Modeling and control of the single-phase photovoltaic grid-connected cascaded H-bridge multilevel inverter

This paper presents the modeling and control of the single-phase photovoltaic grid-connected five-level cascaded H-bridge multilevel inverter. For the unity power factor, the proportional and integral current controller with the duty ratio feed-forward compensation method is used. And in order to track the maximum power point and to reduce the partial shading due to stacked photovoltaic modules, each DC voltage is stably controlled to their maximum power points by dedicated voltage controllers of each H-bridge module. The modeling approach and the control loop design method are provided in this paper. The proposed control schemes are validated from experimental results of the 2-kW prototype hardware.