Design and Development of Hybrid Current Sensors for Wide-Bandgap Power Electronics Applications

Hybrid current sensors are becoming increasingly common in applications, such as power electronics, due to their ability to cover an ultrawide frequency range by combining a DC/low-frequency detector with a high-frequency current transducer. Designing such current sensors to measure switching waveforms proposes challenges considering size and dimensions, intrusiveness (or parasitic elements and losses), nonlinearity (or temperature drift), EMI immunity, accuracy, and cost. This work provides design and considerations to optimize hybrid current sensors specifically for switch-current measurement applications. A tunnel magneto-resistor, as well as an on-chip flux gate sensor, are each integrated with a PCB-embedded Rogowski coil to provide practical implications. It is shown that the proposed sensors provide compact, inexpensive, and accurate current measurements. Furthermore, these sensors are applied to measure switch-current waveforms of high-frequency wide bandgap power converters to showcase their superior performance in capturing the switching current waveform in such applications.