Abstract: A heat pump device capable of efficiently and reliably preventing a liquid refrigerant from stagnating in a compressor an air conditioner, a heat pump water heater, a refrigerator, and a freezing machine including the heat pump device. The configuration is such that, when the compressor is under operation standby, a high-frequency voltage synchronizing with a carrier signal is supplied to the compressor motor to carry out the locked energization of the compressor motor. From respective inter-phase voltages, respective phase voltages, or respective phase currents of the compressor motor for a plurality of high-frequency energization cycles, the detection values for one high-frequency energization cycle are restored. A power value calculated using the restored detection values for one high-frequency energization cycle is controlled to coincide with a heating power command necessary for discharging the liquid refrigerant stagnated in the compressor to the outside of the compressor.

Abstract: A heat pump device that can efficiently feed a high-frequency current to an electric motor and effectively heat a compressor includes a compressor including a compression mechanism configured to compress a refrigerant and a motor configured to drive the compression mechanism, heat exchangers, an inverter configured to apply a voltage to the motor, and an inverter control unit configured to drive the inverter. The inverter control unit includes a stagnation detecting unit configured to determine whether heating of the compressor is necessary and notify the determination result and a high-frequency-alternating-current-voltage generating unit and a PWM-signal generating unit configured to shift to a heating operation mode when the heating is necessary and, in the heating operation mode, generate PWM signals to provide, based on a heating time carrier signal having two or more frequencies, a period in which a reflux current flows.

Abstract: A DC power-supply device that suppresses an increase of a harmonic current and deterioration of a power factor without causing any imbalance among respective phase currents, in a configuration in which a three-phase alternating current is converted into a direct current and supplied to a load. The DC power-supply device includes a rectifier circuit, a reactor connected to an input side or an output side of the rectifier circuit, a first capacitor and a second capacitor serially connected between output terminals to a load, and a charging unit. During a cycle combining a charging period and a non-charging period of a pair of the first capacitor and the second capacitor, the charging unit is controlled so that a charging frequency becomes 3n times (n is a natural number) the frequency of the three-phase alternating current.

Abstract: A high efficiency refrigerant compressor standby heating method reduces vibrations and noise in a bearing of the compressor. The compressor comprises a motor, an inverter, an inverter controller, and a bus voltage detector to detect a bus voltage of the inverter. The inverter controller includes a dormant refrigerant detector to detect a dormant state of refrigerant in the compressor, a high-frequency AC voltage generator to output a high-frequency AC voltage command, which is out of a range of an operating frequency when the compressor is running, to a coil of the motor on the basis of an output of the dormant refrigerant detector, an amplitude, and a phase. A pulse width modulation signal generator to cause the inverter to generate a high-frequency AC voltage by generating a signal on the basis of the output of the high-frequency AC voltage generator and the output of the bus voltage detector.

Abstract: A motor driving circuit includes a magnetic-pole-position detecting unit that detects a rotating position of a rotor of a permanent magnet synchronous motor, a voltage output unit that converts a direct-current voltage and generates a driving voltage for the permanent magnet synchronous motor, a voltage control unit that controls the voltage output unit on the basis of a comparison result of a modulation wave and a carrier wave, a voltage-phase adjusting unit that determines, using a differential amplifier circuit that receives a rotating speed control signal and an offset signal, a phase of the modulation wave generated by the voltage control unit and causes the voltage control unit to generate the modulation wave in the determined phase, and an offset generating unit that generates the offset signal.

Abstract: A charging/discharging device includes a charging/discharging connector that electrically connects a storage battery and the charging/discharging device, a cable that is connected to the charging/discharging connector at one end and is connected to the charging/discharging device at the other end, a power conversion unit, a control unit that controls an operation of the power conversion unit, and an abnormality detection unit that outputs an abnormality detection signal for stopping an operation of the power conversion unit to at least any of the control unit and the power conversion unit, when an output from a comparator and an ON signal from the control unit are input to an AND circuit.

Abstract: An object of the present invention is to efficiently heat a refrigerant retained in a compressor. An inverter control unit generates six drive signals corresponding to the respective switching elements of the inverter, and outputs the generated drive signals to the corresponding switching elements of the inverter to cause the inverter to generate a high-frequency AC voltage. Particularly, the inverter control unit generates a drive signal having a switching pattern A for turning on all the three switching elements on a positive voltage side or a negative voltage side of the inverter, and subsequent thereto, generates a drive signal having a switching pattern B for turning on two switching elements of the three switching elements and turning off one switching element thereof.

Abstract: A heat pump device includes: a compressor that compresses a refrigerant; a motor that drives the compressor; a wiring switching unit that switches a wiring structure of the motor; an inverter that applies a desired voltage to the motor; and an inverter control unit that generates a PWM signal for driving the inverter, that includes, as an operation mode, a heating operation mode in which a heating operation is performed on the compressor and a normal operation mode in which a refrigerant is compressed by performing a normal operation on the compressor, and that controls a switching operation of the wiring switching unit in accordance with an operation mode.

Abstract: 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.

Abstract: A heat pump device includes a compressor including a compression mechanism that compresses a refrigerant and a motor that drives the compression mechanism, an inverter that applies a voltage for driving the motor, a converter that applies a voltage to the inverter, an inverter control unit that generates a driving signal for driving the inverter, and a converter control unit that generates a driving signal for driving the converter, wherein the inverter control unit includes a heating operation mode in which a heating operation of the compressor is performed and a normal operation mode in which a refrigerant is compressed by performing a normal operation of the compressor and the converter control unit sets, in the heating operation mode of the inverter control unit, a voltage applied to the inverter on the basis of a voltage command value for the motor.

Abstract: The air-conditioning apparatus includes a coolant circuit configured by sequentially connecting a compressor, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger; a motor that operates a compressor mechanism disposed inside the compressor; an inverter for driving the motor; and a control unit that controls the inverter. The control unit includes a liquefaction detecting unit that detects coolant liquefaction in the compressor; includes a first PWM signal generating unit that generates an inverter control signal for driving the motor; includes a second PWM signal generating unit that generates an inverter control signal for making the motor perform a preheating operation; and includes a switching unit that performs switching in such a way that the first PWM signal generating unit or the second PWM signal generating unit outputs the corresponding inverter control signal to the inverter.

Abstract: An air conditioner includes: an outdoor fan provided in an outdoor unit; a permanent magnet synchronous motor that drives the outdoor fan; an inverter that uses a DC power source as a power source and applies a voltage to the permanent magnet synchronous motor; an inverter control means that controls the output voltage of the inverter; and a shunt resist connected between the DC power source and the inverter. If the outdoor fan is rotating due to an external force while the inverter is stopped, the inverter control means causes the inverter to operate using a brake sequence that brakes the rotation of the outdoor fan, and then causes the inverter to operate using a drive sequence that power-drives the outdoor fan.

Abstract: A motor driving circuit includes a magnetic-pole-position detecting unit that detects a rotating position of a rotor of a permanent magnet synchronous motor, a voltage output unit that converts a direct-current voltage and generates a driving voltage for the permanent magnet synchronous motor, a voltage control unit that controls the voltage output unit on the basis of a comparison result of a modulation wave and a carrier wave, a voltage-phase adjusting unit that determines, using a differential amplifier circuit that receives a rotating speed control signal and an offset signal, a phase of the modulation wave generated by the voltage control unit and causes the voltage control unit to generate the modulation wave in the determined phase, and an offset generating unit that generates the offset signal.

Abstract: 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 coolant sleeping amount in the compressor, and, when having determined that heating to the compressor is necessary, selects, according to the coolant sleeping 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.

Abstract: The present invention is a heat pump device that includes a compressor including a compression mechanism and a motor, a heat exchanger, an inverter, and an inverter control unit including a drive-signal generation unit generating a drive signal for the inverter and a heating-operation-mode control unit controlling the drive-signal generation unit when the compressor is heated by applying, to the motor, a high-frequency voltage with which the motor cannot be rotationally driven, wherein the heating-operation-mode control unit includes a magnetic-pole-position estimation unit estimating a magnetic pole position indicating a stop position of a rotor of the motor, and a high-frequency energization unit determining 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, notifies the drive-signal generation unit of determined amplitude and phase, and causes the drive-signal generation unit to generate a drive signal.

Abstract: A power supply switching device and switch board checks whether or not a primary-side voltage of a remote shutoff breaker and a secondary-side voltage thereof become a rated voltage after a commercial power system is recovered from a blackout. Next, when both primary-side voltage and secondary-side voltage become the rated voltage, a contactor is actuated to interconnect a home power system with the commercial power system. Hence, charging of the home power system without causing a user to notice such a charging upon recovery of the commercial power system from a blackout can be prevented. As a result, the safety for the user can be ensured.

Abstract: A converter circuit capable of being compact and light-weight and capable of reducing switching loss, a motor drive control apparatus, an air-conditioner, a refrigerator, and an induction heating cooker provided with the circuit. The converter circuit including: a step-up converter including a rectifier, a step-up reactor, a switching element, and a reverse current prevention element; a step-up converter having a step-up reactor, a switching element, and a reverse current prevention element and connected in parallel with the step-up converter; switching control unit that controls switching elements; and a smoothing capacitor that is provided at the output of the step-up converters. The switching control unit switches the current mode of the current flowing through the step-up reactors into any of a continuous mode, a critical mode, and a discontinuous mode based on a predetermined condition.

Abstract: A drive device driving a power converter that includes a switching element formed from a wide bandgap semiconductor, includes a PWM-signal output unit that generates a drive signal that drives the switching element with PWM; an on-speed reducing unit that, when the switching element is changed from off to on, reduces a change rate of the drive signal; and an off-speed improving unit that, when the switching element is changed from on to off, draws charge from the switching element at a high speed and with a charge drawing performance higher than that at a time when the switching element is changed from off to on.

Abstract: A converter circuit including a step-up converter including a rectifier, a step-up reactor, a switching element, and a reverse current prevention element; a step-up converter having a step-up reactor, a switching element, and a reverse current prevention element and connected in parallel with the step-up converter; a switching control unit that controls switching elements; and a smoothing capacitor that is provided at the output of the step-up converters. The switching control unit switches the current mode of the current flowing through the step-up reactors into any of a continuous mode, a critical mode, and a discontinuous mode based on a predetermined condition.

Abstract: A direct-current power supply device includes a reactor, one end of which is connected to one output end of an alternating-current power supply, a switching unit for short-circuiting the other end of the reactor and the other output end of the alternating-current power supply, a rectifying unit configured to rectify an alternating-current voltage supplied from the alternating-current power supply and generate a voltage equal to or higher than a double voltage, a smoothing capacitor connected to the rectifying unit via backflow preventing diodes and configured to smooth a direct-current voltage output from the rectifying unit, and a control unit configured to control the switching unit and stop the supply of the alternating-current voltage to the rectifying unit in a predetermined period after a predetermined time has elapsed from a zero cross point of the alternating-current voltage output from the alternating-current power supply.