Research On Topology And Control Strategy Of Photovoltaic Grid-connected Micro-inverter

With the rapid growth in world energy demand and the gradual reduction offossil energy, in recent years the research and application of photovoltaic powerhas been expanded extensively. In the traditional photovoltaic system, in order toget a certain power and voltage level, the solar panels are connected in series andparallel. PV modules, there are different characteristics and some shadow, it willcause the dismatch loss and hot spots in the battery string. In order to overcome theabove defects, a single PV module grid-connected system may be one of thedevelopment trends of the future. The power level of the individual PV module isgenerally between90W to500W, so the power of the inverter matched with thesingle PV module is very small, this inverter has been called “micro-inverter”.This paper summarizes the topologies of existing micro-inverter, analyzes itsworking principle, advantages and disadvantages, and then through comparison inmany performance of various topologies, I has chosen the topology of interleavedflyback photovoltaic grid-connected micro-inverter as the object of study. theworking principle and existing two control strategies (control strategy of the DCMand the control strategy of BCM) of interleaved flyback photovoltaicmicro-inverter has been analyzed detailedly, through the advantages anddisadvantages of the above two control strategies, this paper proposes a hybridcontrol strategy. Hybrid control strategy is appropriate for high-power andlow-power situations, and can also improve the efficiency of the inverter at variouspower levels and the quality of the grid-connected current. The working principleand the advantages have been analyzed detailedly, and through the MATLABsimulation, the feasibility of hybrid control strategy is verified. Using the topologyof interleaved flyback photovoltaic grid-connected micro-inverter, a190Wmicro-inverter has been designed, and the design process of hardware and softwarehas been analyzed detailedly.