Abstract: A converter for converting AC power from an AC power supply into DC power and outputting the DC power, an inverter for converting the DC power outputted from the converter into AC power of a variable frequency and a variable voltage value, and supplying the AC power to a load, a shunt resistor for detecting an output current of the converter, and a control device for controlling the inverter based on the detected output current are provided. The control device calculates an input current of the converter from the output current detected by the shunt resistor, and, when the calculated input current exceeds a predetermined threshold value, the control device causes the manner of operation of said inverter to be changed so as to reduce the input current of the converter.

Abstract: 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.

Abstract: In a control device performing PWM control over an inverter for driving a motor, voltage command values are generated using voltage values obtained by performing proportional and integral calculation on current deviations and non-interference control during normal operation, and the voltage command values are generated without using the result of the integral calculation and performing only the non-interference control, at the time of over-modulation. Moreover, the voltage command values are corrected based on a modulation factor. A correction coefficient is so determined that the AC voltages applied to the motor become close to values proportional to the modulation factor. The motor can be operated over a wide range within an over-modulation range.

Abstract: 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.

Abstract: A power converter includes a converter circuit, a capacitor, and an inverter circuit. The converter circuit includes diodes that are connected in a half-bridge configuration. An alternating-current input end of the converter circuit is connected to one side of an alternating-current power supply. The inverter circuit includes semiconductor switching elements that are connected in a three-phase bridge configuration. An alternating-current output end of the inverter circuit is connected to a motor as a load, and an alternating-current output end is further connected to another side of the alternating-current power supply.

Abstract: 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.

Abstract: A direct current power supply device 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; an inrush current preventing circuit disposed on a charging path from the alternating current power supply to the smoothing capacitor; a current detection unit detecting direct current representing an operating state on an output side of the converter; a current detection unit detecting power supply current representing an operating state on an input side of the converter; and a control unit receiving the direct current and the power supply current and controlling an operation of the converter. The control unit receives a detected value of saturated current from at least one of the direct current and the power supply current when the power supply voltage recovers from a state in which the power supply voltage is reduced.

Abstract: 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.

Abstract: An inverter for driving a motor that has a switchable connection of windings and drives a load element having a periodically varying load torque is provided. The inverter is controlled so that an output torque of the motor follows the periodic variation of the load torque. The inverter is controlled so that a current flowing through the motor is zero during a period including a minimum torque phase at which the load torque is at or near a minimum value. The connection is switched while the current flowing through the motor is zero. It is possible to switch the connection of the windings while the motor is rotating, and avoid an increase in apparatus size.

Abstract: A motor driver for driving a motor including three-phase windings includes: an inverter that applies a desired voltage to the motor; and an inverter controller that controls an operation of the inverter. The inverter includes: a current detector that detects a direct current in a first connecting line among three-phase connecting lines connecting the respective three-phase windings and the inverter; and a current detector that detects an alternating current in a second connecting line among the three-phase connecting lines, and a maximum direct current is caused to flow to the first connecting line in a first control mode for positioning a rotor of the motor.

Abstract: A motor driving device includes: a connection switcher that has an electromagnetic contactor connected to a winding of a motor and switches connection condition of the winding by switching condition of the electromagnetic contactor; an inverter to apply an output voltage as an AC voltage to the winding via the connection switcher; a short-circuiting circuit having a rectification circuit and a switch; and a controller to control the electromagnetic contactor, the inverter and the switch, wherein a circulating circuit is formed by the short-circuiting circuit and the winding when the switch is set at ON, and the connection switcher switches the connection condition of the winding in a period in which the output voltage of the inverter is set at zero in a rotating operation of the motor and a current caused by the rotating operation circulates in the circulating circuit.

Abstract: A motor drive device that drives motors with one inverter includes a step-out control unit that detects step-out in which the operating frequency of at least one of the motors does not match the inverter output frequency, or the operating frequency of at least one of the motors does not match the operating frequency of another one of the motors, and stops the motors by switching an energization state of the inverter when at least one of the motors is out of step.

Abstract: A power converter for converting a voltage of direct-current power output from a direct-current power supply, the power converter including: a printed circuit board; a reactor being configured with a conductor pattern of the printed circuit board; a semiconductor element that is connected to another end of the reactor and performs switching for storing electrical energy in the reactor so as to boost the voltage of the direct-current power from a first voltage to a second voltage; a capacitor that smooths the direct-current power boosted to the second voltage; a diode that is connected to the another end of the reactor and supplies the direct-current power boosted to the second voltage to the capacitor; and a cooler, wherein the reactor, the semiconductor element, and the diode are included in a module in a single package, and the module is cooled by the cooler.

Abstract: A motor driving apparatus for driving a single-phase motor includes an inverter disposed between a battery and the single-phase motor, the inverter applying a first voltage to the single-phase motor at startup and applying a second voltage to the single-phase motor during a normal operation. A stop time period is present after application of the first voltage, application of the first voltage being stopped during the stop time period, and the inverter applies the second voltage after a lapse of the stop time period.

Abstract: In a motor driving apparatus having an inverter which can drive n (n being an integer not smaller than 2) motors each having a permanent magnet in its rotor, and a connection switching device for switching the connection state of the n motors, the connection switching device is operated to change the number of the motors connected to the inverter thereby to change the impedance as seen from the inverter towards the motors. When i (i being any of 2 to n) motors among the n motors are concurrently driven by the inverter, the voltage outputted by the inverter may be controlled such that the inductance values of the i motors are identical. It is possible to prevent hunting and step-out due to the phase difference between the motors driven by the inverter.

Abstract: A controller includes: a connection switch that switches a connection state of a winding of a synchronous motor during a rotating operation of the synchronous motor; a current detector that detects a rotary machine current flowing in the synchronous motor; a position/speed estimator that estimates a magnetic pole position and speed of a rotor; a voltage applicator that applies a voltage to the synchronous motor; and a control circuitry that generates a voltage command given to the voltage applicator on the basis of the magnetic pole position and the speed, and outputs a switching operation command for switching the connection state to the connection switch. The control circuitry generates the voltage command to bring the rotary machine current close to zero before the connection state of the winding is switched.

Abstract: 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.

Abstract: A refrigerating cycle device includes a compressor, a motor, and a wiring switch part. The compressor compresses a refrigerant. The motor generates power for compressing the refrigerant by rotating a rotor with voltage applied to a plurality of wirings. The motor is disposed in the compressor. The wiring switch part switches between a plurality of wiring states by changing connection between the plurality of wirings. When a rotational speed of the rotor exceeds a predetermined value, the wiring switch part switches to a first wiring state of the plurality of wiring states. The first wiring state differs from a second wiring state of the plurality of wiring state. Efficiency of the second wiring state is highest at the rotational speed.

Abstract: 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.

Abstract: 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.