Abstract: A system and method for providing constant-frequency electrical power from variable-speed mechanical power are disclosed. The system includes a wound-rotor induction machine generator (WRIMG), a first power converter, e.g., an inverter or a bridge rectifier, that provides power from the stator assembly of the WRIMG to the load, and a second power converter, e.g., an inverter or a bridge rectifier, that provides power from the rotor assembly of the WRIMG to the load. A controller controls the output stator-current based on comparisons between measured DC load bus data and a reference DC load bus voltage value, measured machine shaft angular position and reference rotor frequency data, and measured stator-current data that is fed-back to the stator-current controller by the power converter device(s).

Abstract: A device, a system, and a method for preventing power-producing wind turbine generators from tripping due to the detection of a low-voltage condition on a power grid are disclosed. The disclosed device includes a resistor bank that absorbs real power and a control system that maintains the collector bus voltage above a threshold voltage level during the duration of low-voltage condition on the power grid. Collector bus voltage is maintained using gating signals that include phase delay angles to adjust the opening/closing of the switching devices.