Superconducting rotating machine and control method for a superconducting rotating machine

Abstract

A superconducting rotating machine comprising: a stator which includes a tubular stator core and a stator winding wound around the stator core and which generates a rotating magnetic field; a superconducting rotor which is held on the inner peripheral side of the stator so as to be rotated by the rotating magnetic field of the stator and which includes a superconducting squirrel-cage winding having one or a plurality of rotor bars and end rings formed from a superconducting material and a rotor core provided with a plurality of slots that accommodate the rotor bars; a pulse voltage output unit which outputs a pulse voltage for shifting the superconducting squirrel-cage winding to a magnetic flux flow state; and a drive voltage output unit which applies a drive voltage to the stator winding in order to drive the superconducting rotor to rotate, wherein the pulse voltage output from the pulse voltage output unit is superimposed on the drive voltage.

Description

Technical Field

[0001] The present invention relates to a superconducting rotating machine and a method for controlling the superconducting rotating machine.

Background Art

[0002] Rotating machines, which are electrical devices, are classified into DC machines and AC machines. Among these, AC machines generate AC power upon receiving mechanical power or generate mechanical power upon receiving AC power, and are mainly classified into induction machines and synchronous machines.

[0003] An induction machine, such as an induction motor, rotates by generating an induced torque on the rotor by a rotating magnetic field generated by applying a polyphase AC voltage (in many cases, a three-phase AC voltage) to the stator winding. Induction motors have a simple structure, are easy to maintain, and are inexpensive, so they are widely used, but they have difficulties in terms of efficiency and speed control.

[0004] A synchronous machine, such as a synchronous motor, rotates when a rotor equipped with an electromagnet or a permanent magnet is attracted by a rotating magnetic field generated by applying a polyphase AC voltage (in many cases, a three-phase AC voltage) to the stator winding. Although synchronous motors are efficient, additional devices are required for starting and synchronization.

[0005] In recent years, a superconducting rotating machine that can rotate synchronously while having the configuration of an induction machine has been proposed (see Patent Document 1 below). For example, according to Patent Document 1, an operating method of a superconducting rotating machine that can perform induction rotation and synchronous rotation and can operate the superconducting rotating machine in an autonomous and stable manner is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] For example, in a conventional superconducting rotating machine using a superconducting squirrel-cage winding as described above, if the machine is cooled to below the critical temperature by a cooling device before starting operation to induce a superconducting state, the superconducting squirrel-cage winding does not capture the magnetic flux of the rotating magnetic field of the stator winding. In this state, if a three-phase AC voltage is applied to the stator winding, a shielding current flows through the superconducting squirrel-cage winding, and the magnetic flux linked to the superconducting squirrel-cage winding becomes zero (hereinafter sometimes referred to as the "magnetic shielding state"). That is, in the magnetic shielding state, the magnetic flux supplied from the stator is shielded, so the superconducting rotor does not start. Therefore, normally, the voltage and frequency must be adjusted to induce a large current in the superconducting squirrel-cage winding for a certain period of time until the magnetic flux links, and the shielding current must be adjusted to exceed the critical current value of the winding (the maximum current at which the magnetic shielding state is maintained; Ic). Specifically, it is necessary to increase the voltage applied to the stator winding and / or the frequency of said applied voltage for a certain period of time until the current value flowing through the superconducting squirrel-cage winding (hereinafter sometimes simply referred to as "current value (Io)") exceeds the critical current value (Ic), thereby changing the superconducting squirrel-cage winding from a magnetically shielded state to a magnetic flux flow state. In the magnetic flux flow state, magnetic flux links with the superconducting squirrel-cage winding, generating an induced current (magnetic flux flow current), which in turn generates an induced torque and a finite resistance, causing the superconducting rotor to rotate by induction (hereinafter, the state in which the superconducting rotor rotates primarily due to induced torque may be referred to as the "induced rotation mode").

[0008] Subsequently, the rotational motion of the superconducting rotor is accelerated, the relative speed between the rotating magnetic field and the superconducting rotor decreases, and finally, when the induced current (magnetic flux flow current) flowing through the superconducting squirrel-cage winding falls below the critical current, the superconducting squirrel-cage winding captures the flux linkage. When the superconducting squirrel-cage winding captures the flux linkage (hereinafter sometimes referred to as the "magnetic flux capture state"), the superconducting rotor can rotate synchronously with respect to the rotating magnetic field (hereinafter, the state in which the superconducting rotor rotates with synchronous torque as the driving force may be referred to as the "synchronous rotation mode").

[0009] On the other hand, in superconducting rotating machines using superconducting squirrel-cage windings, once magnetic flux links with the superconducting squirrel-cage windings and the machine transitions to an induced rotation mode, the current required for driving becomes smaller than the starting current as inertial energy accumulates in the rotor. Therefore, using a power supply that can constantly provide the large steady-state current needed only for a short time during startup has many disadvantages in terms of cost and size. Furthermore, supplying a large starting current to a superconducting rotating machine for a long period of time is also disadvantageous in terms of energy loss and may further increase the load on the power supply and the rotating machine.

[0010] Furthermore, there is a strong demand for minimizing the start-up time in superconducting rotating machines using superconducting squirrel-cage windings. In particular, in superconducting rotating machines using superconducting squirrel-cage windings, energy loss occurs with the elapsed time during the transition from the magnetic shielding state to the magnetic flux flow state and then to the magnetic flux capture state, so it is desirable to shorten the time required to transition to synchronous rotation mode as much as possible. In addition, in superconducting rotating machines using superconducting squirrel-cage windings, after the magnetic flux flow state is achieved, the starting voltage needs to be set to the drive voltage so that the desired rotation characteristics can be obtained, so it is desirable for the voltage control during startup to be simpler. Moreover, if a voltage higher than the voltage required for driving is continuously applied after transitioning to the magnetic flux capture state (synchronous rotation mode), the current may be converted into rotor torque, resulting in energy loss, or the synchronous rotation mode may be canceled.

[0011] In these respects, conventional superconducting rotating machines still have room for improvement, and there is a need to develop technology that can easily transition from a magnetic shielding state to a magnetic flux capture state (i.e., synchronous rotation mode) during startup and other times.

[0012] The present invention aims to solve the above-mentioned problems by providing a superconducting rotating machine capable of both induced and synchronous rotation, and a control method thereof, that can easily transition to a magnetic flux flow state. [Means for solving the problem]

[0013] Conventionally, in order to shift a superconducting rotating machine to the synchronous rotation mode, it has been necessary to induce a large current in the superconducting cage winding for a certain period of time at startup or the like. However, the inventor of the present invention has found that by applying a short-time pulse voltage and superimposing it on the driving voltage, the superconducting rotating machine can be quickly shifted to the synchronous rotation mode, leading to the present invention.

[0014] The present invention provides a superconducting rotating machine including a cylindrical stator core and a stator winding wound around the stator core for generating a rotating magnetic field, a stator, a superconducting cage winding having rotor bars and end rings formed of one or more superconducting materials and rotatably held by the rotating magnetic field of the stator, and a rotor core having a plurality of slots for accommodating the rotor bars, a pulse voltage output unit for outputting a pulse voltage to shift the superconducting cage winding to a magnetic flux flow state, and a driving voltage output unit for applying a driving voltage to the stator winding to rotationally drive the superconducting rotor, wherein the pulse voltage output from the pulse voltage output unit is superimposed on the driving voltage.

[0015] As described above, when the superconducting cage winding is in a magnetic shielding state, the relationship between the current value (Io) (in this case, the shielding current) flowing in the superconducting cage winding and the critical current value (Ic) is Io < Ic. According to the superconducting rotating machine of the present invention, when the superconducting cage winding is in a magnetic shielding state at startup or after driving, by applying a pulse voltage of an extremely short time to the superconducting rotating machine and superimposing it on the driving voltage, the relationship between the current value (Io) flowing in the superconducting cage winding and the critical current value (Ic) of the superconducting cage winding can be quickly changed from Io < Ic to Io > Ic. As a result, the superconducting cage winding becomes a magnetic flux flow state and quickly shifts to the induction rotation mode, so that the time until the subsequent shift to the synchronous rotation mode can be significantly shortened.

[0016] Similarly, when the superconducting cage winding is in the flux trapping state, the relationship between the current value (Io) (in this case, the persistent current) flowing through the superconducting cage winding and the critical current value (Ic) is Io < Ic. According to the superconducting rotating machine of this embodiment, when the superconducting cage winding is in the flux trapping state in the synchronous rotation mode or the like, a pulse voltage with an extremely short time is applied to the superconducting rotating machine and superimposed on the driving voltage, so that the relationship between the current value (Io) flowing through the superconducting cage winding and the critical current value (Ic) of the superconducting cage winding can be quickly changed from Io < Ic to Io > Ic. As a result, the superconducting cage winding enters the flux flow state and quickly shifts to the induction rotation mode, so that when the amount of trapped magnetic flux is insufficient, the magnetic flux can be recaptured again.

[0017] As one aspect of the present invention, there is provided a superconducting rotating machine in which the voltage obtained by superimposing the pulse voltage on the driving voltage is a phase voltage and is equal to or higher than Vmin represented by the following formula.

[0018]

Number

[0019] According to this aspect, by setting the pulse voltage to be equal to or higher than Vmin, the current value (Io) can be sufficiently increased.

[0020] As one aspect of the present invention, the application time (T) of the pulse voltage, the electrical time constant (τ e ) of the superconducting rotating machine, and the mechanical time constant (τ m ) of the superconducting rotating machine satisfy the formula: τ e < T < τ m There is provided a superconducting rotating machine represented by.

[0021] According to this aspect, by setting the application time (T) to be between the electrical time constant (τ e ) and the mechanical time constant (τm By setting this between ) and ), it is possible to generate a shielding current in the superconducting squirrel-cage winding while suppressing vibrations caused by the conversion of excess pulse voltage into driving energy for the superconducting rotor. This prevents the rotational synchronization mode from being canceled after it has been entered into synchronous rotation mode.

[0022] Another aspect of the present invention provides a superconducting rotating machine comprising: a stator having a cylindrical stator core and stator windings wound around the stator core, which generates a rotating magnetic field; a superconducting rotor having a rotor core having a rotor bar and end rings formed of one or more rotor bars and end rings, which are rotatably held by the rotating magnetic field of the stator and which house the rotor bars; a drive voltage output unit that applies a drive voltage to the stator windings to rotate the superconducting rotor; a pulse voltage output unit that outputs a pulse voltage to transition the superconducting squirrel-cage windings to a magnetic flux flow state; and a pulse magnetic field output unit that generates a pulse magnetic field by the pulse voltage output from the pulse voltage output unit, wherein the pulse magnetic field output from the pulse magnetic field output unit is applied to the superconducting rotor.

[0023] According to this embodiment, by converting a pulsed voltage into a pulsed magnetic field and applying the pulsed magnetic field to the superconducting rotor, the critical current value (Ic) of the superconducting squirrel-cage winding can be reduced. As a result, the relationship between the current value (Io) flowing through the superconducting squirrel-cage winding and the critical current value (Ic) of the superconducting squirrel-cage winding can be quickly set to Io > Ic.

[0024] One aspect of the present invention provides a superconducting rotating machine in which the pulse voltage output unit and the drive voltage output unit are provided in the same voltage output circuit.

[0025] According to this embodiment, for example, when the waveform of the pulse voltage is a ramp wave such as a triangular wave, the pulse voltage and the drive voltage can be output from a single voltage output circuit.

[0026] As one aspect of the present invention, there is provided a superconducting rotating machine in which the pulse voltage output unit and the drive voltage output unit are provided in different voltage output circuits.

[0027] According to this aspect, for example, when the waveform of the pulse voltage is a rectangular wave, etc., the pulse voltage and the drive voltage can be output from different voltage output circuits.

[0028] As one aspect of the present invention, there is provided a control method for a superconducting rotating machine, wherein the superconducting rotating machine has a cylindrical stator core and a stator winding wound around the stator core, a stator that generates a rotating magnetic field, a superconducting cage winding that is rotatably held by the rotating magnetic field of the stator and has rotor bars and end rings formed of one or more superconducting materials, and a rotor core having a plurality of slots for accommodating the rotor bars, and the control method includes a step of applying a drive voltage to the stator winding to rotationally drive the superconducting rotor, and a step of applying a pulse voltage to the superconducting rotating machine to shift the superconducting cage winding to a magnetic flux flow state and superimposing the pulse voltage on the drive voltage.

[0029] According to the control method of the superconducting rotating machine of the present invention, as described above, when the superconducting cage winding is in a magnetic shielding state at the start or after driving, by applying a pulse voltage of an extremely short time to the superconducting rotating machine and superimposing it on the drive voltage, the relationship between the current value (Io) (shielding current) flowing through the superconducting cage winding and the critical current value (Ic) of the superconducting cage winding can be quickly changed from Io < Ic to Io > Ic. As a result, the superconducting cage winding becomes a magnetic flux flow state and quickly shifts to the induction rotation mode, so that the time until it shifts to the subsequent synchronous rotation mode can be significantly shortened.

[0030] Similarly, when the superconducting cage winding is in the flux trapping state, the relationship between the current value (Io) (persistent current) and the critical current value (Ic) is Io < Ic. According to the control method of the superconducting rotating machine of the present embodiment, when the superconducting cage winding is in the flux trapping state in the synchronous rotation mode or the like, a very short pulse voltage is applied to the superconducting rotating machine and superimposed on the driving voltage, so that the relationship between the current value (Io) flowing through the superconducting cage winding and the critical current value (Ic) of the superconducting cage winding can be quickly changed from Io < Ic to Io > Ic. As a result, the superconducting cage winding enters the flux flow state and quickly transitions to the induction rotation mode, so that when the trapped magnetic flux amount is insufficient or excessive, the magnetic flux can be recaptured in an appropriate amount again.

[0031] As another aspect of the present invention, there is provided a control method for a superconducting rotating machine, wherein the superconducting rotating machine includes a cylindrical stator core and a stator winding wound around the stator core, a stator that generates a rotating magnetic field, a superconducting cage winding that is rotatably held by the rotating magnetic field of the stator and has rotor bars and end rings formed of one or more superconducting materials, and a rotor core having a plurality of slots for accommodating the rotor bars. The control method includes a step of applying a driving voltage to the stator winding to rotationally drive the superconducting rotor, a step of outputting a pulse voltage to shift the superconducting cage winding to a flux flow state and converting the pulse voltage into a pulse magnetic field, and a step of applying the pulse magnetic field to the superconducting rotor.

[0032] According to this aspect, by converting the pulse voltage into a pulse magnetic field and applying the pulse magnetic field to the superconducting rotor, the critical current value (Ic) of the superconducting cage winding can be reduced. As a result, the relationship between the current value (Io) flowing through the superconducting cage winding and the critical current value (Ic) of the superconducting cage winding can be quickly changed to Io > Ic.

Effect of the Invention

[0033] According to the present invention, it is possible to provide a superconducting rotating machine capable of both induced and synchronous rotation, which can easily transition to a magnetic flux flow state, and a control method thereof. [Brief explanation of the drawing]

[0034] [Figure 1] This is a schematic diagram illustrating the magnetic shielding state, magnetic flux flow state, and magnetic flux trapping state. [Figure 2] This is a schematic diagram showing an example of the motor body of a superconducting rotating machine. [Figure 3] This is an explanatory diagram showing the relationship between the stator and superconducting rotation. [Figure 4] This is an explanatory diagram showing an example of the configuration of a superconducting rotor. [Figure 5] This is a block diagram showing one embodiment of the configuration of the superconducting rotating machine of this embodiment. [Figure 6] This graph shows the waveform of the pulse voltage and its relationship to the pulse voltage (Vp) and drive voltage (Vb) in the first embodiment. [Figure 7] This is a schematic diagram showing the relationship between the pulse voltage application time (T), ton, W, and toff. [Figure 8] This is a flowchart illustrating the starting method for the superconducting rotating machine 100. [Figure 9] This is a flowchart illustrating another embodiment of the driving method for the superconducting rotating machine 100. [Figure 10] This is a block diagram showing one embodiment of the configuration of the first modified superconducting rotating machine. [Figure 11] This graph shows the waveform of the pulse voltage and its relationship to the pulse voltage (Vp) and drive voltage (Vb) in the first modified example. [Figure 12] This is a flowchart illustrating the starting procedure for the Superconducting Rotating Machine 200. [Figure 13] This is a block diagram showing one embodiment of the configuration of a superconducting rotating machine according to the second embodiment. [Figure 14] This is a flowchart illustrating the starting procedure for the Superconducting Rotating Machine 300. [Modes for carrying out the invention]

[0035] The superconducting rotating machine and its control method according to this embodiment will be described below with reference to the figures as appropriate. However, the present invention is not limited to the following embodiments. In addition, in the following description, the same or equivalent components will be denoted by the same reference numerals, and their descriptions may be omitted. In this specification, unless otherwise specified, the AC voltage applied to the superconducting rotating machine is a multiphase AC voltage (for example, a three-phase AC voltage), and unless otherwise specified, the voltage applied to the superconducting rotating machine means "line voltage".

[0036] As described above, the superconducting rotating machine of this embodiment is equipped with a superconducting rotor and, by driving the superconducting squirrel-cage winding with a superconducting conductor, is a rotating machine that can be driven primarily by synchronous torque, even though it is an induction motor. The superconducting rotating machine of this embodiment can be driven primarily by synchronous torque when the superconducting rotor moves from a magnetic shielding state to a magnetic flux flow state and then to a magnetic flux capture state. Furthermore, the superconducting rotating machine of this embodiment is equipped with a pulse voltage output unit, and when the superconducting squirrel-cage winding is in a magnetic shielding state or a magnetic flux capture state, a pulse voltage can be applied to the superconducting rotating machine and superimposed on the drive voltage to quickly transition it to a magnetic flux flow state.

[0037] The superconducting rotating machine of this embodiment outputs a pulse voltage from a pulse voltage output unit to transition the superconducting squirrel-cage winding to a magnetic flux flow state, and superimposes the pulse voltage on the drive voltage. Specifically, the superconducting rotating machine of this embodiment can: 1) when the superconducting squirrel-cage winding is in a magnetic shielding state, output a pulse voltage from the pulse voltage output unit to quickly transition it to a magnetic flux flow state; and 2) when the superconducting squirrel-cage winding is in a magnetic flux trapping state, output a pulse voltage from the pulse voltage output unit to quickly transition it to a magnetic flux flow state.

[0038] In the case of 1) above, the superconducting rotating machine of this embodiment outputs a pulse voltage when the superconducting squirrel-cage winding is in a magnetically shielded state, such as during startup, and by superimposing the pulse voltage on the drive voltage, it can quickly transition to a magnetic flux flow state. As a result, the superconducting rotating machine of this embodiment can quickly transition to the inductive rotation mode and the subsequent synchronous rotation mode after startup, and the time required to transition to the synchronous rotation mode can be significantly reduced compared to the case where a pulse voltage is not used.

[0039] In the case of (2) above, the superconducting rotating machine of this embodiment outputs a pulse voltage when driven in synchronous rotation mode, and by superimposing the pulse voltage on the drive voltage, the superconducting squirrel-cage winding can be transitioned from a magnetic flux capture state to a magnetic flux flow state. This allows, for example, when the amount of magnetic flux captured is insufficient or excessive in synchronous rotation mode and it is desired to adjust the amount of magnetic flux being captured, the superconducting squirrel-cage winding can be transitioned to a magnetic flux flow state by the pulse voltage, thereby recapturing the magnetic flux of the rotating magnetic field. At this time, the superconducting rotating machine transitions from synchronous rotation mode to induction rotation mode by the transition to the magnetic flux flow state, but because the decrease in the rotation speed of the superconducting rotor during the transition is small, it is possible to quickly return to synchronous rotation mode after magnetic flux capture.

[0040] The magnetic shielding state, magnetic flux flow state, and magnetic flux capture state in this embodiment will be described below with reference to the figures. Figure 1 is a schematic diagram illustrating the magnetic shielding state, magnetic flux flow state, and magnetic flux capture state. Figure 1 shows the electromagnetic phenomena in one loop of the superconducting squirrel-cage winding (see 22A in Figure 2, which will be described later).

[0041] When driving the superconducting rotating machine of this embodiment, when the stationary superconducting cage winding is cooled below the critical temperature by a cooling device, the superconducting cage winding is in a state where it does not capture the magnetic flux by the stator winding while being in the superconducting state. In this state, when a three-phase alternating voltage is applied to the stator winding, a screening current flows in the superconducting cage winding and a magnetic shielding state is formed. In the magnetic shielding state, the relationship between the current value (Io) of the screening current flowing in the superconducting cage winding and the critical current value (Ic) is Io < Ic, and the magnetic flux linked to the superconducting cage winding becomes zero (see Fig. 1(A)). In this case, no synchronous torque is generated, and since no induced current flows either, no induced (slip) torque is generated.

[0042] Next, in order to drive the superconducting rotating machine of this embodiment, first, the superconducting cage winding is shifted from the magnetic shielding state to the magnetic flux flow state. In order to shift the superconducting cage winding to the magnetic flux flow state, it is necessary to release the magnetic shielding state by the screening current by making the current value (Io) flowing in the superconducting cage winding higher than the critical current (Ic) (Io > Ic). In the superconducting rotating machine of this embodiment, by applying a pulse voltage to the superconducting rotating machine and superimposing the pulse voltage on the driving voltage, the relationship between the current value (Io) of the screening current and the critical current (Ic) can be quickly made Io > Ic. When the superconducting cage winding shifts to the magnetic flux flow state, the magnetic flux of the rotating magnetic field can link to the superconducting cage winding, and an induced current (magnetic flux flow current) flows in the superconducting cage winding (see Fig. 1(B)). As a result, a finite resistance is generated between the rotating magnetic field and the superconducting rotor, and the superconducting rotor rotates inductively (inductive rotation mode).

[0043] Subsequently, the superconducting rotor is accelerated, and as a result, the relative speed between the rotating magnetic field and the superconducting rotor decreases, and the current flowing through the superconducting rotor automatically decreases as well. Finally, when the current value (Io) flowing through the superconducting rotor falls below the critical current value (Ic), the superconducting rotor captures the flux linkage, and the superconducting squirrel-cage winding transitions from a flux flow state to a flux capture state (see Figure 1(C)). In the flux capture state, the superconducting rotor can capture the flux of the rotating magnetic field and rotate primarily using synchronous torque (synchronous rotation mode).

[0044] Superconducting Rotating Machine <Motor body> A preferred embodiment of the motor body of this embodiment will be described with reference to the drawings. Figure 2 is a schematic diagram showing an example of the motor body of the superconducting rotating machine 100 of this embodiment. Figure 3 is a 3-3 cross-sectional view of the motor body 1 in Figure 2, and is an explanatory diagram showing the relationship between the stator and the superconducting rotor. As shown in Figure 2, the superconducting rotating machine 100 includes a motor body 1, which includes a stator 10 that generates a rotating magnetic field and a superconducting rotor 20 that is rotatably held on the inner circumference side of the stator 10. The stator 10 and the superconducting rotor 20 are housed in a cylindrical case 30. As will be described below, in the superconducting rotating machine 100 of this embodiment, the superconducting rotor 20 rotates around the rotation shaft 40 by passing a three-phase current through the stator 10.

[0045] (stator) As shown in Figures 2 and 3, the stator 10 has a cylindrical stator core 12 and stator windings 16U, 16V, and 16W (hereinafter sometimes simply referred to as "stator windings 16") wound around the stator core 12 and made of superconducting wire. A rotating magnetic field is generated by passing a three-phase current through the stator windings 16.

[0046] The stator core 12 is a cylindrical member with an annular radial cross-section. Alternatively, the stator core 12 can be made of a member formed by laminating electromagnetic steel sheets, such as silicon steel sheets, in the axial direction. The stator core 12 is also provided with slots (not shown), within which the stator windings 16 are housed. In Figure 2, the stator core 12 is fixed to the inner wall of the case 30 of the motor body 1, but the stator core may also be fixed to the inner wall of the case 30 via a joint. While a stator with slots is used in this embodiment, the present invention is not limited to this embodiment, and it is also possible to use a stator with open slots or grooves instead of slots.

[0047] The stator winding 16 is made up of a bundle of multiple superconducting wires (in this embodiment, bismuth-based high-temperature superconducting wires), and each wire has a rectangular cross-sectional shape (however, it is not limited to this cross-section). The superconducting wire is made up of multiple bismuth-based high-temperature superconducting filaments coated with a highly conductive metal such as copper, aluminum, silver, or gold. From the viewpoint of ease of starting the superconducting rotating machine 100, it is preferable to use a superconducting wire with a critical temperature higher than that of the superconducting wire used in the superconducting squirrel-cage winding 22 as the superconducting wire used in the stator winding 16 of the stator 10.

[0048] As described above, the stator windings 16 are inserted through slots on the surface of the stator core 12 and function as coils. In this embodiment, 24 slots are provided on the inner circumferential surface of the stator core 12, arranged at equal intervals in the circumferential direction. Furthermore, as shown in Figure 3, the stator windings 16 are arranged (wound) clockwise along the circumferential direction of the stator core 12 in the order of stator windings 16U, 16V, and 16W so that a rotating magnetic field is created.

[0049] In this embodiment, the stator winding 16 is a three-phase winding, and each phase is connected. The superconducting rotating machine 100 is a three-phase motor, and each stator winding 16 is assigned to either a U-phase coil, a V-phase coil, or a W-phase coil. In other words, 24 superconducting coils are arranged in the stator core 12. To put it another way, 8 U-phase superconducting coils (stator winding 16U), 8 V-phase superconducting coils (stator winding 16V), and 8 W-phase superconducting coils (stator winding 16W) are arranged in the stator core 12. The 8 U-phase superconducting coils are each electrically connected in series, the 8 V-phase superconducting coils are each electrically connected in series, and the 8 W-phase superconducting coils are each electrically connected in series. Note that the connection method for each stator winding 16 may be series connection or parallel connection.

[0050] The method of connecting each stator winding 16 is not particularly limited; it may be a star connection, a delta connection, or the like. Also, the winding of the stator winding 16 on the stator core 12 may be concentrated winding or distributed winding. In this embodiment, a rotating magnetic field with 4 poles is formed on the stator core 12 by passing a three-phase current through the stator winding 16. In this embodiment, the number of turns per pole per phase of the stator winding 16 is 12.

[0051] The stator 10 is electrically coupled to a drive circuit that applies a drive voltage to the stator windings 16 and a pulse application circuit that applies a pulse voltage superimposed on the drive voltage to the stator windings 16.

[0052] (Superconducting rotor) As shown in Figures 2 and 3, the superconducting rotating machine 100 of this embodiment includes a superconducting rotor 20 rotatably held on the inner circumference side of the stator 10. Furthermore, as shown in Figures 3 and 4, the superconducting rotor 20 includes a superconducting squirrel-cage winding 22 and a rotor core 24. Figure 4 is an explanatory diagram showing an example of the configuration of the superconducting rotor.

[0053] As shown in Figure 3, the superconducting rotor 20 is arranged on the inner circumference side of the stator 10 at predetermined intervals. Next, as shown in Figure 4(A), the rotor core 24 of the superconducting rotor 20 is cylindrical and has a plurality of slots 24S on its outer circumferential surface for accommodating each rotor bar of the rotor winding. Furthermore, the superconducting rotor 20 includes a rotating shaft 40 coaxially attached to the rotor core 24. The superconducting rotor 20 also includes a superconducting squirrel-cage winding 22 having rotor bars 26 and end rings 28 formed from superconducting wire, as shown in Figure 4(B). Although a rotor with slots is used in this embodiment, the present invention is not limited to this embodiment, and it is also possible to use a rotor with open slots or grooves instead of slots.

[0054] The rotor core 24 can be formed by laminating electromagnetic steel sheets, such as silicon steel sheets, in the axial direction. As shown in Figure 4(A), a rotating shaft receiving hole 24H for receiving the rotating shaft 40 is formed in the center of the rotor core 24. Furthermore, as described above, a plurality of slots 24S that penetrate in the axial direction are formed near the outer circumference of the rotor core 24 at predetermined intervals in the circumferential direction. In this embodiment, the slots 24S are formed obliquely with respect to the axial direction of the rotor core 24, resulting in an oblique slot (skew) configuration. However, the present invention is not limited to this embodiment, and for example, the slots 24S may be parallel to the axial direction of the rotor core 24 (the angle between the axial direction of the rotor core 24 and the slots 24S is 0°).

[0055] As shown in Figure 4(B), the superconducting squirrel-cage winding 22 consists of a plurality of rotor bars 26 and a pair of annular end rings 28 that short-circuit both ends of each rotor bar 26. The plurality of rotor bars 26 are housed in slots 24S of the rotor core 24.

[0056] The rotor bars 26 are made up of a bundle of multiple superconducting wires (bismuth-based high-temperature superconducting wires in this embodiment) and have a rectangular cross-section (however, they are not limited to a rectangular cross-section). The superconducting wires can be made, for example, by coating multiple bismuth-based high-temperature superconducting filaments with a highly conductive metal such as copper, aluminum, silver, or gold. The number of rotor bars 26 is the same as the number of slots 24S in the rotor core 24. That is, in this embodiment, the number of rotor bars 26 and slots 24S are both 24.

[0057] The rotor bars 26 are arranged at predetermined intervals in the circumferential direction and obliquely with respect to the axial direction of the cage in order to form a cylindrical and skewed cage. However, the present invention is not limited to this embodiment, and as described above, for example, the superconducting squirrel cage winding 22 may be configured such that the rotor bars 26 are parallel to the axial direction of the rotor core 24 (the angle between the axial direction of the rotor core 24 and the rotor bars 26 is 0°). The rotor bars 26 are formed to be longer than the axial length of the rotor core 24, so that they protrude from the slot 24S when housed in the slot 24S. The end rings 28, like the rotor bars 26, are constructed using superconducting wires such as bismuth-based high-temperature superconducting wires. Each end of the rotor bars 26 protruding from the slot 24S is joined to a pair of end rings 28.

[0058] In this embodiment, the case in which a superconducting rotor 20 is used in which only superconducting squirrel-cage windings 22 are installed on the rotor core 24 has been described. However, the superconducting rotating machine 100 may also have a configuration that includes a normal-conducting squirrel-cage winding in addition to the superconducting squirrel-cage winding. Examples of normal-conducting materials used for the normal-conducting squirrel-cage windings include highly conductive materials such as copper, aluminum, silver, and gold.

[0059] The rotating shaft 40 is inserted into and mounted in the rotating shaft receiving hole 24H of the rotor core 24. The rotating shaft 40 is rotatably supported within the case 30 via bearings or the like (not shown).

[0060] The control and driving methods of the superconducting rotor of this embodiment will be described below with reference to each embodiment. While the first and second embodiments and their variations will be described throughout this specification, the priority of the embodiments of the present invention is not limited by the order in which they are described.

[0061] <First Embodiment> As a first embodiment, a configuration in which the pulse voltage output unit applies a rectangular pulse wave to the stator winding and superimposes it on the drive voltage will be described.

[0062] The drive circuit and pulse application circuit of this embodiment will be described with reference to Figure 5. Figure 5 is a block diagram showing one aspect of the configuration of the superconducting rotating machine of this embodiment.

[0063] As shown in Figure 5, the superconducting rotating machine 100 comprises a motor body 1 (three-phase HTS-ISM motor), a control circuit 50, a pulse application circuit 60, and a drive circuit 70. In this embodiment, the pulse output unit and the drive voltage output unit are configured as separate circuits.

[0064] The control circuit 50 outputs control signals to control the opening and closing of switches SW1 to SW6. Furthermore, the control circuit 50 controls the time, timing, voltage, and frequency of the pulse voltage output from the pulse application circuit 60. In addition, the control circuit 50 controls the time, timing, voltage, and frequency of the drive voltage output from the drive circuit 70.

[0065] As shown in Figure 5, the control circuit 50 includes a CPU (Central Processing Unit) 52, an interface (I / F) 54, and memory 56. The control circuit 50 can be configured based on application-specific circuits such as an ASIC (Application Specific Integrated Circuit).

[0066] The CPU 52 executes instructions according to the control program and controls each switch SW1-6, pulse application circuit 60, and drive circuit 70. The interface 54 outputs control signals for controlling the pulse application circuit 60 and drive circuit 70, and control signals for controlling the open / closed state of each switch SW1-6. The memory 56 includes ROM (Read Only Memory) or RAM (Random Access Memory) which serves as the main recording unit, and volatile or non-volatile memory which serves as an auxiliary recording unit. The control program described above may be stored in either the main recording unit or the auxiliary recording unit.

[0067] The pulse application circuit 60 is a PWM-controlled inverter that includes a capacitor and applies a rectangular pulse voltage to the motor body 1. The pulse application circuit 60 is connected via switches SW1 to SW3 to enable the application of a pulse voltage to the stator windings of the motor body 1. The pulse application circuit 60 converts the voltage supplied from a power supply (not shown) into a three-phase rectangular pulse voltage (square pulse) and applies this pulse voltage to the stator.

[0068] The drive circuit 70 is a PWM-controlled inverter that applies a drive voltage to the motor body 1. The drive circuit 70 is connected via switches SW4 to SW6 so that a drive voltage can be applied to each stator winding of the motor body 1. The drive circuit 70 converts the voltage supplied from a power supply (not shown) into a three-phase voltage and applies it as a drive voltage to the stator of the motor body 1.

[0069] (Pulse voltage) In this embodiment, a rectangular pulse voltage is applied to the stator winding from the pulse application circuit 60 in order to superimpose it on the drive voltage output from the drive circuit 70. Figure 6 is a graph showing the waveform of the pulse voltage and the relationship between the pulse voltage (Vp) and the drive voltage (Vb) in the first embodiment. In Figure 6, the vertical axis of Figure 6(A) shows the input voltage to the stator winding (rectangular pulse wave), and the horizontal axis shows time. Figure 6(B) shows the relationship between the fluctuation of the input voltage supplied to the stator winding and time, with the time axis magnified. Figure 6(C) is a schematic diagram showing the application timing of the pulse voltage (Vp) and the drive voltage (Vb).

[0070] As shown in Figures 6(A) to (C), in this embodiment, the control circuit 50 controls the drive circuit 70 to apply a drive voltage (Vb) to the stator winding at time S0, and controls the pulse application circuit 60 to apply a rectangular pulse wave to the stator winding between time S0 and time S1 to superimpose a pulse voltage (Va) on the drive voltage (Vb).

[0071] Here, the drive voltage (Vb) is controlled so that the superconducting rotating machine achieves appropriate rotation after the superconducting rotor transitions to a rotating state, and it is preferable to set it to satisfy the maximum efficiency condition during steady-state operation. Also, during startup, it is usually set to a voltage that satisfies the maximum torque. As shown in Figure 6, when the pulse voltage (Vp) applied from the pulse application circuit 60 is superimposed on the drive voltage (Vb), the superimposed voltage (Vp+b) is set to be higher than the drive voltage (Vb) during steady-state operation.

[0072] Hereinafter, throughout this specification, the "pulse voltage" output from the pulse voltage output unit is a voltage used to transition the state of the superconducting squirrel-cage winding, and is preferably a voltage with an application time of 2 seconds or less. Although not particularly limited, from the viewpoint of shortening the start-up time (time until reaching synchronous rotation mode), the application time of the pulse voltage is more preferably 1 second or less, and particularly preferably 0.5 seconds or less. Furthermore, the waveform of the pulse voltage is not particularly limited and may be a square wave, ramp wave, sawtooth wave, etc.

[0073] In the case where a pulse voltage is applied to the stator winding as in this embodiment, from the viewpoint of making the current value (Io) flowing through the superconducting squirrel-cage winding higher than the critical current value (Ic) within a preferred voltage application time, it is preferable that the voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) applied from the pulse application circuit 60 onto the drive voltage (Vb) is greater than or equal to Vmin shown in the following formula.

[0074]

number

[0075] In the formula, r1: stator winding resistance, x1: stator winding leakage reactance, x2': rotor winding leakage reactance converted to the primary side, and Ic': rotor bar critical current converted to the primary side can be calculated by referring to "T Nakamura, et al., “Novel rotating characteristics of a squirrel-cage-type HTS induction / synchronous motor”, Superconductor Science and Technology, vol. 20 (2007) 911-918", as well as general no-load rotation tests or rotor-restrained tests. The rotor bar critical current converted to the primary side (Ic') can be calculated from Ic' = Ic / α (α: number of stator windings / number of rotor windings (usually assumed to be 1)), where Ic is the critical current of the rotor bar.

[0076] Furthermore, when applying a pulse voltage to the stator winding as in this embodiment, the voltage (Vp + b) obtained by superimposing the pulse voltage (Vp) on the drive voltage is preferably set with reference to the voltage (hereinafter sometimes referred to as "voltage (Vw)") necessary to capture the magnetic flux required to start the motor under appropriate driving conditions (rotational speed, torque). On the other hand, if the pulse voltage (Vp) is too high, the pulse voltage may be converted into kinetic energy of the rotor or the like, causing adverse effects such as vibration and possibly preventing the synchronous rotation mode from being maintained. Considering such a perspective, the upper limit value (Vmax) of the voltage (Vp + b) obtained by superimposing the pulse voltage (Vp) on the drive voltage (Vb) can be set to a value about 1.4 times higher than Vw.

[0077] Considering the above perspectives, the range of the voltage (Vp + b) obtained by superimposing the pulse voltage (Vp) on the drive voltage (Vb) is preferably Vb ≦ Vp + b ≦ Vmax, more preferably Vmin ≦ Vp + b ≦ Vmax, and particularly preferably Vw ≦ Vp + b ≦ Vmax.

[0078] The application time (T) of the pulse voltage means the time (s) from the start of the application of the pulse voltage (start of startup) (S0) to the end of the application of the pulse voltage (end of shutdown) (s1) in FIG. 6. The application time (T) of the pulse voltage can be set in relation to the electrical time constant (τ e ) of the superconducting rotating machine and the mechanical time constant (τ m ) of the superconducting rotating machine. Here, strictly speaking, as shown in FIG. 7, the application time (T) is t on (the time from the start of the application of the voltage to when the voltage (Vp + b) obtained by superimposing the pulse voltage (Vp) on the drive voltage (Vb) is reached), W (the time from when the voltage (Vp + b) is reached to the start of the shutdown of the pulse voltage), and t off (the time from the start of the shutdown to when the drive voltage (Vb) is reached), and the total value (that is, T = t on + W + t off ). However, in a rectangular wave, since t on and t off are extremely short times, the electrical time constant (τ e ) of the superconducting rotating machine and the mechanical time constant (τ mIn relation to ), W can be considered as the application time (T). Figure 7 shows the relationship between the pulse voltage application time (T) and t on And, W and, t off This is a schematic diagram showing the relationship between T, t on ,W,t off This does not indicate a ratio. Furthermore, the electrical time constant (τ) of a superconducting rotating machine... e ) and the mechanical time constant (τ) of a superconducting rotating machine. m These can be calculated from either a general rotor restraint test or a general no-load rotation test, respectively.

[0079] Here, the electrical time constant (τ e ) is calculated using the average inductance (L:H) of each phase of a superconducting rotating machine and the resistance value (R:Ω) of the stator windings of each phase, and "τ e It can be calculated from "=L / R". The average inductance of each phase can be calculated as "average flux linkage Ψ / current".

[0080] Furthermore, the mechanical time constant (τ) of a superconducting rotating machine m ) is the moment of inertia (J;Nms) of a superconducting rotor. 2 Using the coefficient of friction of the superconducting rotor (D: Nms / rad) and the coefficient of friction of the superconducting rotor, "τ m It can be calculated from "=J / D".

[0081] The application time (T) of the pulse voltage mentioned above is determined by the electrical time constant (τ) in order to generate a sufficient current in the superconducting squirrel-cage winding. e It is preferable that the pulse voltage application time (T) is sufficiently higher than ). Also, the pulse voltage application time (T) should be such that excess pulse voltage is converted into kinetic energy and does not affect the rotation of the superconducting rotor, and the mechanical time constant (τ) is set accordingly. m Preferably, it is sufficiently lower than ).

[0082] Also, the above t on and t off Regarding this, there are no particular limitations, but from the viewpoint of efficiently raising the pulse voltage and widening the range of pulse voltages (Vp) and (applied time T) that allow transition to synchronous rotation mode, t in a square wave onis 10 -5 seconds~10 -2 It is preferable that it be around t seconds. Similarly, from the viewpoint of reducing the effect on the rotation of the superconducting rotor due to the rapid voltage drop that occurs when the pulse voltage falls down, the t in the square wave is preferable. off is 10 -5 seconds~10 -2 It is preferable that it be around a second.

[0083] [Method for driving superconducting rotating machines] The superconducting rotating machine 100 configured as described above can be widely applied to applications where rotating machines are used, such as automobiles (small cars, medium cars, large vehicles such as buses and trucks), railways, submarines, aircraft, ships, and liquid circulation transfer pumps. For example, it can be applied to the superconducting motive system described in International Publication WO2009 / 116219.

[0084] For example, the superconducting rotating machine 100 can be applied to a system that includes driven means such as wheels, propellers, and screws that rotate when connected to the rotating machine. The system may be configured to include, for example, the superconducting rotating machine 100, driven means such as wheels connected directly to the superconducting rotating machine 100 or via other components, a cooling device capable of cooling the superconducting rotating machine 100 until it becomes superconducting, and a battery for driving the superconducting rotating machine 100.

[0085] The following describes a method for driving a superconducting rotating machine by using a pulsed voltage to bring the superconducting squirrel-cage winding into a magnetic flux flow state, with reference to Figure 8. Figure 8 is a flowchart illustrating the starting method of a superconducting rotating machine. However, the present invention is not limited to this embodiment.

[0086] First, before starting up, the stator windings 16 and superconducting squirrel-cage windings 22 of the superconducting rotating machine 100 are cooled by a cooling device, and both windings are in a superconducting state. The cooling device is not particularly limited as long as it can cool the stator 10 and superconducting squirrel-cage windings 22, which use superconductivity within the superconducting rotating machine 100, until they become superconducting (below the critical temperature). For example, a cooling device using helium gas or liquid nitrogen as a refrigerant can be used.

[0087] When the superconducting rotating machine 100 is started, the control circuit 50 turns on SW1 to SW6, applies a drive voltage from the drive circuit 70, and also starts applying a pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 100 in order to move the superconducting squirrel-cage winding 22 into a magnetic flux flow state (step S101). In this embodiment, in order to capture the magnetic flux necessary to start the motor under appropriate driving conditions (speed, torque), the control circuit 50 adjusts the amplitude and frequency of the AC voltage of the pulse application circuit 60 so that the voltage when the pulse voltage is superimposed on the drive voltage is higher than the drive voltage during steady-state driving, and furthermore, the voltage when the pulse voltage is superimposed on the drive voltage is higher than the above-mentioned Vmin and Vw but less than Vmax, and applies a rectangular pulse voltage (Vp) to the stator winding 16 and superimposes it on the drive voltage. As a result, the shielding current value (Io) of the superconducting squirrel-cage winding 22 becomes higher than the critical current value (Ic), causing the superconducting squirrel-cage winding 22 to transition from a magnetically shielded state to a magnetic flux flow state, and the superconducting rotor 20 begins to rotate in induction mode.

[0088] The control circuit 50 applies a pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 100 until a predetermined time (W) has elapsed (step S102 is negated). As described above, strictly speaking, before and after the predetermined time (W), there is a time (t) from the start of voltage application until the voltage (Vp+b) is reached when the pulse voltage is superimposed on the drive voltage. on ) and the time (t) from the start of the fall-off of the pulse voltage until it reaches the drive voltage (Vb). off ) and exist, therefore the actual application time (T) is t on +W+t off The predetermined time (W) is τ e<T<τ m The electrical time constant (τ) of the superconducting rotating machine 100 is such that e ) and the mechanical time constant (τ) of a superconducting rotating machine m It can be determined in relation to ).

[0089] In this embodiment, a pulse voltage is applied to the stator 10 under the above conditions and superimposed on the drive voltage, so that the rotational speed of the superconducting rotor 20 reaches the speed of the rotating magnetic field of the stator 10 before the predetermined time (W) has elapsed. As a result, before the predetermined time (W) has elapsed, the superconducting squirrel-cage winding 22 transitions from a magnetic flux flow state to a magnetic flux capture state, and the superconducting rotor 20 enters a synchronous rotation mode.

[0090] When a predetermined time (W) has elapsed (step S102 affirmed), the control circuit 50 switches the switches so that SW1 to SW3 are turned off and SW4 to SW6 are turned on (step S103). Subsequently, the control circuit 50 applies a synchronous rotation control pattern to the superconducting rotating machine 100, which rotates with synchronous torque as the main drive, and proceeds to control the drive voltage, which adjusts the amplitude and frequency of the three-phase AC voltage applied to the stator winding 16 via the drive circuit 70.

[0091] Next, using Figure 9, a method for driving a superconducting rotating machine in synchronous rotation mode, where the superconducting squirrel-cage winding is brought into a magnetic flux flow state by pulse voltage to replenish the magnetic flux, will be described. Figure 9 is a flowchart illustrating another embodiment of the method for driving a superconducting rotating machine. However, the present invention is not limited to this embodiment.

[0092] In synchronous rotation mode, there is an optimal amount of magnetic flux captured by the rotor depending on the rotational speed. Therefore, in synchronous rotation mode, depending on the rotational speed, the initially captured amount of magnetic flux may be insufficient or excessive, and it may be necessary to change the amount of magnetic flux captured in order to efficiently maintain synchronous rotation mode. However, when changing the insufficient amount of magnetic flux in synchronous rotation mode, it is necessary to first release the magnetic flux capture state of the superconducting squirrel-cage winding 22, switch to a magnetic flux flow state, and replenish the magnetic flux.

[0093] The control circuit 50 monitors the amount of magnetic flux trapped in the superconducting rotor 20 in synchronous rotation mode, and continues monitoring until it becomes necessary to transition the superconducting squirrel-cage winding 22 to a magnetic flux flow state in order to adjust the amount of magnetic flux trapped in relation to the rotational speed (step S201 negated). Then, when the control circuit 50 determines that it is necessary to transition the superconducting squirrel-cage winding 22 to a magnetic flux flow state (step S201 affirmed), the control circuit 50 turns on SW1 to SW3 (step S202) and starts applying a pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 100 (step S203). There is no particular limitation on the timing at which the control circuit 50 determines that it is necessary to transition the superconducting squirrel-cage winding 22 to a magnetic flux flow state, but it is preferable to set a predetermined timing in accordance with the increase or decrease in rotational speed based on the amount of magnetic flux trapped. Furthermore, in this embodiment, the configuration allows the pulse voltage to be supplied while switches SW4 to SW6 remain ON. However, the superconducting rotating machine 100 may also be configured to supply the pulse voltage after switches SW4 to SW6 have been turned OFF.

[0094] In this embodiment, in order to recapture a magnetic flux that can efficiently maintain the synchronous rotation mode according to the rotational speed, the control circuit 50 adjusts the amplitude and frequency of the AC voltage of the pulse application circuit 60 to apply a rectangular pulse voltage (Vp) to the stator winding 16 such that the voltage when the pulse voltage is superimposed on the drive voltage is higher than Vw and less than Vmax. The control circuit 50 applies the pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 100 until a predetermined time (W) has elapsed (step S204 is negated). As described above, the predetermined time (W) is τ e <T<τ m The electrical time constant (τ) of the superconducting rotating machine 100 is such that e ) and the mechanical time constant (τ) of a superconducting rotating machine m It can be determined in relation to ).

[0095] In this embodiment, since a pulse voltage is applied to the stator 10 under the above conditions, the current value (Io) of the shielding current of the superconducting squirrel-cage winding 22 becomes higher than the critical current value (Ic), causing the superconducting squirrel-cage winding 22 to transition from a magnetic shielding state to a magnetic flux flow state, enabling it to recapture the magnetic flux of the rotating magnetic field. In this case, according to this embodiment, since a sufficient amount of magnetic flux is generated in the rotating magnetic field by applying a pulse voltage (Vp), the amount of magnetic flux linked with the superconducting squirrel-cage winding 22 when it transitions to a magnetic flux flow state can be increased.

[0096] When a predetermined time (W) has elapsed (step S204 affirmed), the control circuit 50 switches the switches so that SW1 to SW3 are turned off and SW4 to SW6 are turned on (step S205). At this time, the superconducting rotating machine transitions from synchronous rotation mode to induction rotation mode due to the transition to the magnetic flux flow state, but because the decrease in the rotational speed of the superconducting rotor during the transition is small, it quickly returns to synchronous rotation mode after magnetic flux capture.

[0097] Subsequently, the control circuit 50 applies a synchronous rotation control pattern to the superconducting rotating machine 100, which rotates primarily with synchronous torque, and then proceeds to control the drive voltage, which adjusts the amplitude and frequency of the AC voltage applied to the stator winding 16 via the drive circuit 70.

[0098] [effect] With the superconducting rotating machine 100 configured as described above, when the superconducting squirrel-cage winding 22 is in a magnetically shielded state, such as during startup, a pulse voltage can be output and superimposed on the drive voltage to quickly transition to a magnetic flux flow state. As a result, the superconducting rotating machine 100 can quickly transition to the inductive rotation mode and the subsequent synchronous rotation mode after startup, and the time required to transition to the synchronous rotation mode can be significantly reduced compared to the case where a pulse voltage is not used. Furthermore, since the application of the drive voltage (Vb) requires an application time equal to the electrical time constant, the superconducting rotating machine 100 can suppress the immediate return to the original magnetically shielded state when transitioning to the magnetic flux flow state by superimposing a pulse voltage (Vp) on the drive voltage (Vb).

[0099] Furthermore, with the superconducting rotating machine 100, the starting control of the voltage can be simplified by using pulse voltage, and the steady-state current capacity of the power supply can be reduced to a value commensurate with the rotational output. As a result, the supply of starting current can be greatly simplified compared to conventional methods, and losses can be dramatically reduced. In other words, since the superconducting rotating machine 100 starts with the application of a short pulse voltage, the losses of the power supply and the superconducting rotating machine 100 associated with this can be minimized, and it becomes possible to design the semiconductor switching elements of the power supply and the windings of the superconducting rotating machine 100 to suppress heat generation. Furthermore, it becomes possible to make the superconducting rotating machine 100 smaller and lighter and reduce manufacturing costs. Moreover, because the supply of starting current can be greatly simplified compared to conventional methods with the superconducting rotating machine 100, it is possible to suppress the release of the rotational synchronization mode after it has been entered into the synchronous rotation mode.

[0100] Furthermore, according to the superconducting rotating machine 100, when driven in synchronous rotation mode, the superconducting squirrel-cage winding 22 can be transitioned from a magnetic flux capture state to a magnetic flux flow state by outputting a pulse voltage. This allows, for example, if the amount of magnetic flux captured is insufficient or excessive when the superconducting rotating machine of this embodiment is driven in synchronous rotation mode, the superconducting squirrel-cage winding 22 to transition to a magnetic flux flow state by a pulse voltage, thereby recapturing the magnetic flux of the rotating magnetic field. In this case, the superconducting rotating machine 100 transitions from synchronous rotation mode to induction rotation mode by transitioning to the magnetic flux flow state, but since it can quickly return to synchronous rotation mode after magnetic flux capture, the duration of synchronous rotation mode can be substantially extended. In addition, since it can quickly return from induction rotation mode to synchronous rotation mode, the reduction in torque when transitioning from synchronous rotation mode to induction rotation mode can be effectively suppressed.

[0101] For example, we confirmed that a superconducting rotating machine can be switched to synchronous rotation mode by a rectangular pulse voltage under the following conditions. (conditions) • Rotor outer diameter: 174.8 mm (Core: Electrical steel sheet, Winding: Superconducting wire (Bismuth-based high-temperature superconducting wire)) • Stator inner diameter: 176.0 mm (Core: Electrical steel sheet, Winding: Superconducting wire (Bismuth-based high-temperature superconducting wire)) ·Axis length: 102.0mm • Number of turns per pole / phase: 12 • Number of poles: 4 Gap length: 0.6mm • Voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) on the drive voltage (Vb): Square wave, 92V~132V (RMS value) • Drive voltage (Vb): 80V (RMS value) • Frequency: 60Hz • Application time (T) = 10 -4 seconds (T on )+W(0.3~1 seconds)+T off (10 -4 seconds) ·V min :80V (phase voltage) • VW: 98V ·V max :130V • Electrical time constant (τ e ): 0.5s ·Mechanical time constant (τ m ):2s

[0102] [Differentiation] Although this embodiment has been described in detail above, this embodiment can be implemented with the following modifications.

[0103] (First variation) For example, in the above example, an embodiment was described in which the waveform of the pulse voltage applied to the stator 10 is rectangular, and the pulse voltage output unit and the drive voltage output unit are provided in different voltage output circuits. However, the present invention is not limited to this embodiment. For example, a superconducting rotating machine may be an embodiment in which the pulse voltage output unit and the drive voltage output unit are provided in the same voltage output circuit.

[0104] The first modified example will be explained with reference to a diagram. Figure 10 is a block diagram showing one embodiment of the configuration of the superconducting rotating machine of the first modified example.

[0105] As shown in Figure 10, the superconducting rotating machine 200 comprises a motor body 1 (three-phase HTS-ISM motor), a control circuit 50, and a drive circuit 70. In this modified example, the pulse output unit and the drive voltage output unit are configured as a single circuit, and a pulse voltage is output from the drive circuit 70.

[0106] (Pulse voltage) In this embodiment, a pulse voltage of a triangular wave (ramp wave) higher than the drive voltage output from the drive circuit 70 is applied to the stator winding from the drive circuit 70 to superimpose the pulse voltage on the drive voltage. Figure 11 is a graph showing the waveform of the pulse voltage, the relationship between the pulse voltage (Vp) and the drive voltage (Vb) in the first modified example. In Figure 11, the vertical axis of Figure 11(A) shows the input voltage (ramp wave) to the stator winding, and the horizontal axis shows time. Figure 11(B) shows the relationship between the fluctuation of the input voltage supplied to the stator winding and time, with the time axis magnified. Figure 6(C) is a schematic diagram showing the application timing of the pulse voltage (Vp) and the drive voltage (Vb).

[0107] As shown in Figures 11(A) to (C), in this embodiment, the control circuit 50 controls the drive circuit 70 to apply a drive voltage (Vb) to the stator winding at time S1, and also controls the drive circuit 70 to apply a triangular ramp wave to the stator winding between time S0 and time S1 to superimpose a pulse voltage (Va) on the drive voltage (Vb).

[0108] In this modified example, the pulse voltage (Vp), drive voltage (Vb), and pulse voltage application time (T) are controlled under the same conditions as in the first embodiment described above. In this modified example, since the pulse voltage is applied as a ramp wave, the effective value (Vpr) of the voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) on the drive voltage Vb is used as the reference. The effective value (Vpr) can be calculated from Vpr = Vp + b × (1 / √3). Therefore, in this modified example, the comparison with the pulse voltage (Vp), drive voltage (Vb), Vmin, Vw, and Vmax described above is based on Vpr calculated from Vp+b.

[0109] [Method for driving superconducting rotating machines] The following describes a method for driving a superconducting rotating machine by putting a superconducting squirrel-cage winding into a magnetic flux flow state using a pulsed voltage, with reference to Figure 12. Figure 12 is a flowchart illustrating the starting method of the superconducting rotating machine 200. However, the present invention is not limited to this embodiment.

[0110] First, before starting up, the stator winding 16 and the superconducting squirrel-cage winding 22 of the superconducting rotating machine 200 are cooled by a cooling device, and both windings are in a superconducting state.

[0111] When the superconducting rotating machine 200 is started, the control circuit 50 turns on switches SW4 to SW6 and starts applying pulse voltage and drive voltage from the drive circuit 70 to the superconducting rotating machine 200 in order to move the superconducting squirrel-cage winding 22 into a magnetic flux flow state (step S301). In this modified example as well, in order to capture the magnetic flux necessary to start the motor under appropriate driving conditions (speed, torque), the control circuit 50 adjusts the amplitude and frequency of the AC voltage of the pulse application circuit 60 so that the voltage when the pulse voltage is superimposed on the drive voltage is higher than the drive voltage during steady-state driving, and furthermore, the voltage when the pulse voltage is superimposed on the drive voltage is higher than the above-mentioned Vmin and Vw and less than Vmax, and applies a ramp wave pulse voltage (Vpr) to the stator winding 16. As a result, the shielding current value (Io) of the superconducting squirrel-cage winding 22 becomes higher than the critical current value (Ic), causing the superconducting squirrel-cage winding 22 to transition from a magnetically shielded state to a magnetic flux flow state, and the superconducting rotor 20 begins to rotate in induction mode.

[0112] The control circuit 50 applies a pulse voltage from the drive circuit 70 to the superconducting rotating machine 200 until a predetermined time (T) has elapsed (step S302 is negated). As described above, the application time (T) is t on +W+t off However, compared to a square wave, a ramp wave has t on and t off Because the influence of τ becomes significant, in this modified example, the application time (T) is used as the reference instead of W. The predetermined time (T) is τ e <T<τm The electrical time constant (τ) of the superconducting rotating machine 200 is set to such a value. e ) and the mechanical time constant (τ) of a superconducting rotating machine m It can be determined in relation to ).

[0113] When a predetermined time (T) has elapsed (step S302 affirmed), the control circuit 50 switches the voltage and frequency of the drive circuit 70, and the drive voltage (Vb) is applied to the stator 10 of the motor body 1 (step S303). Subsequently, the control circuit 50 applies a control pattern for synchronous rotation to the superconducting rotating machine 200 which rotates with synchronous torque as the main drive, and proceeds to control the drive voltage, which adjusts the amplitude and frequency of the AC voltage applied to the stator winding 16 via the drive circuit 70.

[0114] In the first modification described above, both a pulse voltage and a drive voltage can be output from a single drive circuit. Therefore, in the first modification, the device can be simplified without requiring any additional structure from a conventional high-temperature superconducting induction synchronous motor, and the same effects as in the first embodiment can be achieved by injecting a pulse voltage into the stator winding.

[0115] In this modified example, as in the first embodiment, when driven in synchronous rotation mode, the superconducting squirrel-cage winding 22 can be transitioned from a magnetic flux-trapping state to a magnetic flux-flow state by outputting a pulse voltage.

[0116] For example, we confirmed that a superconducting rotating machine can be switched to synchronous rotation mode by a pulsed voltage of a ramp wave under the following conditions. (conditions) • Rotor outer diameter: 174.8 mm (Core: Electrical steel sheet, Winding: Superconducting wire (Bismuth-based high-temperature superconducting wire)) • Stator inner diameter: 176.0 mm (Core: Electrical steel sheet, Winding: Superconducting wire (Bismuth-based high-temperature superconducting wire)) ·Axis length: 102.0mm • Number of turns per pole / phase: 12 • Number of poles: 4 Gap length: 0.6mm • Voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) on the drive voltage (Vb): Ramp wave, 112V~200V (RMS value) • Drive voltage (Vb): 80V (RMS value) • Frequency: 60Hz • Application time (T) = 10 -4 seconds (T on )+W(0.3~1 seconds)+T off (10 -4 seconds) ·V min :80V • VW: 98V ·V max :130 V • Electrical time constant (τ e ): 0.5s ·Mechanical time constant (τ m ):2s

[0117] <Second Embodiment> For example, in the first embodiment described above, a pulse voltage is applied to the stator winding and superimposed on the drive voltage to increase the shielding current flowing through the superconducting squirrel-cage winding, thereby changing the relationship between the current value (Io) and the critical current value (Ic) of the superconducting squirrel-cage winding to Io > Ic and transitioning to a magnetic flux flow state. However, the present invention is not limited to this embodiment. For example, the superconducting rotating machine may further include a pulse magnetic field output unit that generates a pulse magnetic field using a pulse voltage output from a pulse voltage output unit, and the pulse magnetic field output from the pulse magnetic field output unit may be applied to the superconducting rotor.

[0118] A second embodiment will be described with reference to the figures. Figure 13 is a block diagram showing one aspect of the configuration of the superconducting rotating machine according to the second embodiment.

[0119] As shown in Figure 13, the superconducting rotating machine 300 comprises a motor body 1 (three-phase HTS-ISM motor), a control circuit 50, a pulse application circuit 60, a drive circuit 70, and a magnetic field generating coil 90. In this modified example, a pulse voltage output from the pulse application circuit 60 is applied to the magnetic field generating coil 90. When a pulse voltage is applied to the magnetic field generating coil 90, a pulsed magnetic field is generated. The magnetic field generating coil 90 is installed on the superconducting rotor 20, and the pulsed magnetic field generated by the application of the pulse voltage is applied to the superconducting rotor 20. The installation location of the magnetic field generating coil 90 is not particularly limited; for example, it may be installed on the end ring 28 of the superconducting squirrel-cage winding 22. Alternatively, the magnetic field generating coil 90 may be a squirrel-cage coil composed of a plurality of rotor bars and a pair of annular end rings that short-circuit both ends of each rotor bar, and may be installed on the rotor core 24 in the same way as the superconducting squirrel-cage winding 22. In this case, it is preferable that the rotor bars of the magnetic field generating coil 90 be positioned radially inward from the iron core than, for example, the rotor bars 26 of the superconducting squirrel-cage winding 22.

[0120] [Method for driving superconducting rotating machines] The following describes a method for driving a superconducting rotating machine by putting a superconducting squirrel-cage winding into a magnetic flux flow state using a pulsed voltage, with reference to Figure 14. Figure 14 is a flowchart illustrating the starting method of the superconducting rotating machine 300. However, the present invention is not limited to this embodiment.

[0121] First, before starting up, the stator winding 16 and the superconducting squirrel-cage winding 22 of the superconducting rotating machine 300 are cooled by a cooling device, and both windings are in a superconducting state.

[0122] When the superconducting rotating machine 300 is started, the control circuit 50 turns on switches SW4 to SW6, and the drive circuit 70 starts applying a drive voltage to the stator 10 of the motor body 1 (step S401). When a drive voltage is applied to the stator 10, a shielding current is generated in the superconducting squirrel-cage winding 22, and the superconducting squirrel-cage winding 22 enters a magnetically shielded state.

[0123] Next, the control circuit 50 turns on switch SW7 to transition the superconducting squirrel-cage winding 22 to a magnetic flux flow state, and begins applying a pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 300 (step S401). In this modified example, since a magnetic field generating coil 90 is connected to the pulse application circuit 60, the pulse voltage is applied to the magnetic field generating coil 90. The pulse voltage applied to the magnetic field generating coil 90 is converted into a pulsed magnetic field.

[0124] As described above, the magnetic field generating coil 90 is installed on the superconducting rotor 20, so the pulsed magnetic field generated from the magnetic field generating coil 90 is applied to the superconducting rotor 20. When a pulsed magnetic field is applied to the superconducting rotor 20, the equivalent Lorentz force acting on the quantized magnetic flux lines in the superconducting material increases, so the critical current value (Ic) of the superconducting squirrel-cage winding 22 decreases. In other words, according to this modified example, by applying a pulsed magnetic field, the critical current value (Ic) is relatively reduced with respect to the current value (Io) of the shielding current flowing through the superconducting squirrel-cage winding 22 generated by the driving voltage, thereby quickly making the relationship between the current value (Io) of the shielding current flowing through the superconducting squirrel-cage winding 22 generated by the driving voltage and the critical current value (Ic) of the superconducting squirrel-cage winding Io > Ic. As a result, according to this modified example, the superconducting squirrel-cage winding 22 can be quickly transitioned to a magnetic flux flow state. When the superconducting squirrel-cage winding 22 transitions to a magnetic flux flow state, the superconducting rotating machine 300 transitions to an inductive rotation mode and begins to rotate with the superconducting rotor.

[0125] The control circuit 50 applies a pulse voltage from the pulse application circuit 60 to the magnetic field generating coil 90 until a predetermined time (W) has elapsed (step S403 negative). Once the predetermined time (W) has elapsed (step S403 affirmative), it turns off the switch SW7 to stop applying the magnetic field pulse voltage to the magnetic field generating coil 90 (step S403). When the application of the magnetic field pulse voltage to the magnetic field generating coil 90 is stopped, the application of a pulsed magnetic field to the superconducting rotor 20 is also stopped. Subsequently, the control circuit 50 applies a synchronous rotation control pattern to the superconducting rotating machine 300, which rotates with synchronous torque as the driving force, and proceeds to control the drive voltage, which adjusts the amplitude and frequency of the AC voltage applied to the stator winding 16 via the drive circuit 70.

[0126] In the second modification described above, the critical current value (Ic) of the superconducting squirrel-cage winding can be reduced by converting the pulsed voltage into a pulsed magnetic field and applying the pulsed magnetic field to the superconducting rotor. This allows the relationship between the current value (Io) flowing through the superconducting squirrel-cage winding and the critical current value (Ic) of the superconducting squirrel-cage winding to be quickly set to Io > Ic. As a result, the superconducting rotating machine 300 can quickly transition to the inductive rotation mode and then to the synchronous rotation mode after starting, and the time it takes to transition to the synchronous rotation mode can be significantly reduced compared to the case where a pulsed voltage is not used.

[0127] In this modified example, as in the first embodiment, when driven in synchronous rotation mode, the superconducting squirrel-cage winding 22 can be transitioned from a magnetic flux-trapping state to a magnetic flux-flow state by outputting a pulse voltage.

[0128] (Second variation) For example, in the first and second embodiments described above, the superconducting rotor 20 was described in which only the superconducting squirrel-cage winding 22 was used as the rotor winding, but the present invention is not limited to these embodiments. For example, the superconducting rotating machine 100 may be an embodiment in which the superconducting rotor 20 further comprises, in addition to the superconducting squirrel-cage winding 22, a normal-conducting squirrel-cage winding having one or more rotor bars and end rings formed of a normal-conducting material.

[0129] In this modified example, the normal-conducting squirrel-cage winding can have the same configuration as, for example, the superconducting squirrel-cage winding 22 shown in Figure 4. Specifically, it consists of a plurality of rotor bars made of a normal-conducting material and a pair of annular end rings that short-circuit both ends of each rotor bar made of a normal-conducting material. The plurality of rotor bars made of a normal-conducting material are housed in slots of the rotor core 24.

[0130] Multiple rotor bars made of normal-conducting material consist of highly conductive materials such as copper, aluminum, silver, and gold, and have a rectangular cross-section (however, they are not limited to a rectangular cross-section). When a normal-conducting squirrel-cage winding is combined with the superconducting rotating machine 100 shown in Figures 2 to 4, the number of rotor bars can be the same as the number of slots 24S of the rotor core 24 (i.e., the number of rotor bars for the normal-conducting squirrel-cage winding is 24). The rotor bars can be arranged at predetermined intervals in the circumferential direction to form a cylindrical and skewed cage larger than the superconducting squirrel-cage winding 22. However, this modification is not limited to this embodiment.

[0131] Rotor bars made of normal-conducting material are formed to be longer than the axial length of the rotor core 24, so that they protrude from the slots when housed in each slot 24S. Rotor bars made of normal-conducting material can be installed, for example, radially outward within the slots 24S of the rotor core 24 than rotor bars 26 made of superconducting wire. When rotor bars made of normal-conducting material are installed in this way, rotor bars 26 made of superconducting wire are positioned on the inside (center side) of the rotor core 24, and rotor bars made of normal-conducting wire are positioned on the outside (outer circumference side).

[0132] Similarly, end rings made of normal-conducting materials can be constructed from highly conductive materials such as copper, aluminum, silver, and gold. Each end of a rotor bar made of normal-conducting material, which protrudes from the slot, is joined to a pair of end rings made of normal-conducting material.

[0133] In this modified example, for instance, when the superconducting rotor 20 is in a non-superconducting state, the superconducting rotating machine 100 can be driven primarily by induction (slip) rotation using the normal-conducting squirrel-cage winding. For example, by driving the superconducting rotor 20 primarily with induction torque when it is in a non-superconducting state, and then applying a pulse voltage when the superconducting rotor 20 becomes superconducting due to cooling, the superconducting squirrel-cage winding 22 can be quickly brought into a magnetic flux flow state even while driving. As a result, even when the superconducting rotor 20 is driven primarily with induction torque when it is in a non-superconducting state, the superconducting rotor 20 can quickly transition to synchronous rotation mode after it becomes superconducting.

[0134] Furthermore, in this modified example, the control circuit 50 can be configured to monitor the primary current signal, which is the signal of the primary current flowing through the stator winding 16, from the superconducting rotating machine 100, in order to determine whether the superconducting squirrel-cage winding 22 is in a superconducting state (whether the superconducting rotating machine 100 is rotating primarily by synchronous torque). For example, if the rotor is rotating primarily by synchronous torque, a control pattern for synchronous rotation can be applied to the superconducting rotating machine 100; otherwise, it can be configured to assume that it is rotating primarily by induced (slip) torque and apply a control pattern for slip rotation.

[0135] (Third variation) For example, in the first and second embodiments described above, only superconducting wires are used for the stator windings 16 of the stator 10, but the present invention is not limited to these embodiments. For example, the stator 10 may have other windings (normal-conducting windings) using normal-conducting wires in addition to the stator windings 16, or normal-conducting wires may be used instead of superconducting wires. In this case, for example, the superconducting rotating machine 100 can be configured to form magnetic poles with normal-conducting windings on the stator 10, so as to be able to generate a rotating magnetic field even in a normal-conducting state. With this configuration, for example, the superconducting rotating machine 100 can be started and driven even before the superconducting wires of the stator windings 16 become superconducting.

[0136] (Other variations) For example, the superconducting wires mentioned above are not limited to bismuth-based high-temperature superconducting wires, but can also be metallic low-temperature superconducting wires such as NbTi or Nb3Sn, yttrium-based high-temperature superconducting wires, or magnesium diboride superconducting wires.

[0137] Furthermore, although the first and second embodiments described above described cases in which wires were used as the superconducting material and the normal conducting material, the present invention is not limited to these embodiments, and for example, bulk materials may be used as the superconducting material and the normal conducting material. For example, bulk materials can be used as the superconducting material and / or normal conducting material depending on the application in which it is desirable to use a material with a large current capacity in the stator or rotor (for example, a large superconducting motor, etc.).

[0138] Although various embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above. Furthermore, the present invention is modifiable without departing from its spirit.

[0139] The disclosure of Japanese Patent Application No. 2020-195167, filed on 25 November 2020, is incorporated herein by reference in its entirety. Furthermore, all documents, patent applications, and technical standards described in this specification are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference. [Explanation of Symbols]

[0140] 10: Stator, 12: Stator core, 16: Stator winding, 20: Superconducting rotor, 22: Superconducting squirrel-cage winding, 60: Pulse application circuit, 70: Drive circuit, 90: Magnetic field generating coil, Pulses 100, 200, 300: Superconducting rotating machine

Claims

1. A stator having a cylindrical stator core and stator windings wound around the stator core, which generates a rotating magnetic field, A superconducting rotor having a superconducting squirrel-cage winding that is rotatably held by the rotating magnetic field of the stator and has one or more rotor bars and end rings made of superconducting material, and a rotor core having a plurality of slots for housing the rotor bars, The superconducting squirrel-cage winding is provided with a pulse voltage output unit that outputs a pulse voltage to transition it from a magnetic shielding state to a magnetic flux flow state, A superconducting rotating machine comprising a drive voltage output unit that applies a drive voltage to the stator windings in order to rotate the superconducting rotor, and capable of transitioning from an inductive rotation mode to a synchronous rotation mode, A superconducting rotating machine that superimposes the pulse voltage output from the pulse voltage output unit onto the drive voltage, thereby transitioning the superconducting squirrel-cage winding from the magnetic shielding state to the magnetic flux flow state and into an inductive rotation mode.

2. The superconducting rotating machine according to claim 1, wherein the voltage obtained by superimposing the pulse voltage on the drive voltage is greater than or equal to Vmin shown in the following formula. [Math 1] (In the formula, Vmin is the phase voltage, and r 1 : Stator winding resistance, x 1 : Leakage reactance of stator winding, x 2 ': Rotor winding leakage reactance converted to primary side, Ic': Rotor bar critical current converted to primary side)

3. The application time (T) of the pulse voltage and the electrical time constant (τ) of the superconducting rotating machine. e ) and the mechanical time constant (τ) of the superconducting rotating machine. m ) and are given by equation: τ e <T<τ m A superconducting rotating machine according to claim 1 or claim 2, as shown in [the provided text].

4. A stator having a cylindrical stator core and stator windings wound around the stator core, which generates a rotating magnetic field, A superconducting rotor having a superconducting squirrel-cage winding that is rotatably held by the rotating magnetic field of the stator and has one or more rotor bars and end rings made of superconducting material, and a rotor core having a plurality of slots for housing the rotor bars, A drive voltage output unit that applies a drive voltage to the stator winding in order to rotate the superconducting rotor, The superconducting squirrel-cage winding is provided with a pulse voltage output unit that outputs a pulse voltage to transition it from a magnetic shielding state to a magnetic flux flow state, A superconducting rotating machine comprising a pulsed magnetic field output unit that generates a pulsed magnetic field by a pulsed voltage output from the pulsed voltage output unit, and capable of transitioning from an inductive rotation mode to a synchronous rotation mode, A superconducting rotating machine that applies a pulsed magnetic field output from the pulsed magnetic field output unit to the superconducting rotor, thereby transitioning the superconducting squirrel-cage winding from the magnetic shielding state to the magnetic flux flow state and into an inductive rotation mode.

5. The superconducting rotating machine according to any one of claims 1 to 4, wherein the pulse voltage output unit and the drive voltage output unit are provided in the same voltage output circuit.

6. The superconducting rotating machine according to any one of claims 1 to 4, wherein the pulse voltage output unit and the drive voltage output unit are provided in different voltage output circuits.

7. A method for controlling a superconducting rotating machine, The superconducting rotating machine comprises a stator having a cylindrical stator core and stator windings wound around the stator core, which generates a rotating magnetic field; and a superconducting rotor having a rotor core with a plurality of slots for accommodating the rotor bars, which is rotatably held by the rotating magnetic field of the stator and has a superconducting squirrel-cage winding having one or more rotor bars and end rings made of superconducting material; and a rotor core which has a plurality of slots for accommodating the rotor bars; and is a superconducting rotating machine that can transition from an inductive rotation mode to a synchronous rotation mode. The control method includes the step of applying a drive voltage to the stator winding in order to rotate the superconducting rotor, A method for controlling a superconducting rotating machine, comprising the steps of applying a pulse voltage to the superconducting rotating machine to transition the superconducting squirrel-cage winding from a magnetic shielding state to a magnetic flux flow state, superimposing the pulse voltage on the drive voltage, and transitioning the superconducting squirrel-cage winding from the magnetic shielding state to the magnetic flux flow state, thereby transitioning to an inductive rotation mode.

8. A method for controlling a superconducting rotating machine, The superconducting rotating machine comprises a stator having a cylindrical stator core and stator windings wound around the stator core, which generates a rotating magnetic field; and a superconducting rotor having a rotor core with a plurality of slots for accommodating the rotor bars, which is rotatably held by the rotating magnetic field of the stator and has a superconducting squirrel-cage winding having one or more rotor bars and end rings made of superconducting material; and a rotor core which has a plurality of slots for accommodating the rotor bars; and is a superconducting rotating machine that can transition from an inductive rotation mode to a synchronous rotation mode. The control method includes the step of applying a drive voltage to the stator winding in order to rotate the superconducting rotor, The process involves outputting a pulse voltage to transition the superconducting squirrel-cage winding from a magnetic shielding state to a magnetic flux flow state, and converting the pulse voltage into a pulsed magnetic field. A method for controlling a superconducting rotating machine, comprising the steps of applying the pulsed magnetic field to the superconducting rotor and transitioning the superconducting squirrel-cage winding from the magnetic shielding state to the magnetic flux flow state, thereby transitioning to an induced rotation mode.

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