I. Introduction
Computer-aided analysis and simulation of power electronic systems are of great significance in the design and control of power converters for engineers. Unlike other common circuits, power electronic systems are usually combined by several power conversion stages composed of basic switching legs and energy storage elements. Multiple switching events cause the frequent change of the circuit topology and introduce discontinuous points. Therefore, power electronic systems are typically hybrid systems consisting of both continuous states and discrete events [1], [2], which bring great challenges to the simulation tools.