A method determines a correction value for a control device for an electric machine, which describes an angular difference between a position of a d-axis of the electric machine and an actual position of the d-axis. The correction value is determined in a rotating state of a rotor of the electric machine as a function of a d voltage value describing a d component of a stator voltage specified by the control device in the initial configuration, of a q voltage value describing a q component of the stator voltage specified by the control device in the initial configuration, of a flux value describing a magnetic flux of the rotor, a speed value describing the speed of the rotor in the rotating state, and of a calibration value describing a speed-dependent voltage error of the d component of the stator voltage.

A method ascertains current-dependent inductances of a polyphase electrical machine. The method generates phase voltages for the polyphase electrical machine by means of a pulse width modulation such that currents of predefined current level flow through stator windings of the electrical machine. During a number of cycles of the pulse width modulation, the method generates a voltage pulse such that a change of current is brought about in a torque-forming axis of the polyphase electrical machine and/or in a field-forming axis of the polyphase electrical machine. The method measures the change of current, and ascertains the current-dependent inductances on the basis of the change of current.

The disclosure relates to a motor parameter measuring device and method. According to the disclosure, a motor parameter measuring device comprises a torque receiver receiving a motor torque of a motor rotated by an external force, a motor constant calculator calculating a motor constant based on the motor torque, and a parameter calculator controlling an inverter connected with the motor to form a closed circuit and calculating a parameter of the motor based on a current generated by the rotating motor in the closed circuit.

The disclosure relates to a motor parameter measuring device and method. According to the disclosure, a motor parameter measuring device comprises a torque receiver receiving a motor torque of a motor rotated by an external force, a motor constant calculator calculating a motor constant based on the motor torque, and a parameter calculator controlling an inverter connected with the motor to form a closed circuit and calculating a parameter of the motor based on a current generated by the rotating motor in the closed circuit.

A method of speed control based on a self-learning model of load torque and a moment inertia is applied to a controller of controlling a motor. The method includes steps of: establishing a relationship between the load torque and the moment inertia by a self-learning manner, correspondingly acquiring a value of the moment inertia according to a value of the load torque, and adjusting parameters of the controller to control rotation of the motor according to the value of the moment inertia.

Technical solutions are described for attenuating dither noise in a steering system. An example method includes computing a torque command based on an input torque, and generating a current command corresponding to the torque command. Further, the method includes determining an adjustment parameter based on a plurality of steering system signals. Further, the method includes reducing dither noise of the steering system by dynamically modifying a controller parameter value using the adjustment parameter. Further, the method includes generating a voltage command using the current command and the modified controller parameter value, the voltage command used to generate torque by a motor.

A control module comprises software instructions for execution by an electronic data processor. An inductance estimator is configured to estimate direct inductance and quadrature inductance associated with the electric machine based on a first set of equations that assume constant rotor resistance and constant magnetic flux. A torque estimator is configured to estimate an observed torque associated with a rotor of the electric machine based a commanded direct-axis voltage and a commanded quadrature-axis voltage, where the observed torque is proportional to the observed power consumption of the electric machine. A pulse-width-modulation (PWM) module is configured to provide pulse-width modulated signals to the electric machine based on the commanded direct-axis voltage and a commanded quadrature-axis voltage. A back-electromotive force adjustment is derived from an estimated, observed torque and a commanded torque.

A motor system can include a motor configured to be operated according to at least a portion of an operation cycle specifying at least one target speed for the motor and a controller configured to obtain an estimated winding resistance of the motor, wherein the estimated winding resistance is determined based at least in part on an estimator gain factor, and wherein the estimator gain factor is inversely dependent on a speed of the motor; wherein the at least one target speed comprises at least one low speed such that at least a portion of the operation cycle is a low speed portion of the operation cycle, the at least one low speed having a speed of less than about 10 percent of a maximum speed of the operation cycle.

One form of a motor control device includes: a waveform generation unit and an amplifier that generate a drive voltage of a voice coil motor (VCM); a DC offset detection unit that detects a DC offset of the drive voltage; a stop control unit that stops application of the drive voltage to a motor coil when the detected DC offset exceeds an operation stop threshold; a temperature correction value setting unit that sets a temperature correction value corresponding to the DC offset when the detected DC offset is lower than the operation stop threshold; a thermistor that detects an ambient temperature; and a vibration level control unit that varies the drive voltage and controls an amplitude level based on the detected ambient temperature and the set temperature correction value.

One form of a motor control device includes: a waveform generation unit and an amplifier that generate a drive voltage of a voice coil motor (VCM); a DC offset detection unit that detects a DC offset of the drive voltage; a stop control unit that stops application of the drive voltage to a motor coil when the detected DC offset exceeds an operation stop threshold; a temperature correction value setting unit that sets a temperature correction value corresponding to the DC offset when the detected DC offset is lower than the operation stop threshold; a thermistor that detects an ambient temperature; and a vibration level control unit that varies the drive voltage and controls an amplitude level based on the detected ambient temperature and the set temperature correction value.