Kabushiki Kaisha Toyota Jidoshokki

Takuya Naruse

Kazuki Najima

Takashi Kawashima

Masashi Kubota

Yoshiki Nagata

Akimitsu Ichihara

An electric motor includes processing circuitry. The processing circuitry estimates the position of a rotor in a mode selected from an induced voltage mode and a harmonic superimposition mode. The induced voltage mode is a mode of estimating the position of the rotor based on an induced voltage that is generated in three-phase coils. The harmonic superimposition mode is a mode of estimating the position of the rotor by superimposing a harmonic on a command value. The processing circuitry estimates the position of the rotor using the induced voltage mode when the output voltage is greater than or equal to a predetermined threshold value and estimates the position of the rotor using the harmonic superimposition mode when the output voltage is less than the threshold value.

Electric motor

An electric motor includes processing circuitry estimates a position of a rotor in a mode selected from an induced voltage mode and a harmonic superimposition mode. The processing circuitry estimates the position of the rotor using the induced voltage mode when the input voltage is less than or equal to a predetermined voltage threshold value or when the phase current is greater than or equal to a predetermined current threshold value and estimates the position of the rotor using the harmonic superimposition mode when the input voltage is greater than the voltage threshold value and the phase current is less than the current threshold value.

The motor-driven compressor includes an electric motor, a housing, a compression portion, and an inverter device. The inverter device includes an inverter circuit, a current sensor, a coordinate converter, a speed controller, a current controller, a PWM controller, and a rotation angle estimator. The speed controller generates a d-axis current command value and a q-axis current command value such that a necessary torque to drive the electric motor occurs. The inverter device includes a heat-generating current command section that increases a temperature of the electric motor by changing the d-axis current command value and the q-axis current command value. The heat-generating current command section changes the d-axis current command value and the q-axis current command value so as to shift them in a direction in which a d-axis current value increases along a constant torque curve in a d-q coordinate system.

Motor-driven compressor

A motor drive device drives a multi-phase synchronous motor in an electric compressor. The multi-phase synchronous motor includes a rotor that is provided with a permanent magnet and a stator having coils of different phases. The motor drive device includes an inverter that supplies current to the coils and a control unit that controls the inverter. The control unit executes an initial angular position calculation processing of detecting a d-axis and a q-axis as an initial angular position of the rotor, a rotating processing of rotating the d-axis and the q-axis in a direction opposite to rotation of the rotor, an acceleration processing of accelerating the rotation of the rotor, and a sensorless control processing of controlling the rotation of the rotor.

Motor drive device and electric compressor

A direct-current to three-phase alternating-current inverter system includes a three-phase motor, a plurality of switching elements, an inverter circuit for the three-phase motor, a capacitor, a direct-current power source and a control circuit. The switching elements arranged in the inverter circuit serve as upper and lower arms for the respective three phases of the three-phase motor, respectively. The capacitor is connected in parallel to the respective pairs of the upper and lower arms. The direct-current power source is arranged between the neutral-point of the three-phase motor and the respective lower arms or the respective upper arms. The control circuit controls the switching elements such that at least the switching frequency of one pair of the switching elements for one phase through which the current having the greatest value flows is lower than the switching frequencies of the other pairs of the switching elements for the other phases.

Direct-current to three-phase alternating-current inverter system

A DC to three-phase AC inverter system includes a three-phase motor, an inverter circuit, switching elements, a capacitor, a DC power source and a control circuit. The DC power source is connected to the three-phase motor at a neutral point thereof. The control circuit calculates voltage commands, first through third divided boost commands by dividing a boost command, and first through third drive signals based on the voltage commands and the first through third divided boost commands. The second and third divided boost commands are used when the PWM control is performed by turning on and off the switching elements for the second and third phases while the switching elements for the first phase continues to be on or off state is set larger than those used when the PWM control is performed by turning on and off the switching elements for the first through third phases.

Growing community of inventors

Aichi-ken, Japan

Takuya Naruse