A power conversion device includes a first inverter and a control circuit that controls an on/off operations of switches in the first inverter and diagnoses disconnection failures of n-phase windings, where n is an integer of three or more. The control circuit generates a control signal to turn off all of n low-side switches and n high-side switches, supplies the control signal to the n low-side switches and the n high-side switches and measures the n-phase voltages that change depending on patterns of on failures of the switches, and executes a first failure diagnosis to diagnose the on failures of the n low-side switches and the n high-side switches based on the measured n-phase voltages by referring to a table associating the patterns of the on failures of the switches with n-phase voltage levels.

A motor control device is provided with a plurality of power converters and a plurality of microcomputers, and controls driving of a motor that has a plurality of sets of windings. The microcomputers perform initial check of components in respective circuits after activation. The microcomputers prohibit driving of the motor by a circuit determined to be abnormal during the initial inspection. When two or more circuits are determined to be normal in the initial check, the microcomputers start driving of the motor by synchronizing the timing between the two or more circuits determined to be normal. When only one circuit is determined to be normal in the initial check, the microcomputers start driving of the motor by the one circuit determined to be normal.

An electric power-steering control device has a substrate, a heat-generating component, and a heat-storing body. The heat-generating component is disposed on one surface of the substrate and generates heat when activated. The heat-storing body is capable of storing the heat from the heat-generating components. The heat-storing body has a main body having a rectangular plate shape and disposed on the one surface of the substrate. The heat-storing body has a notch section or a recess section.

According to this invention, provided is an electric power steering device, including: a motor having a winding; and a control unit configured to control the motor, the motor and the control unit being integrated with each other in alignment with each other in an axial direction of a rotary shaft of the motor. The winding of the motor includes a winding end portion configured to receive a current supplied thereto. The control unit includes: a current supply circuit, which includes a supply terminal, and is configured to supply the current to the winding end portion; an extension member connected to the supply terminal; and a first connection portion at which the extension member and the winding end portion are connected to each other. The first connection portion is arranged on a radially outer side of the motor with respect to the current supply circuit.

An actuator that applies force to a member associated with steering, and a control device that controls the actuator, have duplex configuration. First and second control devices compute the same controlled variable as first and second controlled variables, respectively. In a normal mode, the control device controls the actuator according to the first controlled variable. The first and second control devices send and receive respectively computed controlled variables to and from each other via communications. When a discrepancy arises between the first and second controlled variables, or an abnormality occurs in communications between the first and second control devices, the operating mode is switched from the normal mode to an independent mode. In the independent mode, the first and second control devices control the first and second actuators, according to the first and second controlled variables, respectively.

A motor control device controls energization of a motor by interchangeably converting a direct current electric power of a power source and an alternating current electric power of the motor with a power conversion circuit according to a power running operation and a regeneration operation of the motor. A voltage instruction value calculation unit calculates a q-axis voltage instruction value and a d-axis voltage instruction value by feedback control of dq-axis currents. A voltage instruction value limit unit limits at least one of the q-axis voltage instruction value and the d-axis voltage instruction value. The voltage instruction value limit unit performs a q-axis voltage limit prioritize process for limiting the q-axis voltage instruction value over the d-axis voltage instruction value, or a d-axis voltage limit prioritize process for limiting the d-axis voltage instruction value over the q-axis voltage instruction value, during the regenerative operation of the motor.

A steering apparatus includes a steering wheel, a support frame, a frame fixation part, and a steering transmission part. The support frame rotatably supports the steering wheel. The frame fixation part fixes the support frame to a vehicle body. The steering transmission part transmits a rotation of the steering wheel relative to the support frame to a steering mechanism of a wheel. The support frame and the frame fixation part are arranged at a position that does not overlap with a rotation center axis line of the steering wheel in a front view of the steering wheel.

Disclosed are a multifunctional electric recirculating ball steering system for commercial vehicles and a control method thereof, including: an electric power module, a mechanical transmission module and a control module; the electric power module includes: a dual-rotor motor module (14) and a power motor (22); the mechanical transmission module includes: a steering wheel (1), a steering shaft (4), couplings (5), a recirculating ball steering gear (16), a gear sector (19), a gear sector shaft (6), a steering drag link (7), a steering tie rod (12), a steering knuckle arm (8), a left tie rod arm (11), a right tie rod arm (26), a left steering knuckle (10), a right steering knuckle (25), a left wheel (9) and a right wheel (24); and the control module includes: an electronic control unit (21), torque sensors (3), a vehicle speed sensor (20), a steering angle sensor (2) and current sensors (23). The system ensures system reliability.

An electronic control unit is provided for an electric power steering system. The electric power steering system includes a housing and an electric motor, and the electronic control unit is arranged inside the housing with an electrical connection to the electric motor. The electronic control unit includes at least one power board and a heat sink. The at least one power board is attached to the heat sink. A heat sink edge of the heat sink includes a groove, into which at least a portion of the housing is crimped to secure the heat sink with the housing. The electric power steering system is also provided.

An electronic control unit is provided for an electric power steering system. The electric power steering system includes a housing and an electric motor. The electronic control unit is arranged inside the housing, and is electrically connected to the electric motor. The electronic control unit includes a first power board having a first electric motor connector for electric connection with the electric motor, and a second power board having a second electric motor connector for electric connection with the electric motor. The electronic control unit also includes a logic board logically connected with the first power board and the second power board. An electric power steering system is also provided.