Bidirectional Current Sensorless Control for the Full-Bridge AC/DC Converter With Considering Both Inductor Resistance and Conduction Voltages

The full-bridge converter is often connected between the ac grid and the dc bus. In the conventional multiloop control, the inner current control loop shapes the ac-side current waveform, and the outer voltage control loop regulates the dc-bus voltage. In this paper, the single-loop bidirectional current sensorless control (BCSC) for the full-bridge ac/dc converter with considering both the inductor resistance and conduction voltage is first proposed. The average-value behavior of the full-bridge ac/dc converter is analyzed and it is simplified to an equivalent single-switch model. Based on this developed equivalent model, BCSC is designed and implemented in the FPGA-based system. There is only voltage control loop in the proposed BCSC (i.e., no current control loop), but BCSC is able to regulate the dc-bus voltage and shape the ac-side current. The provided results in both the rectifier operation and the inverter operation demonstrate the effectiveness of the proposed BCSC.