Effects of System Parameters on the Steady-State Characteristics of a Wind Turbine Generator Based on Self-Excited Synchronous Generator for HVDC-Connected Wind Power Plants

A wind turbine generator based on self-excited synchronous generator (SESG) feeding a diode rectifier for high-voltage direct current (HVdc) connected offshore wind power plants has been proposed and an excitation system using a duplex reactor to obtain a sufficient operating range has been developed. In this paper, the effects of the system parameters such as short-circuit ratio of synchronous generator (SG) on the steady-state characteristics of the system are investigated. A simulation model considering magnetic saturation and residual flux of the SG is developed and the steady-state characteristics are calculated with the model. To confirm the validity of the simulation model, experimental investigations using a laboratory-scale system are carried out. Also, the effects of the short-circuit ratio of the SG on the operating range of the system with the duplex reactor, and it is shown that when the short-circuit ratio is too small, sufficient system operating range cannot be obtained. The effects of the parameters for the magnetic saturation and residual flux on the steady-state characteristics of the SESG-based wind generator system are discussed and its appropriate values of the tested system are studied.