Modeling and Control of Dual-Stage High-Power Multifunctional PV System in d - Q - $o$ Coordinate

A high-power photovoltaic (PV) system based on dual-stage topology of boost converter plus paralleled four-leg inverter is presented, which can perform as both grid-connected inverter and active power filter. The system not only can allow a wide range of input voltage from PV arrays, but also can compensate the nonlinear and unbalanced load current. This paper first presents the small-signal model of the presented inverter with LCL filter in d -q-o coordinate; then, the unified control strategy which combines PV power injection and distortional current compensation is demonstrated; finally, a method to control the zero-sequence circulating current between paralleled inverters is proposed. Simulations and experimental results are carried out on a 100-kVA prototype to validate the practicability of the whole system.