This article proposes a new lumped-charge model for power semiconductor devices. The existing lumped-charge model, due to its linear modeling method, has some limitations that will impair the accuracy of the model. First, this article analyses the restriction of the traditional lumped-charge modeling method. Then, based on the limitation analysis, a new lumped-charge modeling method is presented and improves the accuracy of the traditional one while keeping its advantages. In this new model, the relationship between the ambipolar current and the LCs in the power devices is redefined. Finally, the new method is implemented to an insulated-gate bipolar transistor (IGBT) model and a PiN freewheeling diode. The accuracy of the models is verified by experiment including both the static and transient characteristics and compared with the traditional IGBT model.