Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K55/00—Dynamo-electric machines having windings operating at cryogenic temperatures
  • H02K55/02—Dynamo-electric machines having windings operating at cryogenic temperatures of the synchronous type
  • H02K55/04—Dynamo-electric machines having windings operating at cryogenic temperatures of the synchronous type with rotating field windings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
  • Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment

Definitions

• the invention relates to a device for supplying at least one superconductor, in particular at least one superconducting winding, which is or can be cooled or cooled to at least one predetermined temperature in order to achieve superconductivity.
• a superconducting rotor is known with a superconducting winding, which can be used as an armature coil in an electric motor.
• the superconducting winding is cooled by a cooling system to a temperature so low that it becomes superconducting.
• a high-temperature superconducting material (HTSL material) is preferably used here, which becomes superconducting even at transition temperatures above 35 K.
• the coil can be cooled by means of a cooling system in which the cooling is carried out using the Gifford-McMahon cycle or the Stirling cycle.
• the superconducting coil is supplied with an alternating current via slip rings.
• this is disadvantageous in view of the life of the motor due to wear of the brushes.
• a power supply that is only cooled by heat conduction introduces at least 45 W / kA into the cooled area at a temperature of 20 to 40 K.
• the higher the heat loss through the power supply the higher the operating temperature. ture of the coil, so that the critical current of the superconductor drops and thus the achievable field strength of the coil. Economical operation and efficient power supply are therefore only possible to a limited extent in the motor known from US Pat. No. 5,482,919.
• the invention is based on the object of specifying a device for supplying at least one superconductor, in particular at least one superconducting winding, with electrical energy which can be operated as efficiently and economically as possible.
• the heat input via the power supply should be as small as possible, so that there is no fear of a loss of superconductivity and therefore no corresponding reduction in the field strength in the winding or coil in the case of a superconducting winding.
• the device according to claim 1 for supplying at least one superconductor, in particular at least one superconducting winding, which can be cooled or cooled to at least a predetermined temperature at which the superconductivity occurs, with a) at least one electrical energy source, b) a transformer for transmitting the electrical energy between the energy source and the superconductor, a primary winding of the transformer being electrically connected or coupled to the energy source and a secondary winding of the transformer being electrically connected or coupled to the superconductor.
• the invention is based on the consideration of using at least one transformer for transmitting the energy between the electrical energy source and the superconductor.
• Transformer enables contactless transmission of electrical energy from the energy source to the superconductor, so that in the case of a rotating winding, for example a rotor coil of an electric motor, there is no need for wearing brushes.
• the heat input to the cooled superconductor can be significantly reduced with the help of the transformer.
• a suitably chosen transformation ratio (voltage transformation ratio) of the transformer namely, in an advantageous embodiment, the voltage supplied by the energy source can be stepped up, so that a lower current from the transformer to the cooled superconductor is necessary for the same electrical supply power.
• the cross section of the current supply between the transformer and the superconductor can be reduced.
• This use of a thinner power supply significantly reduces the heat input through the power supply.
• This embodiment is particularly advantageous when the primary winding and secondary winding of the transformer are at a warm level, that is to say outside the cooled area with the superconductor, and the transition from the warm area to the cooled or cold area takes place through the power supply.
• the primary winding connected to the energy source is at a warm level and the secondary winding of the transformer connected to the superconductor is at a cold level. Since the power supply can now also run completely within the cold area, it no longer contributes to heat transfer to the superconductor. The thermal insulation now takes place between the two contactless windings of the transformer.
• the transformation ratio can be set practically arbitrarily here and in particular can also be 1.
• the transmission of the electrical energy into the superconductor or the superconducting winding is thus carried out free, so there is no fear of wear.
• the choice of a transformer as a means of introducing electrical energy into the superconductor also ensures that the heat input into the cooled area remains low, so that the efficiency of the superconductivity is maintained.
• the device is constructed as compactly as possible or can be built up in order to be able to achieve a high power density with which a re-excitation of a rotor coil is possible under changing operating conditions.
• the primary winding and the secondary winding of the transformer can be arranged axially next to one another.
• a radial positioning of the primary and secondary coils is also possible.
• the primary winding and the secondary winding of the transformer can be arranged axially next to one another.
• Secondary winding of the transformer can be arranged on, on or in a common magnetic flux guide body or also on, on or in a respective associated magnetic flux guide body.
• the primary winding of the transformer can also be arranged in a recess of the secondary winding, as it is also possible, conversely, to arrange the secondary winding in a recess of the primary winding.
• the primary winding and the secondary winding of the transformer are spaced apart by an air gap.
• the spacing between the two windings is preferably carried out by a layer or wall made of electrically non-conductive (dielectric), electrically insulating, in particular also thermally poorly conductive (heat-insulating) material, in particular glass fiber plastic.
• This wall can in particular be the container wall of a cryogenic loading be holder, inside which the superconductor is arranged.
• the transformer generally converts an AC voltage from the energy source applied to its primary winding into an AC voltage in the secondary winding.
• the AC voltage in the secondary winding of the transformer is smaller in magnitude (in terms of amplitude) than the AC voltage in the primary winding of the transformer. In an alternative, preferred embodiment, the AC voltage in the secondary winding of the transformer is greater in magnitude than the AC voltage in the primary winding of the transformer.
• a second transformer is arranged between the transformer and the superconducting armature coil. It is particularly advantageous if both the primary winding and the secondary winding of the transformer are outside the cooled one
• the second transformer is preferably arranged within the cooled area.
• the second transformer transforms an AC voltage on its primary winding, which is connected to the secondary winding of the first transformer, into an AC voltage provided on its secondary winding for the superconductor.
• This AC voltage applied to the secondary winding of the second transformer is preferably smaller in magnitude than the AC voltage at the primary winding of the second transformer, in particular in order to transform the high-transformed voltage of the first transformer back down for the superconductor.
• the AC voltage applied to the secondary winding of the second transformer can, however, also be greater in amount than the AC voltage on the primary winding of the second transformer, if necessary.
• At least one rectifier can furthermore be arranged between the transformer and superconductor or coil or between the second transformer and superconductor or coil, wherein in particular a circuit with at least one MOSFET switch is intended; the rectifier can be controlled telemetrically.
• the frequencies of the transformer voltages can be selected within wide limits.
• the efficiency of the motor is maximized in particular by the fact that the transformer and / or the second transformer are operated at high frequency.
• the at least one superconductor is rotated or rotatable, in particular in an electric motor as a rotor coil.
• the primary winding of the transformer is then preferably fixed relative to the superconductor and the secondary winding of the transformer can be rotated or rotated with the superconductor.
• FIG. 1 shows a section through a synchronous motor with a superconducting armature coil according to a first embodiment
• FIG. 2 shows another embodiment of the motor according to FIG. 1,
• FIG. 3 shows a further alternative embodiment to FIG. 1 or FIG. 2,
• FIGS. 1, 2 and 3 and 5 shows the course of the current strength in the rotor coil over time.
• FIG. 1 schematically shows an electric motor 1 which contains a superconducting armature coil (winding) 2.
• the rotor coil 2 must be cooled so that superconductivity can occur in it.
• the electric motor 1 has a cooled area 9, which is indicated by dash-dotted lines in FIG. 1 and lies within a cryocontainer 13.
• a cooling device is used, which uses the Gifford-McMahon cycle or the Stirling cycle, for example.
• the armature coil 2 consists of high-temperature superconducting material (HTSL material), so that superconducting already occurs at step temperatures above 35 K.
• HTSL material high-temperature superconducting material
• the rotor coil 2 is fed by an electrical energy source 3, which is provided in particular in a fixed power supply unit 15.
• a first transformer 4 is provided for the transmission of the electrical energy.
• This has a primary winding 5 which axially adjoins a secondary winding 6, an air gap 7 being present between the two windings 5, 6. While the primary winding 5 is arranged in a stationary manner, the secondary winding 6 is arranged rotatably, wherein it is firmly connected to the rotor 13, which is only schematically outlined, and which is mounted by means of the shaft 14 in bearings, not shown.
• the primary winding 5 of the transformer 4 is electrically connected to the energy source 3.
• the energy source 3 generates an alternating voltage U1, that is to say a voltage which changes over time and in particular alternates in polarity and which is applied to the primary winding 5 of the transformer 4.
• the AC voltage U1 is inductively transformed into the secondary winding 6 of the transformer 4 via the air gap 7.
• the transformed output voltage of the secondary winding is also an AC voltage and is designated U2. While the frequency of the alternating voltage U2 generally coincides with the frequency of the original alternating voltage Ul, the ratio U2 / U1 of the two alternating voltages U2 and Ul, the so-called transformation or voltage transformation ratio, can be chosen, in particular, by appropriate choice of the primary winding 5 and the secondary winding 6 whose number of turns are set.
• both windings 5 and 6 of the first transformer 4 are located outside the cooled area 9, that is to say essentially at the ambient temperature Tu.
• a second transformer 8 is connected to the first transformer 4 and in particular to its secondary winding 6.
• the second transformer 8 is arranged in the cooled area 9, in which the superconducting temperature T s prevails.
• the primary winding 80 of the second transformer 8 is electrically connected to the secondary winding 6 of the first transformer 4 via a power line (power supply) 68.
• the secondary winding 81 of the transformer 8 is electrically connected to the armature coil 2, in FIG. 1 in a center tap.
• the supply voltage generated at the secondary coil 81 of the second transformer 8 is again an AC voltage and is designated U3.
• the AC voltage U 1 supplied by the power supply unit 15 is transformed up into a by the transformer 4 significantly higher voltage U2.
• the transformation ratio can be at least 2, in particular at least 5, or can be above 10.
• the higher voltage U2 allows the current in the power line 68 can be reduced with the same electrical power to be transmitted, so that the cross section of the power line 68 can be significantly reduced without increasing the power loss due to the increase in resistance caused thereby.
• Both transformers 4 and 8 operate in high frequency mode.
• the operating frequency (s) is typically in the range between 100 Hz and 1 MHz, but may or may also be below or above.
• Both transformers 4 and 8 each have a transformation ratio that can be freely selected within wide limits.
• the energy from the electrical energy source 3 is preferably conducted "from the cold" by the first transformer 4 at a higher voltage U2 and a smaller current via the electrical connection, the power line 68 to the second transformer 8.
• the electrical energy is transformed to a low voltage U3 and a high current.
• the current in the circuit of the superconductor 2 can thus be brought to the required size via the second transformer 8 by transforming the voltage U2 down to the lower voltage U3.
• the cooled area 9 that is to say at a cryogenic temperature, only slight thermal losses occur.
• the air gap 7 thus runs in the form of a hollow cylinder. Otherwise, the construction of the electric motor 1 essentially corresponds to that according to FIG. 1.
• FIG 3 shows an electric motor 1 in which the primary winding 5 of the transformer 4 is arranged in an annular recess 11 of a common magnetic flux body (yoke) 65 for primary winding 5 and secondary winding 6.
• the flux-leading yoke 65 of the transformer 4 consists of layered iron sheets (transformer sheets) made of ferrite in order to avoid eddy currents.
• transformer sheets layered iron sheets
• the fixed primary winding 5 of the transformer 4 is “in the warm”, that is to say essentially at the level of the ambient temperature Tu.
• the secondary winding 6 that is also rotating is arranged “in the cold”, that is to say at the superconducting temperature T s .
• the gap between the two windings 5, 6 is a
• Wall 12 filled out of non-conductive material.
• glass fiber reinforced plastic is used here. The fact that this may result in a greater distance between the windings 5, 6 than in the solutions according to FIGS. 1, 2 and 3 is not problematic in the case of high-frequency transformer operation.
• the wall 12 is here part of the wall of the cryocontainer 13.
• a high power transmission is necessary for the rapid charging of the coil 2 (charging phase 18, MOSFET in charging circuit).
• the gate supply of the rectifier bridge in the charging circuit is synchronized and high energy transfer is ensured with high voltage and / or high frequency of the power supply.
• MOSFETs metal-oxide-semiconductor field-effect transistors
• the advantage of using MOSFETs is that high voltages and frequencies can be realized, so that they can be quickly adapted to changing operating conditions.
• Protective diodes can be used to protect the windings in the event of incorrect synchronization.
• the coil is therefore discharged according to the transformer-rectifier principle with cold MOSFET switches.
• the motor can be operated without wear because brushes can be dispensed with. There is still a very compact overall construction and thus a high power density of the motor. Finally, the heat introduced into the cooled area by the introduction of energy is minimal, so that the superconducting effect can be used efficiently.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Superconductive Dynamoelectric Machines (AREA)

Applications Claiming Priority (3)

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• 2001
  • 2001-11-15 DE DE10156212A patent/DE10156212A1/de not_active Ceased
• 2002
  • 2002-10-31 WO PCT/DE2002/004071 patent/WO2003047077A1/de active Application Filing
  • 2002-10-31 JP JP2003548381A patent/JP4309274B2/ja not_active Expired - Fee Related
  • 2002-10-31 EP EP02791595A patent/EP1454404A1/de not_active Ceased
  • 2002-10-31 KR KR1020047007373A patent/KR100991301B1/ko not_active IP Right Cessation
• 2004
  • 2004-05-14 US US10/846,361 patent/US20040256922A1/en not_active Abandoned
• 2006
  • 2006-06-09 US US11/423,186 patent/US7355307B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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