A motor control unit which drives a motor through an inverter based on a calculated command value of a control section to which a power supply voltage is supplied, including: a charging/discharging mechanism for charging and discharging electric charges of an inverter voltage supplied to the inverter; and a separation means for separating the charging/discharging mechanism from the power supply voltage, wherein when a warning signal informing of a drop in the power supply voltage is inputted, the charging/discharging mechanism is separated from the power supply voltage by the separation means as well as a voltage is applied to the control section from the charging/discharging mechanism to avoid power supply reset of the control section. The motor may be a motor with multi-system windings.

Electric power steering systems and a method for controlling an electric power steering system are provided. The method, for example, includes, but is not limited to, determining, by a controller, a speed of a vehicle based upon data from a sensor, and adjusting, by the controller, a stiffness of an isolator in an electric power steering system via at least one piezoelectric device embedded in the isolator based upon the determined speed of the vehicle.

A method for supplying power to an electrically assisted steering system is described. In one example, the method adjusts alternator field current to increase energy supplied to the electrically assisted steering system in response to an automatic engine stop request. The method may improve operation of the electrically assisted steering system.

An extensible actuator includes a motor, a rod, a conversion unit and an electromagnetic braking system. The motor generates rotating force. The rod freely reciprocates in an axial direction. The conversion mechanism converts the rotating force of the motor into a reciprocating motion of the rod. The electromagnetic braking system brakes the reciprocating motion of the rod.

To achieve a fail-safe fully utilizing the advantage of plural motors, a second controller performs a one-motor SBW mode when at least one of a first turning controller, a first turning motor and a torque sensor malfunctions in a state where the first turning controller and the second turning controller perform a two-motor SBW mode. Furthermore, the first controller performs a one-motor EPS mode when at least one of the second turning controller and the second turning motor malfunctions in the state where the first turning controller and the second turning controller perform a two-motor SBW mode.

A rotary electric machine control device for a rotary electric machine having winding sets with coils includes: an inverter for each winding set; a power source relay for each inverter; a terminal voltage detector detecting a terminal voltage of each coil; and a controller including an inverter controller, a relay controller and an abnormality determination unit. Each winding set and a corresponding inverter provides a system. When the rotary electric machine is driven using a normal system: the relay controller controls the power source relay to cut off power supply from a power source to the inverter in an abnormal system; the abnormality determination unit specifies a short-circuited location based on the terminal voltage in the abnormal system; and the inverter controller corrects a command value related to control of the inverter in the normal system according to a specified short-circuited location.

An electric power steering system is provided. The electric power steering system includes an electric motor (12), a battery (14) configured to provide power, and a motor drive circuit (18) configured to provide power from the battery (14) to the motor (12). The motor drive circuit (18) includes a set of branches (28a, 28b 28c), each including two transistors (30a, 30b; 30c 30d; 30e, 30f) configured to operate in a conducting or non-conducting state. The electric power steering system includes a phase isolation circuit (20) including a set of phase isolation branches (32a, 32b, 32c), the branches (32a, 32b, 32c) being coupled to the phase windings (26a, 26b, 26c) of the electric motor (12). A phase isolation branch (32a, 32b, 32c) includes a bidirectional TVS diode (36a, 36b, 36c) and a phase isolation transistor (34a, 34b, 34c), the phase isolation transistor (34a, 34b, 34c) being configured to operate in a conducting or non-conducting state. The electric power steering system includes a fault detector configured to detect a fault condition and switch the phase isolation transistors (34a, 34b, 34c) to the non-conducting state in response to detecting the fault condition.

A rotation limiting device including: a first member having a first protrusion; a second member having a second protrusion disposed on an axial one side with respect to the first protrusion, the second member being disposed coaxially with the first member and configured to rotate relative to the first member; and at least one intermediate member supported in a relatively rotatable manner with respect to the first member and the second member, the intermediate member including a side plate portion disposed between the first protrusion and the second protrusion in an axial direction, an intermediate side first protrusion protruding toward an axial other side from an axial other side surface of the side plate portion, and an intermediate side second protrusion protruding toward the axial one side from an axial one side surface of the side plate portion.

The present embodiments relate to a control device and method for an electric power steering (EPS) system, and an EPS system including the same. A control device according to an embodiment may include a steering controller configured to control a rotation of a motor linked to a steering wheel, and a wake-up circuit configured to, in an ignition-off state of a vehicle, wake up the steering controller using back electromotive force generated in the case of a forced rotation of the motor by an external force, wherein the steering controller may apply a reaction torque to the motor to suppress the forced rotation of the motor after waking up.

A steering device according to the present invention includes: a steering input device including a reaction force actuator that applies a steering reaction force to a steering operation input member; and a control device including a steering gear ratio change unit that changes a steering gear ratio in accordance with a vehicle speed, a reaction force actuator control unit that controls an output amount of the reaction force actuator in accordance with an operation angular velocity of the steering operation input member, and a reaction force actuator output amount change unit that changes, based on the steering gear ratio, the output amount of the reaction force actuator. This makes it possible to set an appropriate steering reaction force applied to the steering operation input member, thereby stably reducing the operational burden on a driver.