A motor control system includes: a voltage command module configured to determine a target d-axis voltage for an electric motor and a target q-axis voltage for the electric motor; a target frequency module configured to: selectively set a target switching frequency to a first predetermined switching frequency; and selectively set the target switching frequency to a second predetermined switching frequency that is at least 2 kilohertz (kHz) greater than the first predetermined switching frequency; and a switching module configured to: based on the target d-axis voltage and the target q-axis voltage, determine target pulse width modulation (PWM) duty cycles for phases, respectively, of the electric motor; and switch switches of legs of an inverter module connected to the phases of the electric motor at the target PWM duty cycles, respectively, and the target switching frequency.

A rotary machine control device includes: a magnetization characteristics determiner that determines a magnet phase of a magnet flux based on an estimated magnetic flux and a detection current, and determines a qm-axis magnetic flux of the estimated magnetic flux, a qm-axis current of the detection current, and a harmonic component of a magnet phase using a dm-qm coordinate system with a dm axis representing the magnet phase and a qm axis representing a phase shifted by 90 degrees from the magnet phase; a ripple compensation determiner that determines a ripple compensation phase using a ripple compensation torque obtained based on the qm-axis current and the harmonic component; a command phase determiner that determines a command phase based on the ripple compensation phase and a torque command; and a command magnetic flux generator that generates a command magnetic flux based on a command amplitude and the command phase.

A control device of a power converter controls a system including a converter that converts alternating current (AC) power of a power supply into direct current (DC) power, an inverter that converts the DC power into AC power, a capacitor that is charged with and discharges the DC power, and a rotary electric machine that is driven by the AC power supplied from the inverter or regenerates the AC power to the power supply, the control device including: a vibration suppression control unit that outputs a torque current command correction value for canceling an axial vibration component due to a vibration frequency of a transmission system including the rotary electric machine and an output compensation control unit that outputs a correction value for suppressing AC power of the power supply fluctuated by the vibration suppression control unit to a voltage control unit of the converter.

A control device of a power converter controls a system including a converter that converts alternating current (AC) power of a power supply into direct current (DC) power, an inverter that converts the DC power into AC power, a capacitor that is charged with and discharges the DC power, and a rotary electric machine that is driven by the AC power supplied from the inverter or regenerates the AC power to the power supply, the control device including: a vibration suppression control unit that outputs a torque current command correction value for canceling an axial vibration component due to a vibration frequency of a transmission system including the rotary electric machine and an output compensation control unit that outputs a correction value for suppressing AC power of the power supply fluctuated by the vibration suppression control unit to a voltage control unit of the converter.

According to one embodiment, a motor drive apparatus includes a first inverter, a second inverter, and a controller. This controller rotationally moves, at the time of startup of a motor, a rotor of the motor to an initial position by DC excitation of supplying DC exciting currents from the first and second inverters to the phase windings of the motor and, after this rotational movement, PWM-controls switching of the first and second inverters in such a manner that a rotational speed of the rotor becomes a target rotational speed. Then, the controller carries out the DC excitation fey which a zero-axis current in each of the phase windings becomes approximately zero.

Embodiments herein relate to a drive system for an electric motor. The drive system including a DC bus having a positive terminal and a ground terminal, an inverter connected to the DC bus configured to provide a plurality of motor excitation signals, and an interface cable operably connected to the inverter, and configured to transmit the plurality of motor excitation signals. The drive system also includes a motor remote from and connected to the inverter via the interface cable, the motor responsive to the motor excitation signals and a plurality of snubber circuits, each of the snubber circuits having a first terminal connected to a winding of the motor, and a second terminal operably connected to a first end of a transmission line and a second end of the transmission line is connected to the positive terminal of the DC Bus.

Embodiments herein relate to a drive system for an electric motor. The drive system including a DC bus having a positive terminal and a ground terminal, an inverter connected to the DC bus configured to provide a plurality of motor excitation signals, and an interface cable operably connected to the inverter, and configured to transmit the plurality of motor excitation signals. The drive system also includes a motor remote from and connected to the inverter via the interface cable, the motor responsive to the motor excitation signals and a plurality of snubber circuits, each of the snubber circuits having a first terminal connected to a winding of the motor, and a second terminal operably connected to a first end of a transmission line and a second end of the transmission line is connected to the positive terminal of the DC Bus.

In a method for operating a controllable converter with an intermediate circuit capacitor, the control behavior can be improved by transmitting, depending on an intermediate circuit voltage applied to the intermediate circuit capacitor, an additional power component via the controllable converter such that the electric current that is generated by the controllable converter for the additional power component counteracts an oscillation of the intermediate circuit voltage. The additional power component is transmitted by the controllable converter to a connected motor as a pulsating additional torque. Also described is a controllable converter with a control unit for carrying out a method, wherein the controllable converter has semiconductors that can be switched off, and an intermediate circuit capacitor designed as a film-type capacitor.

In a method for operating a controllable converter with an intermediate circuit capacitor, the control behavior can be improved by transmitting, depending on an intermediate circuit voltage applied to the intermediate circuit capacitor, an additional power component via the controllable converter such that the electric current that is generated by the controllable converter for the additional power component counteracts an oscillation of the intermediate circuit voltage. The additional power component is transmitted by the controllable converter to a connected motor as a pulsating additional torque. Also described is a controllable converter with a control unit for carrying out a method, wherein the controllable converter has semiconductors that can be switched off, and an intermediate circuit capacitor designed as a film-type capacitor.

A driving apparatus includes an inverter and a controller. The inverter converts, based on pulse width modulation (PWM) signals, an input voltage into output voltage signals that are used to drive a multi-phase load. The controller includes: a sequence generating module generating a first switching sequence and at least one second switching sequence based on duty cycle values; a selecting module selecting, to serve as a selected switching sequence, one of the first and second switching sequences that is determined to make phase currents which flow through the multi-phase load due to the output voltage signals have lowest total harmonic distortion; and an output generating module generates the PWM signals based on the selected switching sequence.