Dual Synchronous Rotating Frame-Based Power Allocation Control of Single-Stage Multiport Inverter in Islanded Microgrids

The single-stage multiport inverter (SSMPI) is a promising configuration for islanded microgrids, eliminating the need for an intermediate DC-DC converter. However, existing control schemes are always executed under mixed reference frames, where the grid-forming control on the AC side is implemented in the rotating frame, and the power allocation control on the DC side is implemented in the stationary frame. This coupled feature, operating under the mixed reference frame, leads to excessive port power ripple and poor dynamic performance. Given this, this article proposes a dual synchronous rotating frame (DSRF)-based power allocation control strategy that achieves low port power ripple and fast dynamic response, where the control objectives on both the AC side and DC side are realized on the rotating frame. In the proposed DSRFbased strategy, the SSMPI is decoupled into dual sub-inverters, with each sub-inverter managed independently in a synchronous rotating frame. The sum of d-axis and q-axis components for the sub-inverters is used for grid-forming control on the AC side, and the magnitude of d-axis and q-axis components of the sub-inverter is employed for power allocation control on the DC side. The range for power allocation capability of the SSMPI with the proposed DSRF-based strategy is also analyzed. Experimental results show that the port power ripple can be reduced by approximately 11.69%, and the dynamic response is significantly improved with the proposed DSRF-based strategy.