Combination of sliding mode control and non-voltage measurement NLM modulation for modular multilevel converter

Abstract

Modular Multilevel Converter (MMC) is an optimal solution for the advanced power conversion for Medium Voltage (MV) and High Voltage
(HV) applications. This paper proposes an enhanced sensorless Nearest Level Modulation (NLM) with a Sliding Mode Controller (SMC)
scheme with Integral Sliding Surface for the grid-connected case of the MMC where it stands as a DC/AC inverter. The proposed SMC
when applied to MMC shows some outstanding advantages such as fast response, good robustness, and stability under transient conditions.
Additionally, the sensorless NLM is proven to be efficient in terms of capacitor voltage balancing while maintaining output voltages tracking
the reference voltages fed by the SMC. The simulation results on MATLAB/SIMULINK for the MMC under varying active and reactive power
are conducted so as to confirm the correctness and efficiency of the proposed method.