Optical Probe Current Sensor Module Using the Kerr Effect of Exchange-Coupled Magnetic Film and its Application to Igbt Switching Current Measurements

An optical probe current sensor module using the Kerr effect of exchange-coupled magnetic film has been fabricated and applied to switching current measurements for IGBT used for the DC-DC converter and the DC-AC inverter of EV/HEV. Since the sensor module using the Kerr effect of the single domain exchange-coupled magnetic film utilizes magnetization rotation only, Barkhausen noise due to domain wall pinning can be excluded. The current sensor consists of a Laser-diode, a polarizer, a Fe-Si/Mn-Ir exchange-coupled film, a quarter-wavelength plate, PIN Photodiodes and a differential amplifier. The current sensor has a current measurement range of ±60 A and a frequency range of DC 200 kHz. The switching current of IGBT has been measured by it.