A motor controller is provided with degradation estimation circuitry configured to calculate an estimated degradation level obtained by estimating a degradation level of a device on which a motor is mounted or a degradation level of an inverter; operation decision circuitry configured to compare the estimated degradation level and a reference degradation level, which is predetermined, and set an operation mode of the motor, in a case in which the estimated degradation level is lower than the reference degradation level, to an normal operation, and set the operation mode, in a case in which the estimated degradation level is higher than or equal to the reference degradation level, to a low-noise pulse operation; and control circuitry configured to control the inverter according to the operation mode. The low-noise pulse operation is designed to reduce switching loss to be less than does the normal operation.

In one embodiment, an offset voltage generator includes a first limiter configured to compare a first phase-voltage signal with a maximum limit value and a minimum limit value to output a first limit-voltage signal; a second limiter configured to compare a second phase-voltage signal with the maximum limit value and the minimum limit value to output a second limit-voltage signal; a third limiter configured to compare a third phase-voltage signal with the maximum limit value and the minimum limit value to output a third limit-voltage signal; and a summer configured to add a difference between the first phase-voltage signal and the first limit-voltage signal, a difference between the second phase-voltage signal and the second limit-voltage signal, and a difference between the third phase-voltage signal and the third limit-voltage signal, to output an offset voltage.

A power convertor includes a power conversion unit, a PWM controller, and a frequency changer. The power conversion unit includes a plurality of switching elements. The PWM controller is configured to perform PWM control of the plurality of switching elements. The frequency changer is configured to change a carrier frequency in the PWM control. The frequency changer includes an outputter, an integrator, and a frequency determiner. The outputter is configured to output a control value in accordance with a control deviation with respect to a control target. The integrator is configured to integrate the control value output from the outputter. The frequency determiner is configured to determine the carrier frequency based on an integral value obtained by the integrator.

A motor driving device includes an inverter circuit having switching elements; and a control device controlling the switching of the switching elements. The control device sets a carrier frequency to f1 when a two-phase modulation scheme is selected, and sets the carrier frequency to f0, which is half of the carrier frequency f1, when a three-phase modulation scheme is selected. Thereby, the frequency of the secondary component of a current flowing in a filter circuit of when selecting the three-phase modulation scheme may be deviated from the resonance frequency of the filter circuit. Accordingly, the current ripple generated in the filter circuit may be reduced even when selectively switching the modulation scheme for the PWM modulation among a plurality of modulation schemes.

A rotating electric machine drive system includes a rotating electric machine and a drive apparatus. The rotating electric machine includes a Y-connected three-phase stator coil. The drive apparatus supplies electric current to the stator coil and thereby drives the rotating electric machine. In a predetermined high-torque region, the drive apparatus supplies the stator coil with the electric current which has a waveform obtained by superimposing a specific harmonic waveform on a first-order harmonic waveform. The specific harmonic waveform is one of third-order and (3+6n)th-order harmonic waveforms, or a harmonic waveform which is obtained by synthesizing at least two of the third-order and (3+6n)th-order harmonic waveforms, where n is a natural number not less than 1. The specific harmonic waveform takes a negative integral value for a positive half cycle of the first-order harmonic waveform and a positive integral value for a negative half cycle of the first-order harmonic waveform.

The device according to the invention controls a polyphase inverter (10, 14, 17) intended for powering from a DC current source (CC) a polyphase rotating electric machine (1). The device is of the type of those generating commutation functions driving commutation elements (9, 13) of the inverter in such a way as to obtain a reduction of the losses in the commutation elements and a decrease of an effective current in a decoupling capacitor (16) of the source (CC). According to the invention, this reduction and this decrease are obtained by means of a set of control strategies (21, 24) determining the commutation functions by using additional degrees of freedom of the polyphase machine (1) with respect to a three-phase reference machine. The polyphase machine comprises first and second phase windings forming a first three-phase system (2, 3, 4) and a second three-phase system (5, 6, 7) with distinct neutral points (11, 15) offset angularly by a predetermined angle of offset (). The first and second phase windings are linked respectively to three first and three second power arms (8, 12) formed by the commutation elements.

A system includes a three phase AC or brushless DC motor, an inverter and a controller. The inverter is electrically coupled to the motor. The controller is -electrically coupled to the inverter. The controller is configured to control the inverter to deliver a three phase pulse width modulated voltage to the AC motor, wherein the three phase pulse width modulation comprises a repeating two-cycle pattern.

A motor driving apparatus including an inverter having a plurality of switching devices, wherein the inverter converts a direct current (DC) power into an alternating current (AC) power according to switching of the switching devices and supplies the AC power to a motor, and a controller to control the inverter, wherein the controller performs a control operation such that a switching frequency of the respective switching devices of the inverter remains constant in a first mode corresponding to a motor operation mode and performs a control operation to change the switching frequency of the respective switching devices of the inverter in a second mode corresponding to a sound output mode for fault diagnosis to output sound corresponding to the changed switching frequency.

A motor controller, a powertrain, and an electric vehicle. The motor controller is configured to output a drive current or a heating current to an asynchronous motor. A waveform of each phase current of the drive current is a sine wave, and the drive current is used to control the asynchronous motor to output torque. A waveform of each phase current of the heating current is a square wave or a step wave, and the heating current is used to control the torque output by the asynchronous motor to be zero, and heat a winding of the asynchronous motor. Heat generated by the heating current on the winding of the asynchronous motor heats a power battery via a heat conduction apparatus. The motor controller adjusts a waveform of the heating current to increase heating power.

A motor controller (100) is provided for smooth operation of an electric motor (102), which mitigates torque ripple, noise and vibration effects, and increases a life span of the motor (102). The motor controller (100) includes a speed controller (120), current transformation units (128 and 130), a current controller (132), and a pulse width modulation (PWM) signal generator (134). The current controller (132) determines a duty cycle of PWM gate signals used for controlling a rotor (104) speed within a particular sector (302A) of the motor (102) based on a reference quadrature-axis current and an actual quadrature-axis current. The PWM signal generator generates the PWM gate signals having the determined duty cycle, controls the rotor (104) speed, and incrementally varies a current speed of the motor (102) to achieve a target speed by modulating operations of a specific pair of inverter switches (502C and 502E) using the PWM gate signals.