Wide Bandwidth Current Sensor for Commutation Current Measurement in Fast Switching Power Electronics

This paper presents a current sensor for commutation current measurement with a bandwidth from DC up to 315 MHz. The sensor is inserted in the commutation loop by a coaxial housing with a low insertion inductance of about 1.2 nH. The sensor is based on the HOKA principle using tunnel magnetoresistance sensors and a Rogowski-coil for low and high frequency current measurement respectively. The current sensor is tested in a half-bridge configuration equipped with gallium nitride transistors and compared to two state-of-the-art current sensors.