Mitsubishi Electric Corporation

Mitsubishi Corporation

Kazunori Hatakeyama

Keisuke Uemura

Yosuke Shinomoto

Shinya Matsushita

Shinsaku Kusube

Tsutomu Makino

Koichi Arisawa

Shota Kamiya

Yuichi Shimizu

Takuya Shimomugi

Takashi Yamakawa

Kenta Yuasa

Yuji Takayama

Atsushi Tsuchiya

Keiichiro Shizu

Haruka Matsuo

Kazunori Sakanobe

Shinya Toyodome

Satoru Ichiki

Mitsuo Kashima

Michio Yamada

Kenji Takahashi

Hiroki Aso

Norikazu Ito

Takahiko Kobayashi

Yasuhiko Wada

Naoki Wakuta

Shoji Isoda

Motoya Suzuki

Yuta Tokuda

Yuhei Shimada

Syota Kamiya

Hiroyuki Ishii

Takashi Matsumoto

Takayuki Kato

Mineo Yamamoto

Masahiro Nigo

Kazuchika Tsuchida

Junichiro Oya

Yuto Urabe

Tomoaki Oikawa

Kenji Iwazaki

Akihiro Tsumura

Akira Satake

Hiroyuki Takayama

Takumi Nishiyama

Tomohiro Kutsuki

Atsushi Kawashima

Naho Adachi

Mitsumasa Hamazaki

Tomoyuki Kamiyama

Akane Hongyo

Masaya Teramoto

Naohide Tsuchimoto

Makoto Kasugai

Takuya Furuyama

Masami Yorita

Takanobu Kondo

A power converter including: a non-boost rectifier circuit that converts a first alternating-current voltage into a direct-current voltage; a reactor connected to the rectifier circuit; a capacitor that smooths a direct-current voltage; an inverter that is connected in parallel to the capacitor, converts the smoothed direct-current voltage into a second alternating-current voltage having desired voltage and frequency, and outputs the second alternating-current voltage to a motor; and a controller that controls an operation of the inverter. Capacitances of the reactor and the capacitor are set such that a resonance frequency of a filter circuit including the reactor and the capacitor is smaller than a first electrical angular frequency based on a voltage command when the controller controls an operation of the inverter such that the second alternating-current voltage is maximized in a range not causing overmodulation.

Power converter and air conditioner

In a power converter, a controller controls the operation of a converter, and a control voltage generator generates a control voltage for operating the controller. When the voltage value of the direct-current voltage output from the power converter is higher than the voltage value of the control voltage and a detection signal is not output from a voltage detector that detects the power supply voltage, the operation of switching elements of the converter is stopped under the control of the controller.

Power converter, motor driver, and air conditioner

A motor drive apparatus includes a connection switching device that switches a connection state of windings of a first motor by switches; an inverter that applies an alternating-current voltage to the windings; a first control device that controls the inverter and the connection switching device; and a second control device that controls a second motor for an element that affects the first motor. Control by the first control device when switching includes a first stage of bringing an effective value of alternating current flowing through the windings close to zero compared to that before the connection state is switched; and a second stage of suspending output of the alternating-current voltage from the inverter. The second control device keeps the second motor running during the first and second stages, and the first control device switches the switches in the second stage.

Motor drive apparatus, refrigeration cycle apparatus, air conditioner, water heater, and refrigerator

Included are a rectifier circuit that rectifies a first alternating-current voltage; a reactor connected to the rectifier circuit; a capacitor connected to an output end of the rectifier circuit; an inverter that is connected to the capacitor, generates a second alternating-current voltage through operations of a plurality of switching elements, and applies the second alternating-current voltage to a motor including a stator and a rotor; and a control unit that performs operation controls on the plurality of switching elements. The control unit causes the inverter to apply, to the motor, the second alternating-current voltage having a higher frequency than when the motor is in compression operation so as not to rotate the rotor. The application of the high-frequency second alternating-current voltage from the inverter to the motor generates a regenerative current and a current flows to the capacitor due to the regenerative current without impairing the capacitor.

Power conversion apparatus and air conditioner

A power converting apparatus includes a converter circuit converting an alternating-current voltage output from an alternating-current power supply into a direct-current voltage. The converter circuit includes unit converters. The power converting apparatus generates a reference duty on the basis of detection values of a current detector and a voltage detector and generates, on the basis of a result of comparison between the reference duty and a carrier signal, a pulse-width modulation signal for controlling the switching element. In each of the unit converters, the pulse-width modulation signal has one pulse within a carrier period and has pulses for the number of phases within a leveling period, the leveling period being obtained by multiplying the carrier period by the number of phases. The pulses for the number of phases within the leveling period have phases all different from each other in the respective carrier periods.

Power converting apparatus, motor driving apparatus, blower, compressor, and air conditioner

A power converting apparatus includes: a reactor including a first end and a second end, the first end being connected to an alternating-current power supply; a rectifier circuit connected to the second end of the reactor and including at least one switching element, the rectifier circuit converting an alternating-current voltage output from the alternating-current power supply into a direct-current voltage; and a detecting unit that detects a physical quantity indicating an operation state of the rectifier circuit, wherein the number of times of switching of the switching element is changed depending on the operation of the rectifier circuit.

Power converting apparatus, and motor driving apparatus

An air-conditioning apparatus includes an indoor unit and an outdoor unit including a compressor that compresses a refrigerant and a motor drive system that drives the compressor. The motor drive system includes an inverter that converts a DC voltage into an AC voltage, and an electric motor including three stator windings with both ends open. The electric motor operates based on the AC voltage obtained by the inverter. The motor drive system further includes a connection state switching unit that has a function to change the connection state of the three stator windings included in the electric motor, and sets the connection state to a star connection at the start of operation of the air-conditioning apparatus.

Air-conditioning apparatus

A motor drive device includes a single-phase inverter that converts a direct-current voltage into an alternating-current voltage applied to a motor. The motor drive device includes a control power supply outputting power having a voltage lower than the direct-current voltage. The motor drive device includes a drive signal generation unit driven by the power. The drive signal generation unit generates drive signals driving switching elements of the inverter. The motor drive device includes a power supply switch operating so as to allow supply of the power from the control power supply to the drive signal generation unit when a rotation speed of the motor is higher than a threshold. The power supply switch operates so as to stop the supply of the power from the control power supply to the drive signal generation unit when the rotation speed is lower than the threshold.

Motor drive device, electric blower, electric vacuum cleaner, and hand dryer

An electric blower includes a fan, a motor to drive the fan, a first board including at least one switching element, and a second board including a microcomputer. The motor, first board, and second board are arranged in this order in a blowing direction of the fan.

Electric blower, vacuum cleaner, and hand dryer

A power conversion apparatus includes a converter circuit converting AC voltage output from an AC power supply into DC voltage. The converter circuit includes unit converters. The power conversion apparatus includes a low current-oriented controller the unit converters to cause current corresponding to a single phase to flow through a current detector, and a high current-oriented controller controlling operation of the unit converters based on a result of comparison between a duty command and a carrier signal, where the duty command is generated based on detection values detected by the current detector and a voltage detector. When the detection value detected by the current detector is less than or equal to a first threshold, the low current-oriented controller is activated, and when the detection value detected by the current detector is greater than the first threshold, the high current-oriented controller is activated.

Power conversion apparatus, motor drive apparatus, blower, compressor, and air conditioner

A heat pump apparatus includes: a compressor including a motor; an inverter that applies a desired voltage to the motor; a current detector that detects current flowing to the motor; a drive-signal generation unit that generates a drive signal for the inverter; a magnetic-pole position estimation unit that changes a voltage phase of a voltage command value for a high-frequency voltage, and estimates a maximum-heat-amount acquisition magnetic-pole position when the generation unit applies the high-frequency voltage to the motor to heat the compressor; a steady heating control unit that determines an amplitude and voltage phase of the voltage command value from the maximum-heat-amount acquisition magnetic-pole position and a defined necessary amount of heat when the generation unit applies the high-frequency voltage to the motor to heat the compressor; and a control switching determination unit that causes one of the estimation unit and the heating control unit to operate.

Heat pump apparatus with compressor heating control

A motor drive apparatus includes a reactor, a converter connected to an alternating current power supply via the reactor, a smoothing capacitor connected between output terminals of the converter, and an inverter that converts a direct current voltage output from the smoothing capacitor into an alternating current voltage to be applied to a motor and outputs the alternating current voltage. The motor drive apparatus includes a plurality of operation modes for controlling conduction of switching elements of the converter and causing the converter to operate in different modes of operation, and changes operation of at least one of the switching elements of the converter and the inverter according to the operation mode when a bus voltage indicates an excessive value.

Motor drive apparatus, blower, compressor, and air conditioner

A motor drive device includes a single-phase inverter converting a direct-current voltage output from a power supply that is a direct-current power supply into an alternating-current voltage having a high level, low level, or zero level potential. The inverter outputs the alternating-current voltage as a motor applied voltage to be applied to a motor. The alternating-current voltage is a voltage that has a high level, low level, or zero level potential. When a rotation speed of the motor is to be reduced, a section in which a potential of the motor applied voltage is zero level is widened.

A load driving device includes a smoothing capacitor, an inverter, and a control unit. The inverter includes two legs, each including upper and lower arm switching elements connected in series and converts direct-current power stored in the smoothing capacitor into alternating-current power. The control unit performs voltage drop prevention control for preventing the voltage across the smoothing capacitor from becoming a negative voltage. The control unit stops power running control on the load when the capacitor voltage is higher than the sum of a first voltage and a second voltage. The first voltage is a potential difference between a second terminal and a first terminal in the upper-arm. The second voltage is a potential difference between a second terminal and a first terminal in the lower-arm in the same leg as the leg of the upper-arm.

Load driving device, refrigeration cycle applicable apparatus, and air conditioner

The power conversion apparatus includes a converter circuit that converts an alternating-current voltage output from an alternating-current power supply into a direct-current voltage. The converter circuit includes unit converters. The power conversion apparatus includes current detectors that detect respective currents flowing through respective reactors. In first and second unit converters adjacent to each other among the unit converters, a phase difference between a first phase and a second phase is changed from a reference phase difference when a total current of currents detected by the respective current detectors is greater than a threshold. The first phase is a phase at a time when the switching element of the first unit converter is turned on. The second phase is a phase at a time when the switching element of the second unit converter is turned on.

Growing community of inventors

Tokyo, Japan

Kazunori Hatakeyama