基于戴维宁定理的MMC子模块等效数学模型的研究

模块化多电平换流器(Modular Multilevel Converter,MMC)的每个子模块都包含两个电力电子开关元件IGBT。随着系统模块数的增加,仿真的速度大大降低,如何在有限的资源中实现MMC的实时仿真成为了仿真系统的瓶颈。根据IGBT在MMC中的工作原理,把IGBT等效为两个不同状态的等效电阻,然后根据戴维宁等效定理建立MMC子模块的等效数学模型。最后在Matlab/Simulink环境下进行该数学模型的仿真,并与采用器件模型的仿真结果进行了对比。仿真结果表明该数学模型在一定的误差范围内可以取代MMC子模块的物理模型,具有一定的实用性。

Research of equivalent mathematical model of MMC sub-modules based on Thevenin's theorem

Every sub-module of modular multilevel converter contains two IGBTs. With increase the number of system module, the simulation speed is greatly reduced, how to realize the MMC in limited resource becomes the bottleneck of the simulation system of real-time simulation. According to the working principle of IGBT in the sub-module of MMC, the equivalence model of IGBT is two different resistors. Then this paper uses the Thevenin's theorem to build the equivalent mathematic model of sub-module. The correctness of the established sub-module is proved with Matlab/Simulink. Compared with the circuit which uses the device model, the simulation results show that the mathematical model can replace the physical model of MMC sub-module in a certain error range. It has a certain practicality.