A Compact DC–200 MHz Hybrid Current Measurement Approach for Fast Switching Power Semiconductor Modules

The accurate current measurement is critical for power semiconductor characterization. Considering the switching speed of power semiconductors has become much faster in recent years, it is difficult to measure the current effectively using existing current probes due to their limited bandwidth. Also, in many cases, it is necessary to directly characterize power semiconductors in real power converters in long-term operations, requiring some other key specifications on current probes including dc accuracy, galvanic isolation, easy installation, etc. This article proposes a novel hybrid current measurement method, including the tunnel-magnetoresistance-based low frequency measurement section, Rogowski coil-based high-frequency measurement section, and signal conditioning circuits for seamless frequency combination. Accordingly, a current probe based on the proposed method is developed, achieving high bandwidth, galvanic isolation, and compact size. The performance is experimentally validated with a double pulse test and long-term continuous pulse test in a 1.2 kV/120 A SiC mosfet power module-based converter platform. Eventually, the proposed probe is comprehensively compared with the commercial shunt and Rogowski coil.