A Single-Carrier PWM Technique for Grid-Tied Modular Multilevel Cascaded Inverters

Grid-integrated solar photovoltaic (PV) systems have gained a lot of traction due to recent developments and the availability of solar panels. The control technique is one of the key factors that determines the effectiveness and dependability of a grid-connected PV system. This paper proposes an advanced single carrier pulse width modulation (SCPWM) for a modular multilevel cascaded (MMC) inverter to interface the PV system with low to medium voltage gird. The proposed SCPWM utilizes third harmonics saturated signal along with a single carrier rather than the conventional Phase Disposition PWM (PDPWM) technique for gate pulse generation of MMC. As such, the proposed SCPWM scheme is easier to implement and ensures lower computing stress on the DSP/FPGA. However, the proposed SCPWM is designed to suppress the total harmonic distortion (THD) of MMC converter. It also ensures overall low semiconductor power loss and better efficiency. The thermal stability of power switches is also achieved by utilizing the proposed SCPWM scheme. Moreover, the proposed SCPWM offers better DC bus utilization, low switching, and conduction loss. MATLAB/Simulink and PLECS computer environment were utilized during simulation validation. A scaled down laboratory prototype is built to support the simulation claim.