基于阵列换能器的水下抗失调超声功率传输系统

Grid-connected inverters play an essential role in renewable energy systems, and their reliability directly impacts grid stability and energy efficiency. This study proposes a fault-tolerant control (FTC) strategy to address output distortion and instability caused by open-circuit (OC) faults in power semiconductor switches. A tiered fault response mechanism is introduced to handle both single and dual switches faults. In the primary fault stage, redundant switches replace faulty devices in the inverter circuit. During the secondary fault stage, the system switches to FTC mode by connecting the faulty phase to the midpoint of the DC-side capacitor. To simplify sector division and modulation calculations under different fault conditions, a sector rotation reconstruction method is employed. By unifying the processing of post-fault space voltage vectors (SVVs) through rotational transformation, the proposed approach streamlines the control process and enhances efficiency. Additionally, a midpoint voltage balancing strategy is designed using an external module and hysteresis control to dynamically balance the midpoint voltage, improving system performance. Experimental results confirm that the proposed method ensures stable operation, maintains phase current total harmonic distortion (THD) below 5%, and keeps DC-side voltage deviation within 1.5%.