Abstract: A power conversion apparatus includes a converter that rectifies a first alternating-current voltage supplied from an alternating-current power supply that is a three-phase alternating-current power supply, a capacitor connected to an output end of the converter and smooths a first direct-current voltage obtained by rectification by the converter into a second direct-current voltage containing a first ripple, an inverter that is connected across the capacitor and converts the second direct-current voltage into a second alternating-current voltage dependent on a desired frequency, and a voltage detection unit that detects a physical quantity correlated with the second direct-current voltage, in which the second alternating-current voltage is controlled such that a second ripple correlated with the first ripple is superimposed on an output voltage from the inverter.

Abstract: A power converter installed in a refrigeration cycle applied equipment includes a rectifier configured to rectify a first alternating-current power supplied from a commercial power supply, a capacitor connected to output ends of the rectifier, an inverter configured to convert power output from the rectifier and the capacitor into a second alternating-current power and to output the second alternating-current power to a motor, and a controller configured to control an operation of the inverter such that the second alternating-current power containing pulsation according to pulsation of power flowing into the capacitor from the rectifier is output from the inverter and to reduce current flowing to the capacitor. The power converter is configured to operate such that the pulsation width of the pulsating current generated by the second alternating-current power is different depending on whether an operation of the refrigeration cycle applied equipment is a cooling operation or a heating operation.

Abstract: A power converting apparatus includes: an inverter that is a power converting unit including switching elements and generating desired power by switching the switching elements; current detecting units detecting a current flowing through the power converting unit; and snubber circuits reducing a surge voltage generated by a switching operation of the switching elements. Circuits each including the switching elements and the current detecting unit are circuits to be protected by the snubber circuits, and the snubber circuits and the circuits to be protected are connected such that an internal inductance of a circuit consisting of the snubber circuit and the circuit to be protected is smaller than an external inductance.

Abstract: A power converting apparatus includes a rectifier unit that rectifies a supply voltage applied from a commercial power supply, a capacitor connected to an output end of the rectifier unit, an inverter that converts direct-current power output from the capacitor into alternating-current power and outputs the alternating-current power to a device including a motor, current detection units that detect a power state of the capacitor, and a control unit that performs, by controlling the inverter, load pulsation compensation and power-supply pulsation compensation and adjusts a degree of at least one of the load pulsation compensation and the power-supply pulsation compensation on a basis of detection values of the current detection units. The load pulsation compensation is performed to compensate a load pulsation in a load unit including the inverter and the device. The power-supply pulsation compensation is performed to compensate a power-supply pulsation in the load unit.

Abstract: A power conversion device includes a converter that rectifies a first alternating-current power supplied from an alternating-current power supply and boosts a voltage of the power rectified; a smoothing unit connected to an output end of the converter; and a control unit that controls the converter to cause an input current to the converter to change in accordance with at least one of a first frequency or a second frequency, and that reduces a current flowing to the smoothing unit, the first frequency being a frequency of pulsation of input power to a load unit connected across the smoothing unit, the second frequency being a frequency of pulsation of input power to the converter due to a frequency of the alternating-current power supply.

Abstract: A power converter includes: a rectifier unit that rectifies a power supply voltage applied from a commercial power supply; a capacitor connected to an output end of the rectifier unit; an inverter that converts direct-current power output from the capacitor into alternating-current power and outputs the alternating-current power to a device equipped with a motor; and a control unit that performs power supply ripple compensation control of reducing ripple of a capacitor current, which is a charge/discharge current of the capacitor, by controlling the inverter. The control unit determines whether or not a compensation operation by the power supply ripple compensation control is normal and, when determining that the compensation operation is not normal, performs control of reducing a drive speed of the motor or stopping driving of the motor.

Abstract: The power converting apparatus includes a rectifier unit rectifying first alternating-current power, a capacitor connected to the rectifier unit, an inverter connected across the capacitor to output second alternating-current power to a motor, a voltage detection unit detecting a power state of the capacitor, and a control unit controlling operations of the inverter and the motor, using a dq-rotational coordinate system rotating in synchronization with a rotor position of the motor. The control unit superimposes a q-axis current pulsation on a drive pattern of the motor in accordance with a detection value of the voltage detection unit to reduce a charge-discharge current of the capacitor, and to cause a d-axis current to the motor to pulsate in synchronization with a frequency that is a positive integer multiple of a frequency of the q-axis current pulsation saturation of a voltage of the inverter.

Abstract: A power converter includes a capacitor connected to an output end of a rectifier unit that rectifies first AC power, an inverter that is connected across the capacitor and generates second AC power for output to a motor, and a control unit that controls the operation of the inverter such that pulsation according to the power state of the capacitor is superimposed on a drive pattern of the motor. The control unit performs load pulsation compensation control to reduce the vibration of the motor and power pulsation compensation control to reduce the charging and discharging current of the capacitor while preferentially performing constant current load control to control the rotational speed of the motor, and generates a torque current command for the load pulsation compensation control such that a torque current command allocatable to the power pulsation compensation control remains.

Abstract: A motor drive device includes a single-phase inverter that converts a direct-current voltage into an alternating-current voltage applied to a motor. The motor drive device includes a control power supply outputting power having a voltage lower than the direct-current voltage. The motor drive device includes a drive signal generation unit driven by the power. The drive signal generation unit generates drive signals driving switching elements of the inverter. The motor drive device includes a power supply switch operating so as to allow supply of the power from the control power supply to the drive signal generation unit when a rotation speed of the motor is higher than a threshold. The power supply switch operates so as to stop the supply of the power from the control power supply to the drive signal generation unit when the rotation speed is lower than the threshold.

Abstract: An electric blower includes a fan, a motor to drive the fan, a first board including at least one switching element, and a second board including a microcomputer. The motor, first board, and second board are arranged in this order in a blowing direction of the fan.

Abstract: A power converter includes: a rectifying and boosting unit that rectifies first alternating-current power supplied from a commercial power supply and boosts a voltage of the first alternating-current power; a capacitor connected to an output end of the rectifying and boosting unit; an inverter to convert power output from the rectifying and boosting unit and the capacitor into second alternating-current power, and output the second alternating-current power to a device; and a control unit that reduces a current flowing through the capacitor by controlling the rectifying and boosting unit and by controlling the inverter such that the inverter outputs, to the device, the second alternating-current power containing a ripple dependent on a ripple of power flowing from the rectifying and boosting unit into the capacitor. The control unit controls operation of the power converter in accordance with an air-conditioning condition of an air conditioner.

Abstract: A power converter includes: a rectifying and boosting unit that rectifies first alternating-current power supplied from a commercial power supply and boosts a voltage of the first alternating-current power; a capacitor connected to an output end of the rectifying and boosting unit; an inverter to convert power output from the rectifying and boosting unit and the capacitor into second alternating-current power, and output the second alternating-current power to a device; and a control unit that reduces a current flowing through the capacitor by controlling the rectifying and boosting unit and by controlling the inverter such that the inverter outputs, to the device, the second alternating-current power containing a ripple dependent on a ripple of power flowing from the rectifying and boosting unit into the capacitor. The control unit controls in accordance with a load state.

Abstract: A power converting apparatus includes a converter, a smoothing unit, inverters, and a control unit. The inverters are connected to the converter, the inverters being in parallel connection with each other. The inverter converts power output from the smoothing unit into a first alternating-current power, and outputs the first alternating-current power to a device in which a motor is installed. The inverter converts power outputted from the smoothing unit into a second alternating-current power, and outputs the second alternating-current power to a device in which a motor is installed. The control unit controls an operation of the converter and the inverters to reduce a current flowing in the smoothing unit and concurrently controls an operation of the inverter in accordance with an operation state of the inverter and a load unit including the device.

Abstract: A control device controls operation of a power conversion apparatus including a converter, a smoothing capacitor, and an inverter. The control device includes a voltage command calculation unit, a torque ripple compensation command calculation unit, and a beat component compensation command calculation unit. The voltage command calculation unit calculates a voltage command including a first compensation command to reduce a first torque ripple pulsating at twice a frequency of a power-supply voltage. The torque ripple compensation command calculation unit calculates a second compensation command to reduce a second torque ripple pulsating at a rotational frequency of a motor. The beat component compensation command calculation unit calculates a third compensation command to reduce a third torque ripple caused by the first torque ripple and by the second torque ripple.

Abstract: A power converter includes a converter, a smoothing capacitor, an inverter, and a controller. The converter rectifies a power supply voltage applied from an alternating-current power supply. The smoothing capacitor smooths a rectified voltage output from the converter into a direct-current voltage including a ripple. The inverter converts the direct-current voltage smoothed by the smoothing capacitor into an alternating-current voltage to be applied to a motor. The controller performs control such that a first physical quantity representing an operation state of the converter is equal to a second physical quantity representing an operation state of the inverter.

Abstract: A power converter includes a converter that rectifies an alternating-current voltage applied from an alternating-current power supply, a capacitor connected to output ends of the converter, an inverter connected both ends of the capacitor, and a controller that controls an operation of the inverter. A voltage output from the converter includes a ripple component due to a voltage fluctuation of the alternating-current voltage. When the controller performs acceleration and deceleration control on the motor, the controller changes a rotational speed command from a command value during the normal control, in a first period in which a rotational speed of the motor is in a first speed range.

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: A power converter includes a converter, a smoothing capacitor, an inverter, and a single calculator. The converter includes a switching element and rectifies a power supply voltage applied from an alternating-current power supply. The smoothing capacitor smooths a rectified voltage output from the converter into a direct-current voltage including a ripple. The inverter converts the direct-current voltage smoothed by the smoothing capacitor into an alternating-current voltage for a motor. The calculator performs control such that a first physical quantity representing an operation state of the converter is equal to a second physical quantity representing an operation state of the inverter.

Abstract: A power conversion apparatus includes a rectification and boost unit that rectifies a first alternating-current power supplied from a commercial power supply and boosts voltage of the first alternating-current power; a capacitor connected to output terminals of the rectification and boost unit; an inverter that is connected across the capacitor, converts power output from the rectification and boost unit and the capacitor into a second alternating-current power, and outputs the second alternating-current power to a load including a motor; and a control unit that performs operation control on the rectification and boost unit, and performs operation control on the inverter to cause the second alternating-current power that includes a pulsation based on a pulsation of power that flows into the capacitor from the rectification and boost unit to be output from the inverter to the load, to restrain a current that flows into the capacitor.

Abstract: A power conversion apparatus includes a rectification unit that rectifies a first alternating-current power supplied from a commercial power supply; a capacitor connected to output terminals of the rectification unit; an inverter that is connected across the capacitor, converts power output from the rectification unit and the capacitor into a second alternating-current power and, outputs the second alternating-current power to a load including a motor; and a control unit that performs operation control on the inverter to cause the second alternating-current power that includes a pulsation based on a pulsation of power that flows into the capacitor from the rectification unit to be output from the inverter to the load, to restrain a current that flows into the capacitor.