Dc-ac three-phase four-wire Z-source converter with hybrid PWM strategy

This paper presents a hybrid PWM strategy for dc-ac three-phase four-wire Z-source converters. The technique combines the theory of space-vector PWM with the ease of implementation of a triangular-comparison PWM. Such strategy reduces the effort of algorithm calculation. The introduction of the distribution ratio in this technique, allows the development of a systematic approach for implementation of either conventional or any modified vector strategies, even including the shoot-through zero vectors inherent of Z-source inverter. Also, the paper proposes a simple software algorithm to generate the hybrid modulation of Z-source inverter with the introduction of the “virtual” dc-link zero point. Simulated and experimental results demonstrate the validity of the proposed method.