CN114070065A - Superconducting magnet periodic lifting magnetic circuit and control method thereof - Google Patents

Superconducting magnet periodic lifting magnetic circuit and control method thereof Download PDF

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Publication number
CN114070065A
CN114070065A CN202111505811.3A CN202111505811A CN114070065A CN 114070065 A CN114070065 A CN 114070065A CN 202111505811 A CN202111505811 A CN 202111505811A CN 114070065 A CN114070065 A CN 114070065A
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current
power supply
power
superconducting coil
capacitor
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CN202111505811.3A
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徐风雨
孙益
唐伟军
马仲英
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Jiangsu Jingkai Zhongke Superconduction High Technology Co ltd
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Jiangsu Jingkai Zhongke Superconduction High Technology Co ltd
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Priority to CN202111505811.3A priority Critical patent/CN114070065A/en
Publication of CN114070065A publication Critical patent/CN114070065A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/025—High gradient magnetic separators
    • B03C1/031—Component parts; Auxiliary operations
    • B03C1/033—Component parts; Auxiliary operations characterised by the magnetic circuit
    • B03C1/0335—Component parts; Auxiliary operations characterised by the magnetic circuit using coils
    • B03C1/0337—Component parts; Auxiliary operations characterised by the magnetic circuit using coils superconductive
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/006—Supplying energising or de-energising current; Flux pumps

Abstract

The invention discloses a superconducting magnet periodic lifting magnetic circuit and a control method thereof, wherein the superconducting magnet periodic lifting magnetic circuit comprises 2 power switches, 3 power diodes, 1 capacitor and 1 programmable direct current power supply, wherein the 2 power switches and the 2 power diodes form four bridge arms of an H-shaped circuit, a superconducting coil is positioned in the center of the H-shaped circuit, and the four bridge arms of the H-shaped circuit are arranged in a way that current can only flow through the superconducting coil in one direction; the capacitor is connected with the H-shaped circuit in parallel, and the direct-current power supply is connected with the 1 power diode in series to form a power supply branch circuit and then is also connected with the H-shaped circuit in parallel. The present invention is provided with: 1. energy is saved, after the current control enters a normal working time sequence, only a small part of energy consumed by the circuit is supplemented by a direct current power supply which takes electricity from a power grid, and therefore the magnetic separator is changed from high-energy-consumption equipment into energy-saving equipment; 2. the efficiency is high, the stability of the superconducting coil is considered, and the working efficiency of the magnetic separator is maximized; 3. reliable and free from the risk of simultaneous conduction of bridge arms on the same side.

Description

Superconducting magnet periodic lifting magnetic circuit and control method thereof
Technical Field
The invention belongs to the technical field of electric energy conversion, and particularly relates to a superconducting magnet periodic lifting magnetic circuit for an electromagnetic slurry magnetic separator and a control method thereof.
Background
The magnetic system is a key functional component of the electromagnetic slurry magnetic separator and consists of a coil, an iron armor and a magnetic pole. The basic principle of the electromagnetic slurry magnetic separator is as follows: loading current to the coil, filling the space where the magnetism gathering medium is located with a magnetic field corresponding to the current, and capturing magnetic ore particles by the magnetism gathering medium under the action of the magnetic field force; when the capture amount is close to saturation, the current of the coil is reduced to zero, the magnetic field force disappears, and the magnetic ore particles leave the magnetism gathering medium and the space under the washing of clear water, gas or the mixture of the clear water and the gas. The two processes are operated alternately, and continuous production of separating magnetic minerals from non-magnetic minerals is realized. It can be seen that the duration of the zero field and the specified field is determined by the manufacturing process and is necessary; the time spent on magnet lifting and magnet lowering is not necessary for the production process, and the time spent on magnet lifting and magnet lowering reduces the working efficiency of the magnetic separator.
Because of the zero resistivity and high upper limit of current density of superconducting conductors, superconducting coils have two obvious benefits over normally conducting coils: firstly, the magnetic field which is several times that of the magnetic field of the normally conducting coil can be provided for a long time in the space with the same volume; second, there is no power loss at all due to resistance. The former can be used for separating ore particles with weaker magnetism, and the application range of the magnetic separator is expanded; the latter has obvious energy saving advantages.
The energy in the normally conductive coil is divided into two parts, one part is stored in the inductance of the normally conductive coil in a magnetic energy mode, and the other part is dissipated on the resistance of the normally conductive coil in a joule heat mode. The former is useful energy for generating a magnetic field, and the proportion thereof determines the energy utilization efficiency of the magnetic separator. The current method for lifting the magnetic field with the highest energy utilization efficiency is as follows: the control circuit is enabled to work in a rectification mode and an inversion mode alternately by utilizing the power switch device, and further energy taking from a power grid and energy feeding to the power grid are achieved alternately. In order to save equipment cost, the normally conductive electromagnetic slurry magnetic separator often uses a simple rectification inverter circuit. The high frequency components resulting from simple inversion make the electrical energy fed back to the grid of low quality, even considered as pollution to the grid, and thus limited. The practical use of this control method is not ideal. Another more direct way to reduce the magnetic flux is to use an external resistor to convert the magnetic energy in the coil into heat energy. So that all the energy in the normally conductive coil is eventually totally consumed by the external resistor.
Magnetic energy density is proportional to the square of the magnetic field strength, and in order to generate a stronger magnetic field, the magnetic energy in a superconducting coil is usually much larger than that in a normally conductive coil. If the former lifting magnetic mode is adopted, the superconducting electromagnetic slurry magnetic separator consumes more energy than a normal-conductivity electromagnetic slurry magnetic separator.
Disclosure of Invention
The invention aims to provide a superconducting magnet periodic lifting magnetic circuit and a control method thereof, which enable a superconducting magnetic slurry magnetic separator to work in a zero magnetic field and a specified magnetic field alternately, and simultaneously give play to the advantage of no resistive power loss of a superconducting coil, thereby achieving the purposes of energy conservation and no pollution to a power grid.
The invention is realized by the following technical scheme:
the superconducting magnet periodic lifting magnetic circuit comprises 2 power switches, 3 power diodes, 1 capacitor and 1 programmable direct-current power supply, wherein the 2 power switches and the 2 power diodes form four bridge arms of an H-shaped circuit, a superconducting coil is positioned in the center of the H-shaped circuit, and the four bridge arms of the H-shaped circuit are arranged in a mode that current can only flow through the superconducting coil in one direction; the capacitor is connected with the H-shaped circuit in parallel, and the direct-current power supply is connected with the 1 power diode in series to form a power supply branch circuit and then is also connected with the H-shaped circuit in parallel.
Preferably, the power switch is of the fully-controlled type, since the ability to cut off large currents is required during the boosting process.
Preferably, the dc power supply allows automatic switching between two modes of operation, a current source and a voltage source, the anode of the power diode in the power branch being connected to the positive pole of the dc power supply.
The circuit formed by connecting the capacitor and the H-shaped circuit in parallel in the circuit is also used for a superconducting energy storage system in the power industry, and the essential difference of the superconducting energy storage system is that the effect of the capacitor is different from that of the superconducting energy storage system in the power industry. In a superconducting energy storage system, a superconducting coil is the only energy storage element, and when energy flows between a power grid and the superconducting coil, a capacitor is needed to stabilize the fluctuation of direct current voltage, so that the function of filtering is exerted. The capacitor and the superconducting coil are energy storage elements and have approximately the same energy storage capacity. When the magnetic separator requires the superconducting coil to operate in a zero magnetic field, energy is transferred to a capacitor for temporary storage; when the magnetic separator requires the superconducting coils to operate in a specified magnetic field, the energy is transferred to the superconducting coils again. This results in two distinct parameter design methods and control methods.
The invention also provides a control method of the superconducting magnet periodic lifting magnetic circuit, which comprises the following processes: when the capacitor voltage is lower than the preset voltage of the direct-current power supply, the power diode of the power supply branch is conducted, the two power switches of the side bridge arm are controlled to be conducted by the H-shaped circuit, and the direct-current power supply works in a current source mode and is a superconducting coil boosting or maintaining magnetic field; when the capacitor voltage is greater than the preset voltage of the direct current power supply, the power supply branch power diode is cut off, the power supply branch current is reduced to zero, the power supply works in a voltage source mode, and the capacitor is used for superconducting coil excitation. Under the initial state that the capacitor voltage is zero and the current of the superconducting coil is zero, controlling the H-shaped circuit to conduct two power switches of the opposite side bridge arm, and loading current for the superconducting coil by a direct-current power supply for excitation; the following three control logics are sequentially executed in a cycle after that:
when the appointed magnetic field reaches the appointed duration time, the H-shaped circuit is controlled to turn off the two power switches of the opposite bridge arm, the current of the superconducting coil cannot change suddenly, the power diodes of the other two bridge arms are turned on, the superconducting coil charges the capacitor, most of the magnetic energy in the superconducting coil is converted into the electric field energy in the capacitor, and a small part of the magnetic energy is consumed in the switching device and the connecting circuit;
when the capacitor voltage reaches the vicinity of the maximum value or the superconducting coil current is reduced to be close to zero, the control logic II controls one power switch of the H-shaped circuit to be conducted, so that the superconducting coil current is reliably reduced to zero; in order to fully absorb the energy from the superconducting coil, the maximum value of the capacitor voltage is far higher than the preset voltage of the direct current power supply;
when the zero magnetic field reaches a specified duration, controlling the two power switches of the bridge arm on the opposite side of the H-shaped circuit to be conducted, and when the capacitor voltage is higher than the direct-current power supply voltage, discharging to the superconducting coil from the capacitor; when the voltage of the capacitor is lower than the voltage of the direct-current power supply, the power diode in the power supply branch is conducted, and the direct-current power supply continues to provide current for the superconducting coil until the current reaches a preset current value and simultaneously reaches a specified magnetic field.
Preferably, the exciting and demagnetizing time of the superconducting coil is 10 seconds or more, and the specified voltage of the capacitor is less than 1 kilovolt.
Preferably, the second control logic is preferably connected with a power switch of a bridge arm connected with the negative electrode of the direct-current power supply and is switched on.
The invention has the beneficial effects that:
the superconducting magnet periodic lifting magnetic circuit has the advantages of ingenious structure and strong practicability, and particularly has the following advantages:
1. energy is saved. After the current control enters a normal working sequence (such as the control logic one to the control logic three), most energy is converted between the superconducting coil and the capacitor, and a small part of energy is lost in the circuit. The direct current power supply for taking electricity from the power grid only needs to supplement the small part of energy, so that the magnetic separator is changed from high-energy-consumption equipment into energy-saving equipment.
2. High efficiency. The magnetic rising time and the magnetic falling time of the coil can be adjusted by selecting different capacitance capacities and the highest charging voltage, and therefore the working efficiency of the magnetic separator is maximized while the stability of the superconducting coil is considered.
3. And (4) reliability. The circuit adopts a mode of combining active control (by utilizing a fully-controlled power switch device) with passive control (by utilizing a power diode), so that the risk of simultaneous conduction of bridge arms on the same side is ensured in principle, and the power switch device has smaller voltage rise rate all the time when being switched between a conduction state and a disconnection state, thereby ensuring the long-term reliability of the superconducting coil and the control circuit.
Drawings
For ease of illustration, the invention is described in detail by the following specific examples and figures.
FIG. 1 is a schematic diagram of a lifting magnetic circuit of a superconducting electromagnetic slurry magnetic separator;
FIG. 2 illustrates the path and direction of current flow in the circuit during initial excitation;
FIG. 3 illustrates the current path and flow direction in the circuit during the process of the superconducting coil demagnetizing the capacitor;
FIG. 4a shows the current path and flow direction in the superconducting coil rapid demagnetization process circuit under the condition of the lower bridge arm power switch being turned on;
FIG. 4b shows the path and flow direction of current in the superconducting coil during the rapid demagnetization process under the conduction condition of the upper bridge arm power switch;
FIG. 5 shows the path and flow direction of current in the circuit during the process of exciting the coil by the capacitor;
FIG. 6 shows the path and flow direction of current in the circuit during the process of exciting the coil by the DC power supply;
FIG. 7 is a typical current curve for a coil of a superconducting magnetic slurry magnetic separator.
Detailed Description
As shown in fig. 1, the superconducting magnet periodic lifting magnetic circuit includes 2 power switches, 3 power diodes, 1 capacitor, and 1 programmable dc power supply, wherein the 2 power switches and 2 power diodes form four arms of an H-type circuit, a superconducting coil is located in the center of the H-type circuit, and the four arms of the H-type circuit are arranged in such a manner that a current can only flow through the superconducting coil in one direction; the capacitor is connected with the H-shaped circuit in parallel, and the direct-current power supply is connected with the 1 power diode in series to form a power supply branch circuit and then is also connected with the H-shaped circuit in parallel.
Because of the ability of cutting off large current in the process of reducing magnetism, the power switch selects a fully-controlled type.
The direct current power supply allows automatic switching between two working modes of a current source and a voltage source, and the anode of a power diode in a power supply branch is connected with the anode of the direct current power supply.
The circuit formed by connecting the capacitor and the H-shaped circuit in parallel in the circuit is also used for a superconducting energy storage system in the power industry, and the essential difference of the superconducting energy storage system is that the effect of the capacitor is different from that of the superconducting energy storage system in the power industry. In a superconducting energy storage system, a superconducting coil is the only energy storage element, and when energy flows between a power grid and the superconducting coil, a capacitor is needed to stabilize the fluctuation of direct current voltage, so that the function of filtering is exerted. The capacitor and the superconducting coil are energy storage elements and have approximately the same energy storage capacity. When the magnetic separator requires the superconducting coil to operate in a zero magnetic field, energy is transferred to a capacitor for temporary storage; when the magnetic separator requires the superconducting coils to operate in a specified magnetic field, the energy is transferred to the superconducting coils again. This results in two distinct parameter design methods and control methods.
The invention also provides a control method of the superconducting magnet periodic lifting magnetic circuit, which comprises the following processes: when the capacitor voltage is lower than the preset voltage of the direct-current power supply, the power diode of the power supply branch is conducted, the two power switches of the side bridge arm are controlled to be conducted by the H-shaped circuit, and the direct-current power supply works in a current source mode and is a superconducting coil boosting or maintaining magnetic field; when the capacitor voltage is greater than the preset voltage of the direct-current power supply, the power supply branch power diode is cut off, the current of the power supply branch is reduced to zero, and the power supply works in a voltage source mode; under the initial state that the capacitor voltage is zero and the current of the superconducting coil is zero, controlling the H-shaped circuit to conduct two power switches of the opposite side bridge arm, and loading current for the superconducting coil by a direct-current power supply for excitation; the following three control logics are sequentially executed in a cycle after that:
when the appointed magnetic field reaches the appointed duration time, controlling the H-shaped circuit to turn off two power switches of the opposite side bridge arm, and because the current of the superconducting coil cannot be suddenly changed, the power diodes of the other two bridge arms are turned on, the superconducting coil charges the capacitor, and most of the magnetic energy in the superconducting coil is converted into the electric field energy in the capacitor;
when the capacitor voltage reaches the vicinity of the maximum value or the superconducting coil current is reduced to be close to zero, the control logic II controls one power switch of the H-shaped circuit to be conducted, so that the superconducting coil current is reliably reduced to zero; in order to fully absorb the energy from the superconducting coil, the maximum value of the capacitor voltage is far higher than the preset voltage of the direct current power supply;
when the zero magnetic field reaches a specified duration, controlling the H-shaped circuit to conduct two power switches of the opposite side bridge arm, and when the capacitor voltage is higher than the direct-current power supply voltage, discharging to the superconducting coil from the capacitor; when the voltage of the capacitor is lower than the voltage of the direct-current power supply, the power diode in the power supply branch is conducted, and the direct-current power supply continues to provide current for the superconducting coil until the current reaches a preset current value and simultaneously reaches a specified magnetic field.
Generally, within the safety allowable range of equipment, the excitation and demagnetization time of the superconducting coil is more than 10 seconds, and the specified voltage of the capacitor is less than 1 kilovolt.
And the second control logic is preferably conducted with a power switch of a bridge arm connected with the negative electrode of the direct-current power supply.
Examples
Referring to the attached figure 1, the lifting magnetic circuit of the superconducting electromagnetic slurry magnetic separator comprises 2 fully-controlled power switches, 3 power diodes, 1 energy storage capacitor and 1 programmable direct current power supply. And 2 power switches and 2 power diodes form four bridge arms of the H-type circuit. The power switching device is of the fully controlled type, preferably an IGBT, represented in the figures by the IGBT circuit symbol. R1 and R2 represent the resistance of all cables and joints in the electrical connection between the two leads of the superconducting coil and the points c and d of the circuit, respectively.
For a better understanding of the present invention and to distinguish it from the prior art, the operating mode of the circuit is divided into 7 different states in the embodiment shown in fig. 1, of which 5 states are shown in fig. 2 to 6, respectively. The flow path and direction of the current are the key criteria for distinguishing these states. The following states are described in conjunction with fig. 2-6 as follows:
state 1: referring to fig. 2, the current of the inductor L (i.e., the superconducting coil) and the voltage of the capacitor C in the circuit are zero at the initial time. The power switching elements Q1 and Q2 are controlled to be conducted, the power diodes D1 and D2 are cut off due to the fact that reverse voltage is borne, and the direct-current power supply PS takes power from the power grid to respectively excite the superconducting coil L to a specified current and charge the capacitor to be close to the power supply voltage.
State 2: the power switching elements Q1 and Q2 are kept turned on, and the direct-current power supply PS continuously supplies a current of a prescribed magnitude to the superconducting coil. At the moment, the magnetic separator works in a specified magnetic field approximately proportional to specified current, and magnetic ore particles in the ore pulp are adsorbed in the space of the magnetic medium.
State 3: referring to fig. 3, when the designated magnetic field is continued for a designated time, the power switching elements Q1 and Q2 are controlled to be turned off. The current in the superconducting coil cannot change immediately, the power diodes D1 and D2 are forced to conduct, the superconducting coil charges the energy storage capacitor, and the current continuously decays. The rate of current decay will be continuously reduced depending on the characteristics of the lc series circuit.
State 4-1: referring to fig. 4a, when the coil current decays to a small amount, controlling the power switching element Q2 to conduct, the coil current will decay rapidly to zero. The current and voltage of the capacitor branch between the points a and b, the current of the coil branch between the points c and d, and the voltage between any two points in the circuit can be used as control signals for triggering the conduction of the Q2.
State 4-2: equivalent to state 4-1, controlling the power switching element Q1 conductive also enables the coil current to decay rapidly to zero, see fig. 4 b.
And state 5: keeping the power switching element Q1 or Q2 on and the other off, the coil current remains zero. At the moment, the magnetic separator works in a zero magnetic field, and magnetic ore particles losing the action of magnetic field force are carried by gas, liquid or gas-liquid mixed fluid and discharged out of the space of the magnetic medium.
And 6: referring to fig. 5, the power switching elements Q1 and Q2 are controlled to be turned on when the zero magnetic field lasts for a designated time. Since the voltage of the energy storage capacitor is much higher than the voltage of the direct current power supply, the power diode D3 is cut off, and the power diodes D1 and D2 are cut off due to the reverse voltage. The energy storage capacitor is excited by the superconducting coil.
And state 7: referring to fig. 6, the power switching elements Q1 and Q2 are kept turned on, and when the voltage of the storage capacitor is lower than the voltage of the dc power supply, the power diode D3 is turned on, and the superconducting coil continues to be excited by the dc power supply.
The above 7 states are switched from 1 to 7 in sequence, and the cycle is repeated.
The designation in the above text refers to designation by the beneficiation process.
Referring to FIG. 7, along the time axis (horizontal axis)The arranged Arabic numerals correspond to the 7 states one by one, and the adjacent states are separated by a dot-dash line, delta I1Indicating a small amount of current, I, in either the state 4-1 or state 4-2 transition conditionsopAnd the current value reached by the energy storage capacitor when the coil is excited is shown. Delta I2The current increment for the coil excitation by the dc power supply to replenish the lost energy is shown. As can be seen, the duration of state 7 should be greater than the time for the DC power supply to supplement the current increment to the coil, and IopThe corresponding magnetic field strength should be equal to or greater than a specified value. From state 3, the separator enters a normal duty cycle, where state 5 corresponds to a zero field and state 7 corresponds to a field above a specified value.
Referring to fig. 1, it is within the scope of the present patent to perform series-parallel processing on a branch between any two nodes in a circuit, but the equivalent result is not to change the modification of the function of the branch. For example using a series or parallel connection of several capacitors instead of a capacitive branch.
Referring to fig. 1, it is still within the scope of the present disclosure to connect the power switching elements in parallel with the reverse power diodes, to configure the snubber circuit, and not to change the on and off functions of the elements.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that are not thought of through the inventive work should be included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.

Claims (5)

1. The superconducting magnet periodic lifting magnetic circuit is characterized by comprising 2 power switches, 3 power diodes, 1 capacitor and 1 programmable direct-current power supply, wherein the 2 power switches and the 2 power diodes form four bridge arms of an H-shaped circuit, a superconducting coil is positioned in the center of the H-shaped circuit, and the four bridge arms of the H-shaped circuit are arranged in a mode that current can only flow through the superconducting coil in one direction; the capacitor is connected with the H-shaped circuit in parallel, and the direct-current power supply is connected with the 1 power diode in series to form a power supply branch circuit and then is also connected with the H-shaped circuit in parallel.
2. The superconducting magnet cycling step-up and step-down magnetic circuit of claim 1, wherein the power switch is a fully controlled power switch.
3. The superconducting magnet cycling and ramping magnetic circuit according to claim 1, wherein the dc power supply is a dc power supply that allows automatic switching between two modes of operation, a current source and a voltage source, and wherein the anode of the power diode in the power branch is connected to the anode of the dc power supply.
4. The method for controlling a superconducting magnet cyclic lift magnetic circuit according to any one of claims 1-3, characterized by comprising the following processes: when the capacitor voltage is lower than the preset voltage of the direct-current power supply, the power diode of the power supply branch is conducted, the two power switches of the side bridge arm are controlled to be conducted by the H-shaped circuit, and the direct-current power supply works in a current source mode and is a superconducting coil boosting or maintaining magnetic field; when the capacitor voltage is greater than the preset voltage of the direct-current power supply, the power supply branch power diode is cut off, the power supply branch current is reduced to zero, the power supply works in a voltage source mode, and the capacitor is used for superconducting coil excitation; under the initial state that the capacitor voltage is zero and the current of the superconducting coil is zero, controlling the H-shaped circuit to conduct two power switches of the opposite side bridge arm, and loading current for the superconducting coil by a direct-current power supply for excitation; the following three control logics are sequentially executed in a cycle after that:
when the appointed magnetic field reaches the appointed duration time, controlling the H-shaped circuit to turn off two power switches of the opposite side bridge arm, and because the current of the superconducting coil cannot be suddenly changed, the power diodes of the other two bridge arms are turned on, the superconducting coil charges the capacitor, and most of the magnetic energy in the superconducting coil is converted into the electric field energy in the capacitor;
when the capacitor voltage reaches the vicinity of the maximum value or the superconducting coil current is reduced to be close to zero, the control logic II controls one power switch of the H-shaped circuit to be conducted, so that the superconducting coil current is reliably reduced to zero;
when the zero magnetic field reaches a specified duration, controlling the H-shaped circuit to conduct two power switches of the opposite side bridge arm, and when the capacitor voltage is higher than the direct-current power supply voltage, discharging to the superconducting coil from the capacitor; when the voltage of the capacitor is lower than the voltage of the direct-current power supply, the power diode in the power supply branch is conducted, and the direct-current power supply continues to provide current for the superconducting coil until the current reaches a preset current value and simultaneously reaches a specified magnetic field.
5. The method for controlling the superconducting magnet periodic lifting and descending magnetic circuit according to claim 4, wherein the second control logic is preferably a power switch of a bridge arm connected with the negative pole of the direct current power supply to be conducted.
CN202111505811.3A 2021-12-10 2021-12-10 Superconducting magnet periodic lifting magnetic circuit and control method thereof Pending CN114070065A (en)

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CN202111505811.3A CN114070065A (en) 2021-12-10 2021-12-10 Superconducting magnet periodic lifting magnetic circuit and control method thereof

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4695932A (en) * 1985-05-15 1987-09-22 Mitsubishi Denki Kabushiki Kaisha Superconductive energy storage circuit
CN201616765U (en) * 2009-12-21 2010-10-27 中国电力科学研究院 DSP-based power conversion device for high-temperature superconductive energy-storage system
CN103546057A (en) * 2013-10-12 2014-01-29 华中科技大学 High-voltage large-power repetition pulse power supply
CN109980743A (en) * 2019-04-16 2019-07-05 中国人民解放军国防科技大学 Pre-polarizing coil current control system and control method for low-field nuclear magnetic resonance

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4695932A (en) * 1985-05-15 1987-09-22 Mitsubishi Denki Kabushiki Kaisha Superconductive energy storage circuit
CN201616765U (en) * 2009-12-21 2010-10-27 中国电力科学研究院 DSP-based power conversion device for high-temperature superconductive energy-storage system
CN103546057A (en) * 2013-10-12 2014-01-29 华中科技大学 High-voltage large-power repetition pulse power supply
CN109980743A (en) * 2019-04-16 2019-07-05 中国人民解放军国防科技大学 Pre-polarizing coil current control system and control method for low-field nuclear magnetic resonance

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