Abstract: A wind powered turbine with low voltage ride-through capability. An inverter is connected to the output of a turbine generator. The generator output is conditioned by the inverter resulting in an output voltage and current at a frequency and phase angle appropriate for transmission to a three-phase utility grid. A frequency and phase angle sensor is connected to the utility grid operative during a fault on the grid. A control system is connected to the sensor and to the inverter. The control system output is a current command signal enabling the inverter to put out a current waveform, which is of the same phase and frequency as detected by the sensor. The control system synthesizes current waveform templates for all three-phases based on a sensed voltage on one phase and transmits currents to all three-phases of the electrical system based on the synthesized current waveforms.

Abstract: A method and apparatus of stator voltage control for an induction generator. Each phase of the induction generator stator is connected through a secondary coil of a transformer to a utility grid. A stator voltage control circuit is connected in parallel with a primary coil of the transformer. The stator voltage control circuit consists of an on/off switch device connected to a full wave rectifier comprised of four silicon diodes. A single pulse width modulation (PWM) control is utilized to control the on/off switch devices of each phase of the induction generator stator.