Hitachi-johnson Controls Air Conditioning, Inc.

Kazuhiro Ueta

Yoji Ogura

Kenji Tamura

Wataru Hatsuse

Koji Tsukii

A boosting operation of a converter and the intermittent energization operation of an inverter are optimally performed in accordant with input or output. The power converter includes the converter capable of boosting a DC voltage outputted by switching operation alternately performing shorting and rectification; the inverter; an inverter capable of performing intermittent energization in which switching around zero cross of a motor current is turned off upon converting the DC voltage outputted by the converter into three-phase AC power; and a controller that controls the converter to perform boosting operation and the inverter to perform the boosting operation of the converter and the intermittent energization operation of the inverter linkingly.

Power converter and refrigeration air conditioner

An air conditioner is provided that reduces user discomfort due to vibrations and noises at a compressor, piping, and the like such as of an air conditioner. To achieve this, an air conditioner includes: a compressor () that has a motor () and a compression mechanism () driven by the motor (); a speed detector () that detects a rotation speed of the motor (); a drive mode controller () that controls a drive mode of the motor (); and refrigerant piping that is connected to the compression mechanism () and allows a refrigerant to flow therethrough, wherein the drive mode controller (), for stopping the motor (), decelerates the motor () to a rotation speed equal to or lower than a resonance frequency between the compression mechanism () and the refrigerant piping.

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Tokyo, Japan

Kazuhiro Ueta