal wassend pin 9 and on output at pin 14 we have a signal with 50 Hz frequency.

Then it will be modulate to have DR1, DR2 signals. They are conducted to twoamplifier-powers. Each one contains six mosfet-transistors (60N06). They were in paralleltogether. DR1, DR2 signals drive two amplifier-powers to have a sine signal with 50 Hzfrequency. Amplifier-powers’ outputs were conducted to primary coil of transformer and onsecondary coil we have a 220/110V AC.



16

DONG BO

T R I G

2

Q

3

R

4

C V o l t

5

T H R

6

D I S

7

VCC8

GND1

555

C L K

1

E N

2

R

7

Q 0

3

Q 1

4

Q 2

5

Q 3

6

U?A4520

C L K

9

E N

1 0

R

1 5

Q 0

1 1

Q 1

1 2

Q 2

1 3

Q 3

1 4

U?B4520

GNDGND

GND

GND

GND

GND

GND

GND GND

GND

10K POT1

470K 10K

RES1

U?

10K

10K

220K

100K

33K

DIODE

800HZ50HZ

5 6

7

U?BMC4558

3 2

1

84U?A

LM393 5 6

7

U?BLM393

51K

3K3

CAP470K

470K

6V

103

6V

1 2 1 3

1 1

U?D4011

5 6

4

U?B4011

8 9

1 0

U?C4011

1 2

3

U?A4011

U?

CAP104

222222RES1

PLUGDR1DR2

47K

103

6V

47K DIODE

103

5 6

7

U?BLM324

1 2

1 3

1 4

U?DLM324

1 0

9

8

U?CLM324

3 2

1

4 11

A

LM324DIODEELECTRO1

3K3

10K

104

6V

5K622K

220K 68K

10K

POT1

DIEU CHE

RES1

47K

6V

VCC

VCC

U?DIODE

DIODE 4.7MF ZENER3

220K VCC

U?

104

10MF

RES1DIODE

DIODE

VCC

IN/LINE

DIODE

LED

U?SCR

10K

RES1

5K6

U?

3K9

10K

VCC

CAP

POT1

GND

CAP

68K

10K

DAT CS

O S C

C I R C UI T



17

5

42

3

1 2

4007

1 0 K

TS

TS 10K

1 . 5

K

3V

6 V

1 . 5

K

10K

10MF

1MF

LM339

TS

TS

+B

GRID

1 . 5

k

1 . 5

k

1 . 5

Charging

Full

Normal

Normal

DISPLAY CIRCUIT

2.3.3 Transfer circuit

Function of this circuit is to transfer between inverter and UPS mode. In circuit we

used OP-AMP LM339 makes comparing circuit to detect signal from grid electricity. Dutyof this circuit control relay 1 and relay 2 to decide automatically supply energy to load fromgrid electricity or Inverter. Transistor A1013 will control charging battery from gridelectricity.

2.3.4 Display circuit

Showing operation state of system by leds. In this circuit, we used OP-AMP LM339compare input signals with correlative reference signals. They will control leds when input

signals change.

TS2K2

1 2 0 K

1M

1 0 K

220K

5 K 6

2 K 7

2 K 2

22K 33K

2 2 K

680K

5 K 6

3 9 K

5K6

51K

820K

COMPARE

1 0 M F

1 0 M F

7

61

B

LM339

9

814

C

LM339

11

1013

D

LM339

5

42

3

1 2

A

LM339

V R 0 1

VCC

V R 0 2

103

VCC

50hz

GND

GND

GND

GND

GND

GND

GND

U?GND

DIODE

0 . 4

7 M F

5 K 6

3 3 K

DIODE 5K6

560K

10K

10K

U?

1 K 5

2 K 2

1K

A1015 NPN800HZ

IN/LINE

CHARGE

PLUG

SYN

3

21

4

1 1

U?A

LM324

12

1314

D

LM324

5

67

U?B

LM324

10

98

C

LM324

4 K 7

51K

6K8

220K

102

6V

22MF

104

104

VCC

104

X0 12X1 13

Y0 2Y1

1

Z0 5Z1 3

INH6A11

B10C9

VEE7

X14

Y15

Z4

4053

CAP

1 0 K

VCC

TRANS1

BD1

BD2100K

100K 100K

51K

2 K 2 / 1

. 2 W

223

DIODE

104

6V

51K

C1815

NPN

DIODE

1 K

1 0 K

4 7 K

1 0 K

VCC

DIODE

104

DIODE

330K

DIODE

0 . 4

7 M F

10K

1 0 K

1 0 4

VCC

10K NPN

U?

DIODE

DIODE B > C

VCB

TRANSFER CIRCUIT



18

DIODE

GND

220MF

GND

1K5

1K5

DIODE

9V

47MF

GND

3 K 3

12

1314

U?D

LM324

5

67

U?B

LM324

3

21

4

1 1

U?A

LM324

3K3

3 3 K

3K9

47K 6 V

GND

DIODE

3 3 0 K

224

GND

5K6

A1013

C1815

GND

4 K 7

2K2

1K/1W DIODE

SCR

SCR

DIODE

RES1

RES1

GND

U?

TRANS3U?

TRANS3

3 3 K

33MF

8 K 2

ZENER2

DIODE GND

DIODE

VCC

VCC

GND330R

1 0 0 K

47K

DIODE

RES1RES1

4 7 M F

2 2 K

3 3 K

50K

3 9 K

1 5 K

1 0 K

2 K 2

LED

1 2

U?

12V

U?GND

PLUG

PLUG

PLUG

PLUG

PLUG

B-

PLUG

PLUG

CHARGE CONTROL CIRCUIT

2.3.5 DC and charging control circuit.

Function of this circuit is to control charge for battery. It can cut off overload andovercharge state. When voltage of battery is low, A1015 transistor will active to control charging for

battery. When battery is full on LM393’s output has a signal to control C1815 transistor on pin B and this transistor active to supply 12V DC to load. At the time, it cut off charging for battery.



19

2.4 Circuit board.

All circuits of Smart were divided into several small circuit boards. It is easy to fitand repair. Include:

- Main board.- Osc board.- Transfer board.- Charge board.- DC out board.- Display board.- AC charge board.

2.4.1 Main board.It’s the motherboard to combine several small circuit boards together. For example:

OSC board, transfer board and charge board.



20

2.4.2 OSC board.It contain oscillator and divide circuit to create a signal at 50 Hz frequency.



21

2.4.3 Transfer board.It contains transfer circuit.



22

2.4.4 Besides, we have some circuit boards. For example: charge board, DC out board,Display board and charge board.



23



24



25

2.5 Technical specification.

Integrated control-battery system in “plug and play” performance installed a mobileroller rack, optional 12 or 24 DC.• Powerful battery bank: 12 – 180 to 400Ah.•

High cycle charge battery bank in low maintenance or maintenance-free performance.• Built-in DC/AC inverter 230/ 110V, optional in 50 or 60 Hz performance, 1000Wcontinuous power, 2000W peak surge power.

• 12V system with step wave inverter • Built-in main charge (230V) and solar charge regulator optional 12V DC for solar

module up to 5000W charging capacity• Built-in uninterrupted power supply (UPS) device activated when connected with public

grid.• Multiple connections for 12V DC power charging system (Wind, Hydro, Generator)• Mains and battery voltage indicators. Protection against

• Current indicator for AC grid charging and DC charging source.• Battery protection against over and low load.• Multiple outlets for 230/110V AC and 12V.• Prepared for direct connection with selected solar, Wind, and Hydro generators.

Equipment AC Voltage DC Voltage Wave formPower Continue

SurgeBatteryBank I Charge

Smart1000 SS

230V/110V ±

5%50 Hz or 60 Hz

10,5 V ÷14VSine

Modification

1000 W 1500W/5sec300 Ah400 Ah 35A max



26

LESSON 3

SINE SQUARE AND SINE MODIFICATION INVERTER

More and more technologies, or circuit designs have involved in the quest for creatinghigher power AC from low voltage DC sources. This lesson will examine some designtechniques in which we already done.

I. LOW FREQUENCY TRANSFORMER BASED INVERTER.

The following technologies are based on low frequency switching of the low DC

voltage, applying the DC pulses to a step- up transformer. Two common technologies arethe PUSH_PULL technology is suitable for production of Square and Modified Squareware and sine-ware outputs.

The block diagram of a low frequency transformer based inverter is shown below.

12VDC 12VAC 120VAC

(Push-pull or Bridge)

SQUARE WARE AND MODIFIED SQUAREWAVE INVERTER .

It is called SQUAREWAVE INVERTER because of its shape of theoutput waveform. (See figure 1)

Figure 1,Square Wave output WaveSquare wave inverter were the “ Original Electronic “ inverter .The first versions such

as Tripplits used a mechanical vibrator type switch to break –up the low DC voltage into pulses are then applied to a step-up transformer. With the advent of semiconductor switch, the mechanical vibrator was completely replaced by “ Solid-state “ transistor switches.

Figure 2 is a common circuit referred to as “ PUSH_PULL “ technology to produce asquare wave output.

BATTEYLow frequencyTransistor Switches

Low frequencyTransformer

AC Loads

120 VAC RMS




27

Figure 2.

The basic theory of a Push-Pull design is as follow: the top Switching transistor closed and causes current to flow from the battery negative through the up-half primarytransformer to the battery positive. This action indices a step-up voltage on the secondaryside of the transformer. (See figure 4A). After a period of time, the switch Flip-Flop.The top switch opens and then the bottom switch closes allowing current to flow in theappositive direction. (See figure 4B) This cycle continues and higher AC voltage isobtained from secondary port of the transformer.

The Turn radio of transformer decides the output voltage, the more turns onsecondary side, the higher voltage is obtained.

(Figure 4A + 4B).

Figure 4A Figure 4 b

The major problem with the Push-Pull approach is that the current in the transformer has to susdely reverse directions. This cause a large reduction in efficiency as well as

potential for large transients, thus degrading the waveform, Another drawback is thetransformer that require for the Push-Pull design must have two-primaries,

The output pulse is directly related to battery voltage Since the radio of transformer isfixed, any charge in battery voltage would effect the peak output voltage .for squarewave, RMS voltage is equal to peak voltage and as a result power output is depended on

battery voltage. Finally, most square wave inverters have mediocre efficiency (typical about 80 %)

and the idle draw is relatively high.

II. MODIFIED SQUARE WAVE INVERTERS.

The addition of an extra winding in the transformer along with few other parts allows

output of a MODIFIED SQUAREWAVE (often referred to as a modified SINE-WAVE by marketing types) while still utilizing a push-pull technology)

Trasistor Switch

Trasistor Switch

BatteryNegative

BatteryNegative

BatteryPoaitive

Transformer

AC OutputSquare Wave

Battery negative

Battery negative

Battery negative

Battery negative

induced curent

induced curent

AC output

Square wave

AC output

Square wave

Transistor Switch Closet

Transistor Switch Closet

Battery positive

Battery positive

CurentFlow

CurentFlow

170Vol Peak120VAC RMS

Pulse height equal to batteryvoltage times the turn radio ofthe output transformer anddependent on battery voltage



28

Figure 5 Modified Square Wave and Off-Time.

The switching cycle is identical to that described in the section on square waveinverters, except for one additional step .In the switching cycle, another step is addedwhich clear out the transformer reducing the problems associated with the suddeedchange in current direction. This is accomplished by the off time shorting winding shownin figure 6 .As one switch opens and before the second switch closes, the switch acrossthe shorting winding closes, effectively removing the current from the transformer. Thiswould be like slowing a car to stop and then shifting to reverse, much better than thesituation mentioned previously. Off-time shorting provides a better zero crossing of thewaveform, which equates to better zero crossing of the waveform, which equates to better ability to operate electronic devices. Improved efficiency and lower total harmonicdistortion of the waveform are other benefits.

Several manufactures accomplish off –teme shorting by placing a solid –siste switchdirectly across the AC output lines. This approach works, however the switch is notisolated from the AC output line, and as a result it is subject to abuse from transients,which can be caused by reactive loads (I.e. electric motor) Utilizing a shorting winding inthe transformer is preferable due to the isolation provided from the AC output

Figure 6 Push-Pull

The major advantage to a modified square wave is the ability to regulate RMSvoltage by means of varying the pulse width, and off-time period. The pulse widthvariation method of regulation is referred to as pulse width modulation or PWM

The idea behind RMS regulation is to keep the area inside the wave from equal at all

times (figure 7A). Since the peak voltage, or pulse height is a product of battery voltageand the transformer ratio, when the prak* voltage increases the area inside the pulse willincrease if the pulse width remains the same. With a square wave inverter, nothing can be

Battery negative

Battery negative

AC outputSquare wave

Transistor Switch

Battery positive

Transistor Switch

Transistor Switch



29

affected about this increasing RMS voltage. But PWM control allows the width of the pulse to be narrowed, thus maintaining a constant area in sine the waveform (Figure 7 B)

On the other hand, if the battery voltage decrease, the RMS voltage would alsodecrease if the pulse width remains the same .In this case .RMS voltage regulation may

be achieved by the pulse width (Figure 7C).

Changing of pulse –width accomplished by controlling the on and off time of thetransistor switch. Realistically, there is a point where the zero time is no longer presentedas the pulse –width is increase and essentially a square wave is present. Beyond this, theRMS voltage becomes unregulated.

Modified square wave inverters are great improvement over square wave types theyoffer good voltage regulation, lower total harmonic distortion and better overallefficiency. Electric motors operate much better from a modified square wave and mostelectronic equipment will operate with less problems

III. DESIGN AND OPERATION

3.1 General Specification of an Inverter

The most important specifications are following:1. Input voltage2. Output voltage3. Output power 4. Stability of the output frequency under loading condition5. Stability of the output voltage under loading condition.6. Wave form on output gate and deformation.7. Efficiency8. Protection scheme (overload, low input voltage etc…)

Nowadays on the market there are several types of Inverter using SCR or transistor.Some type are using transformation, some not using transformation.

Example: The type using SCR gives high efficiency, impulse – resistance capacityis higher but the exciting cut – off under heavy power is more complicate and itinvolves an over current during the starting that make SCR unable to cut – off. Theoutput impulse is not sinusoidal; getting a sinusoidal impulse will make high loss inthe filter. The type-using transistor is limited by output power but the circuit is more

simple and is easy to operate. It unable to give a good impulse, bad efficiency at theline polarity, good impulse at the on – off polarity. The types not using transformation

120VAC RMS

Peak voltage

Peak voltage

Peak voltage

A B

C

Nominal Battery Voltage High Battery Voltage Low Battery Voltage



30

have disadvantage in low output power and high cost, due to not using transformationthe current loss is low under the not – loading condition.

3.2 Classification & block scheme

There are some Inverter-types as following:a. Using SCR series inversion

b. Using SCR parallel inversionc. Using impulse inversiond. Using current feed – back transistor e. Using voltage feed – back transistor f. Using both current and voltage feed – back transistor g. Using feed – back transistor with separate exciter or using amplifier –

exciter IC for transistor.h. Using high frequency DC Inverter with an exciter to Control Mospet

Generally, in three types using SCR the output impulse is rectangular. To have asinusoidal impulse it needs a filter.

Types 4, 5, and 6, using transistor give output impulse almost sinusoidal, it’sfrequency and form tightly depends on the load.

Type 7 gives rectangular output impulse almost sinusoidal, it’s frequency isrelatively stable under the various loading condition but the form is strongly dependson the load.

Analyzed the advantages and disadvantages of above presented types. The step – method may use. Transistor has following advantages:

- More economical, low cost- Good output impulse form: The filter is simple, low harmony distortion.- High frequency stability- High efficiency due to the transistor operates at D condition.- Possible of stabilization of the output voltage by means of limiting the exciting

impulse amplitude for transistor. General block – scheme:This scheme is now using in SOLAR LAB



31

Fig. 1 Block scheme of an Inverter

- Block 1: Multi – Harmony oscillator or oscillator outputting a rectangular 50Hz impulse.

- Block 2: Single circuit stabilizer, used to create impulse amplitude for eachhalf – period of excitation. It is possible to control amplitude by means of feed – back from block 3, 4.

- Block 5a, 5b: Excitation cascade for the power output transistor.- Block 6a, 6b: Power transistors, connected depending on the output power - Bock 7: consists of under – voltage and over current protections and an

accumulator charger.- LC: Output filter (AC)

3.3 Electrical Circuit Scheme

The actual Inverter scheme is showed below: Oscillator creating Q1, Q2. IC 4047with capacitor C1 and adjustable resistor VR1 creates an impulse with frequency of 100 Hz at position 13 and then this frequency will be divided into 50Hz at position10, 11.

Single circuit stabilizer consists of: Amplifier IC 4081 and transistors Q7, Q8,Q9, Q10.

To create an impulse with amplitude is that enough for the excitation cascade. To control the impulse amplitude of the single stabilizer, a voltage of 10V is

taken from transformation, and then via a rectifier is passed to the position 9 and 10

(U 2). The amplifier takes signal from 7 gives to 2, 6 (U 3). By this way the impulseamplitude giving to the stabilizer is stable. Excitation cascade of power transistor is a



32

transistor H 1061. Power transistors are connected by Darlington type, each sideconsist of three transistor s 3055 with a disturbance protection

Output transformation is winded such as suitable for the voltage of 12V or 24V.Voltage at the outlet is 110V and 220V; the power must reach the range of 300W ÷

500W A regulator for adjusting the output voltage is available here. There is also a

batteries protection circuit for the case of overload and voltage drop lower then 11V. Voltage for the power cascade (6) is feeded directly because of heavy current.

Voltage for the oscillator and blocks 1,2,3,4,5 is given from the relay. The protection circuit controls relay winding. As the voltage becomes lower

than 11V. The control transistor will cut – off the voltage to the relay, so the blocks1,2,3,4,5 will not operate, in consequence the Inverter will stop working.

To make the Inverter work again, it needs to charge the battery and push theSET button for feeding the relay. When the relay is energized, it’[s contacts will beclosed, so block 1,2,3,4,5 will be energized and it make the Inverter work again.



33



35

LESSON 4

HIGH FREQUENCY INVERTERS

I. INTRODUCTION:

High frequency inverter is another approach to creating higher power AC from lowDC voltage. The name HIGH FREQUENCY refers to the speed at which the transistorsswitch on and off.

II. OPERATION:

This type of inverter creates low DC voltage from battery power through a transistor switching stage to change it to AC square wave and then apply it to a high frequencystep-up transformer (which made-up of by Ferrite core) to creates high AC voltage. Now,this high AC voltage is then be rectified (change back to DC), apply to a low frequencyswitcher (H-BRIDGE) creates Utility power AC.

II.1 Block diagram: (Figure 1)

High Frequency Switcher (Bridge)

High frequency inverters may be either modified square or sine wave output.Drawbacks to the high frequency approach are poor source ability for starting motors

and other reactive loads, and the fact that there is transistor switches on the AC outputwhich are not isolated from the AC load. Transients, which may be created by reactive

loads, can cause failure in the output transistors. Additionally in general the batterynegative is not isolated from the AC outlet neutral in a High Frequency inverter.

The transistor-switching configuration is a H-BRIDGE switch layout with thetransformer replaced the high voltage power supply, often utilizing a fly back configuration (Figure 12). The high voltage switcher takes a low voltage DC input and

produces a higher voltage DC output. The positive and negative ends of the high voltagesupply are then alternately connected to the AC output lines by the bridge and output is

pulse width modulated. This provides excellent voltage regulation.

.

HighVoltageSwitcher

170Volts

Transistor Switch Transistor Switch

0 Volts AC OutputModified Square Wave

+ -


Battery

12VDC

HighFrequencyTransistor Switches

High

FrequencyTransforme

High

FrequencyRectifier

LowFrequency

Transistor Switches

AC

Load

170VDC 120VAC



36

Figure 2: HF Inverter with H-BRIDGE Technology

The voltage being switched in a HF inverter is the high voltage DC .In a lowfrequency transformer based H-BRIDGE; the low voltage from the battery was switchedthrough a transformer. Off time shorting is provided in the high frequency approach byclosing the two transistors across the AC output on the Zero volt side of the high voltageswitcher. Remember, the switcher must off-time short between switch changes.

The three figures below show the states of the switches in one cycle of the highfrequency inverter. Since the H-BRIDGE switcher has already been discussed only agraphic depiction of the output switch states and current flow is shown.

Figure 3, 4,5

HighVoltageSwitcher

170Volts

Transistor Switch

Transistor Switch

0 Volts AC OutputModified Square Wave

+ -

Battery Positive

Battery Negative

Curent flow

Figure 3

HighVoltageSwitcher

170Volts

Transistor Switch

Transistor Switch

0 Volts

+ -

Battery Positive

Battery Negative

Figure 4

ACOutput

ACOutput

HighVoltageSwitcher

170Volts

Transistor Switch

0 Volts

Curent flow



37

The main advantage behind frequency switchchers is the very light in weight and physical size is small.

Disadvantages of HF inverters are poor surge ability due to the characteristics of theswitching power section supplying the bridge (limits their usage to motor load) Lack of isolation between the transistor and AC loads makes them very vulnerable to transientscaused by reactive loads since there is no transformer to isolate and act as a “ flywheel “to oppose fast changes in output current. HF inverter exhibits high idle current becausethe high voltage switcher runs constantly and this also often causes interference withTV’s radios. etc.

II. 2 Sine wave output inverters

Just as with modified square wave and square wave output inverters, multipleapproaches and topologies have deloped to produce sine wave output inverters. Theseinverters are desirable in that they will run loads more like the utility grid. The downfallis complexity and expense in building some types of this inverter. A Sine wave is shownin figure 14 along with several key points of the waveform.

II. 3 Rotary inverters

The earliest type of DC to AC inverters was the ROTARY INVERTER. Essentiallythis piece of equipment was a DC motor that turned an AC generator. The rotary inverter has the advantage of producing a very nice sine wave output at the expense of lowefficiency (typical 60 %) and very kigh idle power consumption.

II. 4 Ferro-resonant transformer inverters

The Ferro-resonant sine wave output inverter takes advantage of the inductivecharacteristics of certain transformers. An inductor is a coil of wire that has the ability tostore energy and to oppose changes in current within a circuit. An inductor acts like amagnetic “ Flywheel “. In other words if voltage is suddenly applied to inductor, theinductor will react by attemping to slowdown the resulting current rise. Conversely, if thecurrent is already flowing through the inductor and is suddenly removed, the inductor will reacts by releasing it stored current and attempt to stop the current from going tozero. (The electromotive field force of inductor expands and collapses) As the result the

fall time of the current is prolonged. This reaction acts to impede the changes in current.Unfortunately, inductance causes the transformer to have a relatively low efficiency(Typically about 50%) and the waveform is very sensitivity to loads



38

II. 4. 1 Circuit description:

Right in center of circuit is IC 1, controlling the “PWM” Pulse widthmodulation) .It contains a saw tooth generator, 2 differential amplifiers and acomparator to modulate the PWM. It also has a comparator to control the cut-off timing, a 5 v reference and 2 output control: push-pull or 1 of 2. The components at

pin 5 and 6 are to put the operation frequency of converter on 25 KHz. Thisfrequency is selected to get the Max output from transformer. . The PWM puts the

pulse which has the width change from pin 9 and 10, these pins are damped by 3 parallel of IC 2 to trigger the gate of Mosfet Q1 + Q2 through 10 Ohm resistor

Mostfet Q1 + Q2 energizers the primary of transformer T1. Which is connectedto +12V, each mosfet is energized by a square wave so that when Q1 is conducted,Q2 is opened and when Q1 Is opened, Q2 is conducted. The ratio of transformer increases the output voltage from the secondary coil of Transformer.

2 zener diodes ZD1 + ZD2 keep Q1 + Q2 from over-voltage. This zener diodeoperates as follow: When mosfet opened, transformer will have a transient voltageon the drain of mosfet. When this voltage is over the breakdown voltage of Zener (75v) is reacts by turn on the mosfet to keep the transient voltage… The silicondiode that is in series with zener diode are to control the negative voltage.

II. 4. 2 Feedback voltage;

The voltage divider which is consists of R1 = 1.2 M ohm and R2 = 3.3 K ohmare used to control the current of high voltage DC from the converter and toenergized the operation amplifier IC5a. This OP-AMP energizes IC 4 (opto-coupler). This IC4 isolates the output voltage from input and energizes IC3b -another OP-AMP IC5b (inside LM358) s not used.

- Trim pot VR1is used to adjust DC from IC4 in order to have high voltage out.- Voltage DC from VR1 is amplified by IC 36 and feed through differential

amplifier IC! Across Diode D8 to control the trigger PWM of mosfets when

DC voltage is over +340v, energized voltage decrease, pulse-width increasesuntil output voltage is corrected.

+12V +12V

B1

B2

B3

B4

B5

B6 B7

B8

T1

385vw

B1-Boäkích ñoâi

B2-Boäkhuyeách ñaïi quaùdoøng

B3-Hoài tieáp caùh li

B4,B5,B6,B7,Boäkích coång caùch l i

B8-Boäsinh soùng xung vuoâng ñi eàu chænh

0v

340v

BOÄÑAÛO DC-DC GOÙI ' H ' SOÙNG VUOÂNG

Q1

Q2

R

~

~

+-

100

+

R2

R1Q3

Q4

Q5

Q6



39

- Notice that 12V is not feed to IC5 and HV of IC4 because HV of IC4 isneeded to be free. There fore these pins are supplied an isolated DC voltage byTransformer T2. This transformer is energized at frequency of 1 MHz throughC=. 0047 Mf by Q 15 + Q 16 .The secondary of TX T2 is rectifier by bridgeD20 –D23 (1n4148) and filtered by 0,1 Mf. Output voltage is regulated byzener diode ZD7 = 12V before supply to IC4 and IC5.

II. 4. 3 Current limited

The drain pins of inverter DC – IC3a controls DC. It controls the droppingvoltage across R=430 M ohm that is connected between Q1 + Q2 and negative port(0V). IC3a amplifier this dropping voltage by 391 and only small amount voltagedrops across resistor just before over current happen. The output of IC 3 is feed Ed

back to pin 16 of IC 1 through diode D7. This would stop the comparator voltage of IC3 when the current over 30A.

II. 4. 4 Stand-off time

In the push-pull class of inverter, there would be stand off time, if not the mostfetor power transistor would short. This action can easily happen because 2 mosfet canopen at same moment. The comparator of stand off time at pin 4 controls the outputof the push-pull at pin 9 & 10 occur at the same time by delaying the output whenone pin are low from the other.

The standoff time increases when the first charge to start first C =10 Mf between 13, 14 and 4 discharge. This action causes the stand off time 100 % at pin 9and 10.When capacitor charges through R=47k to ground, standoff time dischargeto ground level. To prevent the over-voltage of the battery, it is necessary to keepthe level of pin 2 of IC1 at low. Check the voltage of battery by a voltage divider 10K –12K when the voltage of battery below 10V, the output port of 9 + 10 is closeto turn off the circuit.

II. 4. 5 The h output

X

240VACoutput

T3

T4

T5

T6

100mf

1.2M

3.3k

1N4148 1N4148

1N4148 1N4148

1N4148 1N4148

1N4148 1N4148

100pf

100pf

100pf

100pf

220k

220k

220k

220k

560pf

560pf

560pf

560pf

BUK655 BUK655

BUK655 BUK655

340V

Y

Q3

Q4

Q5

Q6



40

As mentioned above 4 mosfet are connected in “ H “ figure through HV. MosfetQ Q3 - Q4 - Q5 - Q6 are trigged by the trigger of analog transformer to isolatefrom low voltage, the gate trigger of Q3 is include transformer T3, Diode Ñ + D10,Transistor Q7, Zener diode ZD3, R = 220 Ohm and capacitor C = 100 mf.

To energize Q3, the frequency of 1 Mhz is apply to primary of T3, The outputvoltage from secondary ports are rectified by Diode D and filtered by C = 100 mf.The DC output is fed back through D1o to gate of Q3. When Zener diode ZD8zener at 15V of gate Q3 -- then T3 open. .

To de-energize Q3, 1Mhz signal is turn off, but this action is not fast enough.Q7 operates - Capacitor 100 Mfd charges through 220 K – until base of Q7 turn

below 0.7 v to the Emitter -- Q7 rapidly opened to ground the capacitor voltage of gate Q3 to turn it off immediately.

As previous described Q3 + Q6 are push – pull and Q4 + Q5 are push-pull. Theseries transformer T3 + T6 --- T4 + T5 are energized sequently.

To energize transformer T3 + T6, it is necessary to have the series of 1 MHzsignal every 10 us in only 70% time (T1 = 70%) = 7 us .IC5 oscillated series 50 Hzthat is needed for 1 Mhz. IC6 is a timer circuit 7555 that vibrates at 1 KHz andtrigged IC 6. A decade counter CD 4017 with 10 output that decode 5 –6 – 7 0f IC 8were connected to OR circuit by diodes D17, D18, D19, to control the high outputof NAND (IC10a) Three high output in only 10% or 30% of time. After reversed

by IC 10a, the output is high in 0% of time as already dad IC 10a triggers pin 8 + 11of IC 10 b + IC 10c, pins 1 + 13 of IC 10b + IC 10c are connected to complementoutput Q + Q every time it get clock-pulse from 5 of IC 8 every 10 us the resetinput of IC 10b + IC 10c are connected to 1MHz oscillator IC 7 incorporated withanother timer LM 7555. IC10b and IC10c can only send signals 1MHz when other 2inputs are high. This occurs in 70% of time in each 10us sequently.

The supply voltage is 12 VDC from the battery through Fuse 30A is connecteddirectly to transformer T1. The low path is connected to switch S1 and resistor 10Ohm; Capacitor 2200 mf in parallel with supply path is used to regulate the currentto inverter. One LED in parallel with supply is to inform the power supply is on andremember LED must be in series with resistor 2.2K Ohm.

This document s include:- Schematic diagram of Inverter - PC board for assembling.



42

LESSON 5

TRUE SINE INVERTER

I. INTRODUCTION.

After almost 50 years of development, nowadays sine modified Inverters technologyis still popular and covered the global market. These Inverters are quite simple, easy for manufacturing, maintenance and an economic price, although that, disadvantages of this kind of inverter are many. First of all they response only for resistive loads. The

inductive and relative loads could not run on them as fan, motor, pump, compressor act… One being technical baries is unregulated sine square wave and uncontrolledfrequency which not allow to make sixnonization among them to increase power fromseveral Inverter as well as grid connected.

Today, a lot application need high confident frequency – band and accuratesynchronization and big power act... The sine-modified wave could not response well.

True sine wave has been born in this situation to put away all limitations of S.MWInverter. True sine wave technology is a mille – store of development, which satisfiesall requirement of development global market. Every kinds of loads, no limited power range, high confident frequency –band and high efficiency of over 90% are basic

advantages of true sine wave inverter. It also response well for high technologyequipments in field of telecommunication, informatics without any interference. T.S.WInverter is ideal product for renewable energy development with grid-on /off technology.

II. DESIGN AND OPERATION

Design idea: For creating a standard AC source from 12VDC is quite complicatedwith several requirements such as: Stable voltage, low coefficient of distortion, and nodrop – power and high conversion efficiency. Transmitting energy from DC source

with frequency 0Hz into AC 50Hz. It could not use line near method but it must carry by high frequency more than 20kHz then on output it is filtered to get energy 50Hz.




43

1. Block of scheme:

Operation of working blocks:

- Block 1: Battery 12 VDC is a DC power source for changing and supplying

energy to other working blocks.- Block 2: Creating standard sine signal 50Hz it is most important block using as a basic signal.

- Block 3: This is the most important to have true sine form reference andcompensation feedback signal from load with standard sine signal tocreate appropriate wave 50Hz to distribute to splitting two channel.

- Block 4: Oscillate for creating triangle puls with high frequency 20kHz, carryingsine wave 50Hz to output terminals of the regulation blocks.

- Block 5: Modulation of appropriate wave and triangle pulse 20kHz to get square pulse 20kHz with different width.

- Block 6: Driving square pulse 20kHz to fit input pulse of power amplifier.- Block 7: Power – amplifier consists of two branches operates by driving pulsesto create output power. This block decides working power of inverter.

2

Oscillator creatingstandard sinesi nal 50Hz

4Oscillator creatingtrigger pulse 20Khz

3Waveformcorrection

D r i v e r

7Amp -power 8

Filter

9Protector

1Battery 12V

10

Indicator

Modulator

Feedback

Feedback Output

220V/50Hz

Low voltage

Overload

5

6



45

IC 555 oscillates to create startup pulse (ck). Out put gate F.F usingresponding resistance to pull up getting step wave. It is called step wavecreative circuit. After that, they are carried out to calibrated circuit them wehave standard sine

Following advanced technology today, some manufacturer order makes specialcompact devices for themselves. It is a security way of knows how and it makesdifficulty for maintenance of lacking replaced devices on the market.

2.1.2 Power amplifier:

There are many designs to do power amplifier. The most important for designer is getting optimum design which must follow the devices appearing onthe market. We propose some schemes for choice

a. Half – bridge inverter

2

6

7

1

4 8

53 D Q

7555¼

4042

D Q D Q

¼

4042

¼

4042

2 7 10 13

8 4

D

Q

¼

4042

11 14

Vcc

BoÄPHAÙT SOÙNG KIEÅU BÖÔÙC

U

t

U

t

R1

R2V i

Voutop-am

Filter

UnfilteredOutput

FilteredOutput



46

With this scheme, which gives high quality of waveform, high transmitting speedwaveform has not been split of in channels. It requests transistor devices Bi–pole,

which can stand in high voltage.

b. Full – bridge inverter

Speed of change has shape of half – bridge but output waveform waschannel split off. This circuit is well for big power range, allowing using lower voltage devices and saving energy. But UPS devices are suitable for this circuit

2.2 Principle Scheme: consists of:

- Sine wave oscillator board

- Modulator board- Chopper board- Power amplifier board

3. Definite principle of operating block:

3.1 Circuit creates sine wave

IC 555 oscillates to create square wave 50Hz to make clock pulse IC 2(4520), this pulse is taken carried out by gate Q0 of IC2 with frequency 20kHz. It

drives modulator and recorrect waveform. Output gate Q1 of IC2 makes pulseclock for IC3 to create pulse 800Hz on output gate Q3 and pulse 50Hz is taken outat sixth pin of IC4, which is a signal to drive IC6.

Op-amp 1 amplifies feedback Voltage from load past to fourteenth pin of IC6. At pin14, 13, and 12 of IC6 can be display switch, when pin 14 links 13 op-amp 2 amplifies IC5 has function to decode BCD 3 line into out 8 linescombining op-amp 2 to create step sine wave which has amplitude V p – p = 12V.

3.2 Modulator and channel splitting off (see above principle diagram)

Filter

UnfilteredOutput

FilteredOutput



47

IC1 recorrects step wave form to become standard sine wave 50Hz. IC2 takesout feed back signal from load to reference and compensate with standard sinesignal then creating distortion sine wave as following chart:

IC 3 Osculate to create triangle pulse high frequency 20kHz. This signal goestogether detective sine wave into IC4 IC5 to modulate and channel splitting of A

and B channels which driver 2 power amplifying channels.

III. TECHNOLOGICAL PARAMETERS:

DC input voltage: 9V – 14.5V distortion rat < 3 %

AC output voltage: 220C AC ±5%

P = 1000W (if overload 1500W, Inverter stands 1.5s and overload to 2000W to be50ms)

Stable frequency f = 50Hz ± 0.5%



--50

LESSON 6

COMPUTER DESIGNING OF INVERTER

I. INTRODUCTION:

Designing with the support of computer has developed so long, it assists us to savemuch of time. Design with the support of computer reach the high exactness if being done

by hand it is very difficult to reach, it is the tool for quick design. One of the works,which the electronic worker should do well, is to draw the printed circuit board to weld

and install all kinds of electric circuit. If having to do this work in craft there will be a lotof restrains. Presently there have been a lot of software running on computer which can

be in charge well this work.

I.1 Software used to design electricity, electronics.

The software which are used to design the electronic circuit there are many,normally they combine in couple to be a group that is Orcad/SDT for Schematic designtool called SDT, to be used commonly with Orcad/PCB to compare and create the

premise for Orcad/PCB when establishing the Printed Circuit Board called PCB. Itmeans that Orcad/PCB will base on the draw of Orcad/SDT to design automaticallythe circuit lines, location of the accessories in order later to give a printed circuit boardin the preeminent manner.

It can stipulate the names of the following software:- Software: PROTEL-AUTOTRAX OF AUSTRALIA.- Software: CIRCUIT MAKER which is the computer program for drawing -design - imitation of the electric circuit running on WINDOWS.- ULT CAP SCHEMATIC DESIGN TOOL.- ULT PAK of Lab Center.

- SMART.- QUICK ROUTE running on the media of Windows.- Easy Professional with the sub-program.

* Pulsar for imitation.* Analyzer for analysis and imitation of the linear circuit.* Z match for analysis of the Smith diagram in high frequency.

I.2 Software used in Vietnam

There are a lot of software lists, but we collect Orcad due to the following reasons:

- Orcad imported into Vietnam so long, there are many users therefore it has been propagated widely.- There are so many software in the market, easily for set-up.




--51

- Orcad does not require about the structure of machinery. It can run on IBM, PCXT, AT Computer or relevant circuits suitable with IBM.

In the field of electricity and electronics the software of ORCAD for designingelectronic circuit, this software settles for two basic matters for making the electricdrawing that is Orcad STD-Schematic Design Tool and designing Orcad PCB PrintedCircuit Board but this software is just in the form of drawing with a preeminent designto automatically run the networks to connects the accessories with each other.

In order to calculate the design of the electronic circuit we should use further PSPISE. It has the effect to settle the mathematics for circuit theory.

Capacity of Orcad is also very strong:- To have capacity for automatic and manual design.- To have a big library.- It can be revolving and symmetric partially.- It can be elastic the connecting wire and bus when moving the objectives.- It can move and wipe the objectives or blocks.

- It can carry out repeating the orders quickly.- It can display the squared net.- There are 05 launching levels.- The user can foist over 100 adding-up orders.- Not to limit the classified drawings.- It can display directly the directories of library.- Statement can set up in horizontal line and it can set up in vertical line.- It can print on the paper of size from A to E and there are a lot of particulars you

will refer further.For the old software Orcad running in the environment DOS therefore if wanting to

use it we should study some orders, nowadays we have had Orcad running in theenvironment of Windows therefore the use is easier.

II. DESIGN:

II.1. Design of Inverter.

We will use the software to draw Electronic Circuit: Orcad/SDT in order to carryout drawing 01 simple Inverter.

In order to be able to draw the electric circuit of Inverter by computer we should

understand function and usage of the orders in menu: Again Block Conditions Delete Edit Find Get Hardcopy Jump

Library Macro Place



--52

Quit Repeat Set Tag Zoom

After appearance in the left corner of the screen a menu board is arranged tolengthwise. There are three ways to develop the orders in Menu as follows:

1- To press the key of the initial character of that order.2- To use the arrow key to move the light bar to the order which we want to call and

press Enter key.3- To use MOUSE to move the arrow and order which we want to call and to click

the left knot of MOUSE.4- A lot of main orders in Menu with the subordinate orders and various effects.

From subordinate Menu, when wanting to return main Menu, press ECS key until main

Menu re-appears (or to click the right knot of Mouse).

II.2. The design steps of Inverter.

II.2.1 Design of block diagram:

Inverter is the machine to transform electricity from DC to AC so it should havethe frequency oscillator 50Hz, this signal need to be sufficiently big to excite for thecapacity of transistors together with transformer (to excite for these transistors toturn off/on to the rhythm 50Hz) to create the secondary rate of the revolving voltage

transformer therefore in circuits should have the impulse amplitudes rating between primary and secondary rate of the transformer output depending on the DC voltageinput from the said conditions we can construct the block diagram of an inverter asfollows:Block diagram of Inverter:

1 2a

2b

3 4

5a

5b

6a

6b

7

LOAD



--53

Block 1: Multi-harmony oscillator or oscillator outputting a rectangular 50 Hzimpulse.

Block 2: Single circuit stabilizer, used to create an impulse amplitude for each half- period of excitation. It is possible to control amplitude by means of feedback from block 3, 4.

Block 5a, 5b: Excitation cascade for the power output transistor.Block 6a, 6b: Power transistors, connected depending on the out put power.Block 7: Consists of under-voltage and over current protections and an accumulator

charger.

LC: Output filter (AC).From the said block diagram we commence to design the electric circuit.Block 1: Oscillator creating Q, Q:

In order to create two signals of opposite phases for frequency 50Hz we have

more various ways, we can use the oscillating circuit to combine between transistorsand accumulator, inductive wire, resistance, or usage of IC 555, but these circuitshould be settled in stability the complex frequency therefore I see that we can useIC4047 to make the oscillating circuit and also dividing frequency, we have thesignal in the position 13 with frequency 100Hz divided into 50Hz to position No.:10 and 11 but opposite with the remaining phase. So, in order to draw the saidcircuit we commence the following steps:

Step 1: Drawing IC

a- Pressing Enter for three times to call main Menu b- From main menu - collect Getc- From the Get dialog line, to type 4047 and press Enter on the screen appearing symbol ICd- To use Mouse or arrow to move the symbol to the location where you want toset-up and press P key. The symbol will change the color. To move cursor out thelocation for continuity to call other accessories, to press <ESC> key to escapeand Enter to return main Menu.

Step 2: To draw resistor, rheostat:

U1

4047

AST5 AST4-T6+T8RET12

RCC3

CX1

RX2RST9

Q10

Q11

OSC13

5k

VR1

10k

R1

.33

C1

+

.1C2

+

Y1

Y1

Y1

VCC

Y

1

Y

1



--54

a- From main Menu to call Get b- From the dialog line to type into Resistor or R and Enter. The screen appears

the symbol of resistor and subordinate menuc- To use mouse or arrow key to move the symbol to location where needing to

locate and pressing P key, the symbol will change the color in case wanting torotate the symbol we press R key (Routate) to rotate the symbol and to press Pkey for location

d- To move cursor out the location to call continuously the other accessories. To press ESC key to escape and Enter to call main Menu.

Step 3: To draw Vr

a- From main Menu to collect get b- From the dialog line to call Get, to type into Vr and Enter.

The screen appears the symbol of rheostat and subordinate menuc- To use Mouse or arrow key to move the symbol to the foot of R and press Pkey. The symbol will change color, if needing to rotate the accessory to press R keyd- To move cursor out the location to call continuously the other accessory.4/. To draw accumulator C1, C2.a- From main Menu, to collect get

b- From dialog line Get, to type into Cap and Enter.The screen appears the symbol of accumulator and subordinate menuc- To use Mouse or arrow key to move the symbol to foot 1 and 3 of IC to press

key (when needing to press R key to collect the characteristic pole of theaccumulator) to press P key the symbol will change color d- To use Mouse or arrow key to move the symbol to foot 5 of IC to press P keythe symbol will change color (when necessary to press R key to collectcharacteristic pole of the accumulator).

Step5: To draw Mass of accumulator and IC

a- From main Menu to call Get, b- From dialog line Get, to type into GND power and Enter. The screen appears

the symbol mass and subordinate menuc- To press arrow key or Mouse to move the symbol to the foot of ICd- To press P key to confirm. The symbol will change the color e- To move cursor out the location to call continuously the other accessories, to

press ESC key to escape and Enter to return main Menu.

Step 6: To mark Vcc

a- From main Menu, to collect Place. A subordinate menu appears b- To collect power. The screen appears symbol Vcc at the location of cursor and

a subordinate menuc- To use arrow key or mouse to move the symbol to any location near IC and to

collect place (pressing P key) the symbol will change color



--55

d- To move cursor out the location to call the other components, to press ESC toescape and Enter to return main menu.

Step 7: To draw circuit line:

a- From main menu, to collect Place to appear subordinate menu b- From subordinate menu, to collect Wire or BUS or Dashed line (accordingly)

and appear a order line. Begin Find jump Zoom Escape.c- To use Mouse or arrow key to move cursor to the point for commencing

drawing. For example to draw the line connecting the feet 9, 12, 8 and mass,to locate cursor at the foot No. 9 of IC and to press <B> key (begin > thescreen appears the order line. Begin End New Find Jump Zoom escape

d- To use Mouse or cursor to draw circuit. When drawing a white line appearsfollowing the location of cursor moving. (To connect to foot 12, foot 8 thenconnect mass located before that), to press key <End> the drawing line will

change color e- To press key ESC to escape and enter to return main menuf- To repeat the practices from a to e to draw the other circuit lines

Step 8: To draw the point connecting circuit:

a- From main menu to collect Place appearing subordinate menu b- From subordinate menu, to collect Junctionc- The screen appears the symbol at the position of cursor and subordinate menu:

place Find Jump Zoom escape

d- To use Mouse or cursor to move cursor to the location which wanting tocollect (for example the cutting point between foot 12 with the connecting lineof foot 9 and mass and to press P key the symbol will change color.

e- To continue moving the symbol to point of foot 8 to cut with the connectingline between foot 9 and mass and to press P key the symbol will change color.

f- To move cursor out the location to press ESC key to escape and Enter to returnmain menu.

Step 9: Remark the exit and entry port of the circuit:

a- From main menu, to collect Place to call subordinate menu b- From subordinate menu, to collect TEXTc- From question <Test?> to type into oscillation and Enter the screen will appear

the word oscillation at the location of cursor and order line. Place Orientationvalue larger smaller find Jump Zoom escape

d- To use arrow key or Mouse to move the word to fixed location and press <P>key. Then to move cursor to the other location. To press ESC to escape andEnter to return main menu.

II. 2 Save of drawing

In order to save the drawing, to carry out the practices as follows:1. From main menu, to collect Quit to call subordinate menu.



2. From subordinate menu, to collect Write to file.3. From the dialog Write file? To type into the name which wants to name for the

drawing in attachment of the enlarging part and Enter the drawing save into aninformation book.

Note * If calling not correctly the name of accessory, in same screen it willinform the words <NOT FOUND>. Therefore, if not to understand clearly what theaccessory wants to call, from the dialog Get? To press Enter key to call library.From the dialog <Which library?> to collect Device.Lib. to collect continuouslySerene order the list will appear for reference.

* Or from main menu to call Library, a page of item listed the names of component concerning the drawing, we can refer and collect correctly the names of the desired components.

Inverter Training Manual

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Transcript of Inverter Training Manual