Press-pack Insulated Gate Bipolar Transistor (IGBT) gradually replaces traditional power module in high power applications such as High Voltage Direct Current and Flexible AC Transmission Systems. There are many IGBT chips connected in parallel inside press-pack IGBT. The uneven distribution of clamping force and temperature will cause the imbalance current distribution of IGBT chips, which may lead to the overcurrent of some of the chips. Therefore, the reliability of press-pack IGBT can be improved by current sensing of each IGBT chip. However, the accurate chip-level current sensing inside press-pack IGBT is difficult due to the size and bandwidth of sensors. To solve this problem, a hybrid current sensor of anisotropic magnetoresistance (AMR) and compact planar Rogowski coil is proposed in this paper. AMR sensor is used to sense low-frequency and DC current and the high-frequency part is measured by Rogowski coil. The parameters of current signal processing circuit are designed by calculation and simulation. The hybrid sensor is verified by sensing the current of a single-chip press-pack IGBT in Buck converter compared to the commercial current probe.
