Abstract: A first inverter circuit and a second inverter circuit are provided for a first winding set and a second winding set of a motor, respectively, and switch over power supply to the winding sets. A control unit controls operations of the inverter circuits. The control unit detects abnormality in the inverter circuits. The control unit calculates a first value with respect to each drive system based on phase currents of the inverter circuit in each system, calculates a second value based on two values selected from a plurality of first values calculated for each drive system, and detects abnormality of the inverter circuits, which corresponds to the selected first value, when the second value deviates from a predetermined range.

Abstract: A power transducer failure detection device detects a failure on a power transducer, making a power transducer control device stop driving the power transducer. A first switching control device turns off a first power supply relay of a power supply source switching device and turns on a second power supply relay of the power supply source switching device. While the power transducer stops driving, a motor may rotate due to an external force to generate a regenerative voltage. The regenerative voltage is then regenerated in a battery through a route from the power transducer via the second power supply relay being turned on and a parasitic diode of the first power supply relay. This can protect elements such as switching elements and a smoothing capacitor of the power transducer against a regenerative voltage and prevent the elements from being destroyed or reducing the useful life due to overvoltage.

Abstract: There is provided a control apparatus that controls a motor of an electric power steering system to assist a steering effort of an operator. The control apparatus includes a sensor, a parameter computer, a difference computer, a target torque computer, and a motor driver. The parameter computer computes a current value of one of physical parameters of one of constituents of the electric power steering system based on a steering parameter determined by the sensor referring to an equation of motion. The difference computer computes a difference between the current value of the one of the physical parameters computed by the parameter computer and a predetermined value of the one of the physical parameters. The target torque computer computes a target torque of the motor which compensates for the difference between the current value and the predetermined value of the one of the physical parameters.

Abstract: There is provided a control apparatus that controls a motor of an electric power steering system to assist a steering effort of an operator. The control apparatus includes a sensor, a parameter computer, a difference computer, a target torque computer, and a motor driver. The parameter computer computes a current value of one of physical parameters of one of constituents of the electric power steering system based on a steering parameter determined by the sensor referring to an equation of motion. The difference computer computes a difference between the current value of the one of the physical parameters computed by the parameter computer and a predetermined value of the one of the physical parameters. The target torque computer computes a target torque of the motor which compensates for the difference between the current value and the predetermined value of the one of the physical parameters.

Abstract: A motor-assisted power steering apparatus includes a DC motor which is fixed to a heat conductive frame, a torque sensor for detecting steering torque and a control circuit for controlling current supplied to the motor. The control circuit includes a first unit disposed in a space defined by the frame and a commutator of the motor and a second unit disposed outside the motor. The first unit includes multiple switching elements connected to the motor, and the second unit includes a microprocessor for setting motor current, a current detecting unit for detecting current supplied to the motor, a current control unit for providing duty ratio signals and a gate driving circuit for driving the switching elements according to the duty ratio signals.