A method for controller a multiphase electric machine includes, in response to a determination that a phase of the multiphase electric machine is in an open circuit condition, determining a desired torque to be generated by the multiphase electric machine and retrieving, based on the determination that the phase is in the open circuit condition and the desired torque, a set of current values to be applied to each of the other phases of the multiphase electric machine to achieve the desired torque. The method may also include applying respective current values of the set of current values to corresponding ones of the other phases of the multiphase electric machine, the set of current values being determined based on a model of the multiphase electric machine that includes the phase is in the open circuit condition.

The present invention relates to a drive control apparatus for an electric motor and a control method thereof. In the present invention, the generation of electric brake is suppressed while protecting a semiconductor relay from excessive surge voltage. The drive control apparatus is configured to include: a drive circuit for controlling the drive of the electric motor; a semiconductor relay arranged on a drive line between the drive circuit and the electric motor to cut off current supply from the drive circuit to the electric motor; and an active clamp circuit for turning on the semiconductor relay when a potential difference between the drive circuit side and the electric motor side of the semiconductor relay is greater than or equal to a predetermined value.

A method of controlling a motor of a power steering system is provided. The method generates a direct-axis voltage command and a quadrature-axis voltage command based on a current measurement signal received from the motor. The method transforms the direct-axis voltage command and the quadrature-axis voltage command into an alpha voltage command and a beta voltage command. The method determines an offset error in the phase current measurement based on the alpha and beta voltage commands.

In a motor control device that can perform more appropriate motor control, a switching arm has a first upper FET, a second upper FET, and a lower FET connected in series to one another. A source electrode of the second upper FET and a drain electrode of the lower FET are connected to each other via an intermediate line. The intermediate line is connected to a U-phase motor coil of a motor via a power line. The first upper FET, the second upper FET, and the lower FET are each provided with a parasitic diode that prevents current from flowing from a battery side to a ground side. A phase opening relay FET is provided on the U-phase power line. A parasitic diode of the phase opening relay FET is provided such that a current is not applied from the U-phase motor coil to the U-phase switching arm.

A power steering apparatus and a control circuit for a power steering apparatus are provided. The power steering apparatus detects an abnormality in the power steering apparatus based on whether there is a periodic change within a predetermined frequency range with respect to the number of rotations of an electric motor, a steering velocity, or a steering torque.

Vehicle state information is input, and a control amount, which is control state information, is calculated from the vehicle state information to control a controlled device. A control state is monitored by a monitor unit, and an abnormality is detected based on a state where the vehicle state information or the control state information exists in an abnormality region in which the vehicle state information or the control state information has not reached a failure region corresponding to a failure. The vehicle state information, the control state information, and monitor information are stored in a buffer for a period set in advance while always updating the latest vehicle state information, control state information, and monitor information. When the abnormality is detected, the above respective information before and after the abnormality detection including the information stored in the buffer are stored in a nonvolatile storage unit.

A motor control apparatus includes an inverter, a driver, a negative voltage circuit, a voltage dividing circuit, and a detection unit. The inverter includes an upper-arm switching element and a lower-arm switching element to supply a voltage of a node between the upper-arm switching element and the lower-arm switching element to a motor as a phase voltage. The driver applies a first voltage or a second voltage to the upper-arm switching element to control and turn the upper-arm switching element on and off. The negative voltage circuit supplies a voltage lower than the voltage of the node to the driver as the second voltage. The voltage dividing circuit performs voltage division between the negative voltage circuit and a negative power supply. The detection unit outputs a signal based on a voltage resulting from the voltage division by the voltage dividing circuit.

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.

Technical solutions are described for mitigating braking torque in a motor of a steering system caused by a FET short. For example, an example mitigation system includes a mitigation module that adjusts a motor torque in response to a FET short. The mitigation system further includes a mitigation-enable module that selectively enables and disables the mitigation module based on a handwheel torque signal. Further, the mitigation system includes a damping module that reduces the motor torque based on a motor velocity signal for the motor.

An electric power steering apparatus has a rotation detection device for calculating an absolute angle that includes a sensor section that detects a rotation of a motor and outputs a mechanical angle and a count value. The rotation detection device also includes a signal acquisition unit that obtains the mechanical angle and the count value from the sensor section, and an absolute angle calculator that calculates an absolute angle based on the mechanical angle and the count value. Where one rotation of the motor is divided into indefinite regions and definite regions, the absolute angle calculator uses the count value from the definite regions to calculate the absolute angle.