In order to calculate electromagnetic transients of power electronic systems, non-ideal physical models considering stray parameters of circuits and time delay of control loops are needed for semiconductor switching device. In this case, the mathematical models describing power electronic system exhibit high-order nonlinearity and tend to be highly rigid. The numerical solution methods through the conventional differential equations shall bring about the problems of long simulation time and poor numerical stability. Thus, this paper puts forward the improved methods for transient simulation of power electronic converters based on discrete state event driven (DSED) methods. These methods use the variation of state variable as the calculation basis rather than the variation of simulation time. It is demonstrated the methods could reduce simulation time effectively and solve the stiff problem of ordinary differential equations, which ensure numerically stable of the simulation.%为分析计算电力电子系统的电磁瞬态过程,需采用非理想开关器件模型,并计及电路中的杂散参数和控制回路中的时间延迟等,此时描述电力电子系统的数学模型呈现出高阶非线性特性,且往往具有较强的刚性.采用常规微分方程的数值解算方法对于这种非线性的电力电子系统瞬态过程进行仿真求解,存在仿真时间超长和数值稳定性很差的问题.为解决这一问题,基于离散状态事件驱动(DSED)思想提出一类电力电子瞬态过程数值仿真方法,摒弃对时间离散的常规数值解算,而直接以状态量的变化值作为仿真计算依据.理论推证和仿真解算比较结果表明:该方法能有效缩短解算时间,同时解决了常微分方程组的刚性问题,使得解算具有很好的数值稳定性.
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