Method for determining of the velocity of an electric motor

An electric power steering system (12) of a vehicle includes a controller (14) for controlling an electric motor (10) connected to a steering column or other steering mechanism. The velocity of the motor (10) must be determined to maintain the proper current to the motor (10). A method of estimating the velocity includes obtaining a first and second velocity signals from one or more sensors (16) monitoring the motor (10). The first and second signals have different characteristics, e.g., the first signal may have a higher resolution than the second signal. An acceleration (or deceleration) of the velocity of the electric motor (10) is computed based on the different representations of the velocity supplied by the different signals. An estimate of the velocity of the motor (10) is then determined based on a switching decision based on the acceleration/deceleration based on the decision criteria, the output is switched between, or composed from a combination of the different representations of the velocity. The electric current provided to the electric motor (10) is then adjusted based on the estimated velocity to meet the desired output of the motor (10) (i.e., torque and/or velocity).