FFT Analysis for Field Oriented Control of SPWM and SVPWM Inverter fed Induction Machine With and Without Sensor

Adjustable speed drives offer significant energy savings and precise responses in industrial applications. The indirect field oriented control can provide good dynamic torque response as that obtained from DC motor drives. The concept of indirect field oriented control is based on the effective pulse width modulation pattern generation and effective estimation of rotor flux and speed. An effective modulation technique can achieve by attaining maximum voltage with lowest harmonic distortion in output waveform. The speed sensors are the most delicate part and often pose serious threats to control issues in the whole drive system. Thus extensive efforts are being made to eliminate the speed sensors from the drive system with an effective speed estimation technique. In this paper, a comparative study of field oriented controlled induction machine with and without sensor using two popular PWM strategies, SPWM and SVPWM. The induction motor drive systems are simulated using MATLAB/Simulink. The comparative study is based on the harmonic distortion in line-to-line inverter voltage waveforms using an FFT analyzer of MATLAB/Simulink.