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An-Najah National UniversityFaculty of Engineering
Electrical Engineering Department
Introduction in Graduation project
Variable speed control of single phase Induction motor
Prepared By: Ala' ‘Mohammad Radwan’ Saleh
Ala' Mohammad MareeSawsan Wahid Alhaj As'ad
Submitted To:Dr. Kamel Saleh
Contents
Results.
H-Bridge Inverter.
VF Control.
Principle of Operation of Induction Motor.
Future Work.
Modelling of Single Phase Induction Motor
Variable Speed Control of Single Phase Induction Motor
• To make simulation includes modelling of single phase induction motor, H-bridge inverter, PWM generator, and presenting the experimental results.
• To build a variable speed drive of the single phase induction motor using frequency control method.
Objectives
Principle of Operation of Induction Motor
• In principle of operation of induction motor, rotating magnetic field rotates at synchronous speed interacts with rotor , this will produce torque that will make the rotor rotates at mechanical speed.
• In three-phase induction motor, the rotating magnetic field is generated by applying three currents shifted by 120 degrees to three windings also shifted by 120 degrees.
• In single-phase induction motor, there are many types based on method of starting, these types are:
Principle of Operation of Induction Motor
Split-phase induction motor.
Capacitor start induction motor.
Permanent-split capacitor motor.
Capacitor start capacitor run motor.
1
2
4
33In this type the auxiliary winding and the capacitor are connected from the motor after starting
In this type two capacitors are used with the auxiliary winding, one for starting and the other during start and run.
• In most of these types the rotating magnetic field is generated by applying two currents shifted by some angle(using capacitor) to main and auxiliary windings.
• In our project, the rotating magnetic field is produced by applying two currents shifted by 90 degrees exactly to auxiliary and main windings using inverter. This two currents are shifted without using capacitor. So we can use any of previous types but without capacitor.
Principle of Operation of Induction Motor
Modelling of Single Phase Induction Motor
• Single-phase induction motors with main and auxiliary winding can be viewed as two-phase machines.
• Therefore, two-phase induction motors have a configuration identical to single-phase induction motors, but a two-phase voltage is supplied to the stator windings terminal.
So, modeling of single phase induction motor can be done as the following:
Mathematical Model
Equivalent circuit of two phase induction motor.
Mathematical Model
Mathematical Model
Modeling Using Matlab/Simulink
Model of induction motor.
H-Bridge Inverter
H-bride inverter is used to control the direction of rotation of induction motor. The following figure shows the H-bridge inverter.
To feed H-bridge inverter by four pulses signal, PWM technique was used.
H-Bridge inverter.
PWM Technique
In PWM technique, an input analog signal (carrier signal) and a saw tooth waveform (modulating signal) are driven in a comparator. Each time saw tooth waveform voltage is less than the input signal, the PWM output is driven high and vice-versa.
The following Figure shows the PWM technique.
PWM Technique.
PWM Technique
PWM technique was simulated using Matlap/Simulink as shown in the following figure.
PWM generator using Matlap/Simulink.
PWM Technique
The H-bridge inverter and the PWM generator were connected as shown in the following figure.
PWM generator+ H-bridge inverter.
The following figure shows the output of PWM generator and H-bridge inverter a reference speed of 1000r.p.m was interred to PWM generator.
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.5
1
Time(s)
V(v
olt)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.5
1
Time(s)
V(v
olt)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.5
1
Time(s)
V(v
olt)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 20
0.5
1
Time(s)
V(v
olt)
PWM0, PWM1, PWM2, and PWM3 signals.
PWM Technique
PWM Technique
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2-300
-200
-100
0
100
200
300
Time(s)
Vs-a
lfa(v
olt)
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2-300
-200
-100
0
100
200
300
Time(s)
Vs-b
eta(
volt)
Outputs of H-bridge inverter.
The PWM generator and the H-bridge inverter were connected to the induction motor model as shown in the following figure.
Model of variable speed control of single phase induction motor.
PWM Technique
VF Control
VF Control
Results
0 1 2 3 4 5 6 7 8 9 10-500
0
500
1000
1500
2000
2500
Time(s)
Spe
ed(r
.p.m
)
is-alfa
is-beta
WmWref
1.9 1.95 2 2.05 2.1 2.15 2.2-50
-40
-30
-20
-10
0
10
20
30
Time(s)
Cur
rent
(A)
Is-alfa
Is-beta
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.050
0.5
1
Time(s)
V(v
olt)
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.050
0.5
1
Time(s)
V(v
olt)
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.050
0.5
1
Time(s)
V(v
olt)
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.050
0.5
1
Time(s)
V(v
olt)
Is-alfa
Is-beta
Outputs of PWM generator (PWM0, PWM1, PWM2 and PWM3).
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05-300
-200
-100
0
100
200
300
Time(s)
Vs-
alf
a(vo
lt)
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05-300
-200
-100
0
100
200
300
Time(s)
Vs-
be
ta(v
olt)
Is-alfa
Is-beta
• Second Test
The reference speed is a step with: step time = 2s, initial value = 0 and final value = 2000r.p.m, with a step load (step time = 1s, initial value = 0 and final value = 10N.m).
The following figure shows the measured speed.
0 1 2 3 4 5 6 7 8 9 10-500
0
500
1000
1500
2000
Time(s)
Spe
ed(
r.p
.m)
Is-alfa
Is-beta
WmWref
0 1 2 3 4 5 6 7 8 9 10-500
0
500
1000
1500
2000
2500
3000
3500
Time(s)
Spe
ed(r
.p.m
)
Is-alfa
Is-beta
Wref
Wm
• Fourth Test
The reference speed is a step with: step time = 2s, initial value = 0 and final value = 3000r.p.m, with a step load (step time = 3s, initial value = 0 and final value = 5N.m).
The following figure shows the measured speed.
0 1 2 3 4 5 6 7 8 9 10-500
0
500
1000
1500
2000
2500
3000
Time(s)
Spe
ed(r
.p.m
)
Is-alfa
Is-beta
Wref
Wm
0 2 4 6 8 10 12-500
0
500
1000
1500
2000
2500
3000
Tme(s)
Spe
ed(r
.p.m
)
Is-alfa
Is-beta
WmWref
1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5-50
-40
-30
-20
-10
0
10
20
30
Time(s)
Cur
rent
(A)
Wm
Wref
is-beta
is-alfa
Future Work
The following figure shows how the project will be built.
Single phase induction motor drive with H-bridge inverter.
The following figure shows the data sheet of PIC16F877 microchip which will be used to generate the PWM signals needed. Pin 16 and pin 17 are the pins that generate PWMs.
Data sheet of PIC16F877
Future Work
Future Work
The following figure shows the typical connection of gate drive, which will be used to convert the voltage from 0-5V to 0-15V.
Typical connection of the gate drive.
Future Work
Reference SpeedReference Speed 0-5V0-5V 0-15V0-15V -300-300V-300-300V
PIC16F877
MicrochipGate Drive
H-Bridge Inverter
Induction Motor
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