Abstract: A wind turbine auxiliary power system configured to receive electrical power from an electrical power generating system of the wind turbine or from a power grid. The auxiliary power system includes an auxiliary transformer having a primary side configured to be coupled to the electrical power generating system of the wind turbine and a secondary side configured to be coupled to auxiliary power consumers of the wind turbine and to provide transformed electrical power to the consumers. It further includes an electronic on-load tap changer provided on the auxiliary transformer, wherein the electronic on-load tap changer includes taps on at least one transformer winding of the auxiliary transformer and semiconductor switches that are coupled to the taps and that are configured such that by controlling the semiconductor switches, the transformation ratio of the auxiliary transformer is adjustable to compensate for voltage variations on the primary side of the auxiliary transformer.

Abstract: An electrical power system of a wind turbine is provided. A power converter of the wind turbine is configured to convert electrical power generated by an electrical generator of the wind turbine and to provide the converted electrical power to a power grid. The electrical power system includes an inductor unit coupled between a grid side converter section of the power converter and the power grid. Electrical power provided by the power converter towards the power grid causes a voltage drop across the inductor unit. The power system further includes an inductance adjustment unit coupled to the inductor unit. The inductance adjustment unit is configured to adjust an inductance value of the inductor unit to thereby adjust the voltage drop across the inductor unit.

Abstract: A method of controlling a wind turbine transformer is provided. The transformer has a primary side with a primary winding coupled to a power grid and a secondary side with a secondary winding coupled to an electrical power generating system of the wind turbine. The wind turbine transformer further includes an electronic on-load tap changer having semiconductor switches that are controllable to change a turns ratio of the primary winding to the secondary winding of the wind turbine transformer. The method includes the step of monitoring a voltage on the primary side of the wind turbine transformer, a voltage on the secondary side of the wind turbine transformer, or both. In response to detecting a change in the monitored voltage, the semiconductor switches of the electronic on-load tap changer are automatically controlled to adjust the turns ratio of the wind turbine transformer to compensate for the change.