Modeling and Control of Single-Phase Modular Multilevel Converter Using Backstepping Approach

This paper introduces the modeling and control of Modular Multilevel Converter (MMC) based on differential equations for n submodules to be used and applied in photovoltaic (PV) systems later. Modular multilevel converters have gained significant importance in power conversion systems due to their highly desirable characteristics. These converters offer modularity and scalability, enabling easy integration with various power systems. In addition, they provide excellent power quality with minimal distortion of the output voltage, making them ideal for a wide range of applications. One of the operational challenges faced by modular multilevel converters (MMC) is regulating the circulating current in the phase leg and submodule capacitor voltage. This requires careful control and management to ensure stable and efficient operation of the converter. A Backstepping approach based nonlinear regulator has been developed using the state space model of the modular multilevel converter (MMC) to regulate the output current. The design of the controller is based on the Lyapunov stability approach, which ensures stable and efficient operation of the converter. By incorporating this approach, the controller can effectively manage the complex dynamics of the MMC and provide precise regulation of the output current. The simulations results are performed for an eight submodules MMC using the MATLAB environment and Simulink/SimpowerSystems toolboxes.