A Control Method for Three-phase Inverters with Unbalanced and Nonlinear Loads

Abstract

Focusing on three-phase inverter control with unbalanced and nonlinear loads in islanded microgrids， an inverter control method including fundamental voltage tracking， harmonic voltage suppression， active damping and output current limiting is proposed. A transfer function model for the inverter operation system is established， and the influence of main hardware circuit and control system parameters on the system stability is analyzed. Simulations and experiments verify the accuracy of the system transfer function model， indicating that the proposed inverter control method can ensure the voltage quality on the inverter side under unbalanced and nonlinear load conditions and achieve current-limiting operation under unbalanced overload conditions with excellent dynamic response characteristics.

Keywords

• microgrid
• three-phase inverter
• unbalanced and nonlinear loads
• voltage control