适用于模块化多电平换流器实时仿真的建模方法

为了实现模块化多电平换流器(MMC)系统的实时仿真,采用理想变压器模型法对MMC进行了模型分割。针对模型分割联解信号延时导致的波形失真问题,提出了采用插值预测和超前预测分别对串行和并行实时仿真延时进行补偿的方法。此外,为了进一步提高模型分割后子模块群组的计算速度,提出了MMC子模块网络的开关函数等效模型和电磁暂态数值模型,并推导了数值模型中子模块输出电压和电容电压的差分方程。然后,以21电平MMC逆变电路为例,将上述MMC建模方法与原整体模型进行了仿真对比分析。结果表明,所提插值预测的方法有效改善了MMC分割模型的稳定性,且具有极高的仿真精度。所提开关函数模型和电磁暂态数值模型均具有很好的加速效果,其中,电磁暂态数值模型与详细模型的仿真结果高度吻合。所提出的建模方法适用于MMC实时仿真测试平台的构建。

Modeling Method for Real Time Simulation of Modular Multilevel Converter

In order to realize real-time simulation of the modular multilevel converter(MMC)system, an ideal transformer model is used to segment the MMC. To deal with the waveform distortion problem caused by model segmentation delay, a method of error compensation for serial and parallel real-time simulation using interpolation prediction and advance prediction is proposed, respectively. In addition, in order to further improve the calculation speed of sub-module groups after model segmentation, the switching function equivalence model and electromagnetic transient numerical model of MMC sub-module network are proposed, and the difference equation of the output voltage and the capacitor voltage of the sub-module in the numerical model are deduced. Then, taking the 21 level MMC inverter circuit as an example, the above MMC modeling method and the original integral model are compared and analyzed. The results show that the proposed method can effectively improve the stability of the MMC segmentation model featuring very high simulation accuracy. The proposed switching function model and the electromagnetic transient numerical model have very good acceleration effect, and the electromagnetic transient numerical model is in good agreement with the simulation results of the detailed model. The proposed modeling method is applied to the construction of the MMC real-time simulation test platform.