A driving device is used with a compressor including a motor including coils. The driving device drives the motor. The driving device includes an inverter connected to the coils, a connection switching unit to switch a connection state of the coils between a first connection state and a second connection state, a controller to control the inverter and the connection switching unit, and a compressor state detection unit to detect a state of the compressor. When the connection state of the coils is the first connection state, the controller controls the motor based on a first detection value detected by the compressor state detection unit and a first threshold. When the connection state of the coils is the second connection state, the controller controls the motor based on a second detection value detected by the compressor state detection unit and a second threshold.

A driving device is used with a compressor including a motor including coils. The driving device drives the motor. The driving device includes an inverter connected to the coils, a connection switching unit to switch a connection state of the coils between a first connection state and a second connection state, a controller to control the inverter and the connection switching unit, and a compressor state detection unit to detect a state of the compressor. When the connection state of the coils is the first connection state, the controller controls the motor based on a first detection value detected by the compressor state detection unit and a first threshold. When the connection state of the coils is the second connection state, the controller controls the motor based on a second detection value detected by the compressor state detection unit and a second threshold.

A rotary machine driving system includes: a rotary machine including a plurality of coils; an inverter device configured to operate the rotary machine at a variable speed, including a control device for controlling power conversion by an inverter circuit, and a coil switching device for switching a connection of the coils according to the control device. The control device commands the coil switching device to switch the connection of the coils when rotation of the rotary machine transitions between a low-speed rotation range and a high-speed rotation range due to acceleration and deceleration. A starting end and a terminal end of at least one set of coils per phase of the rotary machine are drawn out in a freely connectable state. The coil switching device includes at least one movable portion driven by one actuator.

A motor driving device includes: a connection switcher that has an electromagnetic contactor connected to a winding of a motor and switches connection condition of the winding by switching condition of the electromagnetic contactor; an inverter to apply an output voltage as an AC voltage to the winding via the connection switcher; a short-circuiting circuit having a rectification circuit and a switch; and a controller to control the electromagnetic contactor, the inverter and the switch, wherein a circulating circuit is formed by the short-circuiting circuit and the winding when the switch is set at ON, and the connection switcher switches the connection condition of the winding in a period in which the output voltage of the inverter is set at zero in a rotating operation of the motor and a current caused by the rotating operation circulates in the circulating circuit.

A motor driving device includes: a connection switcher that has an electromagnetic contactor connected to a winding of a motor and switches connection condition of the winding by switching condition of the electromagnetic contactor; an inverter to apply an output voltage as an AC voltage to the winding via the connection switcher; a short-circuiting circuit having a rectification circuit and a switch; and a controller to control the electromagnetic contactor, the inverter and the switch, wherein a circulating circuit is formed by the short-circuiting circuit and the winding when the switch is set at ON, and the connection switcher switches the connection condition of the winding in a period in which the output voltage of the inverter is set at zero in a rotating operation of the motor and a current caused by the rotating operation circulates in the circulating circuit.

A motor includes a first inverter electrically connected to a first end of a winding of each phase, and a second inverter electrically connected to a second end of the winding of each phase. Each of the first and second inverters includes low-side switching elements and high-side switching elements. FETs of the first inverter are electrically connected to a first end of a U-phase winding. FETs of the second inverter are electrically connected to a second end of the U-phase winding. At least a portion of a current flowing from one of the FETs of the first inverter to the U-phase winding flows to one of the FETs of the second inverter. One of the FETs of the first inverter and one of the FETs of the second inverter are adjacent to each other.

An object of the present invention is to provide a winding switching device capable of enhancing the reliability of electrical contact between a movable unit and a fixed unit, and a rotating electrical machine drive system including such a winding switching device. A winding switching device switches a connection state of a plurality of windings, and includes a plurality of electrodes to which the plurality of windings are connected; a movable unit that includes a plurality of conductor portions in contact with the plurality of electrodes, and that is driven in a predetermined direction in which the plurality of electrodes are arranged; and a fixed unit including a regulating portion that regulates movement of the movable unit in the predetermined direction; where the connection states of the plurality of windings are switched according to the position of the movable unit; and when the movable unit moves in the predetermined direction, the plurality of conductors are displaced in a direction of moving away from the plurality of electrodes by the regulating portion.

An object of the present invention is to provide a winding switching device capable of enhancing the reliability of electrical contact between a movable unit and a fixed unit, and a rotating electrical machine drive system including such a winding switching device. A winding switching device switches a connection state of a plurality of windings, and includes a plurality of electrodes to which the plurality of windings are connected; a movable unit that includes a plurality of conductor portions in contact with the plurality of electrodes, and that is driven in a predetermined direction in which the plurality of electrodes are arranged; and a fixed unit including a regulating portion that regulates movement of the movable unit in the predetermined direction; where the connection states of the plurality of windings are switched according to the position of the movable unit; and when the movable unit moves in the predetermined direction, the plurality of conductors are displaced in a direction of moving away from the plurality of electrodes by the regulating portion.

A rotary machine control device includes a voltage application unit that applies a voltage to a rotary machine with three phases, a current detection unit that outputs current information representing information on a current caused to flow to the rotary machine by application of the voltage, a control unit that outputs a voltage command to apply a voltage between each of pairs of the phases of the rotary machine, and an open phase determination unit that performs open phase determination to determine whether an open phase occurs in the rotary machine, by detecting the values of currents flowing between the respective pairs of the phases by monitoring the voltage command and the current information, and by comparing the sum of the values of the currents flowing between the respective pairs of the phases with a predetermined reference value.

A rotary machine control device includes a voltage application unit that applies a voltage to a rotary machine with three phases, a current detection unit that outputs current information representing information on a current caused to flow to the rotary machine by application of the voltage, a control unit that outputs a voltage command to apply a voltage between each of pairs of the phases of the rotary machine, and an open phase determination unit that performs open phase determination to determine whether an open phase occurs in the rotary machine, by detecting the values of currents flowing between the respective pairs of the phases by monitoring the voltage command and the current information, and by comparing the sum of the values of the currents flowing between the respective pairs of the phases with a predetermined reference value.