Stray Inductance Reduction of Commutation Loop in the P-cell and N-cell-Based IGBT Phase Leg Module

This paper proposes a novel packaging method for insulated-gate bipolar transistor (IGBT) modules based on the concepts of P-cell and N-cell. The novel packaging reduces the stray inductance in the current commutation path in a phase-leg module and hence improves the switching behavior. A P-cell- and N-cell-based module and a conventional module are designed. Using finite-element-analysis-based Ansys Q3D Extractor, electromagnetic simulations are conducted to extract the stray inductance from the two modules. Two prototype phase-leg modules based on the two different designs are fabricated. The parasitics are measured using a precision impedance analyzer. Finally, a double pulse tester based-switching characterization is performed to illustrate the effect of stray inductance reduction in the proposed packaging design. The experimental results show the reduction in overshoot voltage with the proposed layout.