Mitsubishi Electric Corporation

Kenta Yuasa

Shinsaku Kusube

Akihiro Tsumura

Kazunori Hatakeyama

Takuya Shimomugi

Koichi Arisawa

Keisuke Uemura

Takashi Yamakawa

Shinya Matsushita

Shota Kamiya

Tsutomu Makino

Noriyuki Matsubara

Yosuke Shinomoto

Akihiko Iwata

Norikazu Ito

Kazunori Sakanobe

Keiwa Tsukano

Shoji Isoda

Syota Kamiya

Shigeo Takata

Kenji Iwazaki

Yasuhiko Wada

Shuta Ishikawa

Yoshihiro Taniguchi

Mamoru Kamikura

Chitose Tanaka

Toshiyuki Kuriyama

Yoshikazu Nozuki

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

A refrigerating and air-conditioning apparatus performs a defrosting operation. The refrigerating and air-conditioning apparatus includes a refrigerant circuit, a temperature sensor, and a heat generation control unit. In the refrigerant circuit, a compressor, a first heat exchanger, an expansion device, a second heat exchanger, and a four-way valve are connected to each other by pipes to allow refrigerant to circulate through the refrigerant circuit. The temperature sensor measures a temperature of the compressor. The heat generation control unit increases a temperature of the compressor when the heat generation control unit detects a decrease in a value measured by the temperature sensor in a defrosting operation performed on the first heat exchanger.

Refrigerating and air-conditioning apparatus

a permanent magnet synchronous motor diagnostic device includes: a negative-sequence current calculator that calculates a negative-sequence current, based on magnitudes of a plurality of phase currents flowing through a permanent magnet synchronous motor that rotates a load; and a deterioration diagnoser that diagnoses deterioration of a plain bearing supporting the permanent magnet synchronous motor, based on the negative-sequence current.

Permanent magnet synchronous motor diagnostic device and inverter comprising the same

A power converter includes a rectifier configured to rectify an AC voltage supplied from an AC power supply, a booster circuit configured to boost the voltage rectified by the rectifier, a smoothing capacitor configured to smooth the voltage output from the booster circuit, a power module configured to convert a DC voltage obtained by smoothing the output voltage by the smoothing capacitor into an AC voltage, and a snubber capacitor configured to absorb a surge voltage superimposed on the DC voltage to be input to the power module. The snubber capacitor is mounted in the power module.

Power converter and air-conditioning apparatus using the same

A power converter includes a first substrate on which a module including a switching element is mounted, a second substrate on which a smoothing capacitor is mounted, and a terminal block connecting the first substrate and the second substrate, with the first and second substrates located to face each other. The terminal block includes a current path over which at least one of current flowing from the module to the smoothing capacitor and current flowing from the smoothing capacitor to the module flows.

Power converter and air-conditioning apparatus employing the same

A heat pump device includes a compressor including a motor, a heat exchanger, an inverter, and an inverter control unit. The inverter control unit generates a drive signal for the inverter. When the compressor is heated, the inverter control unit applies, to the motor, a high-frequency voltage with which the motor cannot be rotationally driven; estimates a magnetic pole position indicating a stop position of a rotor of the motor; determines an amplitude and a phase of a voltage command based on an estimation result of the magnetic pole position and a necessary amount of heat, and generates a drive signal.

Heat pump device, air conditioner, and freezer

A backflow preventing device includes a backflow preventing element that is connected between a power supply and a load and that prevents electric current from flowing backward from the load side toward the power supply side, and a commutating device that performs a commutation operation for causing the electric current to flow to a commutation path connected in parallel with the backflow preventing element. A plurality of elements including at least one or more of elements constituting the commutating device are configured as a module, so that, for example, the device can be reduced in size. Moreover, a simplified heat-dissipation design and a simplified air-duct design can be achieved.

Backflow preventing device, power conversion apparatus, and refrigerating and air-conditioning apparatus

A power converter includes a transformation circuit configured to transform a rectified voltage, and a converter control unit configured to control a switching element of the transformation circuit. The converter control unit calculates a current command value based on a line voltage or the phase voltage, calculates a current deviation between the current command value and the reactor current, and calculates a switching command value from the current deviation. The converter control unit includes a plurality of integrators for the respective different phase angles of a power supply voltage. The integrator corresponding to a power supply phase angle is caused to accumulate the current deviation, and the integrator corresponding to a phase angle that is advanced by a set delay phase from the power supply phase angle is caused to output the control amount. A switching signal is generated with use of the control amount and the switching command value.

A heat pump device includes an inverter control unit for controlling an inverter. The inverter control unit includes a constraint-energization control unit that, during operation standby of a compressor, determines whether heating to the compressor is necessary, on the basis of a refrigeration stagnation amount in the compressor, and, when having determined that heating to the compressor is necessary, selects, according to the refrigeration stagnation amount, any one of direct-current energization for supplying a direct-current voltage to the motor and high-frequency energization for supplying a high-frequency voltage having a frequency higher than a frequency during a normal operation to the motor, so as to output a constraint energization command for carrying out constraint energization of the motor; and a driving-signal generating unit that generates a driving signal on the basis of the constraint energization command.

Heat pump device, and air conditioner, heat pump water heater, refrigerator and freezing machine including heat pump device

Provided is a power conversion device configured to convert electric power from a power source to a load, including: a boosting device including a boost rectification unit configured to prevent backflow of a current from the load side to the power source side, the boosting device being configured to change a voltage of power from the power source to a predetermined voltage based on a drive signal; a commutation device configured to perform commutation operation in which a current flowing through the boosting device is caused to flow into an other path based on a commutation signal; and a signal generating module device configured as a module to generate and send an output signal based on an input signal that is input thereto. The input signal has an on-pulse width greater than a length of time where the output signal generated by the signal generating module device is turned on.

Power conversion device and refrigerating and air-conditioning apparatus

A backflow preventing device includes a backflow preventing element connected between a power source and a load, for preventing a backflow of a current from the load side to the power source side, a commutation device configured to perform a commutation operation of causing a current to flow through an other path connected in parallel to the backflow preventing element, and a controller configured to change a pulse width of a commutation drive signal for controlling the commutation device to perform the commutation operation based on a current flowing through the backflow preventing element, and transmitting the commutation drive signal having the changed pulse width to the commutation device. The controller transmits the pulse to the commutation device only for a necessary time period so that the commutation device performs the commutation operation, to thereby reduce electric power relating to the commutation operation not contributing to the power conversion.

Backflow preventing device, power conversion device, and refrigeration air-conditioning apparatus

A power conversion device is provided that includes a rectifier, a booster circuit configured to boost an output voltage of the rectifier, a smoothing capacitor configured to smooth an output voltage of the booster circuit, and an inverter circuit configured to convert a DC voltage of the smoothing capacitor to an AC voltage and drive a motor forming a part of a device supplied with the voltage after the conversion. In addition, a reactor, a first backflow prevention element, a second backflow prevention element, a first switching element, a second switching element, an intermediate capacitor, and a controller configured to control the first switching element and the second switching element, are included.

Boost converter with flying capacitor and refrigeration circuit

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

A motor drive control apparatus according to the present invention includes: a three-phase rectifier to rectify an AC voltage supplied from a three-phase AC source; a booster circuit including a reactor, a switching element, and a backflow preventing element, to boost a DC bus voltage supplied from the three-phase rectifier; a smoothing capacitor to smooth an output of the booster circuit; and an inverter circuit to convert the DC bus voltage smoothed by the smoothing capacitor into an AC voltage and supplying the AC voltage to a motor. During a starting operation of a boosting operation of the booster circuit or a stopping operation of the boosting operation thereof, a rotation speed of the motor is fixed.

Motor drive control apparatus, compressor, fan, and air-conditioning apparatus

A heat pump device includes: a compressor including a compression mechanism compressing a refrigerant and a motor driving the compression mechanism; an inverter unit applying a voltage for driving the motor; an inverter control unit generating a driving signal for driving the inverter unit; and temperature sensors detecting temperatures of the compressor, wherein the inverter control unit includes a normal operation mode in which a refrigerant is compressed by performing a normal operation of the compressor and a heating operation mode in which a heating operation of the compressor is performed by applying, to the motor, a high-frequency voltage, and in the heating operation mode, the inverter control unit determines an amplitude and a phase of a voltage command for generating the high-frequency voltage on a basis of a temperatures detected by the temperature sensors and a necessary amount of heat specified in advance.

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Tokyo, Japan

Kenta Yuasa