A Generic Multicell Network Control for Three-Phase Grid-Connected Inverters

Abstract

The inherent resonance of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> filters threatens the inverter stability seriously. Moreover, the strong <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$dq$</tex-math></inline-formula> -axis cross-coupling of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCL</i> -filtered grid-connected inverters in a synchronous frame goes against the independent regulation of active ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$P$</tex-math></inline-formula> ) and reactive ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$Q$</tex-math></inline-formula> ) power that is required in various applications. Besides, the imbalance and harmonics of the grid voltage will deteriorate the injected grid current, so the disturbance suppression performance of grid-connected inverters is important. Furthermore, excellent steady-state and dynamic performance is essential for grid-connected inverters. To solve the above four issues simultaneously, a complex-domain model of grid-connected inverters is established, and a generic multicell network control (GMNC) structure is proposed in this article. Based on the proposed GMNC structure, a number of control schemes are obtained, and the quantitative relationship between inverter performance and control parameters can be given directly and precisely for each scheme. Therefore, it is convenient and simple for engineers to select proper control schemes depending on the practical conditions and to design all the control parameters for an expected steady-state, dynamic, and antidisturbance performance without the resonance and the coupling issues. Finally, the effectiveness of the proposed control is verified by the experiments.