Design of PCB Rogowski Current Sensor with Digital Compensation for Three-Phase Inverter

Reliable current closed loop and rapid current short-circuit protection are essential for the stable and safe operation of the three-phase inverter. It can be achieved by the Hall current sensor and desaturation detection circuit before. However, with continuous improvement of silicon carbide metal-oxide-semiconductor field-effect transistors (SiC MOSFETs) device technology, power electronic devices posed higher challenges to current sensing technology. Attention has been drawn to the Rogowski current sensor (RSCS) in recent years because of its advantages in terms of bandwidth, volume, and cost. However, the result of PCB RSCS is mixed with droop, drift and offset errors which can damage the normal operation of power devices. This paper proposes a digital bias and drift compensation method aimed at offset voltage of op-amps and charge injection of analog switches. The effectiveness of the proposed method is proved in a 10 kW three-phase inverter.