Generalized Scalar PWM Algorithm for VSI Fed Induction Motor Drives with Reduced Complexity

Abstract

This paper presents a simple and novel generalized pulse width modulation (GPWM) algorithm for voltage source inverter fed induction motor drives. The classical space vector approach requires angle and sector information for the calculation of switching times, which increases the complexity of the PWM algorithm. Hence, to reduce the complexity, the proposed GPWM algorithm generates the modulating signals by using the instantaneous phase voltages only. In the proposed algorithm, a unique zero sequence signal is added to the instantaneous phase voltages in order to generate the modulating waveforms. By varying a constant in the zero sequence signal from 0 to 1, various PWM algorithms such as space vector PWM (SVPWM) and discontinuous PWM (DPWM) algorithms are generated. Moreover, a simple overmodulation algorithm is also presented in this paper. Thus, the proposed GPWM algorithm generates all possible PWM algorithms in the entire modulation region. To validate the proposed algorithm, several simulation and experimental results are presented and compared. The results show the best agreement with the published work.