A Quasi-Trapezoidal Modulation Method with Zero-Voltage Switching for Single-Phase Inverters

Single-phase inverters working in triangular current mode (TCM) can achieve soft switching, but TCM causes large inductor current ripple and wide variation in switching frequency. To address these issues, an improved quasi-trapezoidal modulation method is proposed, which allows for reduced inductor current ripple and controllable switching frequency while achieving zero-voltage switching. Besides, the switching sequence is optimized to eliminate the waveform distortion at ac voltage zero crossing. Finally, a simulation model and an experimental prototype have been developed, which validate the correctness of the proposed modulation strategy.