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

Abstract

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 <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> filter in <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</i> 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.