Optical probe current sensor module using the Kerr effect and its application to IGBT switching current measurements

An optical probe current sensor module using the Kerr effect 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 thin film utilizes magnetization rotation only, the 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, a Glan-Laser polarizer, PIN Photodiodes and a differential amplifier. The optical probe 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.