A DC-Bus Planar Rogowski Coil Based Current Sensor for Half-Bridge Applications

This paper investigates the utilization of a planar Rogowski coil located between the dc-bus traces to measure the half-bridge’s switching transient current. The sensor’s fundamentals are explained, and design considerations are derived from a comprehensive parametric study analyzing the impact of a non-uniform dc-bus current distribution on the sensor’s mutual inductance. A compact current sensor prototype is designed and fabricated for a SiC MOSFET half-bridge application. Simulations show a minimal increase in the current communication loop stray inductance of 399 pH. The current sensor’s performance is experimentally validated with double pulse tests.