A Grid-Connected Multilevel Converter for Interfacing PV Arrays and Energy Storage Devices

摘要

This paper presents a design procedure and a udcontrol strategy for a grid-connected single-phase multilevel udconverter. The proposed system uses two series connected H-bridge modules, one fed by photovoltaic panels, the other by udenergy storage devices. The former switches at line frequency, udwhile the latter operates in PWM. The system is designed to udminimize the voltage stress on the switches, while the control udstrategy is such that a constant active power is delivered to the udgrid with high power factor, even if the energy produced by the udphotovoltaic panels is variable. The paper illustrates the power udconverter design procedure, the hybrid PWM method and the udsmall signal modeling used to design the controllers of each udinverter. In addition, the performance of the multilevel converter udis verified by means of simulation and experimental results, udwhich show the system ability to operate as expected