A Closed-Loop Compensated Rogowski Coil Current Sensor for Three-Phase Inverter

Accurate current measurement is crucial in power electronic converters to achieve fault protection and current control. Among the various options available, the printed circuit board Rogowski coil current sensor (PCB RCCS) emerges as a strong contender due to its advantages of higher bandwidth, smaller volume, and lower cost. However, the presence of offset voltage and offset current in operational amplifiers (op-amps) greatly limits the measurement accuracy of PCB RCCS, and is greatly affected by the individual differences of op-amps and temperature changes. Traditional error compensation methods lack self-adjusting capabilities, leading to significant limitations in compensation effectiveness. This article proposes a closed-loop error compensation method that can monitor the compensation effect in real-time under actual operating conditions, adjust the compensating signal promptly, and achieve precise compensation of integral errors in PCB RCCS. Moreover, the proposed PCB RCCS is highly integrated into a three-phase inverter, achieving not only reliable short-circuit protection for power devices but also recovering phase current information for successful utilization in system current control.