Hitachi Industrial Equipment Systems Co., Ltd.

Keisuke Tanabe

Fumihiro Sato

Daisuke Matsumoto

Masahiro Hiraga

Yusuke Arao

Naoki Takata

Kazushige Hotta

Koji Hamano

Shigetoshi Yagihara

Kiyotaka Tomiyama

Hiroyoshi Miyazaki

With the aim of improving the reliability of a power conversion device for driving a motor, this power conversion device is provided with a rectifying portion for rectifying an AC voltage and outputting a DC voltage, a smoothing capacitor for smoothing the DC voltage, an inverter portion into which the DC voltage is input and which outputs AC power, an inverter drive portion for outputting a gate signal to the inverter portion, a regenerative braking portion connected in parallel with the smoothing capacitor, a regenerative braking drive portion for outputting a gate signal to the regenerative braking portion, a control portion for outputting drive signals to the inverter drive portion and the regenerative braking drive portion, a regenerative braking overcurrent detecting portion for outputting an overcurrent detection signal if the current flowing through the regenerative braking portion exceeds a determination value, and a latch portion into which the overcurrent detection signal output from the regenerative braking overcurrent detecting portion is input and which outputs a gate output interruption signal to the control portion, wherein switching elements of the inverter portion and the regenerative braking portion stop in an off state when the regenerative braking overcurrent detection portion detects an overcurrent.

Power conversion device

Provided is a power conversion device which comprises a main circuit board, a first board, and a second board and which has a reduced size. The main circuit board has a rectifier circuit and an inverter circuit which are disposed in a high-power section, the rectifier circuit rectifying AC voltage and The second board is provided with a The first board is connected to the main circuit board and to the second board, and is provided with: a first circuit disposed in a low-power section. The second board is provided with a second circuit disposed in a low-power section. section from each other in a reinforced manner; an insulating transformer disposed in the reinforced insulation region and constituting a constituent component of a power supply circuit for receiving the DC voltage and supplying power to the first circuit and to the second circuit; and an insulating element disposed in the reinforced insulation region and allowing a signal to be exchanged between the first circuit and the second circuit.

This voltage imbalance assessment method is for a power conversion device comprising a forward converter for rectifying the voltage of a three-phase AC power supply, a smoothing capacitor for smoothing the rectified voltage, a detection unit for detecting the smoothed voltage, and a control unit. The control unit: uses the detected voltage to generate data indicating frequency components; compares, in the data indicating frequency components, the magnitude of the component that is four times the power supply frequency with the magnitude of the component that is six times the power supply frequency; and assesses the voltage imbalance of the three-phase AC power supply on the basis of the comparison.

Voltage imbalance assessment method and power conversion device

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Tokyo, Japan

Keisuke Tanabe