Abstract: A refrigerant circuit includes a compressor, an outdoor heat exchanger, a throttle device, an indoor heat exchanger, and a four-way valve, and it is configured such that refrigerant circulates therethrough. An inverter is configured to control the compressor as being variable in speed. The refrigerant circuit is configured to perform a defrosting operation in which refrigerant discharged from the compressor is introduced into the outdoor heat exchanger. The compressor includes a motor. The inverter has, as an operation mode, a speed control mode in which the motor is controlled such that a rotation speed thereof is closer to a rotation speed corresponding to a command value and an output control mode in which the rotation speed of the motor is controlled such that output from the motor is closer to a target value. The inverter is configured to operate by using the output control mode in the defrosting operation.

Abstract: A power supply control device includes: a power conversion device; a controller; a current detection device; a comparison device configured to output a shut-off start signal when a value of current detected by the current detection device is larger than a preset current threshold value; a shut-off device configured to shut off, based on a shut-off control signal, a conversion operation signal; a latch device configured to output the shut-off control signal based on the shut-off start signal output by the comparison device and to perform, until a latch release signal is input, a latch operation, in which the shut-off device is caused to maintain a state in which a conversion operation signal is shut off; and a delay device configured to output a latch release signal after a delay time elapses, the delay time being determined by components of the delay device.

Abstract: A motor control device includes: a power converter to which a first motor and a second motor are connected in parallel, the power converter being configured to convert a direct-current voltage into an alternating-current voltage and supply the alternating-current voltage to the first motor and the second motor; a switching unit provided between the second motor and the power converter; a current detector configured to detect an electric current flowing through the first motor and the second motor; and a controller configured to control the power converter based on at least a current value detected by the current detector. The controller deactivates the power converter upon receiving from outside an abnormal step signal, attributed to the occurrence of an abnormality, that excludes a normal stop signal representing a stop command and switches the switching unit from an on state to an off state upon deactivation of the power converter.

Abstract: A motor control device includes a power converter that supplies a three-phase voltage to two motors being connected in parallel, a three-phase power line that connects between one of the two motors and the power converter, a branch three-phase power line that connects between the other of the two motors and the power converter, a switching device having two switches that are provided on the branch three-phase power line, a current detection device that detects three-phase currents flowing in the two motors, and a controller. The controller performs a failure determination of the switching device by identifying a phase of a power line in which no current flows in the three-phase power line and the branch three-phase power line, and, when a failure is detected in one of the two switches in the failure determination, controls to change a state of the other switch, which operates normally, to coincide with a state of the failed switch.

Abstract: A power converter includes a rectifier configured to rectify an AC voltage supplied from an AC power supply, a booster circuit configured to boost the voltage rectified by the rectifier, a smoothing capacitor configured to smooth the voltage output from the booster circuit, a power module configured to convert a DC voltage obtained by smoothing the output voltage by the smoothing capacitor into an AC voltage, and a snubber capacitor configured to absorb a surge voltage superimposed on the DC voltage to be input to the power module. The snubber capacitor is mounted in the power module.

Abstract: A motor control device includes a power converter that supplies a three-phase voltage to two motors being connected in parallel, a three-phase power line that connects between one of the two motors and the power converter, a branch three-phase power line that connects between the other of the two motors and the power converter, a switching device having two switches that are provided on the branch three-phase power line, a current detection device that detects three-phase currents flowing in the two motors, and a controller. The controller performs a failure determination of the switching device by identifying a phase of a power line in which no current flows in the three-phase power line and the branch three-phase power line, and, when a failure is detected in one of the two switches in the failure determination, controls to change a state of the other switch, which operates normally, to coincide with a state of the failed switch.

Abstract: An electric motor control device that drives and controls a plurality of electric motors connected in parallel, includes: a power conversion device; a current detection device; and a controller that includes a first control unit to perform first control on each of the plurality of electric motors based on the electric current, a second control unit to perform second control of controlling the plurality of electric motors such that an estimated speed of each of the plurality of electric motors obtained based on the current value follows the speed command value, and a switching determination unit to perform switching determination processing of switching between the first control performed by the first control unit and the second control performed by the second control unit according to drive information on at least one or more of the plurality of electric motors.

Abstract: A motor control device includes: an inverter circuit configured to convert a direct-current voltage into an alternating-current voltage, and to supply the alternating-current voltage to a plurality of motors connected in parallel; current detectors configured to detect motor currents flowing through the respective motors; a relay provided between at least one of the plurality of motors and the inverter circuit; and a controller configured to change the number of motors to be driven. When one of two or more motors under driving is stopped, the controller lowers a current instruction value to the two or more motors under driving. When a monitor current that is the motor current detected by the current detector of the motor connected to the relay is decreased, the controller switches the relay from an on state to an off state.

Abstract: A motor control device includes: a power converter to which a first motor and a second motor are connected in parallel, the power converter being configured to convert a direct-current voltage into an alternating-current voltage and supply the alternating-current voltage to the first motor and the second motor; a switching unit provided between the second motor and the power converter; a current detector configured to detect an electric current flowing through the first motor and the second motor; and a controller configured to control the power converter based on at least a current value detected by the current detector. The controller deactivates the power converter upon receiving from outside an abnormal step signal, attributed to the occurrence of an abnormality, that excludes a normal stop signal representing a stop command and switches the switching unit from an on state to an off state upon deactivation of the power converter.

Abstract: A motor control device includes: an inverter circuit configured to convert a direct-current voltage into an alternating-current voltage, and to supply the alternating-current voltage to a plurality of motors connected in parallel; current detectors configured to detect motor currents flowing through the respective motors; a relay provided between at least one of the plurality of motors and the inverter circuit; and a controller configured to change the number of motors to be driven. When one of two or more motors under driving is stopped, the controller lowers a current instruction value to the two or more motors under driving. When a monitor current that is the motor current detected by the current detector of the motor connected to the relay is decreased, the controller switches the relay from an on state to an off state.

Abstract: A power converter that includes a rectifier rectifying a voltage supplied from a three-phase AC power supply, a voltage step-down circuit including a voltage step-down switching element, a reactor, a backflow prevention element, and a smoothing capacitor and stepping down a DC voltage supplied from the rectifier, and an inverter circuit converting the DC voltage smoothed by the smoothing capacitor into an AC voltage. The power converter includes an imbalance determining unit determining, based on states of the voltage step-down circuit and the smoothing capacitor, whether or not voltage imbalance has occurred in the three-phase AC power supply and a voltage step-down control unit performing switching of the voltage step-down switching element in a case where the imbalance determining unit determines that the voltage imbalance has occurred.

Abstract: An electric motor control device controls driving of electric motors connected in parallel with each other and includes a power converter converting power from a power supply, and supply the converted power to each of the electric motors, a switching device to be turned on to electrically connect the power converter and at least one of the electric motors and to be turned off to electrically disconnect the power converter and the at least one of the electric motors, a current detection unit detecting a current that flows in the electric motors, and a controller controlling the power converter on the basis of operation of the switching device, rotation frequency command values from an external device, and a value of the current detected by the current detection unit. The controller turns the switching device from off to on so that start timing of control is different for each electric motor.

Abstract: A drive system includes a current detection unit that detects a current flowing to a main synchronous motor, and a current detection unit that detects a current flowing to a secondary synchronous motor. The drive system includes a magnetic pole position estimation unit that estimates the magnetic pole position of the rotor of the main synchronous motor, and a magnetic pole position estimation unit that estimates the magnetic pole position of the rotor of the secondary synchronous motor. The drive system includes a current control unit that outputs a voltage command, and a secondary torque current pulsating component extraction unit that extracts a pulsating component. The drive system includes a subtracter that determines an angle difference, and a magnetic flux current command determination unit that determines a magnetic flux current command.

Abstract: An electric motor control device that drives and controls a plurality of electric motors connected in parallel, includes: a power conversion device; a current detection device; and a controller that includes a first control unit to perform first control on each of the plurality of electric motors based on the electric current, a second control unit to perform second control of controlling the plurality of electric motors such that an estimated speed of each of the plurality of electric motors obtained based on the current value follows the speed command value, and a switching determination unit to perform switching determination processing of switching between the first control performed by the first control unit and the second control performed by the second control unit according to drive information on at least one or more of the plurality of electric motors.

Abstract: A motor control device includes an inverter configured by a plurality of arms, a smoothing unit supplying a direct-current voltage to the inverter, a shunt resistor inserted between a lower-arm switching element for each phase of the inverter and a negative-electrode side of the smoothing unit, a master motor current sensor outputting a voltage according to a current flowing in a first motor connected in parallel to the inverter, and a computing unit generating driving signals for a plurality of switching elements based on an output of the master motor current sensor and an output corresponding to a voltage drop on the shunt resistor.

Abstract: A drive system includes a current detection unit that detects a current flowing to a main synchronous motor, and a current detection unit that detects a current flowing to a secondary synchronous motor. The drive system includes a magnetic pole position estimation unit that estimates the magnetic pole position of the rotor of the main synchronous motor, and a magnetic pole position estimation unit that estimates the magnetic pole position of the rotor of the secondary synchronous motor. The drive system includes a current control unit that outputs a voltage command, and a secondary torque current pulsating component extraction unit that extracts a pulsating component. The drive system includes a subtracter that determines an angle difference, and a magnetic flux current command determination unit that determines a magnetic flux current command.

Abstract: An electric motor control device controls driving of electric motors connected in parallel with each other and includes a power converter converting power from a power supply, and supply the converted power to each of the electric motors, a switching device to be turned on to electrically connect the power converter and at least one of the electric motors and to be turned off to electrically disconnect the power converter and the at least one of the electric motors, a current detection unit detecting a current that flows in the electric motors, and a controller controlling the power converter on the basis of operation of the switching device, rotation frequency command values from an external device, and a value of the current detected by the current detection unit. The controller turns the switching device from off to on so that start timing of control is different for each electric motor.

Abstract: A power converter includes a rectifier configured to rectify an AC voltage supplied from an AC power supply, a booster circuit configured to boost the voltage rectified by the rectifier, a smoothing capacitor configured to smooth the voltage output from the booster circuit, a power module configured to convert a DC voltage obtained by smoothing the output voltage by the smoothing capacitor into an AC voltage, and a snubber capacitor configured to absorb a surge voltage superimposed on the DC voltage to be input to the power module. The snubber capacitor is mounted in the power module.

Abstract: A power converter that includes a rectifier rectifying a voltage supplied from a three-phase AC power supply, a voltage step-down circuit including a voltage step-down switching element, a reactor, a backflow prevention element, and a smoothing capacitor and stepping down a DC voltage supplied from the rectifier, and an inverter circuit converting the DC voltage smoothed by the smoothing capacitor into an AC voltage. The power converter includes an imbalance determining unit determining, based on states of the voltage step-down circuit and the smoothing capacitor, whether or not voltage imbalance has occurred in the three-phase AC power supply and a voltage step-down control unit performing switching of the voltage step-down switching element in a case where the imbalance determining unit determines that the voltage imbalance has occurred.

Abstract: A motor control device includes an inverter configured by a plurality of arms, a smoothing means supplying a direct-current voltage to the inverter, a shunt resistor inserted between a lower-arm switching element for each phase of the inverter and a negative-electrode side of the smoothing means, a master motor current sensor outputting a voltage according to a current flowing in a first motor connected in parallel to the inverter, and a computing unit generating driving signals for a plurality of switching elements based on an output of the master motor current sensor and an output corresponding to a voltage drop on the shunt resistor.