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

Jiahe Ju,Bochen Shi,Zhengming Zhao,Zhujun Yu,Yicheng Zhu

doi:10.1109/access.2021.3058417

Jiahe Ju, Bochen Shi + Show 3 more

Open Access

https://doi.org/10.1109/access.2021.3058417

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Abstract

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.

Highlights

Power electronic (PE) systems have a hybrid nature, which refers to the coexistence of continuous states and discrete events [1], [2]
In this paper, the backward DSED (BDSED) simulation approach is proposed for the simulation of stiff PE systems, which are usually parasitic-parameter-included circuits
Applying the idea of event-driven and the formulas of backward integration, this paper puts forward a mechanism of choosing step size and order, namely S-variable-step variable-order (VSVO) mechanism, which can achieve a balance between the computational cost of step size change and the flexibility brought by the change

Summary

INTRODUCTION

Power electronic (PE) systems have a hybrid nature, which refers to the coexistence of continuous states and discrete events [1], [2]. BDSED simulation approach has the following characteristics: 1) It applies an S-VSVO mechanism that provides the flexibility of changing the step size to multiple times larger and reduces the computational cost by keeping the same step size for several steps and using the calculated history values directly for the new step size. The BDSED simulation approach can integrate continuous states with relatively low computational cost and can efficiently take all the discrete events into consideration, which makes it an efficient tool for solving stiff power electronic systems. It may have the potential for extending to other fields, but further researches are needed

EFFICIENCY VERIFICATION WITH A CASE STUDY

ACCURACY VERIFICATION WITH EXPERIMENTAL PROTOTYPE

CONCLUSION