Patent ID: 8237385

Claim:
A system for determining a commutation state for a brushless DC motor, the system comprising: a controller configured to control current that is applied to drive each of a plurality of phases of the motor; a time delay system configured to measure, for a given commutation state, a time delay from when a voltage associated with a driven phase of the plurality of phases crosses a predetermined threshold and a voltage associated with a floating phase of the plurality of motor phases crosses the predetermined threshold; and logic configured to determine the commutation state for the motor based on the measured time delay, wherein the time delay system provides a plurality of time delay measurements corresponding to the measured time delay for the given commutation state, and wherein, after the motor has begun moving, the logic is programmed to determine a next commutation state in a predefined commutation sequence based on detecting a characteristic change in the plurality of the time delay measurements for a current commutation state.