Abstract: A drive system for a three phase brushless AC motor is arranged to optimize the transistor switching pattern to improve power output whilst allowing current measurement in all of the phases using a single sensor. This is achieved by defining voltage demand vectors x where more than two states are required to meet a minimum state time requirement determined by the single sensor method, and calculating three or more state vectors which produce the demanded vector x whilst still allowing single current sensing. Various methods of optimising the PWM pattern so as to give maximum output whilst using single current sensing are also disclosed.

Abstract: A method and system are provided for controlling an electric assist motor in a vehicle steering system during an enablement of an overuse algorithm. Electric power is provided to the electric assist motor of the vehicle steering system via a switching circuit. Temperature of one of at least electric assist motor and power driving circuitry that provides power to the electric assist motor is sensed. A determination is made whether the sensed temperature of the one of at least electric assist motor and power driving circuitry is increasing over a predetermined period of time. The electric power provided to electric assist motor is reduced in response to a lack of increase in said sensed temperature.

Abstract: A method and system are provided for controlling an electric assist motor in a vehicle steering system during an enablement of an overuse algorithm. Electric power is provided to the electric assist motor of the vehicle steering system via a switching circuit. Temperature of one of at least electric assist motor and power driving circuitry that provides power to the electric assist motor is sensed. A determination is made whether the sensed temperature of the one of at least electric assist motor and power driving circuitry is increasing over a predetermined period of time. The electric power provided to electric assist motor is reduced in response to a lack of increase in said sensed temperature.

Abstract: A drive system for a three phase brushless AC motor that is operative to optimize a transistor switching pattern to improve power output while allowing current measurement in all of the phases using a single sensor. This is achieved by defining a voltage demand vector where more than two states are required to meet a minimum state time requirement determined by the single sensor and calculating three or more state vectors that produce the demand vector while still allowing single current sensing.

Abstract: An electrically assisted power steering system includes an anti-theft feature. Upon detection of an event that is indicative of a vehicle theft situation, the drive circuit for the electric assist motor is selectively actuated to excite the motor windings to either prevent or oppose movement of the steering system.

Abstract: A method and apparatus for determining a motor fault in an electric motor (50) determines a calculated rotor position (&thgr;calc) of the electric motor. The calculated rotor position (&thgr;calc) is compared to a measured rotor position (&thgr;meas) of the electric motor (50) to determine a rotor position error (&thgr;err). A motor fault in the electric motor (50) is determined when the rotor position error (&thgr;err) exceeds a predetermined maximum rotor position error (&thgr;err—max).

Abstract: A method of controlling the bandwidth of electromagnetic interference generated by a pulse modulation controlled automotive motor is disclosed. The method comprises providing a controller including at least one register thereof; the controller in signal communication with the motor for controlling the motor based upon operating parameters thereof; selecting a first pulse modulation frequency from a set of pulse modulation frequencies; selecting a first clock frequency; selecting a first hopping frequency; selecting a first switching frequency; initializing the at least one register, establishing thereby a prescribed at least one number; based upon the prescribed at least one number of the at least one register, the first clock frequency and the first hopping frequency randomly changing the switching frequency of the pulse modulation.

Abstract: A method and apparatus for determining a motor fault in an electric motor (50) determines a calculated rotor position (&thgr;calc) of the electric motor. The calculated rotor position (&thgr;calc) is compared to a measured rotor position (&thgr;meas) of the electric motor (50) to determine a rotor position error (&thgr;err). A motor fault in the electric motor (50) is determined when the rotor position error (&thgr;err) exceeds a predetermined maximum rotor position error (&thgr;err—max).

Abstract: An apparatus and method are described for adjusting the modeled resistance used in the control of an electric motor drive to match the actual resistance of the motor. The system comprises sensors for measuring motor current and motor speed, which data is inputted into a processing unit. The processor uses the measured rotational speed to calculate what the proper current should be based upon the torque desired. If the calculated current is not equal to the measured current, then the modeled resistance of the motor is altered to correct the current. The invention is particularly useful for permanent magnet brushless motors operating in voltage mode.