Optimal Rotational Rest Control With Resistance Ratio Estimation for RMS Current Balancing of Parallel WBG Bridge Arms

作者：Ruihao Song, Guangze Chen, Zhen Li, Z C Zhang · 发表于：IEEE Transactions on Power Electronics · 年份：2026 · DOI：10.1109/tpel.2026.3699684 · 研究领域：HVDC Systems and Fault Protection、Magnetic Bearings and Levitation Dynamics、Electric Motor Design and Analysis

On-resistance mismatches among wide-bandgap MOSFETs pose a critical challenge that limits the lifetime of inverters employing parallel-arm topologies. The rotational rest control provides an effective means of arm-level RMS current balancing with negligible interference to the primary control loop and acceptable hardware costs. However, the millisecond-level rotation cycles employed in the existing rapid rotational rest control method lead to significant distortion in the arm currents, thereby disturbing the balancing control loop and reducing the balancing accuracy. To address this, an optimal rotational rest control method is proposed in this paper. The proposed method employs a proactive, retrospective rolling optimization algorithm based on resistance ratio estimation, in contrast to previous approaches that rely on reactive correction. With this new control configuration, the method supports rotation cycles spanning multiple fundamental periods, thereby eliminating arm current distortion caused by short rest windows and improving current balancing accuracy. Simulation and experimental results demonstrate that the proposed method significantly improves current balancing accuracy under severe mismatches and provides increased computational flexibility.