Three-Phase ARCP Inverter Using Soft-Switching With a Single Shared Inductor

Soft-switching in power inverters for drive and grid applications can both enhance the efficiency by reducing switching losses and improve electromagnetic interference (EMI) due to lower switching speeds with their associated $\mathrm{d}v/\mathrm{d}t$. An advantageous topology is the well-known auxiliary resonant commutated pole (ARCP) inverter. The development of such power electronic inverters often focuses on reducing weight, volume, and cost. Considering a three-phase ARCP system, this article presents a novel single shared inductor $(\mathrm{S}^{2}\mathrm{I})$-ARCP approach to reduce the passive component count in the auxiliary circuit from three to one. The simultaneous use of the shared inductor by more than one phase must be detected and avoided by the control algorithm. A frequency analysis of such occurrences is performed, and a method for avoiding them by shifting the switching edges is presented. The proposed $\mathrm{S}^{2}\mathrm{I}$-ARCP topology together with an appropriate control algorithm is implemented and validated at 10 kW with an 800 V dc-link. Efficiency measurement results indicated a significant loss reduction under soft-switching operation by more than 38% compared with hard-switching, with a peak efficiency value of 99.58%. It is demonstrated that a mere adjustment in the control signal generation can save two resonant inductors without significant disadvantages.