Superconducting rotating machine and control method for superconducting rotating machine

Abstract

A superconducting rotating machine comprises: a stator for generating a rotating magnetic field, having a cylindrical stator core and a stator winding wound around the stator core; a superconducting rotor held to rotate on its inner circumference by the rotating magnetic field of the stator, the superconducting rotor having a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, the rotor core having a plurality of slots for receiving the rotor bars; a pulse voltage output section for outputting a pulse voltage to convert the superconducting cage winding into a flux-flow state; and a drive voltage output section for applying a drive voltage to the stator winding to drive the rotation of the superconducting rotor, wherein the superconducting rotating machine superimposes the pulse voltage output from the pulse voltage output section with the drive voltage.

Description

Technical Field

[0001] This invention relates to a superconducting rotating machine and a control method for the superconducting rotating machine. Background Technology

[0002] Rotating machines, as electrical equipment, are classified into DC machines and AC machines. Among them, AC machines, which receive mechanical power to generate AC electricity or receive AC electricity to generate mechanical power, are mainly classified into induction machines and synchronous machines.

[0003] Induction motors, such as induction engines, utilize the rotating magnetic field generated by applying multiphase AC voltage (often three-phase AC voltage) to the stator windings to induce torque in the rotor, thus causing it to rotate. Induction motors are widely used due to their simple construction, ease of maintenance, and low cost, but they face challenges in efficiency and speed control.

[0004] Synchronous machines, such as synchronous motors, rotate because their rotors, which have electromagnets or permanent magnets, are pulled by a rotating magnetic field generated by the application of multiphase AC voltage (often three-phase AC voltage) to the stator windings. Although synchronous motors are highly efficient, they require additional devices for starting and synchronizing.

[0005] In recent years, superconducting rotating machines that function as both induction machines and synchronous rotating mechanisms have been proposed (see Patent Document 1 below). For example, Patent Document 1 discloses an operation method for a superconducting rotating machine capable of both induction and synchronous rotation, enabling the superconducting rotating machine to operate autonomously and stably.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2013-55733 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] For example, in conventional superconducting rotating machines using superconducting squirrel-cage windings as described above, when the superconducting squirrel-cage windings are cooled to below the critical temperature before operation begins, thus establishing a superconducting state, the superconducting squirrel-cage windings do not capture the magnetic flux of the rotating magnetic field of the stator windings. When a three-phase AC voltage is applied to the stator windings in this state, a shielding current flows through the superconducting squirrel-cage windings, and the magnetic flux linked to the superconducting squirrel-cage windings is zero (hereinafter sometimes referred to as the "magnetically shielded state"). That is, in the magnetically shielded state, the magnetic flux supplied from the stator is shielded, and therefore the superconducting rotor does not start. Therefore, it is usually necessary to adjust the voltage and frequency to induce a large current in the superconducting squirrel-cage windings for a fixed period of time, thereby adjusting the shielding current to exceed the critical current value of the winding (the maximum current that can maintain the magnetically shielded state; Ic) until the magnetic flux links. Specifically, the applied voltage and / or the frequency of that applied voltage need to be increased over a fixed period of time until the current flowing through the superconducting cage winding (hereinafter sometimes simply referred to as the "current value (Io)") exceeds the critical current value (Ic), thus switching the superconducting cage winding from a magnetically shielded state to a flux-flowing state. In the flux-flowing state, the magnetic flux links with the superconducting cage winding to generate an induced current (flux-flowing current), thereby generating an induced torque and thus a finite resistance. Therefore, the superconducting rotor rotates induction (hereinafter sometimes referred to as the state in which the superconducting rotor rotates primarily due to induced torque as the "induction rotation mode").

[0011] Subsequently, the rotational motion of the superconducting rotor is accelerated, and the relative speed between the rotating magnetic field and the superconducting rotor decreases. Eventually, when the induced current (magnetic flux flow current) flowing through the superconducting cage winding is lower than the critical current, the superconducting cage winding captures the linked magnetic flux. When the superconducting cage winding captures the linked magnetic flux (hereinafter sometimes referred to as the "magnetic flux capture state"), the superconducting rotor can rotate synchronously with the rotating magnetic field (hereinafter sometimes referred to as the state in which the superconducting rotor rotates mainly with synchronous torque as the "synchronous rotation mode").

[0012] On the other hand, in superconducting rotating machines using superconducting cage windings, if the magnetic flux links with the superconducting cage windings and transitions to an induction rotation mode, the current required for drive becomes smaller than the starting current as inertial energy gradually accumulates in the rotor. Therefore, using a power supply capable of consistently providing the large, stable current needed only for a short period during startup has many disadvantages in terms of cost and size. Furthermore, continuously supplying a large starting current to the superconducting rotating machine for an extended period is also detrimental from an energy loss perspective, and there are concerns about increased loads on the power supply and the rotating machine.

[0013] Furthermore, in superconducting rotating machines using superconducting cage windings, there is a significant need to minimize start-up time. In particular, energy losses occur in superconducting rotating machines using superconducting cage windings, accompanying the transition from a magnetically shielded state to a flux-flow state and then to a flux-capturing state. Therefore, it is desirable to minimize the time required to transition to synchronous rotation mode. Moreover, after the superconducting rotating machine using superconducting cage windings enters the flux-flow state, the start-up voltage needs to be set to the drive voltage to obtain the specified rotational characteristics; therefore, simpler voltage control during start-up is desirable. In addition, when a voltage exceeding the required drive voltage is continuously applied after transitioning to the flux-capturing state (synchronous rotation mode), current is sometimes converted into rotor torque, resulting in energy losses, or the synchronous rotation mode is deactivated.

[0014] There is still room for improvement in these aspects of the existing superconducting rotating machine. We are seeking to develop a technology that can easily switch from a magnetic shielding state to a magnetic flux trapping state (i.e., synchronous rotation mode) during startup.

[0015] The present invention aims to solve the above-mentioned problems and provides a superconducting rotating machine and its control method that can be easily converted into a magnetic flux flow state in a superconducting rotating machine capable of inductive rotation and synchronous rotation.

[0016] Solution for solving the problem

[0017] Previously, in order to switch a superconducting rotating machine to synchronous rotation mode, it was necessary to induce a large current in the superconducting cage winding for a fixed period of time during startup. However, the inventors of this invention discovered that a superconducting rotating machine could be quickly switched to synchronous rotation mode by applying a short-duration pulse voltage and superimposing it with the driving voltage, thus completing this invention.

[0018] The present invention provides a superconducting rotating machine comprising: a stator for generating a rotating magnetic field, having a cylindrical stator core and a stator winding wound around the stator core; a superconducting rotor held to rotate by the rotating magnetic field of the stator, the superconducting rotor having a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, the rotor core having a plurality of slots for receiving the rotor bars; a pulse voltage output section for outputting a pulse voltage to convert the superconducting cage winding into a flux-flow state; and a drive voltage output section for applying a drive voltage to the stator winding to drive the rotation of the superconducting rotor, wherein the superconducting rotating machine superimposes the pulse voltage output from the pulse voltage output section with the drive voltage.

[0019] As described above, when the superconducting cage winding is in the magnetic shielding state, the relationship between the current value (Io) flowing through the superconducting cage winding (which is the shielding current in this case) and the critical current value (Ic) is Io < Ic. In the superconducting rotating machine according to the present invention, when starting or after driving, when the superconducting cage winding is in the magnetic shielding state, by applying a pulsed voltage for a very short time to the superconducting rotating machine and superimposing it on the driving voltage, 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. Thus, the superconducting cage winding becomes a magnetic flux flow state and quickly changes to the induction rotation mode, so the time to transition to the subsequent synchronous rotation mode can be significantly shortened.

[0020] Similarly, when the superconducting cage winding is in the magnetic flux capture state, the relationship between the current value (Io) flowing through the superconducting cage winding (which is the permanent current in this case) and the critical current value (Ic) is Io < Ic. In the superconducting rotating machine according to this embodiment, when the superconducting cage winding is in the magnetic flux capture state under the synchronous rotation mode or the like, by applying a pulsed voltage for a very short time to the superconducting rotating machine and superimposing it on the driving voltage, 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. Thus, the superconducting cage winding becomes a magnetic flux flow state and quickly changes to the induction rotation mode, so that the magnetic flux can be recaptured again when the captured magnetic flux is insufficient.

[0021] As one aspect of the present invention, there is provided a superconducting rotating machine, wherein the voltage obtained by superimposing the pulsed voltage on the driving voltage is not less than Vmin which is the phase voltage shown in the following formula.

[0022] [Equation 1]

[0023]

[0024] (In the formula, Vmin is the phase voltage, r1 is the stator winding resistance, x1 is the leakage reactance of the stator winding, x2' is the leakage reactance of the rotor winding after primary side conversion, and Ic' is the critical current of the rotor bar after primary side conversion)

[0025] According to this aspect, by setting the pulsed voltage to not less than Vmin, the current value (Io) can be increased sufficiently.

[0026] As one aspect of the present invention, there is provided a superconducting rotating machine, wherein the application time (T) of the pulsed 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: τe <T<τ m express.

[0027] According to this method, the application time (T) is set to the electrical time constant (τ). e ) and the mechanical time constant (τ) of the superconducting rotating machine m Between these points, a shielding current can be generated in the superconducting cage winding, and vibrations caused by the conversion of residual pulse voltage into driving energy of the superconducting rotor can be suppressed. Thus, it is possible to prevent the rotational synchronization mode from being deactivated after a temporary transition to synchronous rotation mode.

[0028] As another aspect of the present invention, a superconducting rotating machine is provided, comprising: a stator for generating a rotating magnetic field, having a cylindrical stator core and a stator winding wound around the stator core; a superconducting rotor held to rotate by the rotating magnetic field of the stator, the superconducting rotor having a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, the rotor core having a plurality of slots for receiving the rotor bars; a drive voltage output section that applies a drive voltage to the stator winding to drive the superconducting rotor to rotate; a pulse voltage output section that outputs a pulse voltage to convert the superconducting cage winding into a flux-flow state; and a pulse magnetic field output section that generates a pulse magnetic field by the pulse voltage output from the pulse voltage output section, the superconducting rotating machine applying the pulse magnetic field output from the pulse magnetic field output section to the superconducting rotor.

[0029] According to this method, by converting the 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 cage winding can be reduced. Therefore, 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 rapidly changed to Io > Ic.

[0030] As one aspect of the present invention, a superconducting rotating machine is provided, wherein the pulse voltage output section and the drive voltage output section are disposed in the same voltage output circuit.

[0031] According to this method, for example, when the waveform of the pulse voltage is set to a triangular wave or other ramped wave, it is possible to output the pulse voltage and the drive voltage from a single voltage output circuit.

[0032] As one aspect of the present invention, a superconducting rotating machine is provided, wherein the pulse voltage output section and the drive voltage output section are disposed in different voltage output circuits.

[0033] According to this method, for example, when the waveform of the pulsed voltage is a rectangular wave or the like, the pulsed voltage and the driving voltage can be output from different voltage output circuits.

[0034] As an aspect of the present invention, there is provided a control method for a superconducting rotating machine, wherein the superconducting rotating machine includes: a stator for generating a rotating magnetic field, having a cylindrical stator core and a stator winding wound around the stator core; and a superconducting rotor held to be rotatable by the rotating magnetic field of the stator, and the superconducting rotor has a superconducting cage winding and a rotor core, the superconducting cage winding having an end ring and one or more rotor bars formed of a superconducting material, the rotor core having a plurality of slots for accommodating the rotor bars, and the control method includes the following steps: applying a driving voltage to the stator winding to rotationally drive the superconducting rotor; and applying a pulsed voltage to the superconducting rotating machine and superimposing the pulsed voltage on the driving voltage in order to change the superconducting cage winding into a magnetic flux flow state.

[0035] According to the control method for a superconducting rotating machine of the present invention, as described above, at the start-up or when the superconducting cage winding is in a magnetic shielding state after driving, by applying a pulsed voltage to the superconducting rotating machine for a very short time and superimposing it on the driving 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 changes to an induction rotation mode, so that the time until the subsequent synchronous rotation mode is reached can be significantly shortened.

[0036] Similarly, when the superconducting cage winding is in a magnetic flux trapping state, the relationship between the current value (Io) (permanent current) and the critical current value (Ic) is Io < Ic. According to the control method for a superconducting rotating machine of the present embodiment, when the superconducting cage winding is in a magnetic flux trapping state in the synchronous rotation mode or the like, by applying a pulsed voltage to the superconducting rotating machine for a very short time and superimposing it on the driving voltage, 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 becomes a magnetic flux flow state and quickly changes to an induction rotation mode, so that an appropriate amount of magnetic flux can be recaptured again when the trapped magnetic flux is insufficient or excessive.

[0037] As another aspect of the present invention, a control method for a superconducting rotating machine is provided, wherein the superconducting rotating machine comprises: a stator for generating a rotating magnetic field, having a cylindrical stator core and a stator winding wound around the stator core; and a superconducting rotor held to rotate by the rotating magnetic field of the stator, wherein the superconducting rotor has a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, and the rotor core having a plurality of slots for receiving the rotor bars, the control method comprising the steps of: applying a driving voltage to the stator winding to drive the superconducting rotor to rotate; outputting a pulse voltage to convert the superconducting cage winding into a flux-flow state and converting the pulse voltage into a pulsed magnetic field; and applying the pulsed magnetic field to the superconducting rotor.

[0038] According to this method, by converting the 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 cage winding can be reduced. Therefore, 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 rapidly changed to Io > Ic.

[0039] The effects of the invention

[0040] According to the present invention, a superconducting rotating machine capable of inductive rotation and synchronous rotation can be easily converted into a magnetic flux flow state, and a control method thereof can be provided. Attached Figure Description

[0041] Figure 1 It is a schematic diagram used to illustrate the magnetic shielding state, magnetic flux flow state, and magnetic flux trapping state.

[0042] Figure 2 This is a schematic diagram showing an example of the main body of the electric motor of a superconducting rotating machine.

[0043] Figure 3 This is an explanatory diagram showing the relationship between the stator and the superconducting rotor.

[0044] Figure 4 This is an illustrative diagram showing an example of the structure of a superconducting rotor.

[0045] Figure 5 This is a block diagram illustrating one possible structure of the superconducting rotating machine according to this embodiment.

[0046] Figure 6 It is a graph showing the waveform of the pulse voltage in the first embodiment and the relationship between the pulse voltage (Vp) and the driving voltage (Vb).

[0047] Figure 7This indicates the application time (T) and t of the pulse voltage. on , W and t off A diagram illustrating the relationship.

[0048] Figure 8 This is a flowchart illustrating the starting method of the superconducting rotating machine 100.

[0049] Figure 9 This is a flowchart illustrating another method for driving the superconducting rotating machine 100.

[0050] Figure 10 This is a block diagram illustrating one possible structure of the superconducting rotating machine of the first modified example.

[0051] Figure 11 It is a graph showing the waveform of the pulse voltage in the first variation example and the relationship between the pulse voltage (Vp) and the driving voltage (Vb).

[0052] Figure 12 This is a flowchart illustrating the starting method of the superconducting rotating machine 200.

[0053] Figure 13 This is a block diagram illustrating one aspect of the structure of the superconducting rotating machine according to the second embodiment.

[0054] Figure 14 This is a flowchart illustrating the starting method of the superconducting rotating machine 300. Detailed Implementation

[0055] The superconducting rotating machine and its control method according to this embodiment will now be described with appropriate use of the accompanying drawings. However, the present invention is not limited to the following embodiments. Furthermore, in the following description, the same or equivalent components are marked with the same reference numerals, and their descriptions are sometimes omitted. In addition, unless otherwise specified, the AC voltage applied to the superconducting rotating machine in this specification refers to a multiphase AC voltage (e.g., a three-phase AC voltage), and unless otherwise specified, the voltage applied to the superconducting rotating machine refers to "line-to-line voltage".

[0056] As described above, the superconducting rotating machine of this embodiment includes a superconducting rotor and utilizes a superconductor to drive the superconducting cage winding. Therefore, the superconducting rotating machine of this embodiment is an induction motor and a rotating machine capable of being driven primarily by synchronous torque. In the superconducting rotating machine of this embodiment, the superconducting rotor changes from a magnetically shielded state to a magnetic flux flow state, thereby enabling driving primarily by synchronous torque. Furthermore, the superconducting rotating machine of this embodiment includes a pulse voltage output unit. When the superconducting cage winding is in a magnetically shielded state or a magnetic flux capture state, by applying a pulse voltage to the superconducting rotating machine and superimposing it with the driving voltage, the superconducting rotating machine can be rapidly switched to a magnetic flux flow state.

[0057] In this embodiment, the superconducting rotating machine outputs a pulse voltage from the pulse voltage output unit to transform the superconducting cage winding into a flux-flowing state, and superimposes the pulse voltage with the driving voltage. Specifically, the superconducting rotating machine of this embodiment can achieve: 1) rapidly transitioning to a flux-flowing state by outputting a pulse voltage from the pulse voltage output unit when the superconducting cage winding is in a magnetically shielded state; and 2) rapidly transitioning to a flux-flowing state by outputting a pulse voltage from the pulse voltage output unit when the superconducting cage winding is in a flux-capturing state.

[0058] In the case described in 1), the superconducting rotating machine of this embodiment, when the superconducting cage winding is in a magnetically shielded state during startup, can rapidly transition to a magnetic flux flow state by outputting a pulse voltage and superimposing the pulse voltage with the driving voltage. Therefore, the superconducting rotating machine of this embodiment rapidly transitions to an induction rotation mode and subsequently to a synchronous rotation mode after startup, significantly shortening the time required to transition to the synchronous rotation mode compared to the case without using a pulse voltage.

[0059] In the case described in 2), when the superconducting rotating machine of this embodiment is driven in synchronous rotation mode, it can switch the superconducting cage winding from a flux trapping state to a flux flowing state by outputting a pulse voltage and superimposing the pulse voltage with the driving voltage. Thus, for example, if the amount of flux trapped is insufficient or excessive in synchronous rotation mode, and it is desired to adjust the amount of trapped flux, the superconducting cage winding can be switched to a flux flowing state by a pulse voltage to recapture the flux of the rotating magnetic field. At this time, due to the transition to the flux flowing state, the superconducting rotating machine switches from synchronous rotation mode to induction rotation mode, but the reduction in the rotational speed of the superconducting rotor during the transition is small, so it can quickly return to synchronous rotation mode after flux trapping.

[0060] The magnetic shielding state, magnetic flux flow state, and magnetic flux capture state in this embodiment will now be described using the accompanying drawings. Figure 1 It is a schematic diagram used to illustrate the magnetic shielding state, magnetic flux flow state, and magnetic flux trapping state. Figure 1 The diagram shows one loop of a superconducting cage winding (see below). Figure 2 Electromagnetic phenomena in 22A).

[0061] When driving the superconducting rotating machine of this embodiment, when the stationary superconducting cage winding is cooled below the critical temperature by the cooling device, the superconducting cage winding is in a superconducting state and is in a state where it does not capture the magnetic flux generated by the stator winding. When a three-phase AC voltage is applied to the stator winding in this state, a shielding current flows in the superconducting cage winding and it becomes a magnetic shielding state. In the magnetic shielding state, the relationship between the current value (Io) of the shielding current flowing through the superconducting cage winding and the critical current value (Ic) is Io < Ic, and the magnetic flux linked to the superconducting cage winding is zero (refer to Figure 1 (A) of

[0062] . In this case, no synchronous torque is generated, and no induced current flows either, so no induced (slip rate) torque is generated. Figure 1 (B) of

[0063] Next, in order to drive the superconducting rotating machine of this embodiment, first, the superconducting cage winding is changed from the magnetic shielding state to the magnetic flux flowing state. In order to change the superconducting cage winding to the magnetic flux flowing state, it is necessary to make the current value (Io) flowing through the superconducting cage winding higher than the critical current (Ic) to解除 the magnetic shielding state caused by the shielding current. 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 drive voltage, the relationship between the current value (Io) of the shielding current and the critical current (Ic) can be quickly made Io > Ic. When the superconducting cage winding changes to the magnetic flux flowing state, the magnetic flux of the rotating magnetic field can be linked to the superconducting cage winding, and thus an induced current (magnetic flux flowing current) flows in the superconducting cage winding (refer to Figure 1 (C) of

[0064] . 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).

[0065] <Motor main body><S

[0066] Refer to the attached drawings to illustrate a preferred mode of the motor main body of this embodiment using the attached drawings. Figure 2 is a schematic diagram showing an example of the motor main body of the superconducting rotating machine Figure 3 Figure 3 is Figure 2 The 3-3 cross-sectional view of the motor body 1 is an explanatory diagram showing the relationship between the stator and the superconducting rotor. For example... Figure 2 As shown, the superconducting rotating machine 100 includes an electric motor body 1, within which is a stator 10 for generating a rotating magnetic field and a superconducting rotor 20 held so as to be rotatable on the inner circumference of the stator 10. Furthermore, the stator 10 and the superconducting rotor 20 are housed in a cylindrical housing 30. As will be explained below, in the superconducting rotating machine 100 of this embodiment, the superconducting rotor 20 rotates about a rotation axis 40 by flowing three-phase current to the stator 10.

[0067] (stator)

[0068] like Figure 2 and Figure 3 As shown, the stator 10 has a cylindrical stator core 12 and stator windings 16U, 16V, and 16W (hereinafter sometimes referred to as "stator windings 16") formed of superconducting wire wound around the stator core 12. A rotating magnetic field is generated by flowing three-phase current into the stator windings 16.

[0069] The stator core 12 is a cylindrical component with a circular annular radial cross-section. Furthermore, the stator core 12 can be a component formed by axially stacking electromagnetic steel sheets, such as silicon steel sheets. Additionally, slots (not shown) are provided in the stator core 12, and the stator winding 16 is housed within these slots. Figure 2 In this embodiment, the stator core 12 is fixed to the inner wall of the housing 30 of the motor body 1. However, the stator core can also be fixed to the inner wall of the housing 30 via a joint. Furthermore, a slotted stator is used in this embodiment, but the present invention is not limited to this method, and a stator with open slots or grooves can also be used instead of slots.

[0070] The stator winding 16 is formed by binding together multiple superconducting wires (in this embodiment, bismuth-based high-temperature superconducting wires), each wire having a rectangular cross-sectional shape (however, it is not limited to this cross-section). The superconducting wires are composed of multiple bismuth-based high-temperature superconducting filaments coated with highly conductive metals such as copper, aluminum, silver, and gold. Furthermore, from the viewpoint of ease of starting the superconducting rotating machine 100, it is preferable to use superconducting wires with a critical temperature higher than that of the superconducting wires used in the stator winding 16 of the stator 10.

[0071] As described above, the stator winding 16 extends through slots on the surface of the stator core 12, serving as a coil. In this embodiment, 24 slots are arranged at equal intervals in the circumferential direction on the inner circumferential side of the stator core 12. Furthermore, as... Figure 3As shown, the stator winding 16 is arranged (wound) clockwise along the circumference of the stator core 12 in a manner that generates a rotating magnetic field in the order of stator windings 16U, 16V and 16W.

[0072] In this embodiment, the stator windings 16 are three-phase windings and are connected separately. The superconducting rotating machine 100 is a three-phase motor, and each stator winding 16 is assigned to be one of the U-phase coils, V-phase coils, or W-phase coils. That is, 24 superconducting coils are arranged in the stator core 12. In other words, there are 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) arranged in the stator core 12. The 8 U-phase superconducting coils are connected in series with ground, the 8 V-phase superconducting coils are connected in series with ground, and the 8 W-phase superconducting coils are connected in series with ground. Furthermore, the stator windings 16 can be connected in series or in parallel.

[0073] The wiring method for each stator winding 16 is not particularly limited; it can be a star connection or a delta connection, etc. Furthermore, the winding method of the stator windings 16 onto the stator core 12 can be either concentrated winding or distributed winding. In this embodiment, by circulating three-phase current into the stator windings 16, a rotating magnetic field with 4 poles is formed in the stator core 12. Moreover, in this embodiment, the number of turns per pole per phase of the stator windings 16 is 12.

[0074] In the stator 10, the drive circuit that applies a drive voltage to the stator winding 16 is electrically coupled to the pulse application circuit that applies a pulse voltage superimposed on the drive voltage to the stator winding 16.

[0075] (Superconducting rotor)

[0076] like Figure 2 and Figure 3 As shown, the superconducting rotating machine 100 of this embodiment includes a superconducting rotor 20 that is held to rotate on the inner circumferential side of the stator 10. Furthermore, as... Figure 3 and Figure 4 As shown, the superconducting rotor 20 has a superconducting cage winding 22 and a rotor core 24. Figure 4 This is an illustrative diagram showing an example of the structure of a superconducting rotor.

[0077] like Figure 3 As shown, the superconducting rotor 20 is arranged at predetermined intervals on the inner circumferential side of the stator 10. Next, as... Figure 4As shown in (A), the rotor core 24 of the superconducting rotor 20 is cylindrical, and its outer circumferential surface has multiple slots 24S for accommodating the rotor bars of the rotor winding. Furthermore, the superconducting rotor 20 has a rotating shaft 40 coaxially mounted with the rotor core 24. Additionally, the superconducting rotor 20 has a superconducting cage winding 22, which has… Figure 4 (B) shows the rotor bar 26 and end ring 28 formed of superconducting wire. Furthermore, in this embodiment, a slotted rotor is used; however, the invention is not limited to this method, and rotors with open slots or grooves can also be used instead of slots.

[0078] The rotor core 24 can be formed by stacking electromagnetic steel sheets, such as silicon steel sheets, axially. For example... Figure 4 As shown in (A), a rotating shaft receiving hole 24H for accommodating the rotating shaft 40 is formed at the center of the rotor core 24. Furthermore, as described above, a plurality of slots 24S extending axially are formed at predetermined intervals in the circumferential direction near the outer periphery of the rotor core 24. In this embodiment, the slots 24S are formed obliquely relative to the axial direction of the rotor core 24, forming a skewed structure. However, the present invention is not limited to this method; for example, the slots 24S may also 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°).

[0079] like Figure 4 As shown in (B), the superconducting cage winding 22 is configured to include a plurality of rotor bars 26 and a pair of annular end rings 28 that short-circuit the two ends of each rotor bar 26. The plurality of rotor bars 26 are housed in slots 24S of the rotor core 24.

[0080] The rotor bars 26 are formed by binding together multiple superconducting wires (in this embodiment, bismuth-based high-temperature superconducting wires) and have a rectangular cross-section (however, they are not limited to a rectangular cross-section). The superconducting wires can be constructed by coating multiple bismuth-based high-temperature superconducting filaments with highly conductive metals 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 is 24 each.

[0081] The rotor bars 26 are arranged at predetermined intervals in the circumferential direction and are configured to be inclined relative to the axial direction of the cage to form a cylindrical and inclined cage. However, the present invention is not limited to this method. As mentioned above, for example, the superconducting cage winding 22 can also 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°).

[0082] The rotor guide bar 26 is formed to be longer than the axial length of the rotor core 24 and protrudes from the slot 24S when housed in it. Furthermore, the end rings 28, like the rotor guide bar 26, are constructed using superconducting wires such as bismuth-based high-temperature superconducting wires. The ends of the rotor guide bar 26 protruding from the slot 24S are respectively joined to a pair of end rings 28.

[0083] Furthermore, this embodiment describes a superconducting rotor 20 in which only a superconducting cage winding 22 is provided in the rotor core 24. However, the superconducting rotating machine 100 may also have a structure that has both a superconducting cage winding and a conventional cage winding. Examples of conventional conductive materials used in the conventional cage winding include highly conductive materials such as copper, aluminum, silver, and gold.

[0084] The rotating shaft 40 is installed by inserting it into the rotating shaft receiving hole 24H of the rotor core 24. The rotating shaft 40 is supported by bearings or other support members (not shown) so that it can rotate within the housing 30.

[0085] The control and driving method of the superconducting rotor of this embodiment will be described below using examples of various embodiments. Furthermore, while the first to second embodiments and their variations are described in this specification, the priority of the embodiments of the present invention is not limited by the order in which these embodiments are described.

[0086] <First Implementation Method>

[0087] As a first embodiment, the following method is described: the pulse voltage output section applies a rectangular pulse wave to the stator winding to superimpose the pulse wave with the drive voltage.

[0088] Reference Figure 5 The driving circuit and pulse application circuit of this embodiment will be explained. Figure 5 This is a block diagram illustrating one possible structure of the superconducting rotating machine according to this embodiment.

[0089] like Figure 5 As shown, the superconducting rotating machine 100 includes an electric motor body 1 (a three-phase HTS-ISM electric motor), a control circuit 50, a pulse application circuit 60, and a drive circuit 70. In this embodiment, the pulse output section and the drive voltage output section are configured as separate circuits.

[0090] The control circuit 50 outputs a control signal 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. Additionally, the control circuit 50 controls the time, timing, voltage, and frequency of the drive voltage output from the drive circuit 70.

[0091] like Figure 5As shown, the control circuit 50 includes a CPU (Central Processing Unit) 52, an interface (I / F) 54, and a memory 56. The control circuit 50 can be constructed based on application-specific circuits such as ASICs (Application Specific Integrated Circuits).

[0092] The CPU 52 executes commands according to the control program, controlling each switch SW1-SW6, the pulse application circuit 60, and the drive circuit 70. Additionally, the interface 54 outputs control signals for controlling the pulse application circuit 60 and the drive circuit 70, and control signals for controlling the opening and closing states of each switch SW1-SW6. The memory 56 includes ROM (Read Only Memory), RAM (Random Access Memory), which functions as the main recording unit, and volatile or non-volatile memory as an auxiliary recording unit. The control program described above can be stored in either the main recording unit or the auxiliary recording unit.

[0093] The pulse application circuit 60 is a PWM-controlled inverter configured with capacitors, and it applies rectangular pulse voltages to the motor body 1. The pulse application circuit 60 is connected to the stator windings of the motor body 1 via switches SW1 to SW3 in a manner that allows pulse voltages to be applied. The pulse application circuit 60 converts the voltage supplied from a power source (not shown) into a three-phase rectangular pulse voltage and applies this pulse voltage to the stator.

[0094] 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 to each stator winding of the motor body 1 via switches SW4 to SW6 in a manner that allows the application of drive voltage. The drive circuit 70 converts the voltage supplied from a power source (not shown) into a three-phase voltage and applies it as the drive voltage to the stator of the motor body 1.

[0095] (Pulse voltage)

[0096] In this embodiment, a rectangular pulse voltage is applied to the stator winding from the pulse application circuit 60 to be superimposed on the drive voltage output from the drive circuit 70. Figure 6 This is a graph showing the waveform of the pulse voltage in the first embodiment and the relationship between the pulse voltage (Vp) and the driving voltage (Vb). Figure 6 middle, Figure 6 In (A), the vertical axis represents the input voltage (rectangular pulse wave) to the stator winding, and the horizontal axis represents time. Figure 6(B) shows the relationship between the variation of the amplified time-axis input voltage supplied to the stator winding and time. Figure 6 (C) is a schematic diagram showing the timing of the application of the pulse voltage (Vp) and the drive voltage (Vb).

[0097] like Figure 6 As shown in (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 a timing of time S0, and controls the pulse application circuit 60 to apply a rectangular pulse wave to the stator winding during the period from time S0 to time S1 to superimpose the pulse voltage (Va) and the drive voltage (Vb).

[0098] Preferably, the drive voltage (Vb) is pre-controlled to ensure proper rotation of the superconducting rotary machine after the superconducting rotor transitions to a rotating state, and is set to meet the maximum efficiency condition during stable drive. Additionally, at startup, it is set to meet the voltage required for maximum torque under normal conditions. Figure 6 As shown, the voltage (Vp+b) after the pulse voltage (Vp) applied from the pulse application circuit 60 is superimposed with the drive voltage (Vb) is set to be higher than the drive voltage (Vb) during stable drive.

[0099] Here, in this specification, the "pulse voltage" output from the pulse voltage output unit refers to the voltage used to change the state of the superconducting cage winding, preferably a voltage with an application time of 2 seconds or less. While not particularly limited, from the viewpoint of shortening the start-up time (the time until synchronous rotation mode is reached), it is more preferable that the pulse voltage application time is 1 second or less, and particularly preferably 0.5 seconds or less. Furthermore, the waveform of the pulse voltage is not particularly limited and can be any type, such as a rectangular wave, a ramp wave, or a sawtooth wave.

[0100] When a pulse voltage is applied to the stator winding as in this embodiment, from the viewpoint that the current value (Io) flowing in the superconducting cage winding becomes 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 and the driving voltage (Vb) is Vmin or higher as shown in the following formula.

[0101] [Number 2]

[0102]

[0103] (In the formula, Vmin is the phase voltage, r1 is the stator winding resistance, x1 is the stator winding leakage reactance, x2' is the primary-side converted rotor winding leakage reactance, and Ic' is the primary-side converted rotor bar critical current.)

[0104] In the formula, r1: stator winding resistance, x1: stator winding leakage reactance, x2': primary-side converted rotor winding leakage reactance, and Ic': primary-side converted rotor bar critical current can be calculated by referring to "T Nakamura, et al., "Novel rotating characteristics of asquirrel-cage-type HTS induction / synchronous motor", Superconductor Science and Technology, vol.20(2007)911-918, and general no-load rotation test or stall test. Furthermore, when the critical current of the rotor bar is set as Ic, the primary-side converted rotor bar critical current (Ic') can be calculated using Ic'=Ic / α (α: number of stator windings / number of rotor windings (usually assumed to be 1)).

[0105] Furthermore, when applying a pulse voltage to the stator winding as in this embodiment, it is preferable to set the voltage (Vp+b) obtained by superimposing the drive voltage and the pulse voltage (Vp) with the goal of capturing the voltage (hereinafter sometimes referred to as "voltage (Vw)") required to start the motor under appropriate drive conditions (speed, torque). On the other hand, when the pulse voltage (Vp) is too high, the pulse voltage may sometimes be converted into the kinetic energy of the rotor, etc., causing adverse effects such as vibration, which may become a reason why the synchronous rotation mode cannot be maintained. Taking this viewpoint into consideration, the upper limit (Vmax) of the voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) and the drive voltage (Vb) can be set to a value that is about 1.4 times higher than Vw.

[0106] Considering the above points, the range of the voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) and the driving voltage (Vb) is preferably Vb≤Vp+b≤Vmax, more preferably Vmin≤Vp+b≤Vmax, and particularly preferably Vw≤Vp+b≤Vmax.

[0107] The application time (T) of the pulse voltage refers to the time from... Figure 6 The time (s) between the start of the pulse voltage application (start of rise) (S0) and the end of the pulse voltage application (end of fall) (s1) is considered. The pulse voltage application time (T) can be determined within the electrical time constant (τ) of the superconducting rotating machine. e ) and the mechanical time constant (τ) of the superconducting rotating machine m This is set under the relationship of ). Strictly speaking, as Figure 7As shown, the application time (T) is t on (The time from the start of voltage application to the point where the voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) and the driving voltage (Vb) is reached), W (The time from the point where the voltage (Vp+b) is reached to the point where the pulse voltage begins to decrease), and t off The total value of (the time from the start of the descent to the attainment of the driving voltage (Vb)) (i.e., T = t on +W+t off However, in a rectangular wave, t on and t off For an extremely short time, therefore the electrical time constant (τ) of the superconducting rotating machine is... e ) and the mechanical time constant (τ) of the superconducting rotating machine m In the relationship, W can be considered as the application time (T). Furthermore, Figure 7 This indicates the application time (T) and t of the pulse voltage. on W and t off The diagram illustrates the relationship between T and t, and does not show the actual T and t values. on W, t off The ratio. Furthermore, the electrical time constant (τ) of the superconducting rotating machine. e ) and the mechanical time constant (τ) of the superconducting rotating machine m Each can be calculated based on a general stall test or a general no-load rotation test.

[0108] Here, regarding the electrical time constant (τ) e It can use the average inductance (L:H) of each phase of the superconducting rotating machine and the resistance value (R:Ω) of each phase's stator winding to determine the "τ" value. e =L / R. In addition, the average inductance of each phase can be obtained by "average linkage flux Ψ / current".

[0109] In addition, regarding the mechanical time constant (τ) of the superconducting rotating machine m It can utilize the moment of inertia (J; Nms) of a superconducting rotor. 2 The coefficient of friction of the superconducting rotor (D: NmS / rad) is used to determine the relationship between τ and the coefficient of friction of the superconducting rotor. m =J / D” to find the answer.

[0110] The application time (T) of the aforementioned pulse voltage is preferably sufficiently higher than the electrical time constant (τ). e This ensures that sufficient current is generated in the superconducting cage winding. Furthermore, the application time (T) of the pulse voltage is preferably sufficiently lower than the mechanical time constant (τ). m This is to prevent the remaining pulse voltage from being converted into kinetic energy and affecting the rotation of the superconducting rotor.

[0111] In addition, regarding the t mentioned above on and t off There are no particular limitations, but from the viewpoint of efficiently increasing the pulse voltage, amplifying the pulse voltage (Vp) capable of transitioning to the synchronous rotation mode, and the amplitude of the pulse voltage (application time T), it is preferable that the t in the rectangular wave... on 10 -5 seconds ~ 10 -2 Approximately one second. Similarly, from the viewpoint of reducing the impact on the rotation of the superconducting rotor caused by the sharp voltage drop during the pulse voltage drop, it is preferable that the t in the rectangular wave... off 10 -5 seconds ~ 10 -2 Approximately one second.

[0112] [Driving method of superconducting rotating machine]

[0113] The superconducting rotating machine 100 configured as described above can be widely used in applications that utilize rotating machines, such as automobiles (small cars, medium cars, buses or trucks, etc.), railways, submarines, aircraft, ships, and liquid circulation pumps. For example, it can be used in the superconducting electric motor system described in International Publication No. WO2009 / 116219.

[0114] For example, the superconducting rotating machine 100 can be applied to a system having driven components such as wheels, propellers, and screws that rotate via a connection to the rotating machine. This system may be configured, for example, to include the superconducting rotating machine 100, driven components such as wheels that are directly connected to the superconducting rotating machine 100 or connected via other components, a cooling device capable of cooling the superconducting rotating machine 100 to a superconducting state, and a battery for driving the superconducting rotating machine 100.

[0115] Next, use Figure 8 This describes a method for driving a superconducting rotating machine by setting the superconducting cage winding into a flux flow state using pulsed voltage. Figure 8 This is a flowchart illustrating a method for starting a superconducting rotating machine. However, the present invention is not limited to this method.

[0116] First, in the superconducting rotating machine 100, the stator winding 16 and the superconducting cage winding 22 have been cooled by the cooling device before startup, and both windings are in a superconducting state. The cooling device is not particularly limited as long as it can cool the superconducting stator 10 and the superconducting cage winding 22 in the superconducting rotating machine 100 to a superconducting state (cooled below the critical temperature), but for example, a cooling device using helium, liquid nitrogen, or the like as a refrigerant can be used.

[0117] When the superconducting rotating machine 100 is started, the control circuit 50 turns on SW1 to SW6, applies a driving voltage from the drive circuit 70, and begins applying a pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 100 to change the superconducting cage winding 22 to a flux-flow state (step S101). In this embodiment, in order to capture the flux required 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 driving voltage is higher than the driving voltage during stable driving, and the voltage when the pulse voltage is superimposed on the driving voltage is higher than Vmin and Vw and less than Vmax, respectively. A rectangular pulse voltage (Vp) is applied to the stator winding 16 and superimposed on the driving voltage. As a result, the shielding current value (Io) of the superconducting cage winding 22 becomes higher than the critical current value (Ic), the superconducting cage winding 22 changes from a magnetic shielding state to a magnetic flux flow state, and the superconducting rotor 20 begins to rotate in an induction rotation mode.

[0118] Control circuit 50 applies a pulse voltage from pulse application circuit 60 to superconducting rotating machine 100 before a predetermined time (W) has elapsed (No in step S102). As described above, strictly speaking, before and after the predetermined time (W), there exists a time (t) from the start of voltage application until the voltage (Vp+b) is reached when the pulse voltage is superimposed on the driving voltage. on ), and the time from the start of the pulse voltage drop until the driving voltage (Vb) is reached (t) off Therefore, the actual application time (T) is t. on +W+t off It can become τ e <T<τ m In this way, through the electrical time constant (τ) of the superconducting rotating machine 100 e ) and the mechanical time constant (τ) of the superconducting rotating machine m The relationship between the two factors determines the specified time (W).

[0119] In this embodiment, a pulse voltage is applied to the stator 10 under the conditions described above and superimposed on the driving voltage. Therefore, before a predetermined time (W) has elapsed, the rotational speed of the superconducting rotor 20 reaches the speed of the rotating magnetic field of the stator 10. Thus, before the predetermined time (W) has elapsed, the superconducting cage winding 22 changes from a flux flow state to a flux trapping state, and the superconducting rotor 20 enters a synchronous rotation mode.

[0120] When a predetermined time (W) has elapsed ("Yes" in step S102), the control circuit 50 switches the switches so that SW1 to SW3 are off and SW4 to SW6 are on (step S103). Afterward, the control circuit 50 applies a synchronous rotation control mode to the superconducting rotating machine 100, which rotates primarily with synchronous torque, and switches to controlling the drive voltage that adjusts the amplitude and frequency of the three-phase AC voltage applied to the stator winding 16 via the drive circuit 70.

[0121] Next, use Figure 9 This describes the driving method of a superconducting rotating machine in synchronous rotation mode, where the superconducting cage winding is set to a flux flow state by pulse voltage to replenish the flux. Figure 9 This is a flowchart illustrating another method for driving a superconducting rotating machine. However, the present invention is not limited to this method.

[0122] The magnetic flux captured by the rotor in synchronous rotation mode has an ideal amount corresponding to its rotational speed. Therefore, in synchronous rotation mode, sometimes the initially captured magnetic flux is insufficient or excessive depending on the rotational speed, resulting in a situation where it is desirable to change the captured magnetic flux to efficiently maintain synchronous rotation mode. However, in the case of changing the insufficient magnetic flux in synchronous rotation mode, it is necessary to temporarily release the magnetic flux capturing state of the superconducting cage winding 22 and switch it to a magnetic flux flowing state to replenish the magnetic flux.

[0123] The control circuit 50 monitors the magnetic flux captured by the superconducting rotor 20 in synchronous rotation mode, and continues to monitor until a need arises to adjust the captured magnetic flux by changing the superconducting cage winding 22 to a magnetic flux flow state based on its relationship with the rotational speed (step S201 "No"). Next, if the control circuit 50 determines that it is necessary to change the superconducting cage winding 22 to a magnetic flux flow state (step S201 "Yes"), the control circuit 50 turns on SW1 to SW3 (step S202) and begins to apply a pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 100 (step S203). The timing at which the control circuit 50 determines that it is necessary to change the superconducting cage winding 22 to a magnetic flux flow state is not particularly limited, but it is preferable to set a predetermined timing based on the captured magnetic flux and corresponding to the increase or decrease of the rotational speed. In addition, in this embodiment, the structure is configured to provide pulse voltage while keeping switches SW4 to SW6 in the on state when providing pulse voltage. However, the superconducting rotating machine 100 may also be configured to provide pulse voltage after switches SW4 to SW6 are turned off.

[0124] In this embodiment, in order to recapture the magnetic flux capable of efficiently and continuously synchronizing with 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 lower than Vmax. The control circuit 50 applies the pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 100 before a predetermined time (W) has elapsed (No in step S204). As described above, it is possible to achieve a voltage of τ e <T<τ m In this way, through the electrical time constant (τ) of the superconducting rotating machine 100 e ) and the mechanical time constant (τ) of the superconducting rotating machine m The relationship between the two factors determines the specified time (W).

[0125] In this embodiment, a pulse voltage is applied to the stator 10 under the conditions described above. Therefore, the shielding current value (Io) of the superconducting cage winding 22 becomes higher than the critical current value (Ic). The superconducting cage winding 22 transitions from a magnetically shielded state to a flux-flowing state, enabling it to recapture the flux of the rotating magnetic field. At this time, according to this embodiment, by applying a pulse voltage (Vp), a sufficient amount of flux is generated in the rotating magnetic field, thus increasing the amount of flux linked to the superconducting cage winding 22 when it transitions to a flux-flowing state.

[0126] When the specified time (W) has elapsed ("Yes" in step S204), the control circuit 50 switches the switches so that SW1 to SW3 are off and SW4 to SW6 are on (step S205). At this time, due to the transition to the magnetic flux flow state, the superconducting rotor changes from synchronous rotation mode to induction rotation mode. However, the reduction in the rotational speed of the superconducting rotor during the transition is small, so it quickly returns to synchronous rotation mode after magnetic flux capture.

[0127] Subsequently, the control circuit 50 applies a synchronous rotation control mode to the superconducting rotating machine 100, which rotates primarily with synchronous torque, and switches to control of the drive voltage that adjusts the amplitude and frequency of the AC voltage applied to the stator winding 16 via the drive circuit 70.

[0128] [Effect]

[0129] According to the superconducting rotating machine 100 configured as described above, when the superconducting cage winding 22 is in a magnetically shielded state during startup, it can rapidly transition to a magnetic flux flow state by outputting a pulse voltage and superimposing it with the driving voltage. Therefore, the superconducting rotating machine 100 can quickly transition to an induction rotation mode and subsequently to a synchronous rotation mode after startup, significantly shortening the time required to transition to the synchronous rotation mode compared to the case without using a pulse voltage. Furthermore, since the application of the driving voltage (Vb) requires the application time of an electrical time constant, the superconducting rotating machine 100, by superimposing the pulse voltage (Vp) with the driving voltage (Vb), can suppress an immediate return to the original magnetically shielded state upon transitioning to a magnetic flux flow state.

[0130] Furthermore, according to the superconducting rotating machine 100, the voltage start-up control can be simplified by using pulsed voltage, reducing the power supply's steady-state current capacity, which is a value adapted to the output during rotation. This significantly simplifies the energizing of the starting current compared to conventional methods, thus dramatically reducing losses. In other words, the superconducting rotating machine 100 can be started by applying a short-duration pulsed voltage, minimizing losses in both the power supply and the superconducting rotating machine 100. This allows for heat suppression designs for the power supply's semiconductor switching elements and the windings of the superconducting rotating machine 100, further enabling miniaturization, weight reduction, and lower manufacturing costs. Moreover, the superconducting rotating machine 100 significantly simplifies the energizing of the starting current compared to conventional methods, thus preventing the temporary transition to synchronous rotation mode from being deactivated.

[0131] Furthermore, according to the superconducting rotating machine 100, when driven in synchronous rotation mode, the superconducting cage winding 22 can be switched from a flux trapping state to a flux flowing state by outputting a pulse voltage. Therefore, for example, if the amount of flux trapping is insufficient or excessive when the superconducting rotating machine of this embodiment is driven in synchronous rotation mode, the superconducting cage winding 22 can be switched to a flux flowing state by a pulse voltage to recapture the flux of the rotating magnetic field. At this time, due to the switch to the flux flowing state, the superconducting rotating machine 100 switches from synchronous rotation mode to inductive rotation mode, but can quickly return to synchronous rotation mode after flux trapping, thus substantially extending the duration of synchronous rotation mode. In addition, since it can quickly return from inductive rotation mode to synchronous rotation mode, the decrease in torque during the transition from synchronous rotation mode to inductive rotation mode can be effectively suppressed.

[0132] For example, it has been confirmed that, under the following conditions, a superconducting rotating machine can be switched to synchronous rotation mode by using rectangular pulse voltages.

[0133] (condition)

[0134] • Rotor outer diameter: 174.8mm (Core: Electromagnetic steel plate, Winding: Superconducting wire (bismuth-based high-temperature superconducting wire))

[0135] Stator inner diameter: 176.0mm (Core: Electromagnetic steel plate, Winding: Superconducting wire (bismuth-based high-temperature superconducting wire))

[0136] Shaft length: 102.0mm

[0137] • Number of turns per pole per phase: 12

[0138] • Number of extremes: 4

[0139] Gap length: 0.6mm

[0140] • The voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) and the driving voltage (Vb): rectangular wave, 92V~132V (RMS).

[0141] • Drive voltage (Vb): 80V (RMS)

[0142] • Frequency: 60Hz

[0143] • Application time (T) = 10 -4 seconds (T) on )+W(0.3 seconds to 1 second)+T off (10 -4 Second)

[0144] ·V min 80V (phase voltage)

[0145] ·Vw:98V

[0146] ·V max 130V

[0147] Electrical time constant (τ) e 0.5s

[0148] Mechanical time constant (τ) m ): 2s

[0149] [Variation Example]

[0150] The above describes this embodiment in detail, but this embodiment can be implemented in variations as follows.

[0151] (First variation)

[0152] For example, in the above example, the waveform of the pulse voltage applied to the stator 10 is described as rectangular, and the pulse voltage output section and the drive voltage output section are arranged in different voltage output circuits. However, the present invention is not limited to this method. For example, the superconducting rotating machine may also be arranged in a manner in which the pulse voltage output section and the drive voltage output section are arranged in the same voltage output circuit.

[0153] The first variation is illustrated using the accompanying drawings. Figure 10 This is a block diagram illustrating one possible structure of the superconducting rotating machine of the first modified example.

[0154] like Figure 10 As shown, the superconducting rotating machine 200 includes an electric motor body 1 (a three-phase HTS-ISM motor), a control circuit 50, and a drive circuit 70. In this modified example, the pulse output section and the drive voltage output section are configured as a single circuit, and a pulse voltage is output from the drive circuit 70.

[0155] (Pulse voltage)

[0156] In this embodiment, a triangular wave (ramp pulse) voltage higher than the driving voltage output from the driving circuit 70 is applied to the stator winding from the driving circuit 70, and the pulse voltage is superimposed on the driving voltage. Figure 11 This is a graph showing the waveform of the pulse voltage in the first variation, and the relationship between the pulse voltage (Vp) and the driving voltage (Vb). Figure 11 middle, Figure 11 In (A), the vertical axis represents the input voltage (ramp wave) to the stator winding, and the horizontal axis represents time. Figure 11 (B) shows the relationship between the variation of the amplified time-axis input voltage supplied to the stator winding and time. Figure 6 (C) is a schematic diagram showing the timing of the application of the pulse voltage (Vp) and the drive voltage (Vb).

[0157] like Figure 11 As shown in (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 a timing of time S1, and controls the drive circuit 70 to apply a triangular wave with a ramp to the stator winding during the period from time S0 to time S1 to superimpose the pulse voltage (Va) and the drive voltage (Vb).

[0158] In this modified example, the pulse voltage (Vp), driving voltage (Vb), and the application time (T) of the pulse voltage are also controlled under the same conditions as in the first embodiment described above. Furthermore, in this modified example, the pulse voltage is applied as a ramp wave, therefore the effective value (Vpr) of the voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) and the driving voltage Vb is used as a reference. The effective value (Vpr) can be calculated using Vpr = Vp+b × (1 / √3). Therefore, in this modified example, the comparison between the pulse voltage (Vp), driving voltage (Vb), Vmin, Vw, and Vmax is based on Vpr calculated from Vp+b.

[0159] [Driving method of superconducting rotating machine]

[0160] Next, use Figure 12 This describes a method for driving a superconducting rotating machine by setting the superconducting cage winding into a flux flow state using pulsed voltage, based on this modified example. Figure 12 This is a flowchart illustrating the starting method of the superconducting rotating machine 200. However, the present invention is not limited to this method.

[0161] First, in the superconducting rotating machine 200, the stator winding 16 and the superconducting cage winding 22 have been cooled by the cooling device before startup, and the two windings are in a superconducting state.

[0162] When the superconducting rotating machine 200 is started, the control circuit 50 turns on switches SW4 to SW6 and begins to apply pulse voltage and drive voltage from the drive circuit 70 to the superconducting rotating machine 200, so that the superconducting cage winding 22 changes to a flux-flow state (step S301). In this modified example, in order to capture the flux required to start the motor under appropriate drive conditions (speed, torque), the control circuit 50 adjusts the amplitude and frequency of the AC voltage of the pulse application circuit 60 to apply a rising pulse voltage (Vpr) to the stator winding 16. This pulse voltage is higher than the drive voltage during stable drive, and the voltage when the pulse voltage and drive voltage are superimposed is higher than Vmin and Vw but lower than Vmax. As a result, the shielding current value (Io) of the superconducting cage winding 22 becomes higher than the critical current value (Ic), the superconducting cage winding 22 changes from a magnetically shielded state to a flux-flow state, and the superconducting rotor 20 begins to rotate in an induction rotation mode.

[0163] Control circuit 50 applies a pulse voltage from drive circuit 70 to superconducting rotary machine 200 before a predetermined time (T) has elapsed (No in step S302). As described above, the application time (T) is t. on +W+t off However, due to the t of the rising wave compared to the rectangular wave... on and toff The influence is significant; therefore, in this variation, the application time (T) is used as the reference, not W. It can be made to become τ. e <T<τ m In this way, through the electrical time constant (τ) of the superconducting rotating machine 200 e ) and the mechanical time constant (τ) of the superconducting rotating machine m The relationship between the two factors determines the specified time (T).

[0164] When a predetermined time (T) has elapsed ("Yes" in step S302), the control circuit 50 switches the voltage and frequency of the drive circuit 70 to apply a drive voltage (Vb) to the stator 10 of the motor body 1 (step S303). Afterward, the control circuit 50 applies a synchronous rotation control mode to the superconducting rotating machine 200, which rotates primarily with synchronous torque, and switches to control the drive voltage by adjusting the amplitude and frequency of the AC voltage applied to the stator winding 16 via the drive circuit 70.

[0165] In the first modification described above, pulse voltage and drive voltage can be output from a single drive circuit. Therefore, in the first modification, no additional construction is required compared to conventional high-temperature superconducting induction synchronous motors, simplifying the device. Furthermore, by injecting pulse voltage into the stator windings, the same effect as in the first embodiment can be achieved.

[0166] Furthermore, in this modified example, similar to the first embodiment, when driven in a synchronous rotation mode, the superconducting cage winding 22 can be switched from a flux trapping state to a flux flowing state by outputting a pulse voltage.

[0167] For example, it has been confirmed that, under the following conditions, a superconducting rotating machine can be switched to synchronous rotation mode by using a pulse voltage of a ramp wave.

[0168] (condition)

[0169] • Rotor outer diameter: 174.8mm (Core: Electromagnetic steel plate, Winding: Superconducting wire (bismuth-based high-temperature superconducting wire))

[0170] Stator inner diameter: 176.0mm (Core: Electromagnetic steel plate, Winding: Superconducting wire (bismuth-based high-temperature superconducting wire))

[0171] Shaft length: 102.0mm

[0172] • Number of turns per pole per phase: 12

[0173] • Number of extremes: 4

[0174] Gap length: 0.6mm

[0175] • The voltage (Vp+b) obtained by superimposing the pulse voltage (Vp) and the driving voltage (Vb): ramp-up wave, 112V~200V (RMS).

[0176] • Drive voltage (Vb): 80V (RMS)

[0177] • Frequency: 60Hz

[0178] • Application time (T) = 10 -4 seconds (T) on )+W(0.3 seconds to 1 second)+T off (10 -4 Second)

[0179] ·V min 80V

[0180] ·Vw:98V

[0181] ·V max 130V

[0182] Electrical time constant (τ) e 0.5s

[0183] Mechanical time constant (τ) m ): 2s

[0184] <Second Implementation Method>

[0185] For example, in the first embodiment described above, it is assumed that by applying a pulse voltage to the stator winding and superimposing it with the driving voltage, the shielding current flowing through the superconducting cage winding is increased, thereby setting the relationship between the current value (Io) and the critical current value (Ic) of the superconducting cage winding to Io>Ic, thus transforming the structure into a flux flow state. However, the present invention is not limited to this method. For example, it could also be in the following manner: the superconducting rotating machine further includes a pulsed magnetic field output unit, which generates a pulsed magnetic field by using a pulse voltage output from a pulse voltage output unit, and the superconducting rotating machine applies the pulsed magnetic field output from the pulsed magnetic field output unit to the superconducting rotor.

[0186] The second embodiment will be described using the accompanying drawings. Figure 13 This is a block diagram illustrating one aspect of the structure of the superconducting rotating machine according to the second embodiment.

[0187] like Figure 13As shown, the superconducting rotating machine 300 includes a motor body 1 (a 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. A pulsed magnetic field is generated when a pulse voltage is applied to the magnetic field generating coil 90. The magnetic field generating coil 90 is disposed on the superconducting rotor 20, and a pulsed magnetic field generated by applying the pulse voltage is applied to the superconducting rotor 20. The location of the magnetic field generating coil 90 is not particularly limited; for example, it may be disposed on the end ring 28 of the superconducting cage winding 22. Alternatively, the magnetic field generating coil 90 may be a cage coil composed of multiple rotor bars and a pair of annular end rings that short-circuit the two ends of each rotor bar, and disposed on the rotor core 24 in the same manner as the superconducting cage winding 22. In this case, it is preferable that the rotor bar of the magnetic field generating coil 90 is positioned, for example, at a position that is radially inner to the core than the rotor bar 26 of the superconducting cage winding 22.

[0188] [Driving method of superconducting rotating machine]

[0189] Next, use Figure 14 This describes a method for driving a superconducting rotating machine by setting the superconducting cage winding into a flux flow state using pulsed voltage, based on this modified example. Figure 14 This is a flowchart illustrating the starting method of the superconducting rotating machine 300. However, the present invention is not limited to this method.

[0190] First, in the superconducting rotating machine 300, the stator winding 16 and the superconducting cage winding 22 have been cooled by the cooling device before startup, and the two windings are in a superconducting state.

[0191] When the superconducting rotating machine 300 is started, the control circuit 50 turns on switches SW4 to SW6 and begins to apply a driving voltage from the drive circuit 70 to the stator 10 of the motor body 1 (step S401). When the driving voltage is applied to the stator 10, a shielding current is generated in the superconducting cage winding 22, and the superconducting cage winding 22 becomes magnetically shielded.

[0192] Next, the control circuit 50 turns on the switch SW7 and begins applying a pulse voltage from the pulse application circuit 60 to the superconducting rotating machine 300, so that the superconducting cage winding 22 changes to a flux-flow state (step S401). In this modified example, a magnetic field generating coil 90 is connected to the pulse application circuit 60, so a 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.

[0193] As described above, a magnetic field generating coil 90 is provided on the superconducting rotor 20, thus applying a pulsed magnetic field generated by the magnetic field generating coil 90 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, thereby decreasing the critical current value (Ic) of the superconducting cage winding 22. That is, according to this modification, by applying a pulsed magnetic field, the critical current value (Ic) decreases relatively relative to the shielding current value (Io) flowing through the superconducting cage winding 22 due to the driving voltage, thereby rapidly making the relationship between the shielding current value (Io) flowing through the superconducting cage winding 22 due to the driving voltage and the critical current value (Ic) of the superconducting cage winding Io > Ic. Thus, according to this modification, the superconducting cage winding 22 can be rapidly converted to a flux-flow state. When the superconducting cage winding 22 changes to a magnetic flux flow state, the superconducting rotating machine 300 changes to an induction rotation mode and begins to rotate through the superconducting rotor.

[0194] Before a predetermined time (W) has elapsed, the control circuit 50 applies a pulse voltage from the pulse application circuit 60 to the magnetic field generating coil 90 (No in step S403). When the predetermined time (W) has elapsed (Yes in step S403), the switch SW7 is set to open, and the application of the magnetic field pulse voltage to the magnetic field generating coil 90 is stopped (step S403). When the application of the magnetic field pulse voltage to the magnetic field generating coil 90 is stopped, the application of the pulsed magnetic field to the superconducting rotor 20 is also stopped. Afterward, the control circuit 50 applies a synchronous rotation control mode to the superconducting rotating machine 300, which rotates primarily with synchronous torque, and switches to control of the drive voltage that adjusts the amplitude and frequency of the AC voltage applied to the stator winding 16 via the drive circuit 70.

[0195] In the second variation described above, by converting the pulsed voltage into a pulsed magnetic field and applying this pulsed magnetic field to the superconducting rotor, the critical current value (Ic) of the superconducting cage winding can be reduced. Therefore, 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 quickly become Io > Ic. Consequently, the superconducting rotating machine 300 can rapidly transition to induction rotation mode and subsequently to synchronous rotation mode after startup, significantly shortening the time required to transition to synchronous rotation mode compared to the case without using pulsed voltage.

[0196] Furthermore, in this modified example, similar to the first embodiment, when driven in a synchronous rotation mode, the superconducting cage winding 22 can be switched from a flux trapping state to a flux flowing state by outputting a pulse voltage.

[0197] (Second variation)

[0198] For example, in the first and second embodiments described above, it was explained that the superconducting rotor 20 only has a superconducting cage winding 22 as the rotor winding, but the present invention is not limited to these embodiments. For example, the superconducting rotating machine 100 may also be configured such that, in addition to having a superconducting cage winding 22, the superconducting rotor 20 also has a conventional cage winding, which has end rings and one or more rotor bars formed of conventional conductive material.

[0199] In this modified example, the normally conducting cage winding can be configured, for example, to be parallel to... Figure 4 The superconducting cage winding 22 shown has the same structure. Specifically, it consists of multiple rotor bars made of a conventionally conductive material and a pair of annular end rings made of a conventionally conductive material that short-circuit the two ends of each rotor bar. The multiple rotor bars made of a conventionally conductive material are housed in slots of the rotor core 24.

[0200] Multiple rotor bars using conventionally conductive materials are formed from highly conductive materials such as copper, aluminum, silver, and gold, and have a rectangular cross-section (however, not limited to a rectangular cross-section). Figures 2 to 4 In the case where the superconducting rotating machine 100 shown incorporates a conventionally conducting cage winding, the number of rotor bars can be set to be the same as the number of slots 24S in the rotor core 24 (i.e., the number of rotor bars in the conventionally conducting cage winding is 24). The rotor bars can be arranged at predetermined intervals in the circumferential direction in a manner that forms a cage with a cylindrical and inclined structure larger than the superconducting cage winding 22. However, this modified example is not limited to this arrangement.

[0201] The rotor bars using a conventionally conductive material are formed to be longer than the axial length of the rotor core 24, protruding from the slots when housed in each slot 24S. For example, the rotor bars using a conventionally conductive material can be positioned radially outward within the slots 24S of the rotor core 24, compared to the rotor bars 26 formed of superconducting wire. In this configuration, the rotor bars 26 formed of superconducting wire are positioned on the inner (center) side of the rotor core 24, while the rotor bars formed of conventionally conductive wire are positioned on its outer (outer peripheral) side.

[0202] Similarly, the end rings using normally conductive materials can be made of highly conductive materials such as copper, aluminum, silver, and gold. The ends of the rotor bars using normally conductive materials, protruding from the slots, are respectively joined to a pair of end rings using normally conductive materials.

[0203] 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 via a conventional cage winding. Therefore, for example, it is possible to drive primarily by induction torque when the superconducting rotor 20 is in a non-superconducting state, and when the superconducting rotor 20 becomes superconducting through cooling, by applying a pulse voltage, the superconducting cage winding 22 can be quickly set to a flux-flow state even during drive. Thus, even when the superconducting rotor 20 is driven primarily by induction torque in a non-superconducting state, it is possible to quickly switch to synchronous rotation mode after the superconducting rotor 20 becomes superconducting.

[0204] Furthermore, in this modified example, the control circuit 50 can monitor the signal of the primary current flowing in the stator winding 16 from the superconducting rotating machine 100, such as the primary current signal, to determine whether the superconducting cage winding 22 is in a superconducting state (whether the superconducting rotating machine 100 is rotating primarily with synchronous torque). For example, it can be configured such that when the rotor is rotating primarily with synchronous torque, a synchronous rotation control mode is applied to the superconducting rotating machine 100; otherwise, when it is rotating primarily with induced (slip) torque, a slip rotation control mode is applied.

[0205] (Third variation)

[0206] For example, in the first and second embodiments described above, only superconducting wire is used in the stator winding 16 of the stator 10, but the present invention is not limited to these methods. For example, the stator 10 may also have other windings (normally conducting windings) using normal conducting wire in addition to the stator winding 16, and normal conducting wire may be used instead of superconducting wire. In this case, for example, the superconducting rotating machine 100 can be configured to form magnetic poles in the stator 10 through the normal conducting winding, and a rotating magnetic field can be generated even in the normal conducting state. According to this structure, for example, the superconducting rotating machine 100 can be started and driven before the superconducting wire of the stator winding 16 becomes superconducting.

[0207] (Other variations)

[0208] For example, the superconducting wires mentioned above are not limited to bismuth-based high-temperature superconducting wires, but can be metal-based low-temperature superconducting wires represented by NbTi or Nb3Sn, yttrium-based high-temperature superconducting wires, or magnesium diboride superconducting wires.

[0209] Furthermore, while the first and second embodiments described above illustrate the use of wire as a superconducting and conventionally conducting material, the present invention is not limited to this approach. For example, bulk materials can also be used as superconducting and conventionally conducting materials. For instance, bulk materials can be used as superconducting and / or conventionally conducting materials, depending on applications where materials with high current capacity are desired in the stator and rotor (e.g., large superconducting motors).

[0210] The above describes various embodiments of the present invention, but the present invention is not limited to the above embodiments. Furthermore, modifications can be made to the present invention without departing from its spirit.

[0211] The disclosure of Japanese Patent Application No. 2020-195167, filed on November 25, 2020, is incorporated herein by reference in its entirety.

[0212] In addition, all documents, patent applications and technical standards recorded in this specification are referenced in this specification to the same extent as those specifically and separately described and cited by reference.

[0213] Explanation of reference numerals in the attached figures

[0214] 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 superconducting rotating machine, comprising: A stator, which is used to generate a rotating magnetic field, has a cylindrical stator core and stator windings wound around the stator core; A superconducting rotor is maintained to be rotatable by the rotating magnetic field of the stator, and the superconducting rotor has a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, and the rotor core having multiple slots for receiving the rotor bars. The pulse voltage output section outputs a pulse voltage to change the superconducting cage winding from at least one of a magnetic shielding state and a magnetic flux trapping state to a magnetic flux flowing state. as well as The drive voltage output section applies a drive voltage to the stator windings to drive the superconducting rotor to rotate. The superconducting rotating machine can switch from induction rotation mode to synchronous rotation mode. The superconducting rotating machine superimposes the pulse voltage output from the pulse voltage output unit with the driving voltage, causing the superconducting cage winding to change from at least one of the magnetic shielding state and the magnetic flux trapping state to the magnetic flux flow state, thereby changing to the induction rotation mode.

2. The superconducting rotating machine according to claim 1, wherein, The voltage obtained by superimposing the pulse voltage and the driving voltage is greater than or equal to Vmin as shown in the following formula. [Number 1] In the formula, Vmin is the phase voltage, r1 is the stator winding resistance, x1 is the stator winding leakage reactance, x2' is the primary side converted rotor winding leakage reactance, and Ic' is the primary side converted rotor bar critical current.

3. The superconducting rotating machine according to claim 1 or 2, wherein, The application time T of the pulse voltage, the electrical time constant τ of the superconducting rotating machine e and the mechanical time constant τ of the superconducting rotating machine m by the formula: τ e <T<τ m is indicated.

4. The superconducting rotating machine according to claim 1 or 2, wherein, The pulse voltage output section and the drive voltage output section are disposed in the same voltage output circuit.

5. The superconducting rotating machine according to claim 1 or 2, wherein, The pulse voltage output section and the drive voltage output section are located in different voltage output circuits.

6. The superconducting rotating machine according to claim 3, wherein, The pulse voltage output section and the drive voltage output section are disposed in the same voltage output circuit.

7. The superconducting rotating machine according to claim 3, wherein, The pulse voltage output section and the drive voltage output section are located in different voltage output circuits.

8. A superconducting rotating machine, comprising: A stator, which is used to generate a rotating magnetic field, has a cylindrical stator core and stator windings wound around the stator core; A superconducting rotor is maintained to be rotatable by the rotating magnetic field of the stator, and the superconducting rotor has a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, and the rotor core having multiple slots for receiving the rotor bars. A drive voltage output section applies a drive voltage to the stator windings to drive the superconducting rotor to rotate. The pulse voltage output section outputs a pulse voltage to change the superconducting cage winding from at least one of a magnetic shielding state and a magnetic flux trapping state to a magnetic flux flowing state. as well as The pulsed magnetic field output unit generates a pulsed magnetic field by means of a pulsed voltage output from the pulsed voltage output unit. The superconducting rotating machine can switch from induction rotation mode to synchronous rotation mode. The superconducting rotating machine applies a pulsed magnetic field output from the pulsed magnetic field output unit to the superconducting rotor, causing the superconducting cage winding to change from at least one of the magnetic shielding state and the magnetic flux trapping state to the magnetic flux flow state, thereby changing to the induction rotation mode.

9. The superconducting rotating machine according to claim 8, wherein, The pulse voltage output section and the drive voltage output section are disposed in the same voltage output circuit.

10. The superconducting rotating machine according to claim 8, wherein, The pulse voltage output section and the drive voltage output section are located in different voltage output circuits.

11. A control method for a superconducting rotating machine, The superconducting rotating machine comprises: a stator for generating a rotating magnetic field, having a cylindrical stator core and stator windings wound around the stator core; and a superconducting rotor, which is maintained to rotate by the rotating magnetic field of the stator, the superconducting rotor having a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, the rotor core having multiple slots for receiving the rotor bars, and the superconducting rotating machine being capable of switching from an induction rotation mode to a synchronous rotation mode. The control method includes the following steps: Apply a driving voltage to the stator windings to drive the superconducting rotor to rotate; and In order to change the superconducting cage winding from at least one of the magnetic shielding state and the magnetic flux trapping state to the magnetic flux flowing state, a pulse voltage is applied to the superconducting rotating machine and the pulse voltage is superimposed on the driving voltage, so that the superconducting cage winding changes from at least one of the magnetic shielding state and the magnetic flux trapping state to the magnetic flux flowing state, thereby changing the superconducting rotating machine into the induction rotation mode.

12. A control method for a superconducting rotating machine, The superconducting rotating machine comprises: a stator for generating a rotating magnetic field, having a cylindrical stator core and stator windings wound around the stator core; and a superconducting rotor, which is maintained to rotate by the rotating magnetic field of the stator, the superconducting rotor having a superconducting cage winding and a rotor core, the superconducting cage winding having end rings and one or more rotor bars formed of superconducting material, the rotor core having multiple slots for receiving the rotor bars, and the superconducting rotating machine being capable of switching from an induction rotation mode to a synchronous rotation mode. The control method includes the following steps: A driving voltage is applied to the stator windings to drive the superconducting rotor to rotate. In order to convert the superconducting cage winding from at least one of a magnetic shielding state and a magnetic flux trapping state to a magnetic flux flow state and output a pulse voltage, the pulse voltage is converted into a pulse magnetic field; and The pulsed magnetic field is applied to the superconducting rotor, causing the superconducting cage winding to change from at least one of the magnetic shielding state and the magnetic flux trapping state to the magnetic flux flow state, thereby causing the superconducting rotating machine to switch to induction rotation mode.

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