WINTER Template Variable speed control of single phase Induction motor An-Najah National University Faculty of Engineering Electrical Engineering Department Introduction in Graduation project Variable speed control of single phase Induction motor Template

Prepared By: Ala' ‘Mohammad Radwan’ Saleh Ala' Mohammad Maree Sawsan Wahid Alhaj As'ad Submitted To: Dr. Kamel Saleh

Contents Principle of Operation of Induction Motor. Modelling of Single Phase Induction Motor H-Bridge Inverter. VF Control. Results. Future Work.

Variable Speed Control of Single Phase Induction Motor Objectives 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.

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 1 Split-phase induction motor.   2 Capacitor start induction motor.   3 Permanent-split capacitor motor. In this type the auxiliary winding and the capacitor are connected from the motor after starting 4 Capacitor start capacitor run motor. In this type two capacitors are used with the auxiliary winding, one for starting and the other during start and run.

Principle of Operation of Induction Motor 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.

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:

Equivalent circuit of two phase induction motor. Mathematical Model Equivalent circuit of two phase induction motor.

Mathematical Model  

Mathematical Model  

Model of induction motor. 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 generator using Matlap/Simulink. PWM Technique PWM technique was simulated using Matlap/Simulink as shown in the following figure. PWM generator using Matlap/Simulink.

PWM generator+ H-bridge inverter. PWM Technique The H-bridge inverter and the PWM generator were connected as shown in the following figure. PWM generator+ H-bridge inverter.

PWM0, PWM1, PWM2, and PWM3 signals. PWM Technique 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. PWM0, PWM1, PWM2, and PWM3 signals.

Outputs of H-bridge inverter. PWM Technique Outputs of H-bridge inverter.

Model of variable speed control of single phase induction motor. PWM Technique 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.

VF Control  

VF Control  

Results  

 

 

Outputs of PWM generator (PWM0, PWM1, PWM2 and PWM3).

 

The following figure shows the measured speed. 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.  

   

The following figure shows the measured speed. 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.  

 

 

 

Single phase induction motor drive with H-bridge inverter. Future Work The following figure shows how the project will be built. Single phase induction motor drive with H-bridge inverter.

Future Work 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

Typical connection of the gate drive. 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 0-5V 0-15V -300-300V Reference Speed PIC 16F877 Microchip Induction Motor Gate Drive H-Bridge Inverter

Thank you