A novel high performance Generalized Discontinuous PWM algorithm for reduced current ripple and switching losses using imaginary switching times

This paper presents a novel high performance generalized discontinuous pulse width modulation (GDPWM) algorithm for reduced current ripple without angle and sector estimation. The conventional space vector modulator with equal division of zero state vectors time is modified to generate different discontinuous modulating waves. A constant-variable mu ranging from 0 to 1 is used to generate infinite number of modulating waves. Also, the classical triangle comparison approach is replaced by a new space vector-based method. Based on the stator flux ripple, the value of mu that gives minimum stator flux ripple will be selected. With mu equal to 0, 1 and 0.5, DPWMMAX, DPWMMIN, and conventional SVPWM (CSVPWM) sequences can be generated respectively. For simplicity only three values of mu are considered. The proposed method results in reduced current ripple and switching losses over CSVPWM at all modulation indices. To validate the proposed method, simulation is carried out on V/f controlled induction motor and the no-load current waveforms at different modulation indices are presented and %THDs is compared.