Three phase Induction motor control using TMS320F2812 DSP Controller

Description

Abstract

This project is used to control the speed of a three-phase induction motor by using a three-phase inverter. The dc voltage is applied to the three-phase inverter. This three-phase VSI operates at a 120-degree mode of operation. Three-phase induction motor speed depends on the frequency of the inverter. The frequency is varied by using switches of the TMS320F2812 DSP Controller

Introduction              

This project is mainly used to control the speed of the induction motor. Induction motor speed can be controlled by using changing the frequency of the inverter. This motor control can be done by TMS320F2812 DSP Controller. This controller is used to generate the PWM pulses.

Proposed System

The dc voltage is applied to the three-phase inverter circuit. It converts the dc voltage into three-phase ac voltage to drive the three-phase induction motor. The controller has a key function for controlling the speed of the induction motor. The F2812 controller has two functions. They are

 1.            INC              2.            DEC

Block Diagram

Block Diagram Explanation

• Pulse generator: – Here we have used TMS320F2812 DSP Controller to generate a PWM signal.
• Driver circuit: It is used to amplify the pulses and provided isolations using an optocoupler. It has two functions,
  •  Amplification
  •  Isolation
• Bridge Rectifier: It converts AC supply to DC Supply.
• Three Phase Inverter: It converts DC supply to three-phase AC Supply to drive the three-phase induction motor. 

Driver Board

TMS320F2812 DSP Controller Board

Working

The TMS320F2812 DSP Controller is used to generate the PWM pulses for a three-phase inverter circuit. The TMS320F2812 DSP Controller pulses are given to the driver circuit as input. Driver board is mainly used to isolate and amplify the input signals from the controller. The amplified driver output is connected to the main power circuit devices. The ac supply is converted into dc by using a bridge rectifier. And the dc voltage is applied to a three-phase inverter circuit and by varying the frequency of the inverter the motor speed also varied.

Circuit Diagram for Three Phase Inverter

Advantages

• High efficiency
• Easy to control the speed
• Switching losses are reduced

Applications

• Industrial applications
• Pumping system

Conclusion

The speed control of the three-phase induction motor can be controlled by using TMS320F2812 DSP Controller. The motor will be running at different speeds by varying the frequency of the inverter circuit. This project is also possible for speed monitoring by using proximity sensors. 

Output Waveforms

Pulse Comparison Waveform

Phase to phase Output Waveform