Denso Corporation

Teruaki Ohyama

Koji Sakai

Tomoyuki Sumi

Yuji Kamiya

Akitomo Yamanaka

Shinji Nakamoto

Yuuji Kamiya

An electric compressor includes a compression portion discharging a high pressure refrigerant by compressing a low-pressure drawn refrigerant, an electric motor driving the compression portion with a rotation of a rotor, a motor drive circuit driving the electric motor, an intermediate pressure port through which an intermediate pressure refrigerant is introduced into the compression portion, and a controller performing a rotation control of the rotor. When the controller stops the electric motor in a two-step compression mode in which the intermediate pressure refrigerant is introduced into the compression portion, the controller stops the rotor rotating by performing short-circuit braking on the electric motor and then fixes a rotational position of the rotor at a predetermined rotational position by performing direct current excitation on the electric motor.

Electric compressor

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

An air conditioner for a vehicle has a compressor, a radiator, a first pressure reducer, a gas-liquid separator, a second pressure reducer, an exterior heat exchanger, an intermediate pressure refrigerant passage, a switching device, and a controller. The controller operates the switching device to switch from a refrigerant circuit of a two-stage compression mode to a refrigerant circuit of a single-stage compression mode when a compressor stop signal is output in the two-stage compression mode. The single-stage compression mode is a mode that blocks at least a flow of an intermediate-pressure refrigerant into the intermediate pressure refrigerant passage and makes refrigerant remained in the intermediate pressure refrigerant passage to flow out of the intermediate pressure refrigerant passage. The controller stops the compressor after controls the compressor to continue operating for a specified time in the single-stage compression mode. The controller restarts the compressor when the compressor stop signal is canceled.

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Kariya, Japan

Teruaki Ohyama