Pulse width modulator for voltage-type inverters with either constant or pulsed DC link

This paper proposes a new hybrid modulator scheme based on the equivalence of different PWM strategies. The modulator consists of simple logic blocks, and allows a systematic and straight approach to generate any continuous or discontinuous PWM. The performance characteristics of different strategies are examined in terms of the amplitude of the ripple current and the influence of the angle between the voltage and output current is taken into account. The analysis is extended to include a total clamping interval with values larger than the usual 120 degrees and applied to voltage source inverters with pulsed DC link. Simulated and experimental results demonstrate the validity of the proposed technique.