Generalized PWM algorithm for VSI fed induction motor drives based on unique zero sequence signal over the entire modulation region

This paper presents a Generalized Pulse Width Modulation (GPWM) algorithm for a Voltage Source Inverter (VSI) fed induction motor drives over the entire modulation region by using a unique zero sequence signal. As the conventional space vector approach requires angle and sector calculations, the complexity involved is more. To reduce the complexity, the proposed algorithm uses instantaneous sampled reference phase voltages only. By adding the zero sequence signal to the original sampled reference phase voltages, the modulating waveforms can be generated. To generate the various PWM algorithms, a unique expression for zero sequence voltage is derived, in which, by varying a constant (k o) value from zero to one, various discontinuous PWM (DPWM) algorithms can be generated along with the space vector PWM (SVPWM) algorithm. Thus, the proposed GPWM algorithm gives the all possible modulators for 3-phase VSI. To validate the proposed PWM algorithms, numerical simulation studies have been carried out and the results have been presented and compared.