Abstract: When an inverter or a coil set of one system in a motor drive apparatus having two systems fails, a power supply relay of a failing system interrupts power supply and a control circuit gradually reduces a current supply limitation value of a normal system to zero. Then when a steering torque becomes greater than a predetermined threshold value, the control circuit increases the current supply limitation value by a predetermined amount. By reducing the current supply limitation value to zero once and then gradually increasing the current supply limitation value to generate steering assist torque, a driver will be caused to sense changes in the steering torque and surely notice occurrence of failure.

Abstract: When an inverter or a coil set of one system fails in a motor drive apparatus having two power supply systems, a power supply relay of a failing system is turned off. In this case, while a travel speed detection value is less than a predetermined threshold value, current supply to a motor by the other system operating normally is stopped to thereby stop driving of the motor and generate no steering assist torque. Thus, a driver will be caused to surely notice occurrence of failure.

Abstract: A power conversion device includes a first inverter circuit and a second inverter circuit, a capacitor, and a microcomputer. The microcomputer switches a control operation, according to the steering state of a steering wheel, between a first state where a first duty center value is shifted to be lower than an output center value and a second duty center value is shifted to be higher than the output center value, and a second state where the first duty center value is shifted to be higher than the output center value and the second duty center value is shifted to be lower than the output center value. This can reduce a difference in heat loss between FETs while reducing the ripple current of the capacitor.

Abstract: A shaft is adapted to be inserted through a circuit apparatus without a need for disassembling a shaft side sensor device from an end part of the shaft to place the shaft side sensor device in an opposed relationship to a circuit board side sensor device at a location adjacent to the circuit board side sensor device. The shaft side sensor device forms a sensor apparatus in cooperation with the circuit board side sensor device to sense a rotational angle of the rotor.

Abstract: An input gear rotates integrally with an input shaft, and an output gear rotates integrally with an output shaft. Pinion gears are rotatably supported by pinion gear shaft members, respectively, and are meshed with both of the input gear and the output gear. An inner end part of each pinion gear shaft member is fitted to an inner peripheral wall of a corresponding primary hole of an inner ring member, and an outer end part of each pinion gear shaft member is fitted to an inner peripheral wall of a corresponding secondary hole of an outer ring member.

Abstract: A voltage application unit applies voltage to windings of a motor without passing though an inverter unit. A first detection unit detects a short circuit failure in switching elements of the inverter unit based on a terminal voltage between each of the switching elements and a corresponding winding and a power voltage of a power supply. Before rotation of the motor, when no short circuit failure is detected and when a switching unit switches at least one of the high and low potential-side switching elements of the inverter unit on and subsequently switches all the switching elements off, a second failure detection unit determines whether the switching unit is incapable of rendering the switching element non-conductive based on the terminal voltage and the power voltage.

Abstract: A power conversion device includes a first inverter circuit and a second inverter circuit, a capacitor, and a microcomputer. The microcomputer switches a control operation, according to the steering state of a steering wheel, between a first state where a first duty center value is shifted to be lower than an output center value and a second duty center value is shifted to be higher than the output center value, and a second state where the first duty center value is shifted to be higher than the output center value and the second duty center value is shifted to be lower than the output center value. This can reduce a difference in heat loss between FETs while reducing the ripple current of the capacitor.

Abstract: In a torque sensor, a torque signal and a monitoring signal have values between a first lower limit and a first upper limit. A limiting section changes the torque signal to a second lower limit when the torque signal is equal to or less than the second lower limit that is greater than the first lower limit, and changes the torque signal to a second upper limit when the torque signal is equal to or greater than the second upper limit that is less than the first upper limit. When abnormality has occurred in the torque signal, an output section transmits a first fault notification signal that is a value between the first and second lower limits or a second fault notification signal that is a value between the first and second upper limits.

Abstract: A rotation angle detection device uses a control unit to acquire output signals Vx1, Vx2, Vy1, Vy2 that are from four half-bridges, from the four half-bridges. The control unit calculates a rotation angle ? of a detection target based on the acquired output signals Vx1, Vx2, Vy1, Vy2. The control unit checks whether a mean value fixation abnormality is caused to any one of the four output signals Vx1, Vx2, Vy1, Vy2, based on calculation values C1 or C4 that are derived/yielded from the four output signals Vx1, Vx2, Vy1, Vy2. The mean value fixation abnormality caused to the output signals Vx1, Vx2, Vy1, Vy2 that yielded the calculation values C1 and C4 is appropriately determined.

Abstract: A bridge circuit includes a plurality of half-bridges formed of sensor elements, which change impedance in accordance with a rotation angle of a detection target. A control circuit acquires output signals of the half-bridges and calculates a phase correction value for correcting a phase deviation. A memory circuit stores the phase correction value. The control circuit corrects a pre-correction rotation angle by the phase correction value. Since the pre-correction rotation angle is corrected by the phase correction value, a rotation angle of the detection target is detected with high accuracy even if the sensor elements are assembled with some positional deviations.

Abstract: When an inverter or a coil set of one system fails in a motor drive apparatus having two power supply systems, a power supply relay of a failing system is turned off. In this case, while a travel speed detection value is less than a predetermined threshold value, current supply to a motor by the other system operating normally is stopped to thereby stop driving of the motor and generate no steering assist torque. Thus, a driver will be caused to surely notice occurrence of failure.

Abstract: When an inverter or a coil set of one system in a motor drive apparatus having two systems fails, a power supply relay of a failing system interrupts power supply and a control circuit gradually reduces a current supply limitation value of a normal system to zero. Then when a steering torque becomes greater than a predetermined threshold value, the control circuit increases the current supply limitation value by a predetermined amount. By reducing the current supply limitation value to zero once and then gradually increasing the current supply limitation value to generate steering assist torque, a driver will be caused to sense changes in the steering torque and surely notice occurrence of failure.

Abstract: When failure of an inverter or a coil set of one system of a motor drive apparatus having two systems, is detected, a power supply relay of the failing system is interrupted. At the same time, a control circuit sets a same maximum current limitation value as set before detection of failure. When an IG switch is in an ON-state and a steering toque detection value exceeds a predetermined threshold value thereafter, a vibration component, which has a predetermined amplitude and frequency, is added to a current command value so that a steering wheel is vibrated in a direction of rotation so that a driver is cautioned to notice the failure surely.

Abstract: A motor drive apparatus has a plurality of motor drive parts and a control unit. The control unit performs first and second failure detection processing for the motor drive parts before starting to drive the motor. If the first motor drive part is determined to have failure by the first failure detection processing, a first power supply relay for the first motor drive part is turned off and the second failure detection processing for the first motor drive part is inhibited. If the second motor drive part is determined to have no failure by the first failure detection processing and then by the second failure detection processing, the motor is started to operate.

Abstract: A motor drive apparatus drives a motor by a first motor drive part and a second motor drive part. The first motor drive part includes a first inverter for supplying current to a first winding set. The second motor drive part includes a second inverter for supplying current to a second winding set. A control unit starts to supply currents to the first winding set and the second winding set at the same time after waiting for completion of all failure detection processing with respect to each of the first motor drive part and the second motor drive part.

Abstract: In a motor drive apparatus having two power supply systems for a motor, output phase currents supplied from inverters and detected by current sensors are added. Sums of the phase currents are fed back to a 3-2 phase conversion section and converted into a d-axis current and a q-axis current. A 2-3 phase conversion section outputs the same three-phase voltage command values to the inverters. Thus, the 3-2 phase conversion section and the 2-3 phase conversion section are both reduced to 1 in number, which is less than 2 of the inverters.

Abstract: An electric power steering device includes: an electric power source for supplying first current; a controller for setting a current instruction value; multiple electric power converters for converting the first current to second current corresponding to the current instruction value; multiple pairs of windings for generating a driving force of a motor; and a failure detection element for detecting failure of the electric power converters and the windings. The controller reduces the current instruction value to be equal to or smaller than a predetermined instruction value of a normal operation when the failure detection element detects the failure. The controller controls the electric power converter in a normal state to supply the second current to a corresponding winding.

Abstract: In a multi-system motor drive apparatus, a power supply relay is interrupted when a first power supply system fails at time t0. A power control unit doubles a current supplied to an inverter of a second power supply system thereby to supplement the electric power, which has been supplied by an inverter of the first power supply system. The total output of inverters is thus maintained before and after the failure. After an elapse of a predetermined period, the electric power supplied by the second power supply system is reduced gradually so that the inverter of the second power supply system will not be operated to supply the doubled power for a long period.

Abstract: A voltage application unit applies voltage to windings of a motor without passing though an inverter unit. A first detection unit detects a short circuit failure in switching elements of the inverter unit based on a terminal voltage between each of the switching elements and a corresponding winding and a power voltage of a power supply. Before rotation of the motor, when no short circuit failure is detected and when a switching unit switches at least one of the high and low potential-side switching elements of the inverter unit on and subsequently switches all the switching elements off, a second failure detection unit determines whether the switching unit is incapable of rendering the switching element non-conductive based on the terminal voltage and the power voltage.

Abstract: Bridge circuits have half bridges formed of sensor elements, which vary respective impedances in accordance with a rotating magnetic field generated by a rotary object. A control unit acquires output signals produced from intermediate points of the half bridges, and calculates a rotation angle of the rotary object based on the output signals. The control unit determines that the output signal is abnormal, if a calculation value of the output signal calculated based on at least four output signals is outside a predetermined range. The control unit thus determines which one of the output signals has become abnormal due to failure or the like.