A method of controlling a multi-phase electric machine includes implementing a first control method to control the operation of a six-phase machine that is configured as a combination of two three-phase machines. The method also includes determining whether a fault exists in the six-phase machine. In response to determining that the fault exists in the six-phase machine, the method includes implementing a second and different control method to control the operation of the six-phase machine.

In the fault-tolerant direct thrust-force control (FT-DTC) method, the generalized Clarke transform matrix and its inverse matrix are derived according to the fault-tolerant phase currents. The stator fluxes in - plane are deduced based on these. Based on the requirement of circular stator flux trajectory, virtual stator fluxes are defined, and then compensatory voltages in the - plane are obtained. Actual stator voltages in the - plane are calculated by modulation function of voltage source inverter. Combining with the compensatory voltages, the actual stator voltages and the stator currents, the virtual stator fluxes and the thrust-force are estimated by the flux and thrust-force observers. The thrust-force reference, the stator flux amplitude reference, the observed thrust-force and virtual stator flux are applied to predict virtual stator voltage references. The actual stator voltage references is calculated according to virtual voltage references and compensatory voltages, and are fed to voltage source inverter.

A control device for an electric motor includes: a controller configured to apply switching control to an inverter configured to execute power conversion in accordance with a torque command, to thereby control AC power to be supplied to the electric motor; and a current sensor configured to detect a phase current, which flows through an AC cable configured to connect the electric motor and the inverter to each other, wherein the controller includes a disconnection detection unit configured to acquire the phase current detected by the current sensor as a phase current detection value, calculate based on the torque command a phase current command value directed to the electric motor, and determine presence or absence of a disconnection of the AC cable in each phase from a transition result of a difference value between the phase current command value and the phase current detection value in each phase.

A power conversion apparatus with an arm fuse melting detector for detecting an arm fuse melting from a ripple current without using a micro switch. The power conversion apparatus includes an inverter for driving a motor, an arm fuse provided in each of U-phase, V-phase, and W-phase arms of the inverter, and a first arm fuse melting detector to detect the arm fuse melting. The first arm fuse melting detector includes a DQ conversion circuit that converts the inverter output current into the D-axis/Q-axis current, an absolute value calculation circuit for calculating the absolute value from the output of the DQ conversion circuit, a ripple current calculator for calculating a ripple current from the difference between the maximum value and the minimum value of the absolute value for each cycle period T of the fundamental wave of the inverter output.

A steering apparatus, a steering method, and a steering control device. A steering motor includes a first winding and a second winding respectively receiving three-phase power. A first steering controller controls the power supplied to the first winding. A second steering controller controls the power supplied to the second winding. A detector detects whether or not a phase among three phases corresponding to each of the first and second windings is open; and a controller. If the phase among the three phases is detected to be open, the controller controls one steering controller corresponding to the open phase, among the first steering controller and the second steering controller, in accordance with an angular velocity of a steering wheel and the rotational speed of the steering motor, so that the steering motor generates additional torque.

A steering device includes: a plurality of electric motors 10 configured to be driven to turn wheels of a vehicle; and three or more drive systems 20 each configured to output a driving force for driving a corresponding one of the electric motors 10 to the corresponding one of the electric motors 10. A total of maximum driving forces each of which is a maximum value of a driving force of each drive system 20 of the steering device is set larger than a required driving force required to turn the wheels with the vehicle stationary, and in an event of a failure occurring in one of the three or more drive systems 20, a total of the maximum driving forces of other properly working drive systems 20 out of the three or more drive systems 20 amounts to the required driving force.

Fault-tolerant electrical drive systems and methods of maintaining electrical balance or continuing operation of a rotary electric machine under a fault condition are provided. One such system comprises: a rotary electric machine comprising pn phases having a common connection point, where p is a prime number and n is an integer greater than or equal to 1; a drive circuit module having pn phase drive circuits and a reserve drive circuit; and a contactor module. The contactor module comprises: pn phase contactors each of which is operable to connect one of the pn phases of the rotary electric machine to a respective one of the pn phase drive circuits; and a phase fault contactor operable to connect the reserve drive circuit to the common connection point.

Systems and methods for extracting motor operational state parameters from an electric motor for improved motor control and motor fault or failure detection are discussed. An exemplary system includes an excitation circuit to apply a drive voltage to an electric motor, and a processor circuit to measure a resulting winding current, extract a current waveform by oversampling the winding current in an entire PWM frame at a sampling rate higher than the PWM frequency, and fit the current waveform in the PWM period to a parametric model. The processor circuit can determine a motor operational state parameter using one or more of the applied drive voltage or the parametric model of the winding current.

A voltage divider circuit is configured by a resistor having one end connected to a positive electrode of a battery configuring a power source and another end connected to a first terminal that is a motor terminal on one side of a wiper motor, and a FET having one end connected to the first terminal and another end grounded. The voltage divider circuit lowers a voltage of the battery to a test voltage that does not cause the wiper motor to rotate. A microcomputer detects a detected voltage that is a voltage output from the voltage divider circuit to a second terminal that is a motor terminal on the other side of the wiper motor via the first terminal of the wiper motor and the wiper motor, and computes a motor terminal voltage, this being a potential difference between the first terminal and the second terminal, from the detected voltage.

The disclosure relates to an electric machine and in particular to the monitoring of the electric machine for the presence of a fault, (e.g., in the stator windings). A monitoring unit is provided, wherein the monitoring unit measures the multiphase electrical time signals transmitted from or to the machine and with the aid of a Hilbert filter determines substantially in real time the envelopes and the phase positions of the individual phases of the time signal. The envelopes corresponding to the different phases or the corresponding phase positions are compared with one another by way of forming differences and, in the event that one or more of the differences deviate(s) from a specified expectation value, the presence of a fault is inferred. The approach allows significantly increased operational reliability of the electric machine to be achieved in particular.