摘要 : This paper presents a multilevel control and maximum power point tracking (MPPT) scheme for variable conversion ratio partial power processing photovoltaic (PV) dc–dc converters. A general system model is derived and linearized in... 展开 This paper presents a multilevel control and maximum power point tracking (MPPT) scheme for variable conversion ratio partial power processing photovoltaic (PV) dc–dc converters. A general system model is derived and linearized in state-space form for a switched-inductor (buck-boost dc–dc) converter with an arbitrary number of series-connected stages. The proposed control law is then used as the basis for a multilevel MPPT scheme that can optimize many series-connected PV cells, substrings, or modules simultaneously. The MPPT algorithm is shown to converge in a timeframe independent of the number of PV units and can work in concert with the central inverter MPPT algorithm without conflict. To validate the control and optimization scheme, we present a hardware prototype designed to fit in the junction box of conventional PV modules, operating at the submodule level. While the control law is developed specifically for the buck–boost topology, the MPPT algorithm is generalized and could be applied to many partial-power processing topologies provided there is capability to regulate the voltage differences or voltage ratios among adjacent PV stages. 收起