JP7724689B2 - Variable magnetic flux magnet control device, power receiving device, power transmission system, and rotating electric machine - Google Patents

Description

This disclosure relates to a variable magnetic flux magnet control device, a power receiving device, a power transmission system, and a rotating electric machine.

In a rotating electric machine (motor) consisting of a stator and a rotor, a variable flux magnet is used as the magnet provided in the rotor, and the magnetic flux of the variable flux magnet is changed.

For example, in electric vehicles or railway vehicles, the operating range of rotating electric machines is wide, from low speed rotation to high speed rotation, and efforts are made to achieve high efficiency by changing the magnetic flux of variable magnetic flux magnets according to the rotation speed.
Specifically, at low speeds (low rotation speeds), a larger magnetic force of the magnets in the rotating electric machine makes it easier to generate a larger torque, while at high speeds (high rotation speeds), a smaller magnetic force of the magnets in the rotating electric machine makes it more efficient. For this reason, in order to increase efficiency at both low and high speeds, the magnetic force is changed according to the rotation speed.

In a variable flux magnet module equipped with a variable flux magnet and a coil (variable flux magnet control coil), the magnetic flux of the variable flux magnet is changed by changing the magnetic field generated by the coil. This allows rotating electric machines to achieve high efficiency even over a wide operating range. Such high efficiency is important for rotating electric machines.

Here, the variable flux magnet is controlled so that it is magnetized or demagnetized by the current flowing through the coil. The control circuit (drive circuit) of the variable flux magnet controls the direction of the current flowing through the coil to differ when magnetizing or demagnetizing.

Patent Document 1 describes a variable flux motor drive system equipped with an inverter that drives a variable flux motor having a fixed magnet and a variable magnet, the variable flux motor drive system including a main control unit that controls the inverter so that the torque of the variable flux motor matches a torque command, a magnetization winding that magnetizes the variable magnet of the variable flux motor, and a magnetization circuit that supplies a magnetization current to the magnetization winding (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2008-125201

However, conventional variable flux magnet control devices require a large number of components in the circuit that passes current through the coil to change the magnetic flux of the variable flux magnet, which can lead to high costs.

This disclosure has been made in consideration of these circumstances, and aims to provide a variable magnetic flux magnet control device, power receiving device, power transmission system, and rotating electric machine that can reduce the number of components in the circuit that passes current through the coil that changes the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

One aspect of the present disclosure is a variable flux magnet control device comprising: an AC power generation unit; and a current direction switching circuit including a first circuit unit and a second circuit unit arranged between a variable flux magnet control coil for controlling magnetization of a variable flux magnet and the AC power generation unit, wherein the first circuit unit has a first switch function and a first direction conduction function, and the second circuit unit has a second switch function and a second direction conduction function, the first switch function being constituted by the switch function of a first gate turn-off thyristor, the first direction conduction function being constituted by the conduction function of the first gate turn-off thyristor, the second switch function being constituted by the switch function of a second gate turn-off thyristor, and the second direction conduction function being constituted by the conduction function of the second gate turn- off thyristor.

One aspect of the present disclosure is a power receiving device that includes the variable magnetic flux magnet control device, wherein the AC power generating unit includes a receiving coil, and the receiving coil receives power transmitted from a transmitting coil of a power transmitting device.
One aspect of the present disclosure is a power transmission system including the power receiving device and the power transmitting device.
One aspect of the present disclosure is a rotating electric machine including a stator, a rotor, and the power transmission system.

This disclosure enables costs to be reduced by reducing the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet in a variable magnetic flux magnet control device, power receiving device, power transmission system, and rotating electric machine.

1 is a diagram illustrating an example of a schematic configuration of a rotating electric machine including a wireless power transmission system according to an embodiment. 1 is a diagram illustrating an example of a schematic external appearance of a rotating electric machine according to an embodiment; FIG. 1 is a diagram showing an example of the appearance of a variable magnetic flux magnet module according to an embodiment. FIG. 2 is a diagram showing a schematic example of a magnetization curve of a variable magnetic flux magnet according to the embodiment. FIG. 2 is a diagram illustrating an example of the configuration of a variable magnetic flux magnet control circuit according to the embodiment. FIG. 10 is a diagram illustrating an example of a first AC voltage of a first control pattern according to the embodiment. FIG. 10 is a diagram illustrating an example of a second AC voltage of a second control pattern according to the embodiment. FIG. 2 is a diagram illustrating a configuration example of a power supply circuit according to an embodiment. FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit according to a modified example. FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit according to a modified example. FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit according to a modified example. FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit according to a modified example. FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit according to a modified example. FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit according to a modified example. FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit according to a modified example. FIG. 10 is an external perspective view showing an example of a schematic configuration of a power transmission system according to another example. FIG. 10 is a partial cross-sectional view showing an example of a schematic configuration of a power transmission system according to another example. FIG. 10 is an exploded view showing an example of a schematic configuration of a power transmission system according to another example.

Embodiments of the present disclosure will be described below with reference to the drawings.

[Rotating Electric Machine with Wireless Power Transmission System]
FIG. 1 is a diagram showing an example of a schematic configuration of a rotating electrical machine 1 including a wireless power transmission system 101 according to an embodiment.
Regarding the configuration of the rotating electric machine 1, detailed description will be omitted except for the components related to the wireless power transmission system 101 according to this embodiment.

The rotating electric machine 1 includes a stator 11 and a rotor 12 .
The stator 11 includes a winding (stator winding) 31 and a wireless power transmitting device 111 .
The rotor 12 includes a variable magnetic flux magnet module 51 and a wireless power receiving device 112 .
The rotor 12 also includes two electric wires E1 and E2 that connect the variable magnetic flux magnet module 51 and the wireless power receiving device 112 .

In this embodiment, the wireless power transmission system 101 includes a wireless power transmitter 111 and a wireless power receiver 112 .
The wireless power transmitter 111 includes a power transmission unit 131. The power transmission unit 131 includes a power transmission coil 151, a power transmission circuit 152, and a power transmission control unit 153.
The wireless power receiver 112 includes a power receiving unit 171. The power receiving unit 171 includes a power receiving coil 191, a power receiving circuit 192, and a power receiving control unit 193.
The wireless power transmission system 101, or the power transmitting unit 131 or the power receiving unit 171 may be called a power supply device or the like.

<Wireless power transmission system>
The wireless power transmission system 101 will be described.
In the wireless power transmission system 101, power is transmitted wirelessly from a wireless power transmitter 111 to a wireless power receiver 112. That is, the wireless power transmitter 111 transmits power wirelessly, and the wireless power receiver 112 receives the power wirelessly.

In the wireless power transmitter 111, the power transmission circuit 152 supplies an AC voltage to the power transmission coil 151, and thereby power is transmitted wirelessly from the power transmission coil 151. The power transmission control unit 153 controls the operation of the power transmission circuit 152 and the like.
In the wireless power receiving device 112, a power receiving coil 191 receives power wirelessly, and a power receiving circuit 192 uses the received power to supply current to the variable magnetic flux magnet module 51. A power receiving control unit 193 controls the operation of the power receiving circuit 192 and the like.
In this embodiment, power is transmitted wirelessly from the power transmitting coil 151 to the power receiving coil 191 by a magnetic field coupling (electromagnetic induction) method or a magnetic field resonance method.

Note that some or all of the functions of the power transmission control unit 153 and the power reception control unit 193 may be provided in a control unit (for example, a main controller) that controls the rotating electric machine 1 .
Furthermore, the power supply unit (not shown in Figure 1) that supplies power to the power transmission unit 131 of the wireless power transmission system 101 and the power supply unit (not shown in Figure 1) that supplies power for the operation of the rotating electric machine 1 (operation of the motor) may be, for example, the same power supply unit, or different power supply units may be used.

In the present embodiment, an example configuration has been shown in which the power transmitting unit 131 includes the power transmitting coil 151, the power transmitting circuit 152, and the power transmitting control unit 153, but the configuration of the power transmitting unit 131 may be arbitrary. For example, one of the power transmitting coil 151, the power transmitting circuit 152, and the power transmitting control unit 153 may be separate, or all of them may be separate. Furthermore, if the power transmitting coil 151, the power transmitting circuit 152, and the power transmitting control unit 153 are integrated, there may be no need to distinguish between these units.
Furthermore, in the present embodiment, an example configuration has been shown in which the power receiving unit 171 includes the power receiving coil 191, the power receiving circuit 192, and the power receiving control unit 193, but the configuration of the power receiving unit 171 may be arbitrary. For example, one of the power receiving coil 191, the power receiving circuit 192, and the power receiving control unit 193 may be separate, or all of them may be separate. Furthermore, if the power receiving coil 191, the power receiving circuit 192, and the power receiving control unit 193 are integrated, there may be no need to distinguish between these units.

FIG. 2 is a diagram showing an example of a schematic external appearance of the rotating electrical machine 1 according to the embodiment.
FIG. 2 shows an example of a schematic external view of the stator 11 and the rotor 12.
The stator 11 has a winding 31 mounted thereon.
The rotor 12 is equipped with a variable magnetic flux magnet module 51 .
In FIG. 2, the wireless power transmission system 101 is omitted.

In this embodiment, the stator 11 includes a plurality of variable magnetic flux magnet modules 51, but in the example of Fig. 2, for the sake of simplicity, only one variable magnetic flux magnet module 51 is labeled with a reference symbol. For the sake of convenience, this embodiment will be described using one variable magnetic flux magnet module 51 as a representative.
Furthermore, in this embodiment, similar control is performed for each of the multiple variable magnetic flux magnet modules 51, but this is not limited to this, and for example, arbitrary control may be performed for each variable magnetic flux magnet module 51.

<Variable magnetic flux magnet module>
FIG. 3 is a diagram showing an example of the appearance of a variable magnetic flux magnet module 51 according to the embodiment.
The variable magnetic flux magnet module 51 includes a variable magnetic flux magnet 211 made of a permanent magnet, and a coil for changing the magnetic flux of the variable magnetic flux magnet 211 (for convenience of explanation, in this embodiment, referred to as a variable magnetic flux magnet control coil 231).
The variable magnetic flux magnet may be called a variable magnet, etc. The variable magnetic flux magnet control coil may be called a magnetizing coil, etc.
In this embodiment, the variable magnetic flux magnet control coil 231 serves as a load for the wireless power receiving device 112. The variable magnetic flux magnet control coil 231 is supplied with power (current) from the wireless power receiving device 112.

An electric wire E1 is connected to one end of the variable magnetic flux magnet control coil 231, and an electric wire E2 is connected to the other end of the variable magnetic flux magnet control coil 231.
For convenience of explanation, the electric wire E1 is shown as Vo(+) and the electric wire E2 is shown as Vo(-).
Here, the electric wires E1 and E2 may be considered to be provided in the variable magnetic flux magnet control coil 231, or may be considered to be external to the variable magnetic flux magnet control coil 231.

The magnetic field (magnetic flux) of the variable magnetic flux magnet 211 can be controlled by the current flowing through the variable magnetic flux magnet control coil 231 .
In this embodiment, the magnetic flux of the variable magnetic flux magnet 211 is strengthened by a predetermined current flowing in a first direction D1 from the electric wire E1 to the electric wire E2, while the magnetic flux of the variable magnetic flux magnet 211 is weakened by a predetermined current flowing in a second direction D2 from the electric wire E2 to the electric wire E1.

The configuration of the variable magnetic flux magnet module 51 shown in FIG. 3 is an example, and any other configuration may be used.
For example, any configuration may be used for the shape or size of the variable magnetic flux magnet 211, the arrangement of the variable magnetic flux magnet control coil 231, and the like.

Here, in this embodiment, for the sake of simplicity, only the variable magnetic flux magnet 211 is shown, but as another configuration example, a fixed magnet with fixed magnetization may be used together with the variable magnetic flux magnet 211.
That is, a combination of a fixed magnet and a variable magnetic flux magnet 211 may be used.
Furthermore, each magnet (for example, a fixed magnet or a variable magnetic flux magnet 211) may be configured by combining a plurality of magnet pieces, for example.

<Magnetization curve of variable magnetic flux magnet>
4 is a diagram showing a schematic example of a magnetization curve 2011 of the variable magnetic flux magnet 211 according to the embodiment. Note that the magnetization curve 2011 shown in FIG. 4 shows a general trend for the purpose of explanation, and is not necessarily precise.
FIG. 4 also shows a first direction D1 and a second direction D2.

In the graph shown in FIG. 4, the horizontal axis represents the magnetic field H applied to the variable flux magnet 211 by the current flowing through the variable flux magnet control coil 231, and the vertical axis represents the magnetization J of the variable flux magnet 211.
The magnetization curve 2011 is a hysteresis curve.
Generally, the magnetic flux density B inside the variable magnetic flux magnet 211 is the result of multiplying the magnetic field H by the magnetic permeability μ (e.g., the magnetic permeability of a vacuum) and adding it to the magnetization J (B = μH + J).
Here, a magnetic field is generated by the current flowing through the variable magnetic flux magnet control coil 231 , and a magnetic field H is applied to the variable magnetic flux magnet 211 by this magnetic field.

FIG. 4 shows a point of high magnetization (high magnetization point P1) and a point of low magnetization (low magnetization point P2) used in this embodiment on the magnetization curve 2011.
FIG. 4 also shows a magnetization path 2021 where magnetization is performed from the low magnetization point P2 to the high magnetization point P1, and a demagnetization path 2022 where demagnetization is performed from the high magnetization point P1 to the low magnetization point P2.
In this specification, an increase in magnetization will be referred to as "magnetization," and a decrease in magnetization will be referred to as "demagnetization."

In this embodiment, when the variable flux magnet 211 is in a state of low magnetization point P2, a predetermined current is passed through the variable flux magnet control coil 231 in the first direction D1, and the magnetization path 2021 causes the variable flux magnet 211 to transition to a state of high magnetization point P1.
On the other hand, in this embodiment, when the variable magnetic flux magnet 211 is in a state of high magnetization point P1, a predetermined current is passed through the variable magnetic flux magnet control coil 231 in the second direction D2, and the variable magnetic flux magnet 211 transitions to a state of low magnetization point P2 via the demagnetization path 2022.

In this way, to vary the magnetic force of the variable magnetic flux magnet 211, the electric field applied to the variable magnetic flux magnet control coil 231 is changed (the direction of the current flowing through the variable magnetic flux magnet control coil 231 is changed). When magnetizing and demagnetizing the variable magnetic flux magnet 211, electric fields with opposite positive and negative polarities are applied.

[Variable magnetic flux magnet control circuit]
FIG. 5 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301 according to the embodiment.
The variable magnetic flux magnet control circuit 301 includes a circuit for the power transmission unit 131 , a circuit for the power reception unit 171 , and a load circuit Z<b>1 including the variable magnetic flux magnet control coil 231 .
In the example of FIG. 5, the variable magnetic flux magnet control circuit 301 is made up of a load circuit Z1 and a power supply circuit (power transmitting unit 131 and power receiving unit 171) that supplies power to the load circuit Z1.

In this embodiment, for convenience of explanation, the entire circuit shown in FIG. 5 will be referred to as the variable magnetic flux magnet control circuit 301, but the variable magnetic flux magnet control circuit 301 may include only a portion of the circuits shown in FIG. 5, or may include other circuits not shown in FIG. 5.
For example, all or part of the circuitry of the power receiving unit 171 may be called a variable magnetic flux magnet control circuit.

<Power transmission circuit>
The circuit of the power transmitting unit 131 includes a power supply circuit 311 , a power transmitting coil 312 (a coil on the primary side in terms of power transmission), and a capacitor 313 .
A capacitor 313 and a power transmission coil 312 are connected in series between one end (one terminal) and the other end (the other terminal) of the power supply circuit 311 .

Specifically, one end of the power supply circuit 311 is connected to one end of the capacitor 313. The other end of the capacitor 313 is connected to one end of the power transmission coil 312. The other end of the power transmission coil 312 is connected to the other end of the power supply circuit 311.

The power supply circuit 311 is configured using, for example, an inverter (INV).
The power supply circuit 311 supplies AC power (AC voltage) to the power transmitting coil 312. As a result, power is transmitted from the power transmitting coil 312 wirelessly.

Here, in the example of Figure 5, among the circuits of the power transmission unit 131, the power transmission coil 312 is an example of the power transmission coil 151 shown in Figure 1, and the other circuit parts are an example of the power transmission circuit 152 shown in Figure 1.
The power transmission control unit 153 shown in FIG. 1 may be provided at any location.

<Power receiving circuit>
The circuit of the power receiving unit 171 includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332 , a diode 351 , a switch 352 , a diode 353 , and a switch 354 .
The capacitor 332 is an example of a resonant capacitor that is combined with the power receiving coil 331 .
The power receiving coil 331 and the capacitor 332 are connected in series. A combination of a diode 351 and a switch 352 and a combination of a diode 353 and a switch 354 are connected in parallel to this series connection circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The other end of the power receiving coil 331 is connected to the anode of the diode 351 and the cathode of the diode 353 .
The other end of the capacitor 332 is connected to one end of the switch 352 and one end of the switch 354 .
The cathode of the diode 351 is connected to the other end of the switch 352 .
The anode of the diode 353 is connected to the other end of the switch 354 .

In this embodiment, the AC power generation unit A1 is configured from the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The diode 351 and the switch 352 constitute a first circuit section A11.
The diode 353 and the switch 354 constitute a second circuit section A12.
The first circuit section A11 and the second circuit section A12 constitute a current direction switching circuit A2.
The first circuit section A11 and the second circuit section A12 are connected in parallel between the AC power generating section A1 and the load circuit Z1. The direction (conduction direction) of the diode 351 of the first circuit section A11 and the direction (conduction direction) of the diode 353 of the second circuit section A12 are opposite to each other.

Here, in the example of Figure 5, among the circuits of the power receiving unit 171, the power receiving coil 331 is an example of the power receiving coil 191 shown in Figure 1, and the other circuit parts are an example of the power receiving circuit 192 shown in Figure 1.
The power receiving control unit 193 shown in FIG. 1 may be provided at any location.

One or both of the diode 351 and the diode 353 may include a plurality of diode elements.
Furthermore, the diode 351 and the diode 353 may each be configured using, for example, a thyristor.

Note that one or both of the switch 352 and the switch 354 may include multiple switch elements. When the switch 352 or the switch 354 is configured with multiple switch elements, for example, these multiple switch elements (a group of switch elements) are controlled simultaneously (or with a predetermined timing difference) so as to achieve a desired conductive state.
Furthermore, for each of the switches 352 and 354, a semiconductor switch such as a field effect transistor (FET) or a contact relay switch may be used.

<Load circuit>
The load circuit Z1 includes a variable magnetic flux magnet control coil 231 and a resistor 411.
The variable magnetic flux magnet control coil 231 and the resistor 411 are connected in series.
Specifically, one end of the variable magnetic flux magnet control coil 231 and the other end of the capacitor 332 in the circuit of the power receiving unit 171 are connected via an electric wire 371 .
The other end of the variable magnetic flux magnet control coil 231 is connected to one end of a resistor 411 .
The other end of the resistor 411 is connected to the other end of the power receiving coil 331 in the circuit of the power receiving unit 171 via an electric wire 372 .

Here, electric wire 371 is an example of electric wire E1 shown in Figures 1 and 3, and electric wire 372 is an example of electric wire E2 shown in Figures 1 and 3. Electric wire 371 and electric wire 372 may be considered, for example, to be components of load circuit Z1, or, as another configuration example, may be considered to be components of the circuit of power receiving unit 171.

In the example of FIG. 5, for ease of explanation, the point where one end of the variable magnetic flux magnet control coil 231 and the electric wire 371 are connected (connection point K1), and the point where the other end of the resistor 411 and the electric wire 372 are connected (connection point K2) are shown.
For convenience of explanation, Vo(+) is shown at the connection point K1 (electric wire 371), and Vo(-) is shown at the connection point K2 (electric wire 372).

5, the direction of voltage when the terminal of the receiving coil 331 connected to the capacitor 332 is at a higher potential is shown as a first voltage direction F1. Also, the direction of voltage when the terminal of the receiving coil 331 connected to the capacitor 332 is at a lower potential is shown as a second voltage direction F2.
FIG. 5 shows a first direction D1 and a second direction D2 of the current flowing through the variable magnetic flux magnet control coil 231.

5 shows an example of a configuration in which the AC power generating unit A1 is provided with the capacitor 313 at one end connected to the first circuit unit A11 and the second circuit unit A12, but a configuration in which a capacitor is provided at the other end connected to the first circuit unit A11 and the second circuit unit A12 instead of the one end may also be used.Furthermore, a configuration in which a capacitor is provided at both the one end connected to the first circuit unit A11 and the second circuit unit A12 and the other end may also be used.
If there is no need to include a capacitor, the AC power generating unit A1 may not include a capacitor.

<Operation of variable magnetic flux magnet control circuit>
6 and 7, an example of the operation of the variable magnetic flux magnet control circuit 301 will be shown.
FIG. 6 is a diagram showing an example of a first AC voltage 3011 of the first control pattern according to the embodiment.
6, the horizontal axis represents time, and the vertical axis represents voltage level. In this embodiment, the voltage in the first voltage direction F1 is a positive voltage, and the voltage in the second voltage direction F2 is a negative voltage.

In this embodiment, the first AC voltage 3011 of the first control pattern is an AC voltage that starts as a positive voltage.
In this embodiment, the first AC voltage 3011 of the first control pattern is generated by applying an AC voltage corresponding to the first control pattern to the power transmission coil 312 by the power supply circuit 311 in the power transmission unit 131.
In this embodiment, the AC voltage corresponding to the first control pattern in the power transmission unit 131 is an AC voltage that starts from a positive voltage on the terminal of the power supply circuit 311 to which the capacitor 313 is connected.

In this embodiment, when the first AC voltage 3011 of the first control pattern is generated in the power receiving circuit 192, the switch 352 is turned on (conductive) and the switch 354 is turned off (non-conductive).
In this state, rectification is performed by the diode 351. In this embodiment, it is sufficient that a current of a predetermined value or more flows through the variable magnetic flux magnet control coil 231, so that current smoothing (voltage smoothing) does not need to be performed, that is, the current does not need to be direct current.

For example, when the first AC voltage 3011 of the first control pattern is generated while the switch 352 is in the off state and the switch 354 is in the off state, the switch 352 is switched to the on state.
In this case, when a positive voltage (voltage in the first voltage direction F1) is generated as the detected voltage Vs in the power receiving circuit 192, the switch 352 turns on, preventing the generation of a negative voltage (voltage in the second voltage direction F2). As a result, the switch 354 remains off and does not turn on. In other words, the switch 352 continues to remain on, causing the switch 354 to remain off.

Specifically, when switch 352 is on and switch 354 is off, even if the voltage in the first voltage direction F1 changes to the voltage in the second voltage direction F2, the loop of receiving coil 331, capacitor 332, diode 351, and switch 352 is short-circuited, so the voltage in the second voltage direction F2 becomes zero (or nearly zero), and no voltage in the second voltage direction F2 is generated. This prevents switch 354 from turning on by itself.

In FIG. 6, portions of the first AC voltage 3011 where a negative voltage (voltage in the second voltage direction F2) is not generated are shown as non-generation portions 3021 and 3022.
6, the first AC voltage 3011 is a sine wave, with a positive voltage occurring from time T1 to time T2 and a positive voltage occurring from time T3 to time T4. Also, a non-generation portion 3021 occurs from time T2 to time T3 and a non-generation portion 3022 occurs from time T4 to time T5.
The times T1 to T5 are equally spaced.

FIG. 7 is a diagram illustrating an example of a second AC voltage 3111 of the second control pattern according to the embodiment.
In the graph shown in FIG. 7, the horizontal axis represents time, and the vertical axis represents voltage level.

In this embodiment, the second AC voltage 3111 of the second control pattern is an AC voltage that starts from a negative voltage.
In this embodiment, the second AC voltage 3111 of the second control pattern is generated by applying an AC voltage corresponding to the first control pattern to the power transmitting coil 312 by the power supply circuit 311 in the power transmitting unit 131.
In this embodiment, the AC voltage corresponding to the second control pattern in the power transmission unit 131 is an AC voltage in which the terminal to which the capacitor 313 is connected, among the two ends of the power supply circuit 311, starts from a negative voltage.

In this embodiment, when the second AC voltage 3111 of the second control pattern is generated in the power receiving circuit 192, the switch 354 is turned on (conductive) and the switch 352 is turned off (non-conductive).
In this state, rectification is performed by the diode 353. In this embodiment, it is sufficient that a current of a predetermined value or more flows through the variable magnetic flux magnet control coil 231, so that current smoothing (voltage smoothing) does not need to be performed, that is, the current does not need to be direct current.

For example, when the second AC voltage 3111 of the second control pattern is generated while the switch 352 is in the off state and the switch 354 is in the off state, the switch 354 is switched to the on state.
In this case, when a negative voltage (voltage in the second voltage direction F2) is generated as the detected voltage Vs in the power receiving circuit 192, the switch 354 turns on, preventing the generation of a negative voltage (voltage in the first voltage direction F1). As a result, the switch 352 remains off and does not turn on. In other words, the switch 354 continues to remain on, causing the switch 352 to remain off.

Specifically, when switch 354 is on and switch 352 is off, even if the voltage in the second voltage direction F2 changes to the voltage in the first voltage direction F1, the loop of receiving coil 331, capacitor 332, diode 353, and switch 354 is short-circuited, so the voltage in the first voltage direction F1 becomes zero (or nearly zero), and no voltage in the first voltage direction F1 is generated. This prevents switch 352 from turning on by itself.

In FIG. 7, portions of the second AC voltage 3111 where a positive voltage (voltage in the first voltage direction F1) is not generated are shown as non-generation portions 3121 and 3122.
7, second AC voltage 3111 is a sine wave, and a negative voltage is generated from time T11 to time T12, and a negative voltage is generated from time T13 to time T14. In addition, a non-generation portion 3121 is generated from time T12 to time T13, and a non-generation portion 3122 is generated from time T14 to time T15.
The times T11 to T15 are equally spaced.

Here, the control of the first circuit unit A11 and the second circuit unit A12 is not necessarily limited to the manner described using Figures 6 and 7, and may be performed in any other manner.

[Example of a power supply circuit]
FIG. 8 is a diagram showing an example of the configuration of a power supply circuit 631 according to the embodiment.
FIG. 8 shows a power supply 611 which is a DC power supply, and a power supply circuit 631 .
The power supply circuit 631 is an example of the configuration of the power supply circuit 311 shown in FIG.

The power supply circuit 631 includes four switching elements 651 to 654. The four switching elements 651 to 654 form a full bridge circuit.
Specifically, a series connection of two switching elements 651 and 652 and a series connection of two switching elements 653 and 654 are connected in parallel to a power supply 611. The characteristic directions of these four switching elements 651 to 654 (for example, in the case of transistors, the arrangement of the gate terminal, collector terminal, and emitter terminal) are the same.

The point between the two switching elements 651 and 652 and the point between the two switching elements 653 and 654 are the two output terminals of the power supply circuit 311 shown in FIG.
In the example of FIG. 5 , the voltage between these two output terminals is supplied to the power transmitting coil 312 via the capacitor 313 .

In the example of Figure 8, a full-bridge circuit (a circuit having four switching elements 651-654) is used as the power supply circuit 631, but as another configuration example, a half-bridge circuit (a circuit having two switching elements) may also be used.

As described above, in the rotating electric machine 1 according to this embodiment, power is transmitted wirelessly from the power transmitting unit 131 of the stator 11 to the power receiving unit 171 of the rotor 12 by the wireless power transmission system 101 .
The rotating electric machine 1 according to this embodiment may be mounted in various devices, such as for driving the wheels of an automobile, the wheels of a train, or the rotating part of a washing machine.

In this embodiment, the wireless power transmission system 101 is configured to transmit power wirelessly from the power transmitting unit 131 of the stator 11 to the power receiving unit 171 of the rotor 12, thereby isolating the power supply unit on the stator 11 side from the load on the rotor 12 side.
In this embodiment, the variable magnetic flux magnet control coil 231 is provided on the side of the rotating rotor 12, while the power transmission unit 131 is provided on the side of the non-rotating stator 11, thereby making it possible to stabilize the power transmission unit 131.

The variable flux magnet control circuit 301 shown in Figure 5 is configured using two diodes 351, 353 and two switches 352, 354 as main circuit elements, allowing for a simple circuit configuration with a small number of diodes and switches. In this way, in the example of Figure 5, the number of components in the circuit that passes current through the coil (in this embodiment, the variable flux magnet control coil 231) that changes the magnetic flux of the variable flux magnet 211 can be reduced, thereby reducing costs.

Here, in the above embodiment, a configuration has been shown in which the power transmission unit 131 is provided on the stator 11 and the power receiving unit 171 is provided on the rotor 12, but as another configuration example, the power transmission unit 131 and the power receiving unit 171 may be provided on the rotor 12.
Furthermore, in the above embodiment, a case where the wireless power transmission system 101 is used is shown, but as another configuration example, the transmission coil 151 of the transmission unit 131 and the receiving coil 191 of the receiving unit 171 may be configured as the primary coil and secondary coil of a transformer.
Although the above embodiment has shown the case where the wireless power transmission system 101 is used, a configuration may be used in which the AC power generating unit of the power receiving unit 171 receives power in a non-insulated manner. In other words, a configuration may be used in which power is transmitted from the power transmitting unit to the power receiving unit via a wire.

<Configuration example>
As one configuration example, a variable magnetic flux magnet control device (in the example of FIG. 5 , for example, the circuit of the power receiving unit 171 of the wireless power receiving device 112) includes an AC power generating unit (in the example of FIG. 5 , AC power generating unit A1) and a current direction switching circuit (in the example of FIG. 5 ) including a first circuit unit (in the example of FIG. 5 , first circuit unit A11) and a second circuit unit (in the example of FIG. 5 , second circuit unit A12) arranged between the AC power generating unit and a variable magnetic flux magnet control coil (in the examples of FIGS. 3 and 5 , variable magnetic flux magnet control coil 231) for controlling the magnetization of the variable magnetic flux magnet (in the example of FIG. 3 , variable magnetic flux magnet 211). The first circuit unit has a first switch function (in the example of FIG. 5 , the function of switch 352) and a first direction conduction function (in the example of FIG. 5 , the function of diode 351). The second circuit portion includes a second switch function (the function of the switch 354 in the example of FIG. 5) and a second direction conduction function (the function of the diode 353 in the example of FIG. 5).

As one configuration example, in a variable magnetic flux magnet control device, the AC power generation unit has a capacitor (capacitor 332 in the example in Figure 5) on at least one of the ends connected to the first circuit unit and the second circuit unit, or the other end connected to the first circuit unit and the second circuit unit.

In one configuration example, the power receiving device (wireless power receiving device 112 in the example of Figure 1) is equipped with a variable magnetic flux magnet control device. The AC power generation unit includes a power receiving coil (power receiving coil 191 in the example of Figure 1), and the power transmitted from the power transmitting coil (power transmitting coil 151 in the example of Figure 1) of the power transmitting device (wireless power transmitting device 111 in the example of Figure 1) is received by the power receiving coil.

As an example configuration, a power transmission system (wireless power transmission system 101 in the example of Figure 1) includes a power receiving device and a power transmitting device.

As an example configuration, a rotating electric machine (in the example of Figure 1, rotating electric machine 1) includes a stator (in the example of Figure 1, stator 11), a rotor (in the example of Figure 1, rotor 12), and a power transmission system.

In one configuration example, in a rotating electric machine, the power transmission device is provided on the stator and the power receiving device is provided on the rotor.

[Variable magnetic flux magnet control circuit according to modified example]
9 to 15, variable magnetic flux magnet control circuits according to modified examples are shown.

FIG. 9 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301a according to a modified example.
The variable magnetic flux magnet control circuit 301 a includes a circuit for the power transmission unit 131 , a circuit for the power reception unit 171 a , and a load circuit Z<b>1 including the variable magnetic flux magnet control coil 231 .
The variable magnetic flux magnet control circuit 301 a also includes an electric wire 371 and an electric wire 372 .
In addition, in the variable magnetic flux magnet control circuit 301a, a connection point K1 and a connection point K2 are shown.
In the example of FIG. 9, a first direction D1 and a second direction D2 are also shown.

Here, the configuration of the variable magnetic flux magnet control circuit 301a is similar to that of the variable magnetic flux magnet control circuit 301 shown in FIG. 5, except that the configuration of the power receiving unit 171a is different.
For ease of explanation, in the variable magnetic flux magnet control circuit 301a, components similar to those in the variable magnetic flux magnet control circuit 301 shown in FIG. 5 are given the same reference numerals.

<Power receiving circuit>
The circuit of the power receiving unit 171 a includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332 , a diode 711 , a switch 712 , a switch 713 , and a diode 714 .
Here, the power receiving coil 331 and the capacitor 332 are the same as those shown in FIG. 5, and for convenience of explanation, the same reference numerals are used.

The receiving coil 331 and capacitor 332 are connected in series. A combination of diode 711 and switch 712 and a combination of switch 713 and diode 714 are connected in parallel to this series circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The other end of the capacitor 332 is connected to one end of the switch 712 and the anode of the diode 714 .
The other end of the switch 712 is connected to the cathode of the diode 711 .
The cathode of the diode 714 is connected to one end of the switch 713 .
The other end of the power receiving coil 331, the anode of the diode 711, and the other end of the switch 713 are connected.

In this embodiment, the AC power generation unit is made up of the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The diode 711 and the switch 712 constitute a first circuit section.
The switch 713 and the diode 714 constitute a second circuit section.
The first circuit section and the second circuit section constitute a current direction switching circuit.
The first and second circuit units are connected in parallel between the AC power generating unit and the load circuit Z1. The orientation (conduction direction) of the diode 711 of the first circuit unit and the orientation (conduction direction) of the diode 714 of the second circuit unit are opposite to each other.

Here, the configuration of the first circuit section made up of the diode 711 and the switch 712 is similar to the configuration of the first circuit section made up of the diode 351 and the switch 352 shown in FIG.
Furthermore, in the configuration of the second circuit section made up of the switch 713 and the diode 714, the order of the switch 713 and the diode 714 is reversed compared to the configuration of the second circuit section made up of the diode 353 and the switch 354 shown in Figure 5.

As described above, the variable magnetic flux magnet control circuit 301a according to the modified example reduces the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

As one configuration example, the first circuit section includes a first switch function (in the example of FIG. 9, the function of switch 712) and a first-directional conduction function (in the example of FIG. 9, the function of diode 711), and the second circuit section includes a second switch function (in the example of FIG. 9, the function of switch 713) and a second-directional conduction function (in the example of FIG. 9, the function of diode 714).

FIG. 10 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301b according to a modified example.
The variable magnetic flux magnet control circuit 301b includes a circuit for the power transmission unit 131, a circuit for the power reception unit 171b, and a load circuit Z1 including a variable magnetic flux magnet control coil 231.
The variable magnetic flux magnet control circuit 301 b also includes an electric wire 371 and an electric wire 372 .
In addition, in the variable magnetic flux magnet control circuit 301b, a connection point K1 and a connection point K2 are shown.
In the example of FIG. 10, a first direction D1 and a second direction D2 are also shown.

Here, the configuration of the variable magnetic flux magnet control circuit 301b is similar to that of the variable magnetic flux magnet control circuit 301 shown in FIG. 5, except that the configuration of the power receiving unit 171b is different.
For ease of explanation, in the variable magnetic flux magnet control circuit 301b, components similar to those in the variable magnetic flux magnet control circuit 301 shown in FIG. 5 are given the same reference numerals.

<Power receiving circuit>
The circuit of the power receiving unit 171 b includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332 , a diode 731 , a switch 732 , a switch 733 , and a diode 734 .
Here, the power receiving coil 331 and the capacitor 332 are the same as those shown in FIG. 5, and for convenience of explanation, the same reference numerals are used.

The receiving coil 331 and capacitor 332 are connected in series. A circuit section consisting of a combination of diode 731, switch 732, switch 733, and diode 734 is connected to this series connection circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The other end of the capacitor 332 is connected to one end of the switch 732 and the anode of the diode 734 .
The other end of the switch 732, one end of the switch 733, the cathode of the diode 734, and the cathode of the diode 731 are connected together.
The other end of the power receiving coil 331, the other end of the switch 733, and the anode of the diode 731 are connected.

In this embodiment, the AC power generation unit is made up of the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The diode 731 and the switch 732 constitute a first circuit section.
The switch 733 and the diode 734 constitute a second circuit section.
The first circuit section and the second circuit section constitute a current direction switching circuit.
The first and second circuit units are connected between the AC power generating unit and the load circuit Z1. The orientation (conduction direction) of the diode 731 of the first circuit unit and the orientation (conduction direction) of the diode 734 of the second circuit unit are opposite to each other.
In this example, some of the conductors are common between the first circuit section and the second circuit section.

As described above, the variable magnetic flux magnet control circuit 301b according to the modified example reduces the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

As one configuration example, the first circuit section includes a first switch function (the function of switch 732 in the example of FIG. 10) and a first-directional conduction function (the function of diode 731 in the example of FIG. 10), and the second circuit section includes a second switch function (the function of switch 733 in the example of FIG. 10) and a second-directional conduction function (the function of diode 734 in the example of FIG. 10).

FIG. 11 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301c according to a modified example.
The variable magnetic flux magnet control circuit 301c includes a circuit for the power transmission unit 131, a circuit for the power reception unit 171c, and a load circuit Z1 including a variable magnetic flux magnet control coil 231.
The variable magnetic flux magnet control circuit 301c also includes an electric wire 371 and an electric wire 372.
In addition, in the variable magnetic flux magnet control circuit 301c, a connection point K1 and a connection point K2 are shown.
In the example of FIG. 11, a first direction D1 and a second direction D2 are also shown.

Here, the configuration of the variable magnetic flux magnet control circuit 301c is similar to that of the variable magnetic flux magnet control circuit 301 shown in FIG. 5, except that the configuration of the power receiving unit 171c is different.
For ease of explanation, in the variable magnetic flux magnet control circuit 301c, components similar to those in the variable magnetic flux magnet control circuit 301 shown in FIG. 5 are given the same reference numerals.

<Power receiving circuit>
The circuit of the power receiving unit 171 c includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332 , a diode 751 , a switch 752 , a switch 753 , and a diode 754 .
Here, the power receiving coil 331 and the capacitor 332 are the same as those shown in FIG. 5, and for convenience of explanation, the same reference numerals are used.

The receiving coil 331 and capacitor 332 are connected in series. A circuit section consisting of a combination of diode 751, switch 752, switch 753, and diode 754 is connected to this series connection circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The point connected to the other end of the capacitor 332 is connected to the point where one end of the switch 752 and the anode of the diode 754 are connected.
The point where the other end of the switch 752 is connected to the cathode of the diode 754 is connected to the point where one end of the switch 753 is connected to the cathode of the diode 751 .
The point where the other end of the power receiving coil 331 is connected is connected to the point where the other end of the switch 753 and the anode of the diode 751 are connected.

In this embodiment, the AC power generation unit is made up of the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The diode 751 and the switch 752 constitute a first circuit section.
The switch 753 and the diode 754 constitute a second circuit section.
The first circuit section and the second circuit section constitute a current direction switching circuit.
The first and second circuit units are connected between the AC power generating unit and the load circuit Z1. The orientation (conduction direction) of the diode 751 of the first circuit unit and the orientation (conduction direction) of the diode 754 of the second circuit unit are opposite to each other.
In this example, some of the conductors are common between the first circuit section and the second circuit section.

As described above, the variable magnetic flux magnet control circuit 301c according to the modified example reduces the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

As one configuration example, the first circuit section includes a first switch function (the function of switch 752 in the example of FIG. 11) and a first-directional conduction function (the function of diode 751 in the example of FIG. 11), and the second circuit section includes a second switch function (the function of switch 753 in the example of FIG. 11) and a second-directional conduction function (the function of diode 754 in the example of FIG. 11).

FIG. 12 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301d according to a modified example.
The variable magnetic flux magnet control circuit 301d includes a circuit for the power transmission unit 131, a circuit for the power reception unit 171d, and a load circuit Z1 including a variable magnetic flux magnet control coil 231.
Furthermore, the variable magnetic flux magnet control circuit 301d includes an electric wire 371 and an electric wire 372.
In addition, in the variable magnetic flux magnet control circuit 301d, a connection point K1 and a connection point K2 are shown.
In the example of FIG. 12, a first direction D1 and a second direction D2 are also shown.

Here, the configuration of the variable magnetic flux magnet control circuit 301d is similar to that of the variable magnetic flux magnet control circuit 301 shown in FIG. 5, except that the configuration of the power receiving unit 171d is different.
For ease of explanation, in the variable magnetic flux magnet control circuit 301d, components similar to those in the variable magnetic flux magnet control circuit 301 shown in FIG. 5 are given the same reference numerals.

<Power receiving circuit>
The circuit of the power receiving unit 171d includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332, a switch 771, and a switch 772.
Here, the power receiving coil 331 and the capacitor 332 are the same as those shown in FIG. 5, and for convenience of explanation, the same reference numerals are used.
The switches 771 and 772 are each an n-type metal oxide semiconductor field effect transistor (MOSFET).

The receiving coil 331 and capacitor 332 are connected in series. A series connection circuit of switches 771 and 772 is connected in parallel to this series connection circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The other end of the capacitor 332 is connected to one end (source terminal) of the switch 771 .
The other end (drain terminal) of the switch 771 is connected to one end (drain terminal) of the switch 772 .
The other end of the power receiving coil 331 is connected to the other end (source terminal) of the switch 772 .
The control terminal (gate terminal) of the switch 771 and the control terminal (gate terminal) of the switch 772 are used to control switching between on and off.

In this embodiment, the AC power generation unit is made up of the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The switch 771 constitutes a first circuit section.
The switch 772 constitutes a second circuit section.
The first circuit section and the second circuit section constitute a current direction switching circuit.
The first and second circuit sections are connected between the AC power generating section and the load circuit Z1. The conduction direction when the switch 771 of the first circuit section is on is opposite to the conduction direction when the switch 772 of the second circuit section is on.
In this example, the first circuit section and the second circuit section are common to each other.

As described above, the variable magnetic flux magnet control circuit 301d according to the modified example reduces the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

As one configuration example, the first circuit unit includes a first switch function (in the example of FIG. 12, the function of switch 771) and a first direction conduction function (in the example of FIG. 12, the function of the body diode of switch 772), and the second circuit unit includes a second switch function (in the example of FIG. 12, the function of switch 772) and a second direction conduction function (in the example of FIG. 12, the function of the body diode of switch 771).

FIG. 13 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301e according to a modified example.
The variable magnetic flux magnet control circuit 301e includes a circuit for the power transmission unit 131, a circuit for the power reception unit 171e, and a load circuit Z1 including a variable magnetic flux magnet control coil 231.
The variable magnetic flux magnet control circuit 301 e also includes an electric wire 371 and an electric wire 372 .
In addition, in the variable magnetic flux magnet control circuit 301e, a connection point K1 and a connection point K2 are shown.
In the example of FIG. 13, a first direction D1 and a second direction D2 are also shown.

Here, the configuration of the variable magnetic flux magnet control circuit 301e is similar to that of the variable magnetic flux magnet control circuit 301 shown in FIG. 5, except that the configuration of the power receiving unit 171e is different.
For ease of explanation, in the variable magnetic flux magnet control circuit 301e, components similar to those in the variable magnetic flux magnet control circuit 301 shown in FIG. 5 are given the same reference numerals.

<Power receiving circuit>
The circuit of the power receiving unit 171 e includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332 , a switch 791 , and a switch 792 .
Here, the power receiving coil 331 and the capacitor 332 are the same as those shown in FIG. 5, and for convenience of explanation, the same reference numerals are used.
The switch 791 and the switch 792 are each an insulated gate bipolar transistor (IGBT).

The receiving coil 331 and capacitor 332 are connected in series. Switches 791 and 792 are connected in parallel to this series connection circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The other end of the capacitor 332 is connected to one end (emitter terminal) of a switch 791 and one end (collector terminal) of a switch 792 .
The other end of the power receiving coil 331 is connected to the other end (collector terminal) of the switch 791 and the other end (emitter terminal) of the switch 792 .
The control terminal (gate terminal) of the switch 791 and the control terminal (gate terminal) of the switch 792 are each used to control switching between on and off.

In this embodiment, the AC power generation unit is made up of the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The switch 791 constitutes a first circuit section.
The switch 792 constitutes a second circuit section.
The first circuit section and the second circuit section constitute a current direction switching circuit.
The first and second circuit sections are connected in parallel between the AC power generating section and the load circuit Z1. The conduction direction when the switch 791 of the first circuit section is on is opposite to the conduction direction when the switch 792 of the second circuit section is on.

As described above, the variable magnetic flux magnet control circuit 301e according to the modified example reduces the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

As one configuration example, the first circuit unit includes a first switch function (in the example of FIG. 13, the switch function of switch 791) and a first direction conduction function (in the example of FIG. 13, the conduction function of switch 791), and the second circuit unit includes a second switch function (in the example of FIG. 13, the switch function of switch 792) and a second direction conduction function (in the example of FIG. 13, the conduction function of switch 792).

FIG. 14 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301f according to a modified example.
The variable magnetic flux magnet control circuit 301f includes a circuit for the power transmission unit 131, a circuit for the power reception unit 171f, and a load circuit Z1 including a variable magnetic flux magnet control coil 231.
The variable magnetic flux magnet control circuit 301f also includes an electric wire 371 and an electric wire 372.
In addition, in the variable magnetic flux magnet control circuit 301f, a connection point K1 and a connection point K2 are shown.
In the example of FIG. 14, a first direction D1 and a second direction D2 are also shown.

Here, the configuration of the variable magnetic flux magnet control circuit 301f is similar to that of the variable magnetic flux magnet control circuit 301 shown in FIG. 5, except that the configuration of the power receiving unit 171f is different.
For ease of explanation, in the variable magnetic flux magnet control circuit 301f, components similar to those in the variable magnetic flux magnet control circuit 301 shown in FIG. 5 are given the same reference numerals.

<Power receiving circuit>
The circuit of the power receiving unit 171 f includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332 , a switch 811 , and a switch 812 .
Here, the power receiving coil 331 and the capacitor 332 are the same as those shown in FIG. 5, and for convenience of explanation, the same reference numerals are used.
The switches 811 and 812 are each a thyristor, which is also called a silicon controlled rectifier (SCR).

The receiving coil 331 and capacitor 332 are connected in series. Switches 811 and 812 are connected in parallel to this series connection circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The other end of the capacitor 332 is connected to one end (cathode) of the switch 811 and one end (anode) of the switch 812 .
The other end of the power receiving coil 331 is connected to the other end (anode) of the switch 811 and the other end (cathode) of the switch 812 .
The control terminal (gate) of the switch 811 and the control terminal (gate) of the switch 812 are used to control switching between on and off.

In this embodiment, the AC power generation unit is made up of the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The switch 811 constitutes a first circuit section.
The switch 812 constitutes a second circuit section.
The first circuit section and the second circuit section constitute a current direction switching circuit.
The first and second circuit units are connected in parallel between the AC power generating unit and the load circuit Z1. The conduction direction when the switch 811 of the first circuit unit is on is opposite to the conduction direction when the switch 812 of the second circuit unit is on.

As described above, the variable magnetic flux magnet control circuit 301f according to the modified example reduces the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

As one configuration example, the first circuit unit includes a first switch function (in the example of FIG. 14, the switch function of switch 811) and a first-directional conduction function (in the example of FIG. 14, the conduction function of switch 811), and the second circuit unit includes a second switch function (in the example of FIG. 14, the switch function of switch 812) and a second-directional conduction function (in the example of FIG. 14, the conduction function of switch 812).

FIG. 15 is a diagram showing an example of the configuration of a variable magnetic flux magnet control circuit 301g according to a modified example.
The variable magnetic flux magnet control circuit 301g includes a circuit for the power transmission unit 131, a circuit for the power reception unit 171g, and a load circuit Z1 including a variable magnetic flux magnet control coil 231.
Furthermore, the variable magnetic flux magnet control circuit 301 g includes an electric wire 371 and an electric wire 372 .
In addition, in the variable magnetic flux magnet control circuit 301g, a connection point K1 and a connection point K2 are shown.
In the example of FIG. 15, a first direction D1 and a second direction D2 are also shown.

Here, the configuration of the variable magnetic flux magnet control circuit 301g is similar to that of the variable magnetic flux magnet control circuit 301 shown in FIG. 5, except that the configuration of the power receiving unit 171g is different.
For ease of explanation, in the variable magnetic flux magnet control circuit 301g, components similar to those in the variable magnetic flux magnet control circuit 301 shown in FIG. 5 are given the same reference numerals.

<Power receiving circuit>
The circuit of the power receiving unit 171 g includes a power receiving coil 331 (a coil on the secondary side in terms of power transmission), a capacitor 332 , a switch 831 , and a switch 832 .
Here, the power receiving coil 331 and the capacitor 332 are the same as those shown in FIG. 5, and for convenience of explanation, the same reference numerals are used.
The switches 831 and 832 are each a gate turn-off thyristor (GTO).

The receiving coil 331 and capacitor 332 are connected in series. Switches 831 and 832 are connected in parallel to this series connection circuit.

Specifically, one end of the power receiving coil 331 and one end of the capacitor 332 are connected to each other.
The other end of the capacitor 332 is connected to one end (cathode) of the switch 831 and one end (anode) of the switch 832 .
The other end of the power receiving coil 331, the other end (anode) of the switch 831, and the other end (cathode) of the switch 832 are connected.
The control terminal (gate) of the switch 831 and the control terminal (gate) of the switch 832 are used to control switching between on and off.

In this embodiment, the AC power generation unit is made up of the power receiving coil 331 and the capacitor 332. The power receiving coil 331 generates AC power (AC voltage) when receiving power transmitted wirelessly from the power transmitting unit 131. That is, the power receiving coil 331 generates an AC voltage via a magnetic field generated by the power transmitting coil 312.
The switch 831 constitutes a first circuit section.
The switch 832 constitutes a second circuit section.
The first circuit section and the second circuit section constitute a current direction switching circuit.
The first and second circuit units are connected in parallel between the AC power generating unit and the load circuit Z1. The conduction direction when the switch 831 of the first circuit unit is on is opposite to the conduction direction when the switch 832 of the second circuit unit is on.

As described above, the variable magnetic flux magnet control circuit 301g according to the modified example reduces the number of components in the circuit that passes current through the coil to change the magnetic flux of the variable magnetic flux magnet, thereby reducing costs.

As one configuration example, the first circuit unit includes a first switch function (in the example of FIG. 15, the switch function of switch 831) and a first direction conduction function (in the example of FIG. 15, the conduction function of switch 831), and the second circuit unit includes a second switch function (in the example of FIG. 15, the switch function of switch 832) and a second direction conduction function (in the example of FIG. 15, the conduction function of switch 832).

[Power transmission system according to another example]
16 to 18, a power transfer system 1001 according to another example is shown.
For convenience of explanation, each of FIGS. 16 to 18 shows XYZ orthogonal coordinate axes, which are three-dimensional orthogonal coordinate axes.
The power transmission system 1001 is an example of a power transmission system that is not wireless.

FIG. 16 is an external perspective view showing an example of a schematic configuration of a power transmission system 1001 according to another example.
FIG. 17 is a partial cross-sectional view showing an example of a schematic configuration of a power transmission system 1001 according to another example.
FIG. 18 is an exploded view showing an example of a schematic configuration of a power transmission system 1001 according to another example.
Here, the cross section shown in FIG. 17 is a cross section of the portion B1 shown in FIG. 16, and shows an example of a cross section cut along a plane parallel to the YZ plane.

The power transmission system 1001 is provided in a rotating electric machine (not shown) having a stator and a rotor.
The power transmission system 1001 comprises a disc portion 1011 provided on the stator side, a disc portion 1012 provided on the rotor side, a transmission coil 1111 (transmission coil of the transmission unit) arranged on the disc portion 1011 on the stator side, a receiving coil 1131 and a receiving coil 1132 (receiving coil of the receiving unit) arranged on the disc portion 1012 on the rotor side, and four magnetic materials 1013a to 1013d.
The disk portion 1011 on the stator side has four holes 1121a to 1121d (which may also be called openings, etc.).
In the examples of Figures 16 to 18, detailed illustrations and descriptions are omitted for detailed circuit sections other than the transmitting coil 1111 in the transmitting unit, and detailed circuit sections other than the receiving coils (receiving coil 1131 and receiving coil 1132) in the receiving unit.

The stator-side disc portion 1011 and the rotor-side disc portion 1012 each have a disc shape. In the examples shown in Figures 16 to 18, the stator-side disc portion 1011 and the rotor-side disc portion 1012 have the same shape (or nearly the same shape) and are arranged so that the centers of the circles face each other and the circles face each other.

Of the two faces of the stator-side disc portion 1011 (faces parallel to the XY plane in the examples of Figures 16 to 18), the power transmission coil 1111 is arranged on the face facing the rotor-side disc portion 1012 (the face facing the positive direction of the Z axis in the examples of Figures 16 to 18). The conducting wire that makes up the power transmission coil 1111 is wound in a predetermined range from the outer periphery toward the center of that face, thereby forming the power transmission coil 1111.

Of the two faces (faces parallel to the XY plane in the examples of FIGS. 16 to 18 ) of the rotor-side disc portion 1012, the face facing the stator-side disc portion 1011 (the face facing the negative direction of the Z axis in the examples of FIGS. 16 to 18 ) has a receiving coil 1131. The conducting wire that makes up the receiving coil 1131 is wound in a predetermined range from the outer periphery toward the center of that face, thereby forming the receiving coil 1131.
Furthermore, of the two faces (faces parallel to the XY plane in the examples of FIGS. 16 to 18 ) of the rotor-side disc portion 1012, the face (face facing the positive direction of the Z axis in the examples of FIGS. 16 to 18 ) that does not face the stator-side disc portion 1011 is provided with a power receiving coil 1132. The conducting wire that constitutes the power receiving coil 1132 is wound in a predetermined range from the outer periphery toward the center of that face, thereby forming the power receiving coil 1132.

Each of the four magnetic members 1013a to 1013d is made of a magnetic material, for example, ferrite.
The magnetic material 1013a has a shape (for example, a U-shape) that surrounds a part of the disk portion (hereinafter, for convenience of explanation, referred to as the combined disk portion) formed by combining the stator-side disk portion 1011 and the rotor-side disk portion 1012 from the outside of the outer periphery, and also has claw portions that fit into the holes 1121a of the stator-side disk portion 1011. Then, the magnetic material 1013a is fixed in an arrangement that surrounds a part of the combined disk portion by fitting the claw portions into the holes 1121a of the stator-side disk portion 1011.

The other three magnetic materials 1013b, 1013c, and 1013d each have the same shape as magnetic material 1013a, and like magnetic material 1013a, their respective claw portions are fitted into holes 1121b, 1121c, and 1121d of the disc portion 1011 on the stator side, thereby being fixed in an arrangement that surrounds a portion of the combined disc portion.
The four magnetic members 1013a to 1013d are arranged at equal intervals (at 90-degree intervals on the surface of the circle) on the circular combination disk portion.

The power transmission coil 1111, which is arranged on the disc portion 1011 on the stator side, and the power receiving coils (power receiving coil 1131 and power receiving coil 1132) which are arranged on the disc portion 1012 on the rotor side, are each arranged in an area surrounded by the respective magnetic materials 1013a to 1013d in the direction from the center of the circle toward the outer periphery (in the examples of Figures 16 to 18, an area surrounded on a plane parallel to the XY plane).

As described above, in another example of the power transmission system 1001, power can be transmitted from the transmitting coil 1111 arranged on the disc portion 1011 on the stator side to the receiving coils (receiving coil 1131 and receiving coil 1132) arranged on the disc portion 1012 on the rotor side.
This power transmission mechanism is similar to a rotating transformer.
In this way, power transmission does not necessarily have to be performed wirelessly. For example, a power transmission system 1001 such as those shown in Figures 16 to 18 may be used instead of the wireless power transmission system 101 shown in Figure 1.

A program for implementing the functions of any of the components of any of the devices described above (e.g., wireless power transmitter 111, wireless power receiver 112, rotating electric machine 1, devices of power transmission system 1001, etc.) may be recorded on a computer-readable recording medium and loaded into a computer system for execution. Note that the term "computer system" as used herein includes hardware such as an operating system or peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and compact discs (CDs) - read-only memories (ROMs), as well as storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording medium" also includes devices that retain a program for a certain period of time, such as volatile memory within a computer system that acts as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. Such volatile memory may be, for example, RAM (random access memory). The recording medium may be, for example, a non-transitory recording medium.

The above program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by transmission waves in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network such as the Internet or a communication line such as a telephone line.
The above program may also be one that realizes part of the above-mentioned functions. Furthermore, the above program may be a so-called differential file that can realize the above-mentioned functions in combination with a program already recorded in a computer system. A differential file may also be called a differential program.

Furthermore, the functions of any of the components in any of the devices described above (e.g., the wireless power transmitter 111, the wireless power receiver 112, the rotating electric machine 1, the devices of the power transmission system 1001, etc.) may be implemented by a processor. For example, each process in the embodiments may be implemented by a processor that operates based on information such as a program and a computer-readable recording medium that stores information such as the program. Here, the functions of each component of the processor may be implemented by separate hardware, or the functions of each component may be implemented by integrated hardware. For example, the processor may include hardware, and the hardware may include at least one of a circuit for processing digital signals and a circuit for processing analog signals. For example, the processor may be configured using one or more circuit devices mounted on a circuit board, or one or both of one or more circuit elements. An integrated circuit (IC) or the like may be used as the circuit device, and a resistor or capacitor may be used as the circuit element.

Here, the processor may be, for example, a CPU. However, the processor is not limited to a CPU, and various types of processors may be used, such as a GPU (Graphics Processing Unit) or a DSP (Digital Signal Processor). The processor may also be a hardware circuit, such as an ASIC (Application Specific Integrated Circuit). The processor may also be configured, for example, by multiple CPUs, or by a hardware circuit made up of multiple ASICs. The processor may also be configured, for example, by a combination of multiple CPUs and a hardware circuit made up of multiple ASICs. The processor may also include, for example, one or more amplifier circuits or filter circuits that process analog signals.

The above describes in detail an embodiment of this disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment and includes designs that do not deviate from the gist of this disclosure.

The above describes an embodiment applied to technology for controlling the direction of current flowing through a coil (variable flux magnet control coil) for controlling the magnetization of a variable flux magnet, but configurations and operations similar to those of the above embodiments may also be applied to technology in other fields. In other words, configurations and operations similar to those of the above embodiments may be used for other control purposes instead of controlling the direction of current flowing through a variable flux magnet control coil.

1...rotating electric machine, 11...stator, 12...rotor, 31...winding, 51...variable magnetic flux magnet module, 101...wireless power transmission system, 111...wireless power transmitter, 112...wireless power receiver, 131...power transmitter, 151, 312, 1111...power transmitter coil, 152...power transmitter circuit, 153...power transmission control unit, 171, 171a, 171b, 171c, 171d, 171e, 171f, 171g...power receiver, 191, 331, 11 31, 1132... power receiving coil, 192... power receiving circuit, 193... power receiving control unit, 211... variable magnetic flux magnet, 231... variable magnetic flux magnet control coil, 301, 301a, 301b, 301c, 301d, 301e, 301f, 301g... variable magnetic flux magnet control circuit, 311, 631... power supply circuit, 313, 332... capacitor, 351, 353, 711, 714, 731, 734, 751, 754... diode, 352, 354, 712, 7 13, 732, 733, 752, 753, 771, 772, 791, 792, 811, 812, 831, 832...switches, 371, 372, E1, E2...electric wires, 411...resistor, 611...power supply, 651 to 654...switching elements, 2011...magnetization curve, 2021...magnetization path, 2022...demagnetization path, 3011...first AC voltage, 3021, 3022, 3121, 3122...non-generation portion, 3111...second AC voltage, A1...AC voltage Force generating unit, A2...current direction switching circuit, A11...first circuit unit, A12...second circuit unit, D1...first direction, D2...second direction, F1...first voltage direction, F2...second voltage direction, K1, K2...connection point, P1...high magnetization point, P2...low magnetization point, Z1...load circuit, 1001...power transmission system, 1011, 1012...disk portion, 1013a, 1013b, 1013c, 1013d...magnetic material, 1121a, 1121b, 1121c, 1121d...hole portion

Claims (6)

an AC power generating unit;
a current direction switching circuit including a first circuit unit and a second circuit unit disposed between a variable magnetic flux magnet control coil for controlling magnetization of the variable magnetic flux magnet and the AC power generating unit;
Equipped with
the first circuit portion includes a first switch function and a first direction conduction function;
the second circuit portion includes a second switch function and a second directional conduction function;
the first switch function is constituted by a switch function of a first gate turn-off thyristor, and the first direction conduction function is constituted by a conduction function of the first gate turn-off thyristor;
the second switch function is constituted by a switch function of a second gate turn-off thyristor, and the second direction conduction function is constituted by a conduction function of the second gate turn-off thyristor.
Variable flux magnet control device. the AC power generation unit includes a capacitor at least at one end connected to the first circuit unit and the second circuit unit or at the other end connected to the first circuit unit and the second circuit unit;
The variable magnetic flux magnet control device according to claim 1 . A variable magnetic flux magnet control device according to claim 1 or 2 is provided,
the AC power generation unit includes a power receiving coil, and receives power transmitted from a power transmitting coil of a power transmitting device by the power receiving coil.
Power receiving device. The power receiving device according to claim 3 ;
The power transmitting device;
A power transmission system comprising: a stator;
The rotor and
The power transmission system according to claim 4;
A rotating electric machine comprising: the power transmission device is provided on the stator,
The power receiving device is provided on the rotor.
The rotating electric machine according to claim 5 .