基于矩阵构造的模块化多电平变换器电压传感器缩减分析与优化

Modular multilevel converters (MMCs), which employ a matrix construction technique to reduce the number of voltage sensors, can significantly decrease hardware costs. However, the performance of the MMC system can be hindered by several factors, such as the occurrence of singular switching matrices and possible inaccurate estimation of submodule capacitor voltages (SM-CVs). To overcome these challenges, this article first analyzes the principle of constructing singular matrices during operation and calculates its probability. It then analyzes the impact of MMC key parameters of the probability and assesses the applicability of the method. Additionally, compensations for power device conduction voltage drop and sampling deviation are proposed to enhance the estimation accuracy. The criteria for determining the number of SMs within a group is presented. The estimated capacitor voltages are employed as feedbacks in the closed-loop voltage control of an MMC system, and the feasibility of the method is thoroughly evaluated under various conditions. Experimental results validate the effectiveness of the work done.