Patent ID: 8198841

Claim:
A method of controlling a motor/generator unit (MGU) comprising: receiving a position signal from a resolver that is electrically connected to a rotor of the MGU, wherein the position signal describes a measured angular position of the rotor; determining the presence of a resolver fault using the value of the received position signal; calculating an estimated position of the rotor when the presence of the resolver fault is determined; determining a duration of the resolver fault; setting a predetermined resolver fault state determined using the duration of the resolver fault; and controlling the MGU using the estimated position of the rotor for at least a portion of the duration of the resolver fault state, including: sustaining a level of torque output of the MGU when the duration of the resolver fault is less than a threshold duration; and reducing the level of torque output of the MGU when the duration of the resolver fault is greater than the threshold duration.