Implementation of Current Sensorless Level Shifted PWM Strategy for Modular Multilevel Converter

In this paper, the implementation of the current sensorless level-shifted PWM algorithm for a modular multilevel converter is proposed. The algorithm is tailored for MMC with N submodules (SMs) per arm, resulting in its universal feasibility. Furthermore, the algorithm does not require arm-current signals, reducing the cost even more. The pole voltage may have two possible voltage levels: N+1 or <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2\mathrm{N}+1$</tex>. The phase difference between the upper and lower arm carriers determines the specific level. The paper provides an extensive description of the mathematical structure of the technique and includes a flowchart to facilitate a better understanding. The cogency of the proposed algorithm is initially tested through single-phase MMC simulations in MATLAB/Simulink and then subsequently verified on an experimental setup.