Study on the Control Strategy of Cascaded H-Bridge Photovoltaic Grid-Connected Inverters

Taking the cascaded H-bridge (CHB) inverter as the object of study, the structure of the inverter system is analyzed and the modulation strategy of the system is investigated. A control strategy based on a three-phase cascaded H-bridge topology is proposed for a PV grid-connected inverter system. The scheme adopts a carrier level phase-shift modulation strategy, which can realize the maximum power point tracking of the front-stage PV string, the control of the grid-connected current, and the grid-connection of the inverter. Finally, the inverter with the proposed strategy is simulated in MATLAB/SIMULINK environment, and the simulation results prove the correctness and feasibility of the control strategy.