InvertersInverters

Alex StantonAlex Stanton

Henry Schober IIIHenry Schober III

Benjamin GarberBenjamin Garber

RanceRance

What is an Inverter?What is an Inverter?

An inverter is an An inverter is an electrical circuit electrical circuit capable of turning DC capable of turning DC power into AC power, power into AC power, while at the same while at the same time regulating the time regulating the voltage, current, and voltage, current, and frequency of the frequency of the signalsignal

Why do I need an inverter?Why do I need an inverter?

Most solar panels provide 12V DC powerMost solar panels provide 12V DC power

Household devices use 120V AC powerHousehold devices use 120V AC power

Necessary for a grid tie in systemNecessary for a grid tie in system

What kind of inverter do I want?What kind of inverter do I want?

Inverters come in all different shapes and Inverters come in all different shapes and sizes, for all different purposessizes, for all different purposes

Inverters vary in output from 50 – 5,000 WInverters vary in output from 50 – 5,000 W

Several different methods of changing DC Several different methods of changing DC power to AC powerpower to AC power

Some inverters put out electricity of higher Some inverters put out electricity of higher ‘quality’ than others. What does that ‘quality’ than others. What does that mean?mean?

Electrical wave formsElectrical wave forms

12V DC Power

Graphs of voltage as a function of time

Power that comes from a PV panel or battery is generally 12V DC Power

Different types of inverters give outputs with different wave forms

Square Wave Modified Sine Wave True Sine Wave

Different types of inverter outputDifferent types of inverter output

Square wave inverters are basically Square wave inverters are basically obsoleteobsoleteModified sine wave output will power Modified sine wave output will power almost everything in your house. almost everything in your house. However, things like power drills, or However, things like power drills, or battery chargers may not workbattery chargers may not workTrue sine wave output is exactly the same True sine wave output is exactly the same as the power provided by a utility as the power provided by a utility company, and is necessary for a grid inter-company, and is necessary for a grid inter-tie systemtie system

Methods of inversionMethods of inversion

Rotary inverters use a DC Rotary inverters use a DC motor to turn an AC motor to turn an AC Power generator, the Power generator, the provide a true sine wave provide a true sine wave output, but are inefficient, output, but are inefficient, and have a low surge and have a low surge capacity ratingcapacity rating

Electrical inverters use a Electrical inverters use a combination of ‘chopping’ combination of ‘chopping’ circuits and transformers circuits and transformers to change DC power into to change DC power into AC. They are much more AC. They are much more widely used and are far widely used and are far more efficient and more efficient and practical. Less expensive practical. Less expensive electrical inverters electrical inverters produce a modified sine produce a modified sine wave, while more wave, while more expensive models give a expensive models give a true sine wave.true sine wave.

How do they work?How do they work?

There are 2 types of electrical inverters, the first takes There are 2 types of electrical inverters, the first takes low voltage high current power from a PV panel or low voltage high current power from a PV panel or battery and sends it through a ‘chopping’ circuit which battery and sends it through a ‘chopping’ circuit which changes it to low voltage high current AC power at changes it to low voltage high current AC power at 60Hz. The power then goes through a series of large 60Hz. The power then goes through a series of large transformers which output 120V AC power at 60Hztransformers which output 120V AC power at 60Hz

How do they work?How do they work?

The second type of electrical inverter is more complex. Two The second type of electrical inverter is more complex. Two chopping circuits are employed to make it possible for a much chopping circuits are employed to make it possible for a much smaller and lighter transformer to be used. The DC power is smaller and lighter transformer to be used. The DC power is converted to very high frequency AC power which is easier to converted to very high frequency AC power which is easier to transform into high voltage low current power. The power is then transform into high voltage low current power. The power is then rectified back into DC power and sent through a second chopping rectified back into DC power and sent through a second chopping circuit to turn it into 60Hz 120V AC.circuit to turn it into 60Hz 120V AC.

How are Inverters rated?How are Inverters rated?

Continuous output rating: The maximum Continuous output rating: The maximum wattage that the inverter can support long term, wattage that the inverter can support long term, includes all everyday appliances, lights and includes all everyday appliances, lights and anything else that consumes power.anything else that consumes power.

Surge capacity rating: The maximum wattage Surge capacity rating: The maximum wattage that cam be supported at any given time. that cam be supported at any given time. Important when starting devices like refrigerators Important when starting devices like refrigerators or water pumps which require more wattage to or water pumps which require more wattage to start then to run.start then to run.

Applications of InvertersApplications of Inverters

Inverters are used for many practical Inverters are used for many practical purposespurposes

Small inverters can plug into your car Small inverters can plug into your car cigarette lightercigarette lighter

Large inverters can be used in a solar or Large inverters can be used in a solar or wind powered homewind powered home