Speed control of a three phase induction motor using DSP controller and harmonic reduction using passive filter

A three phase inverter, controlled by SPWM technique driving a three phase induction motor with low pass passive filter is implemented on MATLAB simulink platform. The harmonic content present in the three phase inverter is analyzed using FFT tool. Hardware implementation of the same is done using DSP (TMS320F2812) controller. The output from the inverter is connected to a three phase induction motor and the speed control is carried out by constant Voltage/frequency method on both open loop and closed loop. The FLUKE 434 series II power analyzer is used for recording the total harmonic distortion (THD) produced at the inverter output. The three phase, 1H.P, 415V, 50Hz star connected induction motor is used for this purpose. In the closed loop system PI controller is connected in the feedback. The experimental result shows that the induction motor speed can be controlled by implementing SPWM technique. The experimental results of the induction motor drive were validated with the theoretical results with a good speed regulation and the desired performance of the drive system has been achieved. The THD content was reduced from 63.4% to 3.44% using low pass passive filter which is well below 5% as per IEEE standards.