Abstract: In a motor driving apparatus including a DC power supply circuit of variable output voltage value, an inverter of variable frequency, and a connection switching device for selecting connection, switching of the connection switching device is performed in a state where an output voltage of the DC power supply circuit is increased, a rotational speed of a motor is increased, and a current flowing through the motor is made not greater than a predetermined threshold. For example, the switching of the connection switching device is performed in a state where the current through the motor is made zero. For example, the switching is performed in a state where the output voltage of the DC power supply circuit is set at a value corresponding to the rotational speed of the motor during the switching. It is possible to prevent increase in apparatus size and switch the connection of windings while the motor is rotating.

Abstract: A motor driving apparatus for driving a motor, the apparatus being connected to the motor by first, second, and third connection lines respectively corresponding to first, second, and third phases, the apparatus including: an inverter converting direct-current voltage into three-phase alternating-current voltage by using first, second, and third switching element pairs respectively connected to the first, second, and third connection lines, and outputting the three-phase alternating-current voltage to the motor; a voltage detection circuit detecting a first voltage based on a potential difference between a potential of the first connection line and a reference potential; and a control unit calculating a voltage value of the direct-current voltage based on the first voltage during a first period in which an upper-arm switching element of the first switching element pair is on, controlling operation of the inverter according to the voltage value, and changing the first period according to the voltage value.

Abstract: A motor driving device that drives a motor with an alternating-current power converted from a direct-current power supply, includes an inverter that receives a pulse-width modulation signal and supplies the alternating-current power to the motor, and an inverter control unit that generates the pulse-width modulation signal and supplies the pulse-width modulation signal to the inverter. The inverter control unit reduces the number of pulses of the pulse-width modulation signal generated during a first period within one period of a mechanical angle of the motor to be lower than the number of pulses of the pulse-width modulation signal generated during a second period within the one period of the mechanical angle of the motor. The first period is a period during which a load torque is lower than a load torque during the second 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: There are provided a single inverter to generate a three-phase alternating-current voltage from a direct-current voltage; n motors connected in series to an output side of the inverter to generate power, n being an integer not less than 2; a moving unit to receive the power to be driven; and a controller to perform sensorless control on the basis of an induced voltage caused by the n motors.

Abstract: A motor driver includes an inverter used for driving a motor and configured to apply an alternating-current voltage to the motor. The inverter drives, during start operation, a switching element of the inverter with a first PWM signal that is PWM modulated with a carrier frequency that is a first integer multiple of a frequency of the alternating-current voltage, and thereafter drives the switching element with a second PWM signal that is PWM modulated with a carrier frequency that is a second integer multiple of the frequency of the alternating-current voltage. The second integer is smaller than the first integer.

Abstract: In a motor driving apparatus including a DC power supply circuit of variable output voltage value, an inverter of variable frequency, and a connection switching device for selecting connection, switching of the connection switching device is performed in a state where an output voltage of the DC power supply circuit is increased, a rotational speed of a motor is increased, and a current flowing through the motor is made not greater than a predetermined threshold. For example, the switching of the connection switching device is performed in a state where the current through the motor is made zero. For example, the switching is performed in a state where the output voltage of the DC power supply circuit is set at a value corresponding to the rotational speed of the motor during the switching. It is possible to prevent increase in apparatus size and switch the connection of windings while the motor is rotating.

Abstract: An outdoor unit includes at least one heat exchanger, a first motor including a first fan, a second motor including a second fan, an inverter that applies voltage to the first motor and the second for respectively, a connection switching unit that switches the voltage applied to the second motor between on and off, and a control unit that controls the inverter and the connection switching unit. The inverter is disposed closer to the first motor than to the second motor.

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: An electric motor drive unit includes a winding switching unit that switches a configuration of windings of an electric motor, a winding switching instruction unit that generates an instruction signal for the winding switching unit, and a winding configuration retention unit to which the instruction signal generated by the winding switching instruction unit is input, and if the input instruction signal has a first value, outputs a signal corresponding to the input instruction signal to the winding switching unit, and if the input instruction signal has a second value different from the first value, continues outputting a signal that has been output to the winding switching unit before the reception of the second value, the first value indicating an instruction on the configuration of the windings.

Abstract: An electric-motor driving device includes an inverter connected to terminals connected to windings of an electric motor including the windings, the inverter applying an alternating-current voltage to the electric motor, a switching unit connected to the terminals and capable of switching a connection state between the terminals, a detecting unit that detects at least one of a voltage and an electric current of the inverter, and a control unit that determines on the basis of a detection value detected by the detecting unit that an abnormality occurs in the switching unit and controls the inverter to short-circuit at least two of the terminals.

Abstract: There are provided an inverter connected to n (n being as integer not less than 2) motors each including a rotor having a permanent magnet and capable of driving the n motors, and a connection switching device to switch a connection state of at least one motor of the n motors and the inverter between connection and disconnection. While the n motors are connected to the inverter and driven by the inverter, when an abnormality is detected in the at least one motor, the connection switching device switches the connection state to the disconnection and the inverter drives the n motors except the at least one motor.

Abstract: A motor driving device includes an inverter to supply an alternating current, a switch unit that switches the number of at least one permanent magnet synchronous motor to which the alternating current is supplied from the inverter, a detector to detect a detection value corresponding to the alternating current supplied to the at least one permanent magnet synchronous motor, and a control device to control the inverter and the switch unit. The control device sets an overcurrent interruption threshold value at a value based on the number. When the detection value is greater than or equal to the overcurrent interruption threshold value, the control device makes the inverter stop the supplying of the alternating current to the at least one permanent magnet synchronous motor.

Abstract: A motor drive system can detect a misconnection. A motor drive system for driving a motor including a plurality of stator windings includes: an inverter that converts a DC voltage supplied from a DC voltage source into an AC voltage and applies the AC voltage to the motor; a connection switching device that is disposed between the inverter and the motor and can switch a connection state of the stator windings; and a controller that performs abnormality determination on a connection state of the connection switching device on the basis of a current value of a current flowing in each of the stator windings.

Abstract: An electric quantity of a power supply of a connection switching device for switching the connection state of a motor, or at least one electric quantity which varies with the first-mentioned electric quantity is detected, the result of the detection is used to detect or predict a fall of a voltage of the switching power supply. Based on the result of the detection or prediction, an inverter is so controlled as to stop the motor before the voltage of the switching power supply falls below the minimum voltage required for the operation of the connection switching device. Breakdown of the connection switching device can be prevented.

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 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 motor drive device includes an inverter to apply power to a motor, and a plurality of relays to switch a connection state of the motor by each switching its state between a first state and a second state. A timing at which at least one of the plurality of relays switches from the first state to the second state is different from a timing at which the other relays switch from the first state to the second state.

Abstract: There are provided at least two disconnection contactors each of which switches between connection and disconnection of each of at least two of three second power lines for supplying a three-phase alternating-current voltage generated by an inverter to a second PM motor, at least two short-circuit contactors each of which switches between connection and disconnection between the two second power lines of each of at least two of the pairs of the three second power lines, and a calculator to control the disconnection contactors and short-circuit contactors.

Abstract: A motor drive device includes a single-phase inverter that converts a direct-current voltage output from a power supply which is a battery, into an alternating-current voltage. The inverter outputs the alternating-current voltage as an applied voltage to be applied to a motor. The applied voltage is lower when the direct-current voltage is a second voltage lower than a first voltage than when the direct-current voltage is the first voltage. Consequently, a discharge current of the battery is reduced, and the motor drive device capable of reducing an increase in battery temperature can be obtained.