A power relay unit includes a high potential side relay connected so that an anode of a parasitic diode is on a high potential side and a cathode is on a low potential side, and a low potential side relay connected in series with a low potential side of the high potential side relay so that a cathode of a parasitic diode is on a high potential side and an anode is on a low potential side. A relay-to-relay connection line connects an intermediate point between the first high potential side relay and the first low potential side relay and an intermediate point between the second high potential side relay and the second low potential side relay. A control unit controls an on/off operation of the first high potential side relay based on a first supply voltage, a second supply voltage, and a relay intermediate voltage.

A motor control method includes acquiring n-phase currents, where n is an integer of three or more, of a first inverter, a GND current of the first inverter, n-phase currents of a second inverter, and a GND current of the second inverter, generating a first fault signal indicating presence or absence of a shunt resistor fault in the first inverter based on the n-phase currents and GND current of the first inverter and generating a second fault signal indicating presence or absence of a shunt resistor fault in the second inverter based on the n-phase currents and GND current of the second inverter, referring to a table representing a relationship between a set of levels of the first fault signal and the second fault signal and control modes and selecting one of the control modes, and controlling a motor in accordance with the selected control mode.

An auxiliary power supply apparatus is disposed on a power supply path from a main power supply apparatus to an electric power steering apparatus. The auxiliary power supply apparatus includes an auxiliary power supply that is a rechargeable power storage device, an on-off switch that is configured to selectively disconnect or connect the electric power steering apparatus and the auxiliary power supply from or to the main power supply apparatus, and an operation unit that is configured to operate the on-off switch. The operation unit is configured to switch the on-off switch from an ON state to an OFF state on a condition that a voltage supplied to the auxiliary power supply apparatus from the main power supply apparatus is less than or equal to a specified voltage reduction determination value and a vehicle speed is greater than a specified low vehicle speed determination value.

A method for diagnosing a functionality having an input or output signal with discrete values or discrete classes of values which are observable quantities of a diagnosis functionality. The signal to be diagnosed is the input or output signal, where the values or classes of values have a cardinality N, where N error counters are provided. The method includes providing a sum signal from the sum of the signals of the error counters. When a value or a class of values is erroneous, the method includes incrementing the signal of the error counter assigned to the erroneous value or the erroneous class. When the value or the class is correct, the method includes decrementing the signal of the error counter assigned to the value or the class and when the sum signal exceeds a pre-established limit value, the method includes outputting an error message of the functionality.

Methods and systems for providing rotary position sensor information. One system includes an electronic processor configured to receive a first set of signals from a first bridge circuit of a rotary position sensor and receive a second set of signals from a second bridge circuit of the rotary position sensor. In response to the receipt of the first set of signals from the first bridge circuit stopping, the electronic processor is also configured to identify a fault associated with the first bridge circuit. The electronic processor is also configured to receive a pulse signal and determine a rotary angle based on the pulse signal and the second set of signals from the second bridge circuit. The electronic processor is configured to generate an output torque value based on the rotary angle for controlling a motor.

Systems and methods for controlling an electric power steering system. The system includes an electric motor configured to provide a torque to a steering mechanism of a vehicle, a torsion bar torque sensor, a vehicle speed sensor, and a steering angle sensor. The system also includes an electronic controller configured to determine a failure of the torsion bar torque sensor, receive a vehicle speed from the vehicle speed sensor and a steering angle from the steering angle sensor, calculate a steering assistance torque based on the vehicle speed and the steering angle, calculate a hysteresis torque based on the steering angle, sum the steering assistance torque and the hysteresis torque to determine a turning torque, calculate a return torque and sum the turning torque and return torque to obtain an output torque, and generate a command for the electric motor to provide the output torque to the steering mechanism.

An automatic steering system comprises a controller. The controller executes target steering angle calculation processing. The controller further calculates a learning value of lateral acceleration. The learning value is calculated based on an error of a detected value of the lateral acceleration by an acceleration sensor and an estimation value of the lateral acceleration calculated using driving speed and yaw rate. In the target steering angle calculation processing, it is judged whether the acceleration sensor is normal. If it is judged that the acceleration sensor is normal, a target steering angle is calculated by using the detected value. Otherwise, the lateral acceleration used to calculate the target steering angle is switched from the detected value to a backup value of the lateral acceleration. The backup value is calculated using the estimation value and the learning value calculated before a timing at which the acceleration sensor is judged to be abnormal.

A controller for a motor includes a first processing circuit and a second processing circuit configured to communicate with each other. The first processing circuit is configured to execute a first operation amount calculation process, an operation process, and an output process. The first operation amount calculation process is a process of calculating a first operation amount. The output process is a process of outputting the first operation amount to the second processing circuit. The second processing circuit is configured to execute a second operation amount calculation process, a first use operation process, a second use operation process, and an elimination process.

With an object of allowing steering wheel operation to be carried out easily at a normal time and when an abnormality occurs, the invention includes a motor having two windings and a control unit having two control systems that supply control signals to each winding of the motor, and when an abnormality occurs in one winding of the motor or in one system inside the control unit, a supply of current to the winding in which the abnormality has occurred is cut to zero, and the motor is driven by a predetermined current necessary at a normal time being supplied to the other winding, while at a time of a normal drive when no abnormality has occurred, the current supply is shared between the two windings, whereby the motor is driven.

A detection signal correction method includes: calculating a rotation angle of a rotation shaft of a motor, based on a detection signal of a sensor; calculating a steering velocity of a steering shaft based on the rotation angle; calculating an error of the detection signal; and correcting the error of the detection signals when the steering velocity is equal to or greater than a steering velocity threshold value and the error of the detection signal is equal to or greater than an error threshold value.