Study on excitation control of VSCF doubly fed wind power generator

The control of variable speed constant frequency (VSCF) for a wind power generation system is implemented by controlling the frequency, amplitude, phase angle and sequence of the rotor winding currents of the doubly fed machine. In this paper, an excitation control experimental system based on the 80C196MC single-chip-computer for the VSCF doubly fed machine is introduced. Based on the analysis of operation principle and excitation control method of the doubly fed machine, some control techniques, such as the constant frequency and constant voltage control for variable speed operation, connecting operation of the generator to the electric mains, switching control between the subsynchronous speed, synchronous speed and supersynchronous speed operation modes etc., are studied experimentally. The study establishes the foundation for the control system design and implementation of the VSCF wind power generator with rated power of 1 MW.