Permanent magnet motors (PMMs) can develop oscillations during motor startup that can cause damage to electric submersible pump (ESP) components. A system and method are presented for identifying mechanical and/or electrical caused oscillations in a PMM through the analysis of oscillations in current and torque measurements. A control system within a surface motor controller receives current and/or torque measurements from downhole sensors. The control system employs one or more algorithms designed to detect oscillations in the measurements. Upon detecting oscillations that are consistent with oscillations in the motor from mechanical or electrical causes, the control system automatically initiates protective action to prevent damage to the ESP components.

An electric power assisted steering apparatus comprises an upper column shaft that is connected to a steering wheel of the vehicle; and a lower column shaft. A torsion bar interconnects the upper column shaft and the lower column shaft; and an electric motor is connected to the lower column shaft of the torque sensor assembly. A first sensor circuit generates a first torque signal based on angular deflection of the torsion bar, and a second sensor circuit generating a second torque signal based on angular deflection of the torsion bar, the apparatus further including: an error determining circuit which produces two error signals, each indicative of the validity of a respective torque signal, and a torque plausibility estimator which generates two plausibility signals each indicative of the plausibility of a respective one of the two torque signals.

A disclosed method can control an electric motor for an electromechanical power steering mechanism for assisting steering for a motor vehicle. The electromechanical power steering mechanism may include a steering column with an upper steering shaft linked to a lower steering shaft by a torsion bar. A torsion angle between the upper steering shaft and the lower steering shaft is configured to be measured or estimated, and an electric motor is configured to apply an assistance torque. The method may involve calculating a desired rotor position with an assist algorithm based on the torsion angle and calculating a PWM pattern by a PWM control unit such that the calculated PWM pattern adjusts a rotor of an electric motor angle such that the torsion angle is decreased.

A method for controlling a current distribution between multiple electric motor devices in a current sharing system of an electrically driven construction machine is described. The method comprises estimating a first current demand for a first electric motor device powered by a battery system and estimating a second current demand for a second electric motor device powered by the battery system. The method comprises determining an available amount of current in the current sharing system. The method comprises splitting the available amount of current into a first portion for driving the first electric motor device and a second portion for driving the second electric motor device. The splitting is based on the estimations of the first current demand and the second current demand. A control device configured to run the method and to run a current sharing system for an electrically driven construction machine is also described.

The present disclosure relates to an apparatus and method for detecting a motor failure capable of detecting a motor failure using a position sensor and, when a motor failure is not detected using the position sensor, detecting a motor failure using a torque sensor. An apparatus for detecting a motor failure according to an embodiment of the present disclosure includes a plurality of position sensors each configured to output signals related to a position of a motor, a torque sensor configured to detect torque of the motor according to rotation of a steering wheel, and a failure detector configured to, when all of the signals related to the position of the motor which have been output from the plurality of position sensors indicate that the motor is stuck, detect whether the motor has failed by using a variation of the torque of the motor.

A feedback control switching unit of an inverter control unit selects, based on a magnitude relationship between a predetermined switching determination amount and at least one switching threshold, at least one of feedback control units to thereby execute switching among feedback control modes, such as a current feedback control mode and a torque feedback control mode, of the respective feedback control units for driving of the AC motor. A switching command generating unit generates a switching command for an inverter based on a manipulated variable calculated by the selected feedback control unit. When a torque response request determining unit determines that a required torque responsiveness is high, the feedback control switching unit reduces the number of executions of switching among the feedback control modes.

A method and system for controlling and regulating operation of a multi-phase rotary electric machine in a manner that minimizes power loss under partial load conditions is described. This includes an instruction set that is executable to determine a torque command and a rotational speed of the electric machine, determine a peak torque per loss parameter for the electric machine based upon the rotational speed, and determine a second torque parameter for the electric machine based upon the rotational speed. A modulated torque command for controlling the electric machine is determined based upon the peak torque per loss parameter and the second torque parameter, wherein the electric machine generates an average torque that is equivalent to the torque command when operating in response to the modulated torque command. The inverter is controlled to operate the electric machine based upon the modulated torque command.

A low-frequency torque controller 9 outputs a low-frequency torque controller output .sub.dc* based on a torque command value * and a torque detection value .sub.det, and a vibrational torque controller 11 outputs a vibrational torque command value .sub.pd* based on the torque command value *, the torque detection value .sub.det, and a rotational phase detection value . Meanwhile, in a high-frequency resonance suppression controller, an inverter torque command value .sub.inv* is outputted based on the torque detection value .sub.det and a corrected torque command value .sub.r* obtained by adding the low-frequency torque controller output .sub.dc* to the vibrational torque command value .sub.pd*. The invention thus provides shaft torque vibrational control of a motor drive system wherein engine vibrational torque command values including distortion components are tracked while entirely removing the influence of resonance, non-periodic disturbances, and periodic disturbances.

In a motor drive device 120, a phase compensation amount calculation unit 110 calculates a phase compensation amount for compensating a voltage phase v* when a control mode is switched in a control selection unit 90. The control selection unit 90 outputs the three-phase voltage command Vuvw* according to any one of the plurality of control modes based on the modulation factor Kh*, the voltage phase v*, and the phase compensation amount . A PWM control unit 100 outputs gate signals Gun, Gup, Gvn, Gvp, Gwn, and Gwv based on the three-phase voltage command Vuvw* and a rotor position d. The inverter 20 has a plurality of switching elements, and controls the plurality of switching elements based on gate signals Gun, Gup, Gvn, Gyp, Gwn, and Gwv to drive the AC motor 10.

According to one or more embodiments, a motor control system includes a first controller computing a first torque command using a first closed loop. The motor control system further includes a second controller computing a second torque command using a second closed loop. Both, the first controller and the second controller, compute the respective first torque command and the second torque command using a uniform calculation in which a pseudo/leaky integrator $\frac{\mathrm{Ki}}{s+\mathrm{.Math.}}$
in s domain (s is Laplace variable) is used and integrator state is calculated as Ki*.sub.0.sup.te()exp(t)d, in time domain, which is implemented by discretization methods in electric control unit (ECU), where e is a tracking error, Ki is a predetermined integral parameter, and is a configurable parameter. The motor control system further includes a motor that receives a torque command for generating corresponding amount of torque based on the first torque command and the second torque command.