A power conversion device includes a power switching circuit that supplies AC voltages generated between switching elements operating as upper arms and switching elements operating as lower arms, and a control circuit that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements by a PWM method in a first operational region in which frequency of an AC power to be outputted is low, and that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements at timings based upon the phase of the AC power to be outputted in an operational region in which the frequency of the AC power to be outputted is higher than in the first operational region.

Power Conversion Device

Provided is a power factor correction circuit correcting a power factor of AC voltage. The power factor correction circuit includes: a rectifying unit stopping rectifying the AC voltage in a transient state and generating an rectified voltage by rectifying the AC voltage in a steady state; a power factor correction unit generating a power-factor-corrected voltage by correcting the rectified voltage; a smoothing unit generating a smoothed voltage by smoothing the power-factor-corrected voltage; and an inrush current limiting unit providing a limited current by limiting an inrush current generated by the AC voltage in the transient state and stopping providing a current to the smoothing unit.

Power factor correction circuit

A converter includes a first converter module and a second converter module coupled to the first converter module in a nested manner Each of the first converter module and the second converter module includes a plurality of switch units When the converter is operated to perform power conversion, at least two of the plurality of switch units is configured to be switched both in a complementary pattern and a non-complementary pattern

System and method for power conversion

An inverter control apparatus and a control method thereof are provided. The inverter control apparatus and a control method thereof stably operate a three-phase motor using a capacitor having a small capacitance for a DC link. The inverter control apparatus includes a current sensor to sense an output current of the inverter, a voltage sensor to sense a DC-link voltage of the inverter, and a controller to generate an average of a periodically varying rotor based q-axis current boundary value based on the output current and the DC-link voltage to generate a current reference on the basis of the average of the rotor based q-axis current boundary value, and to drive a three-phase motor based on the current reference. Stabilized variable speed control of a motor by using a small-capacitance capacitor for a DC link of an inverter is performed and reliability of an inverter circuit improved.

Inverter control apparatus and control method thereof

Malfunctions of a switching device included in a power factor corrector are reduced when an instantaneous voltage drop or an instantaneous power failure occurs. If the instantaneous voltage drop or the instantaneous power failure occurs in an AC power source while the power factor corrector is performing a power factor correction operation by boosting an input voltage, an instantaneous power failure controller turns off the switching device included in the power factor corrector so that the power factor correction operation stops. When the commercial power source recovers, too, the power factor corrector suspends the power factor correction operation.

Power converter and air conditioner

A rectifier connected with an AC source through a reactor, a plurality of capacitors connected in series between output terminals of the rectifier, first switching means connected between one input terminal of the rectifier and a connection point of a plurality of capacitors, second switching means connected between the other input terminal of the rectifier and the connection point of a plurality of capacitors, and a plurality of diodes connected with the plurality of capacitors in inverse-parallel are provided.

AC-DC converter, method of controlling the same, motor driver, compressor driver, air-conditioner, and heat pump type water heater

Provided is an alternating-current direct-current converter capable of controlling a harmonic current and improving a power factor at reduced costs. The alternating-current direct-current converter includes two capacitors connected in series between output terminals of a rectifier; a first switch connected between one input terminal of the rectifier and a connection point of the capacitors; a second switch connected between the other input terminal of the rectifier and the connection point of the capacitors; a voltage detector which detects terminal voltages of the capacitors; a current detector which detects a current input from the alternating current power supply; and a control means which drives and controls the first switch and the second switch, in which the control means drives and controls the first switch and the second switch such that the terminal voltages of the capacitors are fixed and a power supply power factor is improved using an active power component and a reactive power component obtained by conversion of detection results of the current detector and detection results of voltage detector.

Alternating-current direct-current converter and electric motor driver

AC-DC converter, air conditioner, and heat pump-type hot-water supply device

To improve power factor by suppressing harmonics current at low cost and at the same time downsize a reactor. A rectifier (2) connected with an AC source through a reactor (5), a plurality of capacitors (6, 7) connected in series between output terminals of the rectifier (2), first switching means (3) connected between one input terminal of the rectifier (2) and a connection point of a plurality of capacitors, second switching means (4) connected between other input terminal of the rectifier (2) and the connection point of a plurality of capacitors, and a plurality of diodes (10, 11) connected with the plurality of capacitors in inverse-parallel are provided.

Ac-dc converter, ac-dc converter control method, motor driving device, compressor driving device, air conditioner, and heat pump-type hot-water supply device

The power conversion device includes a power-supply shunt resistance provided between an inverter and the negative-voltage side of a DC power supply, respective-phase lower-arm shunt resistances provided between the power-supply shunt resistance and respective-phase lower-arm switching elements, a first overcurrent detection unit performing overcurrent detection on a current that flows through the power-supply shunt resistance on the basis of a power-supply shunt-resistance voltage, and a second overcurrent detection unit performing overcurrent detection on each current that flows through the respective-phase lower-arm shunt resistances on the basis of respective-phase lower-arm voltages, wherein overcurrent detection is performed on each phase current using either one of the overcurrent detection result of the first overcurrent detection unit and the overcurrent detection result of the second overcurrent detection unit.

Power conversion device, motor drive device including power conversion device, air blower and compressor including motor drive device, and air conditioner, refrigerator, and freezer including air blower and compressor

Makoto Tanikawa

Papers

AC-DC converter, method of controlling the same, motor driver, compressor driver, air-conditioner, and heat pump type water heater

Alternating-current direct-current converter and electric motor driver

AC-DC converter, air conditioner, and heat pump-type hot-water supply device

Ac-dc converter, ac-dc converter control method, motor driving device, compressor driving device, air conditioner, and heat pump-type hot-water supply device

Power conversion device, motor drive device including power conversion device, air blower and compressor including motor drive device, and air conditioner, refrigerator, and freezer including air blower and compressor