Power Module Design for Integrated Three-Phase Current Sensing Using a Single 3-D Point Field Detector

Past work has demonstrated that arrays of magnetoresistive (MR) point field detectors (PFDs) can be integrated into power modules and busbars for compact current sensing in multiphase power electronic systems. This paper presents a methodology to design three-phase full-bridge power modules with integrated current sensing using a single 3-D PFD. Frequency-dependent skin and proximity effects are investigated in the power module to increase the magnetic field bandwidth. Designs for leadframes, terminals, and baseplates are recommended for producing a net 3-D magnetic field that includes cross-coupling from all three phase currents. A 3-D field decoupling technique, presented in previous papers, is used to decouple the phase currents from the net magnetic field sensed by the 3-D PFD. Three-phase high-bandwidth current sensing is experimentally implemented in custom-designed leadframes with cross-coupled field decoupling using a single 3-D MR PFD. This integrated current sensing method provides advantages in power density, cost, manufacturing, and implementation.