A fan driving circuit includes a primary winding, an activating capacitor, a control circuit, a switch circuit and a secondary winding. The primary winding and the activating capacitor are electrically coupled to an external power source. The control circuit generates a control signal. The switch circuit is electrically coupled to the first winding. The switch circuit is also electrically coupled to the activating capacitor. The switch circuit has at least one control terminal electrically coupled to the control circuit for receiving the control signal. The secondary winding is electrically coupled to the switch circuit. The secondary winding is electrically coupled to the switch circuit. The secondary winding electromagnetically drives a fan according to a flowing direction of its driving current. The switch circuit conducts the secondary winding's driving current's flowing direction based on the control signal's voltage level.

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.

In response to a measured value of temperature of a stator by a thermometer exceeding a first temperature threshold, an overheat signal may be output to a rotor of a rotary connector via a communication device. In response to the measured value of the temperature exceeding a second temperature threshold higher than the first temperature threshold, power supply to a transmission coil that transmits power to a receiving coil of the rotor in a non-contact manner is stopped. In response to the overheat signal being received or a measured value of temperature of the rotor by a thermometer exceeding a third temperature threshold, a limit signal for limiting current flowing through a load circuit is output. In response to the measured value of the temperature by the thermometer exceeding a fourth temperature threshold higher than the third temperature threshold, output of power received from the stator is stopped.

An electric machine comprising a first and a second three-phase winding and comprising a stator formed of a cylindrical yoke made of a soft ferromagnetic material extended radially by a set of teeth, a portion of the set of teeth bearing the windings, the windings being distinct from one another, the first three-phase winding being connected in a delta configuration, the second three-phase winding being connected in a star configuration.

A motor driving apparatus which drives a motor having a plurality of windings corresponding to a plurality of phases includes: a first inverter having a plurality of first switching elements and connected to a first end of each winding; a second inverter having a plurality of second switching elements and connected to a second end of each winding; and a controller configured to control pulse width modulation, by distributing a preset voltage command of the motor into a voltage command of the first inverter and a voltage command of the second inverter at the same rate and by generating duties of the first switching elements, wherein the controller determines the duties of the second switching elements and determines the duties of the first switching elements on and the duties of the first switching elements.

An electric motor includes a rotor, a stator, and a connection switching unit. The stator includes a stator core including 6×n (n is an integer equal to or larger than 1) slots, and three-phase coils forming 2×n magnetic poles. The connection switching unit switches a connection state of the three-phase coils between a first connection state and a second connection state. The three-phase coils include 2×n U-phase coils, 2×n V-phase coils, and 2×n W-phase coils in a coil end. Each coil of the three-phase coils is disposed in two slots across one slot on one end side of the stator core.

According to one embodiment, a motor drive unit includes a motor including a plurality of phase windings in a mutually unconnected state, a first inverter which controls application of electric power to one ends of the phase windings, a second inverter which controls application of electric power to the other ends of the phase windings, relays each of which includes a make break contact connected between the other ends of the phase windings, and a controller which switches, according to a value of a current flowing through the motor, between an open-windings mode and a star-connection mode.

According to one embodiment, a motor drive unit includes a motor including a plurality of phase windings in a mutually unconnected state, a first inverter which controls application of electric power to one ends of the phase windings, a second inverter which controls application of electric power to the other ends of the phase windings, relays each of which includes a make break contact connected between the other ends of the phase windings, and a controller which switches, according to a value of a current flowing through the motor, between an open-windings mode and a star-connection mode.

A motor/generator/transmission system includes: an axle; a stator ring having a plurality of stator coils disposed around the periphery of the stator ring, wherein each phase of the plurality of stator coils includes a respective set of multiple parallel non-twisted wires separated at the center tap with electronic switches for connecting the parallel non-twisted wires of each phase of the stator coils all in series, all in parallel, or in a combination of series and parallel; a rotor support structure coupled to the axle; a first rotor ring and a second rotor ring each having an axis of rotation coincident with the axis of rotation of the axle, at least one of the first rotor ring or the second rotor ring being slidably coupled to the rotor support structure and configured to translate along the rotor support structure in a first axial direction or in a second axial direction.