A Matrix Construction Based Capacitor Voltage Measuring Scheme for Modular Multilevel Converter With Reduced Voltage Sensors

This letter proposes a matrix construction and calculation-based submodule capacitor voltage (SM-CV) measurement method for the MMC with reduced voltage sensors. The SMs in the same arm are divided into groups, and a voltage sensor is allocated to measure the group output voltage. After multiple sampling, a group output voltage vector is obtained and can be expressed by the product of the corresponding SM switching state matrix and SM-CV vector. Thus, the SM-CVs can be acquired by solving a matrix equation Ax = b. The sampling method is exquisitely manipulated so that the matrix equation is solvable, while easy and rapid to implement. The rationality and feasibility of the proposed measurement method have been verified by experimental results.