Test-Bed of Doubly Fed Induction Generator for Variable-Speed Constant-Frequency Wind Power Generation

In this paper, a test-bed built for the experiments of variable-speed constant-frequency (VSCF) wind power generation is described. The test-bed is composed of a doubly fed induction generator (DFIG), a VVVF inverter driven squirrel motor for wind turbine simulation, dual-DSP-based controllers, as well as a PC-based data-acquisition and control system. In this system, a pair of bidirectional PWM voltage-source converters in a back-to-back configuration is inserted between the rotor windings and the grid lines to control the rotor currents in order to vary the slip power thereby implementing the VSCF operation. Vector-control is used to independently control the flow of active and reactive power between the system and grid line, and to make it easy for the system to implement maximal power point tracking (MPPT) and optimal reactive power splitting in wind power plants