Abstract: A motor drive apparatus driving a motor as a three-phase motor converting direct current into three-phase alternating current, includes: inverter modules and equivalent in number to phases of the motor; and a control unit generating PWM signals used to drive the inverter modules with PWM. The inverter modules each include a plurality of switching element pairs connected in parallel, each of the switching element pairs including two switching elements connected in series.

Abstract: 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.

Abstract: An electric motor includes a stator, a rotor provided to be rotatable with respect to the stator, and a driving circuit board including a power IC applying a driving voltage to the stator, a Hall IC detecting a rotation position of the rotor, and a control IC adjusting a phase of the driving voltage in accordance with a magnetic-pole-position signal from the Hall IC and rotation speed information calculated on the basis of the magnetic-pole-position signal. The Hall IC is provided at a position at which an advance angle is larger than zero when a rotation speed of the rotor is zero.

Abstract: 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.

Abstract: A power converting device includes: a rectifying circuit connected to an alternating-current power supply for converting alternating-current power from the alternating-current power supply into direct-current power; a short-circuit unit constituted by a diode bridge and a short-circuit element connected to opposite output ends of the diode bridge for short-circuiting the alternating-current power supply via a reactor; and a control unit that generates plural drive signals to control the short-circuit unit during a half cycle of the alternating-current power supply. The control unit generates a sine-wave-shaped current control range that is a target control range of power supply current of the alternating-current power supply, and maintains values of the power supply current of the alternating-current power supply within the current control range.

Abstract: A switch device in a power conversion device is located between a power supply and a load, wherein the power conversion device includes a shunt resistance and a switching element and is capable of executing stable control, the switch device includes a switching element that includes a gate terminal, a gate drive circuit that applies a drive voltage Vcc to a gate terminal of the switching element, and a control unit that generates a drive signal to the gate drive circuit, wherein a value obtained by subtracting a threshold voltage Vth of the switching element from the drive voltage Vcc to be applied to the gate terminal of the switching element is greater than a product of a resistance value Rsh+Rdc from an emitter of the switching element to a negative electrode of the gate drive circuit and a maximum current value Ipeak that flows through the switching element.

Abstract: A power conversion device includes a rectifier circuit that converts an AC power from an AC power supply, into a DC power, a short-circuit unit that short-circuits the AC power supply via a reactor connected between the AC power supply and the rectifier circuit, a control unit that generates a plurality of drive signals to control the short-circuit unit in a half cycle of the AC power supply, and a smoothing capacitor. The control unit stepwise varies threshold values that limit a value of a power-supply current of the AC power supply, in an on-section or an off-section of the plurality of drive signals.

Abstract: A power conversion device is configured to have reactors and is configured to have chopper circuit units, connected in series, that chop the output of a rectifier configured to rectify an AC voltage from an AC power supply. The power conversion device includes: an AC switch disposed on a side closer to the AC power supply than the chopper circuit units; an AC reactor that is connected in parallel to the AC switch; and a switching control unit that stops the switching of the switching elements when the contact of the AC switch is open.

Abstract: A power conversion device includes a switching control unit that controls respective switching elements constituting a plurality of chopper circuits, a rectified-voltage detection unit, a bus-bar voltage detection unit, and a bus-bar current detection unit. The switching control unit includes an on-duty calculation unit that calculates a reference on-duty of respective drive pulses with respect to the switching elements based on a bus-bar voltage and a bus-bar current, an on-duty correction unit that corrects the reference on-duty to output on-duties of the respective drive pulses based on the bus-bar current, so that change amounts of respective reactor currents become substantially the same, and a drive-pulse generation unit that generates the respective drive pulses, based on the respective on-duties.

Abstract: An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.

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 motor drive apparatus driving a motor as a three-phase motor converting direct power into three-phase alternating power, includes: inverter modules equivalent in number to phases of the motor; and a control unit generating PWM signals used to drive the inverter modules with PWM. The inverter modules each include a plurality of switching element pairs connected in parallel, each of the switching element pairs including two switching elements connected in series.

Abstract: A power conversion device includes an inverter configured by arms including phase upper-arm switching elements and phase lower-arm switching elements, a power-supply shunt resistor, lower-arm shunt resistors, and a control unit that generates drive signals corresponding to the phase upper-arm switching elements and the phase lower-arm switching elements from detection values of the voltage detectors. The power conversion device changes a ratio of time in which all of the upper-arm switching elements are in an ON state and time in which all of the lower-arm switching elements are in the ON state in one cycle of switching of the inverter according to a modulation ratio.

Abstract: A motor drive apparatus driving a motor as a three-phase motor converting direct current into three-phase alternating current, includes: inverter modules and equivalent in number to phases of the motor; and a control unit generating PWM signals used to drive the inverter modules with PWM. The inverter modules each include a plurality of switching element pairs connected in parallel, each of the switching element pairs including two switching elements connected in series.

Abstract: A heat pump apparatus includes a compressor compressing a refrigerant, a motor driving the compressor, an inverter device, and an inverter control unit controlling the inverter device. The inverter device includes the same number of bridge circuits as those of phases of the motor, and each of the bridge circuits includes plural pairs of series-connected switching elements. The pairs of switching elements are connected in parallel. The inverter device applies to the motor a high-frequency voltage of a frequency at which the motor does not rotate.

Abstract: A power converter for converting electrical power from a power source to a load, including: a boosting device including a boost rectifier configured to prevent a backflow of a current from the load to the power source, the boosting device being configured to change a voltage of electrical power from the power source to a predetermined voltage; and a commutation device including: a commutation operation device configured to perform a commutation operation of directing a current flowing through the boosting device to an other path; and a commutation rectifier including a plurality of rectifiers and connected in series on the other path, the commutation rectifier being configured to rectify a current relating to commutation, thereby reducing a capacitance component.

Abstract: A power conversion device located between an AC power source and a load includes: a rectifier circuit unit that rectifies a voltage of the AC power source; a smoothing unit that smooths a DC voltage on the load side of the rectifier circuit unit; a short-circuiting unit that short-circuits the AC power source; a step-up reactor—located on the AC power source side of the short-circuiting unit; at least one of a reactor current detecting unit—that detects the current of the step-up reactor and a bus voltage detecting unit that detects an output voltage of the smoothing unit; a counterflow preventing element that prevents a counterflow of the current from the smoothing unit to the AC power source; a switching control unit that outputs a control signal for the short-circuiting unit; and a switching frequency changing unit that changes a frequency of the control signal using a logic operation.

Abstract: A power converting device includes: a rectifying circuit connected to an alternating-current power supply for converting alternating-current power from the alternating-current power supply into direct-current power; a short-circuit unit constituted by a diode bridge and a short-circuit element connected to opposite output ends of the diode bridge for short-circuiting the alternating-current power supply via a reactor; and a control unit that generates plural drive signals to control the short-circuit unit during a half cycle of the alternating-current power supply. The control unit generates a sine-wave-shaped current control range that is a target control range of power supply current of the alternating-current power supply, and maintains values of the power supply current of the alternating-current power supply within the current control range.

Abstract: A power conversion apparatus includes a rectifier, a converter including a reactor, a switching element, and a reverse current prevention element, a smoothing capacitor configured to smooth the output voltage, a current detector configured to detect a reactor current, a voltage detector configured to detect the output voltage, and a converter control unit configured to control operation of the switching element of the converter. The converter-control unit includes a switching command calculation unit configured to calculate a switching command value responsive to a ratio of the rectified voltage to the output voltage in accordance with the output voltage and the reactor current, a switching control unit configured to control operation of the switching element in accordance with the switching command value, and a supply abnormality determination unit configured to determine occurrence of a momentary power failure or voltage sag in accordance with the switching command value.

Abstract: A power conversion device includes a rectifier circuit that converts an AC power from an AC power supply, into a DC power, a short-circuit unit that short-circuits the AC power supply via a reactor connected between the AC power supply and the rectifier circuit, a control unit that generates a plurality of drive signals to control the short-circuit unit in a half cycle of the AC power supply, and a smoothing capacitor. The control unit stepwise varies threshold values that limit a value of a power-supply current of the AC power supply, in an on-section or an off-section of the plurality of drive signals.