Control strategy for grid-connected solar inverters

As an essential interface between the photovoltaic (PV) panels and the utility grid, solar PV inverters are responsible for converting intermittent solar energy to meet the utility grid requirement, where the inverter output should be synchronized with the grid voltage in terms of phase frequency and amplitude. In addition, consider- ing system cost, conversion efficiency, power quality, and reliability of the grid- connected PV system, the control strategy of solar inverters should be carefully designed. Regarding grid-connected solar inverters, the basic control strategies include a maximum power point tracking (MPPT) algorithm (i.e., increasing effi- ciency and maximizing the energy harvesting), a DC-link voltage control, and a grid-connected current control (i.e.. responsible for the power injection and current quality). In this chapter, the model of PV modules and a few typical MPPT meth- ods are briefly introduced. Then, the DC-link voltage control and grid-connected current control are presented for the single-phase and three-phase solar inverters, respectively.