A steering apparatus and method for a vehicle. Steering controllers are connected via an internal communications network. Each of the steering controllers monitors the operating state of another steering controller using the internal communications network, so that, if one of the steering controllers currently controlling the steering motor operates abnormally, the steering motor is controlled by at least one steering controller of the remaining steering controllers.

A method of controlling an electric power assisted steering (EPS) system comprises the steps: During a first mode of operation of the EPS system driving a motor using two inverter bridges simultaneously, the nominal current that is applied to the motor at any time by each bridge being limited to a first value, and during a fault mode of operation driving the motor using only one of the two inverter bridges whereby the nominal current that is applied to the motor at any time in the fault mode is limited to a second value, the method varying the second value as a function of one or more operating parameters of the EPS system whereby the second value is set higher than the first value when it is deemed safe to do so.

A current sensor state determination device determines that an abnormality is caused in a current sensor when a sum of phase currents based on current detection values from each of the current sensors in three phases is greater than a first determination value, and determines that no abnormality is caused in the current sensor when the sum of phase currents is equal to or less than the first determination value. The state determination device determines that the current sensor is normal when it is determined that (i) no abnormality is caused in a preset electric angle range equal to or less than one electric-angle cycle of the rotating electric machine and (ii) a value of an electric current flowing in the rotating electric machine in a rotating coordinates system calculated based on the current detection value is equal to or greater than a second determination value.

An electric power conversion apparatus includes a first inverter electrically connected to one end of each of phase windings of a motor, and a second inverter electrically connected to the other end of each of the phase windings, and a neutral point potential setting circuit electrically connected to the first inverter to set a potential of a neutral point in the first inverter when the first inverter is determined to be in an abnormal state.

A motor control unit that vector-controls a 3-phase brushless motor based on a d-axis voltage command value and a q-axis voltage command value via an inverter with feedback-controlling, comprises: a central processing unit which comprises: a dq-axes dead time compensating section to calculate dq-axes dead time compensation values of the inverter and perform a dead time compensation; and a dq-axes disturbance estimating observer to input a d-axis current command value, a q-axis current command value, a motor rotational number, a motor angular velocity, a d-axis feedback current, a q-axis feedback current, the d-axis voltage command value and the q-axis voltage command value and calculate a d-axis disturbance compensation value and a q-axis disturbance compensation value, which cannot be compensated by the dead time compensation, by respectively adding the d-axis disturbance compensation value and the q-axis disturbance compensation value to the d-axis voltage command value and the q-axis voltage command value.

An aspect of a drive controller controls drive of a three-phase motor, and includes an imbalance calculation unit that calculates an electrical imbalance between phases in the three-phase motor, a control value calculation unit that calculates current control values in respective axial directions of a rotating coordinate system of the three-phase motor according to a given target, and a balance compensation unit that reduces the imbalance by adding a compensation value to a current control value in an axial direction other than a q-axis of the current control values calculated by the control value calculation unit.

A first microcomputer is configured to identify the cause (a content of the abnormality) of a communication abnormality based on a combination of whether communication through a first communication line is established, whether communication through a second communication line is established, and whether a second clock is normal. Specifically, the first microcomputer separately determines whether the communication abnormality between the first microcomputer and a second microcomputer is simply due to an abnormality in the first communication line and the second communication line, or due to stop of a function of the second microcomputer. The second microcomputer is configured to identify the cause of the communication abnormality based on a combination of whether the communication through the first communication line is established, whether the communication through the second communication line is established, and whether a first clock is normal.

A steering control device configured to control a steering device includes a control unit. The control unit is configured to calculate a torque command value which is a target value of the motor torque based on execution of angle control for adjusting a convertible angle which is able to be converted to a rotation angle of the motor to a target angle; calculate the motor control signal based on the torque command value; and change a control gain which is used for the angle control based on a change of a factor influencing a behavior of a vehicle in response to steering.

A system for controlling an electrical current flowing between a power source and a multi-phase electromagnetic machine includes a first lane, A, comprising a first plurality of phases capable of providing said current from said power source to said machine, and further comprises a second lane, B, comprising a second plurality of phases capable of providing said current to said machine. The system is configured to provide said current via said first lane, A, while no current is being provided via said second lane, B. Each of said first plurality of phases comprises at least one inverter switch positioned between said power source and said machine. The system further includes means for detecting a fault in one of the first plurality of inverter switches of lane A, and further comprises a first phase isolation means provided on said first lane, A.

An active fault tolerance and fault mitigation system based on steer-by-wire dual motors and a mode switching control method thereof are provided. The system includes an acquisition unit, a steering wheel assembly, an ECU control module, a front wheel steering assembly, and a fault tolerance controller (18) which are sequentially connected. The acquisition unit transmits an acquired vehicle signal to the ECU control module, and then a corresponding compensation strategy is selected by means of a fault tolerance control strategy unit, a yaw rate calculation unit, a stability control unit, and a dual-motor compensation unit to act on a rack and pinion mechanism (15). The system and method can perform switching in an active fault tolerance and fault mitigation mode to achieve optimal control of the real-time performance of a vehicle, thereby ensuring the driving performance and higher performance of the vehicle in a field fault condition.