Backward Discrete State Event-Driven Approach for Simulation of Stiff Power Electronic Systems

Power electronic systems are intrinsically hybrid systems, consisting of continuous states and discrete events. The hybrid nature makes their accurate and efficient simulation challenging to achieve. A novel approach called discrete state event-driven (DSED) is able to solve such hybrid systems efficiently, but it shows unsatisfying simulation speed when calculating circuits containing parasitic parameters, namely stiff systems. Since the effect of parasitic parameters brought by connection lines can be destructive when they produce voltage peak or resonance, it is crucial to evaluate the impact of parasitic elements during the design phase of the converters by simulation. This paper proposes a backward DSED (BDSED) approach that can solve stiff systems efficiently by cooperating with the event-driven framework. The BDSED adopts a semi-variable-step-variable-order (S-VSVO) mechanism for integrating continuous states and uses interpolation method for dealing with discrete events. With this simulation approach, the effect of parasitic elements in power electronic systems can be analyzed more efficiently compared to other commercial software. In a case study, the proposed approach shows 60 times faster in simulation speed compared with ode15s in Simulink and more than 3 times faster compared with stiff solver in a commercial software called PLECS at the same level of accuracy.