One-stage and two-stage schemes of high performance synchronous PWM with smooth pulse-ratio changing

This paper presents detailed description of one-stage and two-stage schemes of novel method of synchronous pulsewidth modulation (PWM) for voltage source inverters for AC drive application. The proposed control functions provide accurate realization of different versions of voltage space vector modulation with synchronization of the voltage waveforms of the inverter and with smooth pulse-ratio changing. Voltage spectra do not contain even harmonics and sub-harmonics (combined harmonics) during the whole control range including the zone of overmodulation. Examples of determination of the basic control parameters of the inverters with low switching frequency, as well as results of its simulations, are presented.