模块化多电平变换器功率模块的电流与损耗

为了便于对电压源变换器功率器件进行系统设计以及对其参数、冷却装置进行有效选择，需要对电流与损耗进行有效估算.通过介绍新型模块化多电平变换器（MMC）的工作模态，对其电流分布进行了详细分析，给出一种基于电流分布和元件特征曲线线性拟合的简单MMC损耗计算方法，并在此基础上分析了开关频率、功率因数等对MMC损耗的影响.仿真计算结果表明，该方法能简单有效地对不同工况下各个元件的损耗进行计算，其计算结果对功率器件及其散热装置的选择有一定的指导作用.

Current and loss for power module of modular multilevel converter

In order to perform the convenient system design for the power devices of voltage source converter（VSC） and the effective selection of parameters and cooling apparatus, it is necessary to carry out the effective estimation of current and loss. Through analyzing the working mode of new modular multilevel converter （MMC）, its current distribution was minutely analyzed. A simple loss calculation method for MMC based on the linear fitting of current distribution and element characteristic curve was proposed, and then the effect of such factors as the switching frequency and power factor on the MMC loss was analyzed. The simulated results show that the proposed method can simply and effectively calculate the loss of various elements under different operating conditions, and the calculated results can provide some guidance for the selection of power devices and cooling apparatus. 