A low cost, simple torque ripple reduction technique for three phase inductor motors

A simple ´end pulse modulation´ PWM technique for three-phase induction motor adjustable speed drives is proposed and analyzed for torque ripple. Fourier analysis is performed on the motor winding voltage to obtain the harmonic amplitudes. Each of the voltage harmonics are applied to the torque equation. A sum of the torque is shown with both those adding and subtracting from the main torque. A comparison is made between the PWM harmonic torque and harmonic torque developed using a six-step at several drive frequencies. The DC link voltage is varied by a single phase input converter so that only the pulse width is varied. This approach is implemented using a very simple general purpose, low cost eight bit microprocessor