Mitsubishi Electric Corporation

Keiwa Tsukano

Shinsaku Kusube

Kenta Yuasa

Akihiko Iwata

Kenji Iwazaki

Akihiro Tsumura

Takahiko Kobayashi

Yoshihiro Taniguchi

A power converter includes a power converting module and a gate drive circuit that includes first and second drive circuits and a power supply module including a limiting resistor, a bootstrap diode, and a bootstrap capacitor, and configured to generate a voltage to be supplied to the second drive circuit. The bootstrap capacitor is charged when a switching element connected to a reference potential side performs switching. A charging period of the bootstrap capacitor includes at least first and second periods. In the first period, the switching element is driven by a pulse signal having a first pulse width. In the second period, the switching element is driven by a pulse signal having a second pulse width greater than the first one. The first pulse width in the first period is determined based on an allowable magnitude of a voltage drop of the control power supply in the first period.

Power converter and air-conditioning apparatus

Provided is a power conversion device including: a step-up converter unit, including a reactor to which a DC voltage is to be input, a switching element connected to the reactor in parallel, and a backflow prevention element connected to the reactor in series; a smoothing capacitor configured to smooth an output voltage from the step-up converter unit; an inverter unit configured to convert the output voltage smoothed in the smoothing capacitor into an AC voltage; a dew condensation state detection unit configured to detect a state of dew condensation, which occurs due to a cooler configured to cool the step-up converter unit and the inverter unit; and a control unit configured to control an operation of the step-up converter unit, wherein the control unit includes: a determination unit configured to determine the state of dew condensation detected by the dew condensation state detection unit; and a step-up control unit configured to control a step-up operation of the step-up converter unit based on a result of determination made by the determination unit.

Power conversion device and air-conditioning apparatus

A power conversion apparatus, including: an MLC circuit configured to boost an input voltage from a three-phase rectifier; a smoothing capacitor configured to smooth an output of the MLC circuit; an inverter control unit configured to generate a PWM signal; an inverter circuit configured to convert a DC voltage of the smoothing capacitor into an AC voltage based on an input of the PWM signal and to supply the AC voltage to a motor; a boost mode switching unit having at least three boost modes in which a boost level of the input voltage is selected and configured to switch among the at least three boost modes depending on an operation status of the motor determined for the purpose of controlling a refrigeration cycle; and an MLC control unit configured to control the MLC circuit based on the switching by the boost mode switching unit.

Power conversion apparatus and air-conditioning apparatus including the power conversion apparatus

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Tokyo, Japan

Keiwa Tsukano