Denso Corporation

Akitomo Yamanaka

Koji Sakai

Akihiro Imura

Tomoyuki Sumi

Shinji Nakamoto

Teruaki Ohyama

Yuji Kamiya

A controller that controls an electric compressor, which is mounted to a vehicle and configures a two-stage compression refrigeration cycle device, has a deceleration section, an operation stop section, and a restart section. The deceleration section reduces a rotational speed of an electric motor by controlling an AC current which is output to the electric motor, when a two-stage compression mode, in which an intermediate-pressure refrigerant flows into the electric compressor from an intermediate-pressure port, is performed and an operation stop request to stop the electric compressor is made. The operation stop section stops the electric motor after the deceleration section reduces the rotational speed of the electric motor. The restart section restarts the electric compressor when the operation stop request is canceled after the operation stop section stops the electric compressor.

Electric compressor controller and refrigeration cycle device

An air conditioning apparatus includes an electric compressor, an inverter, a temperature detection element, and an ECU. The electric compressor compresses a refrigerant drawn from a refrigerant intake port and discharges the refrigerant from a refrigerant discharge port. The inverter is integrated with the electric compressor so as to be cooled by the drawn refrigerant, and operates the electric compressor according to a control signal. The temperature detection element detects a temperature of the inverter. The ECU outputs a control signal to control the inverter. The ECU performs any one or both of a control for reducing a self-cooling amount of the electric compressor and a control for increasing a self-heat generation amount of the inverter with respect to the inverter when the temperature detected by the temperature detection element is lower than a predetermined reference temperature.

Air conditioning apparatus

A motor driving device for a motor having a stator and a rotor rotationally driven by an input of an AC voltage includes: an inverter circuit having multiple units corresponding to multiple phases respectively, each unit having a pair of a switching element and a reflux diode connected in anti-parallel to the switching element; and a control device controlling the inverter circuit to convert a DC voltage into the AC voltage and to output the AC voltage to the stator coil. The control device includes: a field weakening control unit adjusting the AC voltage to control a magnetic field of the stator coil to weaken a field magnetic flux of the rotor; and a regenerative current control unit switching an anti-regenerative side switching element to flow a regenerative current when the AC voltage stops while the field weakening control unit performs the field weakening control.

Motor driving device

A driving device includes a driving circuit and a control circuit. The driving circuit has an input terminal and an output terminal and applies a driving voltage to a switching element through the output terminal. The control circuit outputs two types of control signals to the input terminal of the driving circuit. The driving circuit has a circuit group including multiple unit circuits which are turned ON by the same control signal. Each unit circuit includes one voltage source, one switch controlled to be turned ON and OFF by the control signals, and one resistor connected in series to the switch between the voltage source and the output terminal. Each voltage source outputs a different voltage, and each resistor has a different resistance. One end of each switch of all the unit circuits is connected to the output terminal.

Driving device

An electric motor drive device has an inverter adjusting the voltage applied to an AC electric motor so as to drive the AC electric motor, a capacitor which is charged by a current supplied from a DC power supply supplying DC voltage between a neutral point at which a plurality of coils of the AC electric motor are connected and a positive rail or negative rail of an inverter and passing through the inverter, and a control circuit controlling the inverter so that the AC electric motor turns at a designated speed. Further, the control circuit selectively uses field weakening control and voltage boosting control for control of the inverter according to the conditions of the induced voltage generated at the AC electric motor, DC power supply, and voltage of the capacitor.

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Kariya, Japan

Akitomo Yamanaka