Abstract: A DC power supply device includes: a rectifier circuit; a reactor connected at one end to one output terminal of the rectifier circuit; a charging unit including a first and second switching element connected in series between another end of the reactor and another output terminal of the rectifier circuit, the charging unit configured to charge a first and second capacitor connected in series between output terminals to which a load is connected; and a control unit that controls the charging unit. The control unit sets, based on the timing at which the zero-crossing occurs, a dead time in which both the and second switching element are off, and when states of the first and second switching element at a time of occurrence of the zero-crossing match a predetermined set of states, reverses the states of the first switching element and the second switching element.

Abstract: A motor driving device that drives a motor and is capable of switching a connection state of stator windings of the motor, includes: relays to switch the connection state of the stator windings by switching positions of contact plates; and a contact control unit to control each of the positions of the contact plates by outputting, to the relays, signals for actuating the contact plates. The contact control unit switches the connection state by sequentially switching output values of the signals such that the output values of the signals are switched at different timings from each other in the relays, and changes a switching order every time the connection state is switched, the switching order being an order in which the output values of the signals are switched.

Abstract: A power conversion apparatus includes: a reactor; a rectifier circuit that includes a first leg including switching elements connected in series and a second leg connected in parallel with the first leg, including switching elements connected in series; and a smoothing capacitor that smooths an output voltage of the rectifier circuit. The power conversion apparatus also includes an inverter that converts a direct-current voltage smoothed by the smoothing capacitor into a drive voltage for a motor and applies the drive voltage to the motor; a voltage detection unit that detects the direct-current voltage; and a control unit that controls operation of the rectifier circuit and the inverter. The control unit controls operations of the switching elements on the basis of an induced voltage induced in the motor and a detected value of the direct-current voltage.

Abstract: An air conditioning apparatus includes an indoor unit and an outdoor unit. The outdoor unit includes a compressor that compresses a refrigerant and a motor drive apparatus that drives the compressor. The motor drive apparatus includes an inverter that converts a direct-current voltage into an alternating-current voltage and a motor that operates on the alternating-current voltage from the inverter. The motor includes six stator windings that are each openable at both ends. The motor drive apparatus further includes a connection state switching unit that includes a function of switching a connection state of the six stator windings of the motor among at least four types of connection states.

Abstract: An air-conditioning apparatus includes an indoor unit and an outdoor unit including a compressor that compresses a refrigerant and a motor drive system that drives the compressor. The motor drive system includes an inverter that converts a DC voltage into an AC voltage, and an electric motor including three stator windings with both ends open. The electric motor operates based on the AC voltage obtained by the inverter. The motor drive system further includes a connection state switching unit that has a function to change the connection state of the three stator windings included in the electric motor, and sets the connection state to a star connection at the start of operation of the air-conditioning apparatus.

Abstract: An electric motor drive device includes: a wire connection switching unit; an inverter; a control device controlling the wire connection switching unit and the inverter; and an overcurrent protection circuit preventing current exceeding a predetermined value from continuously flowing through the electric motor. The overcurrent protection circuit includes: determination circuits each correlated one-to-one with any one of possible wire connection states of a stator winding and determining whether current flowing through the inverter is abnormal; a combining circuit combining determination results; and an invalidation circuit invalidating a determination process by one or more of the determination circuits, and causing the combining circuit to output a determination result by the determination circuit correlated with a selected wire connection state of the stator winding.

Abstract: A direct current power supply device includes a rectifier circuit that rectifies alternating current power supplied from an alternating current power supply and converts the alternating current power into direct current power, a charge storage unit that includes a function of storing a charge, a charger that charges the charge storage unit, and a heat sink. The charger includes a positive-side switching element, a negative-side switching element, a positive-side backflow prevention diode, and a negative-side backflow prevention diode. The positive-side switching element, the negative-side switching element, the positive-side backflow prevention diode, and the negative-side backflow prevention diode are discrete semiconductor elements. The negative-side backflow prevention diode is a full mold package element. The positive-side switching element, the negative-side switching element, and the positive-side backflow prevention diode are elements that are not full mold packages.

Abstract: A DC power supply device includes: a rectifier circuit; a reactor connected at one end to one output terminal of the rectifier circuit; a charging unit including a first and second switching element connected in series between another end of the reactor and another output terminal of the rectifier circuit, the charging unit configured to charge a first and second capacitor connected in series between output terminals to which a load is connected; and a control unit that controls the charging unit. The control unit sets, based on the timing at which the zero-crossing occurs, a dead time in which both the and second switching element are off, and when states of the first and second switching element at a time of occurrence of the zero-crossing match a predetermined set of states, reverses the states of the first switching element and the second switching element.

Abstract: A motor driving device that drives a motor and is capable of switching a connection state of stator windings of the motor, includes: relays to switch the connection state of the stator windings by switching positions of contact plates; and a contact control unit to control each of the positions of the contact plates by outputting, to the relays, signals for actuating the contact plates. The contact control unit switches the connection state by sequentially switching output values of the signals such that the output values of the signals are switched at different timings from each other in the relays, and changes a switching order every time the connection state is switched, the switching order being an order in which the output values of the signals are switched.

Abstract: An electric motor drive device includes a wire-connected-state switching unit to switch a wire connected state of stator windings of an electric motor to either a delta connected state or a star connected state, an inverter to drive the electric motor, and a relay-voltage detection circuit to detect a relay voltage (VR) that is a power-supply voltage of the wire-connected-state switching unit, and to deactivate the inverter when the relay voltage (VR) is decreased below a threshold.

Abstract: An electric motor drive device includes a wire-connected-state switching unit to switch a wire connected state of stator windings of an electric motor to either a delta connected state or a star connected state, an inverter to drive the electric motor, and a relay-voltage detection circuit to detect a relay voltage (VR) that is a power-supply voltage of the wire-connected-state switching unit, and to deactivate the inverter when the relay voltage (VR) is decreased below a threshold.

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: 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 motor drive device capable of switching the connection configuration of the stator windings of a motor includes three relays each including a first contact, a second contact, and a contact plate, where the contact plate has one terminal coupled to a stator winding of one phase among the stator windings and the contact plate has another terminal to be connected to the first contact or to the second contact; and a control unit to control the three relays to cause all the three relays to have a same connection state in a case in which not all the three relays have a same connection state with respect to connections between the another terminal of the contact plate and the first contact and the second contact.

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: 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 drive device includes: a wire connection switching unit; an inverter; a control device controlling the wire connection switching unit and the inverter; and an overcurrent protection circuit preventing current exceeding a predetermined value from continuously flowing through the electric motor. The overcurrent protection circuit includes: determination circuits each correlated one-to-one with any one of possible wire connection states of a stator winding and determining whether current flowing through the inverter is abnormal; a combining circuit combining determination results; and an invalidation circuit invalidating a determination process by one or more of the determination circuits, and causing the combining circuit to output a determination result by the determination circuit correlated with a selected wire connection state of the stator winding.

Abstract: A motor drive device capable of switching the connection configuration of the stator windings of a motor includes three relays each including a first contact, a second contact, and a contact plate, where the contact plate has one terminal coupled to a stator winding of one phase among the stator windings and the contact plate has another terminal to be connected to the first contact or to the second contact; and a control unit to control the three relays to cause all the three relays to have a same connection state in a case in which not all the three relays have a same connection state with respect to connections between the another terminal of the contact plate and the first contact and the second contact.

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.