Patent ID: 9391554
Filing Date: 2016-07-12
CPC Classification: H02P

Claim Text:
1. A method for direct-current control of a permanent magnet synchronous generator (PMSG) wind turbine comprising: receiving, by a speed-loop controller, a PMSG output power signal and a generator rotating speed signal, wherein the PMSG output power signal indicates current power being generated by the PMSG generator of the wind turbine and the generator rotating speed signal indicates current rotating speed of the PMSG generator; determining, by the speed-loop controller using a virtual lookup table, a speed reference signal from the PMSG output power signal; outputting, by the speed-loop controller, a torque reference depending on an error signal by comparing the speed reference signal and the generator rotating speed signal; estimating, by the speed-loop controller, a reference q-axis current signal, the reference q-axis current signal being in quadrature with a d-axis current signal; receiving by a d-axis current-loop controller, a reference d-axis current signal and a present d-axis current being generated by the PMSG generator of the wind turbine; receiving by a q-axis current-loop controller, the reference q-axis current signal and a present q-axis current being generated by the PMSG generator of the wind turbine; outputting, by the d-axis current-loop controller, a d-axis current regulating signal; outputting, by the q-axis current-loop controller, a q-axis current regulating signal; computing a d-axis reference voltage based on the d-axis current regulating signal and the q-axis current regulating signal; computing a q-axis reference voltage based on the d-axis current regulating signal and the q-axis current regulating signal; and controlling reactive power of the wind turbine using the q-axis reference voltage and controlling torque of the wind turbine using the d-axis reference voltage, wherein the wind turbine comprises the permanent magnet synchronous generator (PMSG) wind turbine.