Demagnetization power supply based on superconducting energy storage

Abstract

The application relates to a demagnetization power supply based on superconducting energy storage. A superconducting charging power unit converts three-phase alternating current into direct current output, charges a superconducting coil L1, and stores three-phase alternating current energy in the superconducting coil in the form of magnetism. The superconducting coil supplies power to a demagnetization coil through a superconducting discharging power unit. A superconducting discharging power unit is designed, and closed-loop control provides a demagnetization pulse sequence with controllable size and adjustable positive and negative for the demagnetization coil. The superconducting energy storage with high power density provides pulse power for demagnetization operation, reduces the impact of pulse power on the power grid, reduces the required power distribution capacity, and enables the demagnetization device to be constructed in a weak power grid area to provide an effective solution.

Description

Technical Field

[0001] This invention relates to a demagnetizing power supply technology, and more particularly to a demagnetizing power supply based on superconducting energy storage. Background Technology

[0002] A demagnetizing power supply is used in a demagnetizing device to provide a pulsed demagnetizing current to the demagnetizing coil. The demagnetizing power supply provides the demagnetizing coil with... Figure 1 The operating current shown is used to generate the operating magnetic field required for comprehensive magnetic processing.

[0003] like Figure 1 The diagram shows the demagnetizing current. The magnetic processing current output by the demagnetizing power supply is an intermittent pulse current sequence with a sufficiently large initial pulse amplitude, alternating between positive and negative pulses, and gradually decreasing amplitude. Its initial pulse power is very high (MW level for a single channel, and nearly 100MW for multiple channels), but the average power is not high (approximately 200kW for a single channel). The pulse power characteristics are significant. To reduce the capacity requirements on the power supply side and the impact and pollution caused by the pulse power, an energy storage demagnetizing power supply with an energy storage component is required. Compared to general pulse power supplies, because the magnetic processing current pulse duration is long (around 10s) and output in the form of a pulse sequence, the instantaneous power is high, and the energy output during the pulse time of the demagnetizing power supply is much greater than that of a general pulse power supply. This places high demands on the power and energy storage capacity of the energy storage component, making energy storage a bottleneck problem that urgently needs to be solved for demagnetizing power supplies.

[0004] In China, three energy storage methods have been adopted: conventional flywheel energy storage, supercapacitor energy storage, and lithium iron phosphate battery energy storage, which have greatly optimized the performance of demagnetizing power supplies. However, conventional flywheel energy storage has low energy density, low stored energy, and low energy utilization; supercapacitor energy storage has low energy density, large size, high price, and a lifespan generally not exceeding 15 years; and lithium iron phosphate battery energy storage has low safety and reliability, and a lifespan generally not exceeding 10 years. In recent years, superconducting energy storage, which has developed rapidly, has outstanding advantages such as high energy density, high power density, fast response speed, and long lifespan, providing a solution to the bottleneck problem of demagnetizing power supply energy storage. Summary of the Invention

[0005] To address the energy storage problem of demagnetizing power supplies, a demagnetizing power supply based on superconducting energy storage is proposed. This provides an intermittent pulse current sequence for the demagnetizing coil, while reducing the impact on the power grid, reducing the required power distribution capacity, and enabling the demagnetizing device to be built in areas with weak power grids.

[0006] The technical solution of the present invention is: a demagnetizing power supply based on superconducting energy storage, comprising a three-phase AC power supply, a superconducting charging power unit, a superconducting coil L1, a superconducting discharging power unit, a monitoring and protection unit, a cryogenic cooling unit, a quench detection and protection unit, a charging switch Q1, and a self-holding continuous current diode D1;

[0007] The three-phase AC power output AC power is converted into DC power output by the superconducting charging power unit. The positive output of the superconducting charging power unit is connected to the cathode of the self-holding current diode D1 and one end of the superconducting coil L1 through the charging switch Q1, and the anode of the self-holding current diode D1 is connected to the negative output of the superconducting charging power unit.

[0008] The other end of the superconducting coil L1 away from the charging switch Q1 is connected to the positive input of the superconducting discharge power unit, the negative input of the superconducting discharge power unit is connected to the negative output of the superconducting charging power unit, and the output of the superconducting discharge power unit is connected to the field coil.

[0009] The quench detection and protection unit performs real-time quench detection on the superconducting coil L1, sends state signals to the monitoring and protection unit, receives control signals from the monitoring and protection unit, and protects the superconducting coil L1 in response to the control signals.

[0010] The low-temperature refrigeration unit provides refrigeration for the superconducting coil L1 according to the control signals from the monitoring and protection unit, and sends state signals to the monitoring and protection unit.

[0011] The monitoring and protection unit monitors the state information of the superconducting charging unit, the superconducting discharge power unit, the low-temperature refrigeration unit, and the quench detection and protection unit, and gives corresponding control signals to provide the field coil with a sequence of intermittent pulse DC currents with positive and negative alternation and gradually decaying amplitude.

[0012] Preferably, the superconducting charging power unit uses a rectifier device with power factor correction function, and the power factor is usually above 99%, and the current harmonic content is within 5%.

[0013] Preferably, the superconducting coil L1 realizes lossless energy storage in the form of DC current. In the superconducting state, the resistivity is less than 10 -26 Ω / m, the total magnetic induction intensity of the superconducting coil is equal to 0, and the energy storage density reaches 10 8 J / m 3 , and multiple superconducting coils are connected in series and parallel.

[0014] Preferably, the superconducting discharge power unit is composed of a discharge switch Q3, a filter inductor L2, a filter capacitor C1, and a chopping switch Q2 connected in series in the order of the positive input, and a commutation bridge composed of Q4-Q7 connected in parallel across the filter capacitor C1, and the connection between the chopping switch Q2 and the filter capacitor C1 is connected to the negative input, wherein Q2-Q7 are full-controlled devices IGBT of corresponding specifications.

[0015] Preferably, the chopper switch Q2 is connected in parallel to the input of the superconducting discharge power unit, receives the control signal of the monitoring and protection unit during discharge, and is turned on or turned off to control the current provided by the superconducting coil L1 to the demagnetizing coil L3; when the chopper switch Q2 is turned on, the current of the superconducting coil L1 flows through the self-holding freewheeling diode D1, and no current is provided to the demagnetizing coil; when the chopper switch Q2 is turned off, the current of the superconducting coil L1 flows through the discharge switch Q3 to provide current to the demagnetizing coil L3.

[0016] Preferably, the discharge switch Q3 is connected to one end of the superconducting coil L1 and one end of the filter inductor L2, controls the discharge of the superconducting coil L1 into the superconducting discharge power unit, and is turned off when the superconducting coil L1 is in a charging state and a self-holding state, and is turned on when the superconducting coil L1 is in a discharging state.

[0017] Preferably, the filter inductor L2 and the filter capacitor C1 are connected in series to form an LC filter to filter the output of the superconducting coil L1.

[0018] Preferably, the Q4-Q7 commutation bridge processes the filtered output of the superconducting coil L1, and outputs alternating positive and negative direct currents to the demagnetizing coil.

[0019] Preferably, the superconducting discharge power unit is directly provided with a current detector between the filter inductor L2 and the commutation bridge to detect the size of the demagnetizing current and send it to the monitoring and protection unit.

[0020] Preferably, the anode of the self-holding freewheeling diode D1 is connected to the negative electrode of the superconducting charging power supply, and the cathode is connected to the charging switch Q1 and the connection end of the superconducting coil L1, which provides a freewheeling circuit when the superconducting coil L1 is in a self-holding state.

[0021] The present application has the advantages that: the present application is based on a superconducting energy storage demagnetizing power supply, based on the characteristics that the superconducting energy storage and the demagnetizing coil are both "current type", a superconducting discharge power unit is designed, which provides a size-controllable and positive-negative-adjustable demagnetizing pulse sequence for the demagnetizing coil in a closed-loop control; the superconducting energy storage with high power density provides pulse power for demagnetization, reduces the impact of pulse power on the power grid, reduces the required power capacity, and makes the demagnetization device available in areas with weak power grids. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a demagnetizing current diagram;

[0023] Figure 2 is a structure diagram of the superconducting energy storage demagnetizing power supply of the present application;

[0024] Figure 3 is a working flowchart of the superconducting energy storage demagnetizing power supply of the present application;

[0025] Figure 4 This is a diagram of the demagnetizing current pulse sequence of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0027] In this embodiment, the demagnetizing coil has a resistance of 0.25 ohms and an inductance of 20mH. The initial pulse current is required to be 2000A, with subsequent pulses decreasing in value. The total number of pulses is 20, with each pulse lasting approximately 10-15 seconds and the pulse interval approximately 10 seconds. The initial pulse has the highest power, approximately 1MW, and the total energy of the entire pulse sequence is approximately 100MJ. Therefore, the designed demagnetizing power supply based on superconducting energy storage needs to have a rated output power of over 1MW and an energy storage capacity of over 150MJ.

[0028] like Figure 2 The diagram shown illustrates the composition of the demagnetizing power supply based on superconducting energy storage of this invention, which includes a superconducting charging power unit, a superconducting coil L1, a superconducting discharging power unit, a monitoring and protection unit, a cryogenic cooling unit, a quench detection and protection unit, a charging switch Q1, and a self-holding continuous current diode D1.

[0029] Superconducting charging power unit: The input terminal is connected to a three-phase AC power supply. The positive terminal of the output terminal is connected to one end of the charging switch Q1, and the negative terminal is connected to the anode of the self-holding continuous current diode D1. The other end of the charging switch Q1 is connected to the cathode of the self-holding continuous current diode D1. The connection between the charging switch Q1 and the self-holding continuous current diode D1 is connected to one end of the superconducting coil L1. The function of the superconducting charging power unit is to charge the superconducting coil L1, storing the three-phase AC energy in the superconducting coil in the form of magnetism.

[0030] The superconducting charging power unit uses a conventional rectifier with power factor correction, typically achieving a power factor of over 99% and current harmonic content below 5%, resulting in minimal pollution to the power grid. Due to the presence of the superconducting coil L1, the superconducting charging power unit can slowly charge it. Therefore, the rated power of the superconducting charging power unit can be designed to be 5%-20% of the rated power of the superconducting discharging power unit, with low requirements for power grid distribution during charging. Considering both the requirements for power grid capacity and charging time, the rated power of the superconducting charging power unit in this embodiment is selected as 200kW, and charging can be completed in approximately 15 minutes.

[0031] The other end of the superconducting coil L1 is connected to a superconducting discharge power unit, which stores electrical energy without loss in the form of direct current and releases the energy rapidly when needed. In the superconducting state, the resistivity of the superconducting coil L1 is less than 10⁻⁶. -26Ω / m, the total magnetic induction intensity of superconductor is equal to 0, and the energy storage density reaches 10 8 J / m 3 The total energy storage of the superconducting coil L1 is 150 MJ, and a plurality of superconducting coils are connected in series and parallel to form the superconducting coil L1.

[0032] The superconducting discharge power unit is connected in series with the superconducting coil L1 at the positive input end, connected with the anode of the self-holding current diode D1 at the negative input end, and connected with the demagnetizing coil L3 at the output end, and has the function of releasing the energy of the superconducting coil L1 to the demagnetizing coil L3 according to the instruction, providing a demagnetizing current to generate a working magnetic field required in the comprehensive magnetic treatment.

[0033] The superconducting discharge power unit is connected in series with the superconducting coil L1 at the positive input end, connected with the anode of the self-holding current diode D1 at the negative input end, and connected with the demagnetizing coil L3 at the output end, and has the function of releasing the energy of the superconducting coil L1 to the demagnetizing coil L3 according to the instruction, providing a demagnetizing current to generate a working magnetic field required in the comprehensive magnetic treatment.

[0034] The superconducting discharge power unit is connected in series with the superconducting coil L1 at the positive input end, connected with the anode of the self-holding current diode D1 at the negative input end, and connected with the demagnetizing coil L3 at the output end, and has the function of releasing the energy of the superconducting coil L1 to the demagnetizing coil L3 according to the instruction, providing a demagnetizing current to generate a working magnetic field required in the comprehensive magnetic treatment.

[0035] The superconducting discharge power unit is connected in series with the superconducting coil L1 at the positive input end, connected with the anode of the self-holding current diode D1 at the negative input end, and connected with the demagnetizing coil L3 at the output end, and has the function of releasing the energy of the superconducting coil L1 to the demagnetizing coil L3 according to the instruction, providing a demagnetizing current to generate a working magnetic field required in the comprehensive magnetic treatment.

[0036] The superconducting discharge power unit is connected in series with the superconducting coil L1 at the positive input end, connected with the anode of the self-holding current diode D1 at the negative input end, and connected with the demagnetizing coil L3 at the output end, and has the function of releasing the energy of the superconducting coil L1 to the demagnetizing coil L3 according to the instruction, providing a demagnetizing current to generate a working magnetic field required in the comprehensive magnetic treatment.

[0037] The superconducting discharge power unit is connected in series with the superconducting coil L1 at the positive input end, connected with the anode of the self-holding current diode D1 at the negative input end, and connected with the demagnetizing coil L3 at the output end, and has the function of releasing the energy of the superconducting coil L1 to the demagnetizing coil L3 according to the instruction, providing a demagnetizing current to generate a working magnetic field required in the comprehensive magnetic treatment.

[0038] The superconducting discharge power unit has a current detector directly installed between the filter inductor L2 and the commutation bridge to detect the magnitude of the demagnetizing current and send it to the monitoring and protection unit.

[0039] The monitoring and protection unit monitors the status information of the superconducting charging unit, superconducting discharge power unit, cryogenic cooling unit, and quench detection and protection unit, and provides corresponding control signals. The control process is as follows: Figure 3 As shown.

[0040] The cryogenic cooling unit provides cooling to the superconducting coil L1 according to the control signal of the monitoring and protection unit, keeping the temperature of the superconducting coil L1 at around 20K, and sends the status signal to the monitoring and protection unit.

[0041] The quench detection and protection unit detects whether the superconducting coil L1 is quenched in real time. If it is quenched, the protection unit responds in time to protect the superconducting coil L1, and at the same time sends the status signal to the monitoring and protection unit.

[0042] One end of the charging switch Q1 is connected to the positive output terminal of the superconducting charging power unit, and the other end is connected to the superconducting coil L1. Its function is to control the charging of the superconducting coil L1. The charging switch Q1 is closed when the superconducting coil L1 is discharging or in a self-holding state, and is turned on when the superconducting coil L1 is charging.

[0043] The self-holding continuous current diode D1 has its anode connected to the negative terminal of the superconducting charging power supply output, and its cathode connected to the connection terminal between the charging switch Q1 and the superconducting coil L1. Its function is to provide a freewheeling circuit when the superconducting coil L1 is self-holding.

[0044] like Figure 3 The diagram shown illustrates the workflow of a demagnetizing power supply based on superconducting energy storage. Figure 2 The structural diagram and working steps are as follows:

[0045] Step 1: The monitoring and protection unit first collects the status of the superconducting charging power unit, the quench detection and protection unit, and the cryogenic cooling unit. If a superconducting quench is detected, quench protection is performed. If a cryogenic cooling fault is detected, shutdown protection is performed.

[0046] Step Two: Under normal operating conditions, the demagnetizing power supply based on superconducting energy storage receives operating commands. Upon receiving a charging command, proceed to Step Three; upon receiving a self-holding command, proceed to Step Four; upon receiving a discharging command, proceed to Step Five.

[0047] Step 3: Upon receiving the charging command, Q1 and Q2 are turned on, while Q3-Q7 are turned off. The superconducting charging power unit forms a circuit through charging switch Q1, superconducting coil L1, and chopper switch Q2 to charge superconducting coil L1. When the superconducting current reaches the set value (2500A), charging ends, and the system switches to self-holding state, proceeding to step 4.

[0048] Step four: under the self-holding instruction or after the charging is completed, Q2 is turned on, Q1, Q3-Q7 are turned off, the charging circuit and the discharging circuit are turned off, and the superconducting current forms a loop through the superconducting coil L1, the chopper switch Q2 and the self-holding freewheeling diode D1 to perform the superconducting current self-holding.

[0049] Step five: under the discharging instruction, Q1 is turned off, Q3 is turned on, the charging circuit is turned off, and the discharging circuit is turned on. If the instruction is a positive pulse current, Q4 and Q7 are turned on, Q5 and Q6 are turned off, and Q2 is alternately turned on and turned off according to the demagnetizing current closed-loop control to provide the positive current with a size tracked by the instruction for the demagnetizing coil. If the instruction is 0, Q2 is turned on, and the superconducting coil L1 self-holding freewheeling provides the demagnetizing coil with 0 current. If the instruction is a negative pulse current, Q5 and Q6 are turned on, Q4 and Q7 are turned off, and Q2 is alternately turned on and turned off according to the demagnetizing current closed-loop control to provide the negative current with a size tracked by the instruction for the demagnetizing coil. According to the demagnetizing current pulse sequence set as shown in Figure 4 , the demagnetizing instruction is sequentially executed.

[0050] Step six: after a demagnetizing pulse sequence is executed, step three is executed to charge the superconducting coil L1 to store energy for the next demagnetizing pulse sequence.

[0051] The above-described embodiments only express several embodiments of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A demagnetizing power supply based on superconducting energy storage, characterized in that, It includes a three-phase AC power supply, a superconducting charging power unit, a superconducting coil L1, a superconducting discharging power unit, a monitoring and protection unit, a cryogenic cooling unit, a quench detection and protection unit, a charging switch Q1, and a self-holding continuous current diode D1; The AC power output of the three-phase AC power supply is converted into DC power output through the superconducting charging power unit. The positive output of the superconducting charging power unit is connected to the cathode of the self-holding continuous current diode D1 and one end of the superconducting coil L1 through the charging switch Q1. The anode of the self-holding continuous current diode D1 is connected to the negative output of the superconducting charging power unit. The other end of the superconducting coil L1, away from the charging switch Q1, is connected to the positive terminal of the input terminal of the superconducting discharge power unit, and the negative terminal of the input terminal of the superconducting discharge power unit is connected to the negative terminal of the output terminal of the superconducting charging power unit. The output of the superconducting discharge power unit is sent to the demagnetizing coil. The quench detection and protection unit performs real-time quench detection on the superconducting coil L1 and sends the status signal to the monitoring and protection unit. It also receives control signals from the monitoring and protection unit, and the protection unit responds to protect the superconducting coil L1. The cryogenic cooling unit provides cooling to the superconducting coil L1 according to the control signal from the monitoring and protection unit, and sends a status signal to the monitoring and protection unit. The monitoring and protection unit monitors the status information of the superconducting charging unit, the superconducting discharge power unit, the cryogenic cooling unit, and the quench detection and protection unit, and provides corresponding control signals to provide the demagnetizing coil with an intermittent pulsed DC current sequence that alternates between positive and negative and gradually decreases in amplitude.

2. The demagnetizing power supply based on superconducting energy storage according to claim 1, characterized in that, The superconducting charging power unit uses a rectifier with power factor correction function, with a power factor typically above 99% and a current harmonic content below 5%.

3. The demagnetizing power supply based on superconducting energy storage according to claim 1, characterized in that, The superconducting coil L1 stores energy without loss using direct current, and in the superconducting state, its resistivity is less than 10⁻⁶. -26 Ω / m, the total magnetic induction of the superconducting coil is equal to 0, and the energy storage density reaches 10 8 J / m 3 It is composed of multiple superconducting coils connected in series and parallel.

4. The demagnetizing power supply based on superconducting energy storage according to claim 1, characterized in that, The superconducting discharge power unit consists of a discharge switch Q3, a filter inductor L2, a filter capacitor C1, and a chopper switch Q2 connected in series in a closed loop starting from the positive input terminal, and a commutation bridge composed of Q4-Q7 connected in parallel across the filter capacitor C1. The connection between the chopper switch Q2 and the filter capacitor C1 is connected to the negative input terminal. Q2-Q7 are selected as IGBTs of appropriate specifications.

5. The demagnetizing power supply based on superconducting energy storage according to claim 4, characterized in that, The chopper switch Q2 is connected in parallel across the positive and negative input terminals of the superconducting discharge power unit. During discharge, it receives control signals from the monitoring and protection unit to turn on or off, controlling the magnitude of the current supplied by the superconducting coil L1 to the demagnetizing coil L3. When the chopper switch Q2 is on, the current in the superconducting coil L1 continues through the self-holding continuous current diode D1 and does not supply current to the demagnetizing coil. When the chopper switch Q2 is off, the current in the superconducting coil L1 supplies current to the demagnetizing coil L3 through the discharge switch Q3.

6. The demagnetizing power supply based on superconducting energy storage according to claim 4, characterized in that, The discharge switch Q3 is connected to the superconducting coil L1 at one end and the filter inductor L2 at the other end, controlling the superconducting coil L1 to discharge into the superconducting discharge power unit; the discharge switch Q3 is open when the superconducting coil L1 is charging and in self-holding state, and closed when the superconducting coil L1 is discharging.

7. The demagnetizing power supply based on superconducting energy storage according to claim 4, characterized in that, The filter inductor L2 and filter capacitor C1 are connected in series to form an LC filter, which filters the output current of the superconducting coil L1.

8. The demagnetizing power supply based on superconducting energy storage according to claim 4, characterized in that, The commutation bridge composed of Q4-Q7 performs commutation processing on the output of the superconducting coil L1 after filtering, and outputs alternating positive and negative DC current to the demagnetizing coil.

9. The demagnetizing power supply based on superconducting energy storage according to any one of claims 4 to 8, characterized in that, The superconducting discharge power unit has a current detector directly installed between the filter inductor L2 and the commutation bridge to detect the magnitude of the demagnetizing current and send it to the monitoring and protection unit.

10. The demagnetizing power supply based on superconducting energy storage according to claim 9, characterized in that, The anode of the self-holding continuous current diode D1 is connected to the negative terminal of the superconducting charging power supply output, and the cathode is connected to the connection terminal between the charging switch Q1 and the superconducting coil L1, providing a freewheeling circuit when the superconducting coil L1 is self-holding.

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