An Enhanced Double Quasi-PR Controller for Grid-Side Inverter with Long Transmission Cable

This paper presents an enhanced double Quasi-PR controller to realize the passivity characteristic of output admittance in the whole frequency range from 0 Hz to Nyquist frequency. This passivity characteristic can be useful in the case of wind turbine generation system which grid-side inverter is connected to main grid with long transmission cable. To realize the passivity characteristic of output admittance, a constraint condition-based design method is proposed. Then, based on the proposed controller structure and design method, stability of grid-side inverter is promised regardless of grid impedance parameters. Finally, simulation results verify the accurateness and effectiveness of the proposed controller.