A Grid-Connected Inverter with Virtual Synchronous Generator Model of Algebraic Type.

This paper presents experimental results on a grid-connected inverter. The control of the inverter is based on a virtual synchronous generator model of algebraic type. When using the virtual synchronous generator model of algebraic type, there is no evidence for satisfactory opera-tion with unbalanced load and nonlinear load, because the generator models are constructed under the assumption that the load is linear and balanced. By choosing the feedback control loop gain appropriately, satisfactory operation is achieved even if an unbalanced and nonlinear load is con-nected. Experimental results show that the power controls, active and reactive, are achieved preferably in grid-connect-ing mode. Smooth transitions are also achieved from the connected mode to the island mode. The inverter can oper-ate satisfactorily when the unbalanced load is connected. Harmonic analysis is performed with a three-phase full-wave rectifier connected as a nonlinear load. The harmonic current is supplied by the inverter and its output LC filter. It is shown that the harmonic current is supplied mainly by the inverter and that the voltage waveform is acceptable for practical use. [ABSTRACT FROM AUTHOR]