2-D Magnetoresistive Point Field Detector-based Current Sensing for High-Density Power Modules

Giant Magnetoresistive (GMR) point field detector (PFD) based current sensing, previously integrated in 2-in-1 power modules provided galvanic isolation and increased power density by sensing 1-D magnetic fields near the leadframes. In this work, 2-D Magnetoresistive (MR) PFDs are utilized to sense 2-D fields to compensate for the inherently weak 1-D fields in commercial 6-in-1 IGBT power modules. This paper leverages 2-D field metrics established previously for busbar current sensing, to analyze the power module's field shape and to optimally position the 2-D MR PFDs in the module. This work also develops a methodology to decouple cross-coupled, planar vector fields. This decoupling methodology is critical to sense the phase currents which have superimposed fields inside the three-phase power modules. This new concept of using 2-D MR PFDs to provide integrated current sensing in high-density 6-in-1 power modules is demonstrated via experiments in an induction machine dynamometer test setup.