Comparison study of MPPT control strategies for double-stage PV grid-connected inverter

For a single-phase double-stage photovoltaic grid-connected inverter, there are two different maximum power point tracking (MPPT) control strategies due to the MPPT function can be accomplished either in the first-stage Boost dc/dc converter or in the second-stage grid-connected inverter. This paper mainly emphasizes analysis and comparison of the two different control strategies. First, the parameters designs for the main power circuit as well as controllers design for different control strategies are given. Second, the simulations of the two different strategies based on PSIM software are presented, and then comparison of the advantages and disadvantages of the two strategies is given in terms of dc-link voltage stability and MPPT performance. The simulation analysis and comparison results have certain theoretical significance for the research and manufacture of the double-stage photovoltaic grid-connected inverter.