Impedance Network Based Isolated Three Phase AC-AC Converter With Enhanced Voltage Gain And Safety

Abstract

The conventional matrix converter has limited voltage gain and requires a large number of switches. The Ultra Sparse Matrix Converter (USMC) was introduced to address this, reducing the number of switches. However, its voltage gain remains significantly low, and being non-isolated, it also raises safety concerns. This paper focused on achieving higher voltage gain, providing electrical isolation, and reducing the switching voltage stress. In this paper, a novel three-phase isolated duodecuple source (DS) impedance network-based USMC is proposed. The DS impedance network consists of a flyback stage with high-frequency transformer isolation, a boost stage, and a voltage tripler stage. The flyback stage provides electrical isolation, the boost stage enhances voltage gain, and the voltage tripler stage makes it triple. Simulation results show that with an input of 220 V AC, the proposed DS-USMC delivers an isolated three-phase output of 2640 V AC, achieving a voltage gain of 12 at a duty ratio of 0.5, compared to the conventional USMC gain of 0.867. The inductor current remains stable with a peak of 12 A, and the maximum voltage stress across the DS switches is 30V and 61V, well below the critical threshold. The proposed DS-USMC retains all the merits of their existing USMC, providing a larger range of output voltage with electrical isolation, safety, and reducing switching voltage stress in a cost-effective manner.