초록 ▼

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

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.

대표청구항 ▼

What is claimed is: 1. A power system with low-voltage ride-through capability comprising: a primary source of power; a generator that converts power from said primary source of power into electrical power; an inverter that conditions at least a portion of said electrical power to voltage and curre

What is claimed is: 1. A power system with low-voltage ride-through capability comprising: a primary source of power; a generator that converts power from said primary source of power into electrical power; an inverter that conditions at least a portion of said electrical power to voltage and current at a frequency and phase angle appropriate for transmission to an AC utility grid having multiple phases; a sensor that detects the voltage frequency and phase angle on one phase of said utility grid during a fault condition on said grid; and, a control system for said inverter that controls said inverter to synthesize current waveform templates for phases of said AC utility grid based on said detected voltage frequency and phase angle of said one phase, thereby providing current to said grid at a frequency and phase angle that are based on said detected voltage frequency and phase angle to thereby utilize said current waveform templates to deliver electrical current to said phases of said AC utility grid during said fault condition. 2. The power system of claim 1 wherein said generator is a synchronous generator and the power system further comprises a rectifier for converting AC power from said generator into DC power. 3. The power system of claim 1 wherein said power system is a wind turbine and wherein said primary source of power is a power in the wind and further comprising a wind turbine rotor for converting power in the wind into rotational power. 4. The power system of claim 1 wherein said utility grid is a multi-phase system and wherein said sensor detects the frequency and phase angle of the voltage on one phase of said multi-phase utility grid during a fault on said grid. 5. The power system of claim 1 wherein said sensor monitors several phases of a multi-phase utility grid and selects one phase on which to detect the frequency and phase angle of the voltage. 6. The power system of claim 1 wherein said control system controls said inverter to provide current to said grid at substantially the same magnitude as provided immediately before said fault on said grid. 7. The power system of claim 1 wherein said control system is implemented in hardware as an analog circuit. 8. The power system of claim 1 wherein said control system is a phase-locked loop. 9. The power system of claim 1 wherein said control system is implemented through software on a microprocessor. 10. The power system of claim 1 wherein said generator is connected to said utility grid at a distribution level voltage. 11. The power system of claim 1 wherein said power system is one of a plurality of power systems wherein said plurality of power systems are connected to said utility grid through a common substation. 12. The power system of claim 1 wherein said power system is one of a plurality of power systems wherein said plurality of power systems are connected to said utility grid at a sub-transmission level voltage. 13. The power system of claim 1 wherein said power system is one of a plurality of power systems wherein said plurality of power systems are connected to said utility grid at a transmission level voltage. 14. A power system including: a primary source of power; a generator that converts power from said primary source of power into electrical power; an inverter that conditions at least a portion of said electrical power to voltage and current at a frequency and phase angle appropriate for transmission to an AC utility grid; a sensor that detects the frequency and phase angle of the voltage on one phase of said utility grid during a fault on said grid, an output of said sensor being sensed line voltage ; and a control circuit for said inverter that controls said inverter to provide current to said grid at a frequency and phase angle that are based on said detected voltage frequency and phase angle; said control circuit comprising: a corrective signal of a phase-locked loop; a multiplier connected to said sensor and to said corrective signal, an output signal of said multiplier being said sensed line voltage multiplied by said corrective signal, said output signal further being a sinusoidal signal component with a DC offset related to a phase difference between said sensed line voltage and said corrective signal; a low pass filter connected to said output signal of said multiplier, an output of said low pass filter being a DC signal absent said sinusoidal signal component; a proportional-integral (P-I) regulator connected to said output of said low pass filter, said P-I regulator having a P-I regulator output; a summation circuit connected to said P-I regulator output; a triangle wave generator connected to an input of said summation circuit, a triangle wave generator output of said triangle wave generator being a steady AC triangle wave, a summation circuit output being a sum of said P-I regulator output and said triangle wave generator output; and, a cosine function circuit connected to said summation circuit output, an output of said cosine function circuit being said corrective signal. 15. The power system of claim 14 further comprising: a number of parallel phase shift circuits connected to said output of said summation circuit, one such phase shift circuit for each phase of said multi-phase utility grid; a number of trigonometric sine function circuits connected to said a number of parallel phase shift circuits, the output of each trigonometric sine function circuit being a fixed amplitude reference sinusoidal wave at a frequency appropriate for the utility grid frequency and substantially in phase with said utility grid; a DC value circuit having a DC output which corresponds to a desired AC output current level; and, a number of scaling multiplier circuits connected to said number of trigonometric sine function circuits and to said DC value output, outputs of said scaling circuits being scaled sinusoidal signals for each phase. 16. The power system of claim 14 wherein said P-I regulator is set to control dynamics of the inverter control circuit response. 17. The power system of claim 15 wherein said DC value circuit is set by a turbine controller to set said AC current level proportional to generator torque level. 18. The power system of claim 15 wherein said P-I output signal is scaled such that by adding it to said triangle wave output said corrective signal is phase shifted to bring it closer to ninety degrees out of phase with said control system input.