Patent ID: 8035240

Claim:
A method of controlling a variable speed wind turbine generator, comprising: determining a generator rotor speed active control range and synchronous speed avoidance characteristics from system power semiconductor characteristics and a generator synchronous speed; determining a generator synchronous speed; determining a lower bound generator rotor speed value for the active control range based on operational junction temperature characteristics of power semiconductors used within a power converter associated with a doubly-fed induction generator, reliability characteristics of the power semiconductors and current ratings of the power semiconductors; determining an upper bound generator rotor speed value for the active control range based on operational junction temperature characteristics of power semiconductors used within a power converter associated with the doubly-fed induction generator, reliability characteristics of the power semiconductors and current ratings of the power semiconductors; accessing the determined generator rotor speed active control range and synchronous speed avoidance characteristics; comparing a current value of the generator rotor speed associated with the doubly-fed induction generator with the accessed determined rotor speed active control range; and controlling the generator rotor speed associated with the doubly-fed induction generator based on the determined active control range and synchronous speed avoidance characteristics.