# presentation.ppt - Faculty of Engineering

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## Presentation Transcript

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

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

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Variable Speed Control of Single Phase Induction MotorTo 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

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Principle of Operation of Induction MotorIn 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:

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Principle of Operation of Induction MotorSplit-phase induction motor.Capacitor start induction motor.Permanent-split capacitor motor.Capacitor start capacitor run motor.24In this type the auxiliary winding and the capacitor are connected from the motor after startingIn this type two capacitors are used with the auxiliary winding, one for starting and the other during start and run.

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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

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Modelling of Single Phase Induction MotorSingle-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:

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Mathematical ModelEquivalent circuit of two phase induction motor.

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Mathematical Model

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Mathematical Model

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Modeling Using Matlab/SimulinkModel of induction motor.

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H-Bridge InverterH-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.

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PWM TechniqueIn 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.

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PWM TechniquePWM technique was simulated using Matlap/Simulink as shown in the following figure. PWM generator using Matlap/Simulink.

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

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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.PWM Technique

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PWM TechniqueOutputs of H-bridge inverter.

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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

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VF Control

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VF Control

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Results

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

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Last Updated: 8th March 2018