DC customized power system with superconducting circuit breaker, energy storage and fuel cell combined compensation

Abstract

The present invention discloses a DC customized power system of superconducting circuit breaker-energy storage-fuel cell combined compensation, including a superconducting DC circuit breaker submodule and a superconducting energy storage-fuel cell combined compensation submodule; the superconducting DC circuit breaker submodule can perform zero current shutdown on the short-circuit faults on the power supply side and the load side to achieve electrical isolation; the superconducting energy storage magnet in the superconducting energy storage-fuel cell combined compensation submodule performs transient power compensation on the load side through a low-temperature power electronic superconducting converter, and the fuel cell performs steady-state uninterrupted power supply to the load side through a low-temperature power electronic battery converter. By using the superconducting circuit breaker protection, superconducting energy storage compensation and fuel cell compensation of the present invention in combination, an economical, fast and large-capacity DC customized power system can be formed.

Description

Technical Field

[0001] The present invention relates to the field of electric power, and in particular to a DC customized electric power system of superconducting circuit breaker-energy storage-fuel cell combined compensation. Background Art

[0002] With the continuous development of power systems dominated by new energy, DC power grids that adapt to large-scale access to new energy are becoming increasingly popular. Since most of the power conversion devices in DC power grids are composed of power electronic devices, the system reliability is low and the failure rate is high, so the fault protection device of DC power grid is very important. At present, the most widely studied protection devices are DC circuit breakers and DC current limiters. Compared with AC power, DC power does not have a natural zero crossing, which increases the design difficulty of DC circuit breakers. Traditional mechanical DC circuit breakers have the disadvantages of slow response speed and large size. The improved solid-state DC circuit breaker has a faster response speed, but its internal room temperature semiconductor switch and copper inductor have large losses, which seriously affect the normal operation efficiency of the equipment. Traditional power electronic current limiters have complex control, high failure rate, and large steady-state loss, which is not conducive to the efficient and stable operation of the system. Benefiting from the low loss and high current characteristics of superconductors, superconducting current limiters have the advantages of low loss, small size, simple structure, and self-triggering. However, the investment cost of superconducting current limiters is high, the action loss is large, and their application has great limitations.

[0003] A fuel cell is a device that directly converts the chemical energy of a fuel into electrical energy. It has the advantages of high power generation efficiency, low environmental pollution, and high reliability. If it is used for dynamic power compensation of new energy power generation and building terminal power loads with intermittent and unstable defects, the compensation device can be made more efficient, environmentally friendly, and reliable. However, the response speed of the fuel cell compensation device is slow and cannot effectively compensate for transient and high-power fluctuations. The superconducting energy storage device uses a superconducting coil to directly store electromagnetic energy and returns the electromagnetic energy to the power grid for power compensation when needed. It has the advantages of fast response speed and high transient power. It can be used to make up for the shortcomings of fuel cell compensation, but its cost is high and it is not suitable for long-term and large-capacity energy compensation. If fuel cell compensation is used in conjunction with superconducting energy storage compensation, an economical, fast, and large-capacity hybrid energy storage compensation device can be formed. Specifically, the transient power fluctuations of the DC power grid are compensated by superconducting energy storage. When the superconducting energy storage is insufficient, the superconducting coil can be supplemented with energy through the fuel cell, so that the superconducting coil always has sufficient energy for long-term power compensation. At the same time, dynamic compensation of series capacitors can also be used to achieve short-circuit fault current limiting of the DC power grid.

[0004] At present, the research on fault protection devices and power compensation devices of DC power grids is still limited to the research on single devices, and there is no public report on the combination of superconducting fault protection devices and superconducting hybrid power compensation devices. At the same time, using the existing low temperature environment of superconducting power devices to cool power electronic switches can achieve low temperature switch devices with higher operating power and lower operating losses, but there is no technical research on the combination of superconducting power devices and low temperature power electronic modules. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a DC customized power system of superconducting circuit breaker-energy storage-fuel cell combined compensation, including a superconducting DC circuit breaker submodule and a superconducting energy storage-fuel cell combined compensation submodule;

[0006] The superconducting DC circuit breaker submodule includes a first low-temperature power switch, a first superconducting inductor, a second superconducting inductor, a first energy release resistor, a first low-temperature diode, a first normal-temperature capacitor, a second low-temperature diode, a second energy release resistor, and a normal-temperature power switch, wherein the first superconducting inductor and the second superconducting inductor form a pair of coupled inductors;

[0007] The first cryogenic power switch is connected to the same-name end of the first superconducting inductor; the same-name end of the second superconducting inductor is connected to a common point between the first cryogenic power switch and the first superconducting inductor;

[0008] The non-same-name end of the second superconducting inductor is connected to one end of the first normal-temperature capacitor, and the other end of the first normal-temperature capacitor is connected to the ground of the power supply;

[0009] The non-same-name end of the first superconducting inductor is connected to one end of the normal-temperature power switch, and the other end of the normal-temperature power switch is connected to the ground of the power supply;

[0010] One end of the first energy release resistor is connected to the anode of the first low-temperature diode, and the other end is connected to the same-name end of the second superconducting inductor, and the cathode of the first low-temperature diode is connected to the non-same-name end of the second superconducting inductor;

[0011] The cathode of the second low-temperature diode is connected to the same-name end of the first superconducting inductor, the anode of the second low-temperature diode is connected to the second energy release resistor, and the other end of the second energy release resistor is connected to the non-same-name end of the first superconducting inductor;

[0012] The superconducting energy storage-fuel cell joint compensation submodule includes a second normal temperature capacitor, a second low temperature power switch, a third low temperature power switch, a fourth low temperature power switch, a fifth low temperature power switch, a superconducting energy storage magnet, a third low temperature diode, a third superconducting inductor, a superconducting current limiting resistor, a fuel cell, and a sixth low temperature power switch;

[0013] One end of the second normal temperature capacitor is connected to a common point between the first superconducting inductor and the normal temperature power switch, and the other end of the second normal temperature capacitor is connected to a load;

[0014] The second low-temperature power switch is connected in series with the third low-temperature power switch, and the two are connected in series and then connected in parallel with the second normal temperature capacitor;

[0015] The fourth low-temperature power switch is connected in series with the fifth low-temperature power switch, and the two are connected in series and then connected in parallel with the second normal temperature capacitor;

[0016] One end of the superconducting energy storage magnet is connected to a common point between the second cryogenic power switch and the third cryogenic power switch, and the other end is connected to a common point between the fourth cryogenic power switch and the fifth cryogenic power switch;

[0017] The cathode of the third low-temperature diode is connected to one end of the superconducting energy storage magnet, the anode of the third low-temperature diode is connected to one end of the third superconducting inductor, the other end of the third superconducting inductor is connected to one end of the superconducting current limiting resistor, the other end of the superconducting current limiting resistor is connected to the positive electrode of the fuel cell, and the negative electrode of the fuel cell is connected to the other end of the superconducting energy storage magnet;

[0018] One end of the sixth low-temperature power switch is connected to a common point between the third superconducting inductor and the third low-temperature diode, and the other end is connected to the negative electrode of the fuel cell.

[0019] Furthermore, the working method of the superconducting DC circuit breaker module includes the following process:

[0020] When the load side works normally, the superconducting DC circuit breaker submodule enters the steady-state mode; the power supply supplies power to the load side through the first low-temperature power switch, the first superconducting inductor, and the second normal temperature capacitor in sequence; the voltage of the first normal temperature capacitor is equal to the power supply voltage, and the current flowing through the first normal temperature capacitor and the second superconducting inductor is zero;

[0021] When the load side needs to disconnect the power supply, the superconducting DC circuit breaker submodule enters the circuit breaking mode by closing the normal temperature power switch; the first normal temperature capacitor forms a closed discharge loop through the second superconducting inductor, the first superconducting inductor, and the normal temperature power switch; when the current of the second superconducting inductor flows out from the same-name end, the same-name end of the first superconducting inductor generates an induced current according to the inductive coupling ratio; when the current amplitude flowing out of the same-name end of the second superconducting inductor rises to be equal to the current of the first superconducting inductor, the current flowing through the first low-temperature power switch will drop to zero, and the first low-temperature power switch will be immediately shut down with zero current to complete the circuit breaking operation on the load side.

[0022] Furthermore, the working method of the superconducting energy storage-fuel cell combined compensation submodule includes the following process:

[0023] The driving signal of the second low-temperature power switch is the same as that of the fifth low-temperature power switch; the driving signal of the third low-temperature power switch is the same as that of the fourth low-temperature power switch, and the driving signal is complementary to the driving signals of the second low-temperature power switch and the fifth low-temperature power switch;

[0024] By changing the duty ratio of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch, the superconducting energy storage magnet absorbs excess energy of the second normal temperature capacitor or compensates for insufficient energy;

[0025] The third low-temperature diode, the superconducting current limiting resistor, the third superconducting inductor, and the sixth low-temperature power switch constitute a boost chopper circuit, and the charging power of the fuel cell to the superconducting energy storage magnet is adjusted by changing the duty cycle of the sixth low-temperature power switch drive signal.

[0026] The superconducting circuit breaker-energy storage-fuel cell combined compensation method of a DC customized power system based on superconducting circuit breaker-energy storage-fuel cell combined compensation includes the following processes:

[0027] When the power supply voltage is equal to the rated voltage of the load, the power supply supplies power to the load through the superconducting DC circuit breaker module and the second normal temperature capacitor; the duty cycle of the drive signal of the second low temperature power switch and the fifth low temperature power switch is equal to 50%, so that the total energy interaction between the second normal temperature capacitor and the superconducting energy storage magnet in the positive and negative half cycles is zero;

[0028] When the power supply voltage is higher than the rated voltage of the load, by adjusting the duty cycle range of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch to 50%-100%, the superconducting energy storage magnet absorbs the excess energy of the second normal temperature capacitor through the second cryogenic power switch and the fifth cryogenic power switch, so that the output terminal voltage of the second normal temperature capacitor is equal to the rated voltage of the load;

[0029] When the power supply voltage is lower than the rated voltage of the load, the duty cycle range of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch is adjusted to 0%-50%, and the superconducting energy storage magnet compensates for the insufficient energy of the second normal temperature capacitor through the third cryogenic power switch and the fourth cryogenic power switch, so that the output terminal voltage of the second normal temperature capacitor is equal to the rated voltage of the load;

[0030] When a short circuit fault occurs on the load side, by increasing the duty cycle of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch, the superconducting energy storage magnet absorbs the power supply power through the second normal temperature capacitor, so that the second normal temperature capacitor generates a voltage with the same amplitude and opposite direction as the power supply voltage, thereby realizing the short circuit fault current limiting operation of the load line;

[0031] When the duration of the short-circuit fault on the load side reaches the upper limit threshold of the current limiting time, the room temperature power switch is closed, the superconducting DC circuit breaker submodule enters the circuit breaking mode, the first low temperature power switch is turned off, and the circuit breaking operation on the load side is completed.

[0032] Furthermore, the superconducting energy storage magnet discharges the second normal temperature capacitor through the third low temperature power switch and the second low temperature power switch to compensate the normal temperature capacitor, and further includes:

[0033] When the current of the superconducting energy storage magnet is lower than the rated operating current, the fuel cell is started, the superconducting energy storage magnet is charged through the superconducting current limiting resistor, the third superconducting inductor, and the third low-temperature diode, and the duty cycle of the driving signal of the sixth low-temperature power switch is dynamically adjusted to maintain the current of the superconducting energy storage magnet at the rated operating value;

[0034] When a short circuit fault occurs in the sixth cryogenic power switch or / and the third superconducting inductor or / and the third cryogenic diode or / and the superconducting energy storage magnet, the superconducting current limiting resistor increases its resistance from zero resistance to limit the short circuit fault current; when all short circuit faults are cleared, the superconducting current limiting resistor returns to a zero resistance state.

[0035] Furthermore, when a short circuit fault occurs on the power supply side, the normal temperature power switch is closed, the superconducting DC circuit breaker submodule enters the circuit breaker mode, and the first low temperature power switch is turned off to achieve electrical isolation between the power supply side and the load side; at the same time, the insufficient energy on the load side is compensated by the superconducting energy storage-fuel cell combined compensation submodule to achieve uninterrupted power supply to the load side.

[0036] The beneficial effects of the present invention are as follows: the fuel cell compensation and the superconducting energy storage compensation are used in combination to form an economical, fast, and large-capacity hybrid energy storage compensation device, wherein the transient power fluctuation of the DC power grid is compensated by the superconducting energy storage. When the superconducting energy storage is insufficient, the superconducting coil can be supplemented with energy by the fuel cell, so that the superconducting coil always has sufficient energy for long-term power compensation. At the same time, the series capacitor dynamic compensation can also be used to achieve short-circuit fault current limiting for the DC power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The schematic diagram of the current limiting circuit for superconducting circuit breaker-energy storage-fuel cell combined compensation;

[0038] Figure 2 A circuit diagram of a current limiting circuit for superconducting circuit breaker-energy storage-fuel cell combined compensation;

[0039] In the figure, 1-the first low-temperature power switch, 2-the first superconducting inductor, 3-the second superconducting inductor, 4-the first energy release resistor, 5-the first low-temperature diode, 6-the first normal-temperature capacitor, 7-the second low-temperature diode, 8-the second energy release resistor, 9-normal-temperature power switch, 10-the second normal-temperature capacitor, 11-the second low-temperature power switch, 12-the third low-temperature power switch, 13-the fourth low-temperature power switch, 14-the fifth low-temperature power switch, 15-superconducting energy storage magnet, 16-the third low-temperature diode, 17-the third superconducting inductor, 18-superconducting current limiting resistor, 19-fuel cell, 20-the sixth low-temperature power switch. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0041] like Figure 1 As shown, a DC customized power system of superconducting circuit breaker-energy storage-fuel cell combined compensation includes a superconducting DC circuit breaker submodule and a superconducting energy storage-fuel cell combined compensation submodule;

[0042] The superconducting DC circuit breaker submodule includes a first low-temperature power switch, a first superconducting inductor, a second superconducting inductor, a first energy release resistor, a first low-temperature diode, a first normal-temperature capacitor, a second low-temperature diode, a second energy release resistor, and a normal-temperature power switch, wherein the first superconducting inductor and the second superconducting inductor form a pair of coupled inductors;

[0043] The first cryogenic power switch is connected to the same-name end of the first superconducting inductor; the same-name end of the second superconducting inductor is connected to a common point between the first cryogenic power switch and the first superconducting inductor;

[0044] The non-same-name end of the second superconducting inductor is connected to one end of the first normal-temperature capacitor, and the other end of the first normal-temperature capacitor is connected to the ground of the power supply;

[0045] The non-same-name end of the first superconducting inductor is connected to one end of the normal-temperature power switch, and the other end of the normal-temperature power switch is connected to the ground of the power supply;

[0046] One end of the first energy release resistor is connected to the anode of the first low-temperature diode, and the other end is connected to the same-name end of the second superconducting inductor, and the cathode of the first low-temperature diode is connected to the non-same-name end of the second superconducting inductor;

[0047] The cathode of the second low-temperature diode is connected to the same-name end of the first superconducting inductor, the anode of the second low-temperature diode is connected to the second energy release resistor, and the other end of the second energy release resistor is connected to the non-same-name end of the first superconducting inductor;

[0048] The superconducting energy storage-fuel cell joint compensation submodule includes a second normal temperature capacitor, a second low temperature power switch, a third low temperature power switch, a fourth low temperature power switch, a fifth low temperature power switch, a superconducting energy storage magnet, a third low temperature diode, a third superconducting inductor, a superconducting current limiting resistor, a fuel cell, and a sixth low temperature power switch;

[0049] One end of the second normal temperature capacitor is connected to a common point between the first superconducting inductor and the normal temperature power switch, and the other end of the second normal temperature capacitor is connected to a load;

[0050] The second low-temperature power switch is connected in series with the third low-temperature power switch, and the two are connected in series and then connected in parallel with the second normal temperature capacitor;

[0051] The fourth low-temperature power switch is connected in series with the fifth low-temperature power switch, and the two are connected in series and then connected in parallel with the second normal temperature capacitor;

[0052] One end of the superconducting energy storage magnet is connected to a common point between the second cryogenic power switch and the third cryogenic power switch, and the other end is connected to a common point between the fourth cryogenic power switch and the fifth cryogenic power switch;

[0053] The cathode of the third low-temperature diode is connected to one end of the superconducting energy storage magnet, the anode of the third low-temperature diode is connected to one end of the third superconducting inductor, the other end of the third superconducting inductor is connected to one end of the superconducting current limiting resistor, the other end of the superconducting current limiting resistor is connected to the positive electrode of the fuel cell, and the negative electrode of the fuel cell is connected to the other end of the superconducting energy storage magnet;

[0054] One end of the sixth low-temperature power switch is connected to a common point between the third superconducting inductor and the third low-temperature diode, and the other end is connected to the negative electrode of the fuel cell.

[0055] The working method of the superconducting DC circuit breaker module includes the following process:

[0056] When the load side works normally, the superconducting DC circuit breaker submodule enters the steady-state mode; the power supply supplies power to the load side through the first low-temperature power switch, the first superconducting inductor, and the second normal temperature capacitor in sequence; the voltage of the first normal temperature capacitor is equal to the power supply voltage, and the current flowing through the first normal temperature capacitor and the second superconducting inductor is zero;

[0057] When the load side needs to disconnect the power supply, the superconducting DC circuit breaker submodule enters the circuit breaking mode by closing the normal temperature power switch; the first normal temperature capacitor forms a closed discharge loop through the second superconducting inductor, the first superconducting inductor, and the normal temperature power switch; when the current of the second superconducting inductor flows out from the same-name end, the same-name end of the first superconducting inductor generates an induced current according to the inductive coupling ratio; when the current amplitude flowing out of the same-name end of the second superconducting inductor rises to be equal to the current of the first superconducting inductor, the current flowing through the first low-temperature power switch will drop to zero, and the first low-temperature power switch will be immediately shut down with zero current to complete the circuit breaking operation on the load side.

[0058] The working method of the superconducting energy storage-fuel cell joint compensation submodule includes the following process:

[0059] The driving signal of the second low-temperature power switch is the same as that of the fifth low-temperature power switch; the driving signal of the third low-temperature power switch is the same as that of the fourth low-temperature power switch, and the driving signal is complementary to the driving signals of the second low-temperature power switch and the fifth low-temperature power switch;

[0060] By changing the duty ratio of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch, the superconducting energy storage magnet absorbs excess energy of the second normal temperature capacitor or compensates for insufficient energy;

[0061] The third low-temperature diode, the superconducting current limiting resistor, the third superconducting inductor, and the sixth low-temperature power switch constitute a boost chopper circuit, and the charging power of the fuel cell to the superconducting energy storage magnet is adjusted by changing the duty cycle of the sixth low-temperature power switch drive signal.

[0062] The superconducting circuit breaker-energy storage-fuel cell combined compensation method of a DC customized power system based on superconducting circuit breaker-energy storage-fuel cell combined compensation includes the following processes:

[0063] When the power supply voltage is equal to the rated voltage of the load, the power supply supplies power to the load through the superconducting DC circuit breaker module and the second normal temperature capacitor; the duty cycle of the drive signal of the second low temperature power switch and the fifth low temperature power switch is equal to 50%, so that the total energy interaction between the second normal temperature capacitor and the superconducting energy storage magnet in the positive and negative half cycles is zero;

[0064] When the power supply voltage is higher than the rated voltage of the load, by adjusting the duty cycle range of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch to 50%-100%, the superconducting energy storage magnet absorbs the excess energy of the second normal temperature capacitor through the second cryogenic power switch and the fifth cryogenic power switch, so that the output terminal voltage of the second normal temperature capacitor is equal to the rated voltage of the load;

[0065] When the power supply voltage is lower than the rated voltage of the load, the duty cycle range of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch is adjusted to 0%-50%, and the superconducting energy storage magnet compensates for the insufficient energy of the second normal temperature capacitor through the third cryogenic power switch and the fourth cryogenic power switch, so that the output terminal voltage of the second normal temperature capacitor is equal to the rated voltage of the load;

[0066] When a short circuit fault occurs on the load side, by increasing the duty cycle of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch, the superconducting energy storage magnet absorbs the power supply power through the second normal temperature capacitor, so that the second normal temperature capacitor generates a voltage with the same amplitude and opposite direction as the power supply voltage, thereby realizing the short circuit fault current limiting operation of the load line;

[0067] When the duration of the short-circuit fault on the load side reaches the upper limit threshold of the current limiting time, the room temperature power switch is closed, the superconducting DC circuit breaker submodule enters the circuit breaking mode, the first low temperature power switch is turned off, and the circuit breaking operation on the load side is completed.

[0068] The superconducting energy storage magnet discharges the second normal temperature capacitor through the third low temperature power switch and the second low temperature power switch to compensate the normal temperature capacitor, and further comprises:

[0069] When the current of the superconducting energy storage magnet is lower than the rated operating current, the fuel cell is started, the superconducting energy storage magnet is charged through the superconducting current limiting resistor, the third superconducting inductor, and the third low-temperature diode, and the duty cycle of the driving signal of the sixth low-temperature power switch is dynamically adjusted to maintain the current of the superconducting energy storage magnet at the rated operating value;

[0070] When a short circuit fault occurs in the sixth cryogenic power switch or / and the third superconducting inductor or / and the third cryogenic diode or / and the superconducting energy storage magnet, the superconducting current limiting resistor increases its resistance from zero resistance to limit the short circuit fault current; when all short circuit faults are cleared, the superconducting current limiting resistor returns to a zero resistance state.

[0071] It also includes closing the normal temperature power switch when a short circuit fault occurs on the power supply side, causing the superconducting DC circuit breaker submodule to enter the circuit breaking mode, turning off the first low temperature power switch, and realizing electrical isolation between the power supply side and the load side; at the same time, compensating for the insufficient energy on the load side through the superconducting energy storage-fuel cell combined compensation submodule to realize uninterrupted power supply to the load side.

[0072] Specifically, Figure 2 The superconducting circuit breaker-energy storage-fuel cell combined compensation DC customized power system shown includes a superconducting DC circuit breaker submodule and a superconducting energy storage-fuel cell combined compensation submodule.

[0073] The superconducting DC circuit breaker submodule includes a first low-temperature power switch 1, a first superconducting inductor 2, a second superconducting inductor 3, a first energy release resistor 4, a first low-temperature diode 5, a first normal-temperature capacitor 6, a second low-temperature diode 7, a second energy release resistor 8, and a normal-temperature power switch 9, wherein the first superconducting inductor 2 and the second superconducting inductor 3 are a pair of coupled inductors.

[0074] The first cryogenic power switch 1 is connected to the same-named end of the first superconducting inductor 2;

[0075] The same-name end of the second superconducting inductor 3 is connected to the common point between the first cryogenic power switch 1 and the first superconducting inductor 2;

[0076] The non-same-name end of the second superconducting inductor 3 is connected to one end of the first normal-temperature capacitor 6, and the other end of the first normal-temperature capacitor 6 is connected to the ground of the power supply;

[0077] The non-identical end of the first superconducting inductor 2 is connected to one end of the normal temperature power switch 9, and the other end of the normal temperature power switch 9 is connected to the ground of the power supply;

[0078] One end of the first energy release resistor 4 is connected to the anode of the first low-temperature diode 5, and the other end is connected to the same-name end of the second superconducting inductor 3, and the cathode of the first low-temperature diode 5 is connected to the non-same-name end of the second superconducting inductor 3;

[0079] The cathode of the second low-temperature diode 7 is connected to the same-name end of the first superconducting inductor 2, the anode of the second low-temperature diode 7 is connected to the second energy-releasing resistor 8, and the other end of the second energy-releasing resistor 8 is connected to the non-same-name end of the first superconducting inductor 2;

[0080] The working principle of the superconducting DC circuit breaker submodule is as follows:

[0081] When the load side is operating normally, the superconducting DC circuit breaker submodule enters the steady-state mode; the power supply supplies power to the load side through the first low-temperature power switch 1, the first superconducting inductor 2, and the second normal temperature capacitor 10 in sequence; the voltage of the first normal temperature capacitor 6 is equal to the power supply voltage, and the current flowing through the first normal temperature capacitor 6 and the second superconducting inductor 3 is zero;

[0082] When the load side needs to disconnect the power supply, the superconducting DC circuit breaker submodule enters the circuit breaking mode by closing the normal temperature power switch; the first normal temperature capacitor 6 forms a closed discharge loop through the second superconducting inductor 3, the first superconducting inductor 2, and the normal temperature power switch 9; when the current of the second superconducting inductor 3 flows out from the same-name end, the same-name end of the first superconducting inductor 2 generates an induced current according to the inductive coupling ratio; when the current amplitude flowing out of the same-name end of the second superconducting inductor 3 rises to be equal to the current of the first superconducting inductor 2, the current flowing through the first low-temperature power switch 1 will drop to zero, and the first low-temperature power switch 1 is immediately shut down with zero current to complete the circuit breaking operation on the load side.

[0083] The structure of the superconducting energy storage-fuel cell combined compensation submodule is as follows:

[0084] It includes a second normal temperature capacitor 10, a second low temperature power switch 11, a third low temperature power switch 12, a fourth low temperature power switch 13, a fifth low temperature power switch 14, a superconducting energy storage magnet 15, a third low temperature diode 16, a third superconducting inductor 17, a superconducting current limiting resistor 18, a fuel cell 19, and a sixth low temperature power switch 20;

[0085] One end of the second normal temperature capacitor 10 is connected to a common point between the first superconducting inductor 2 and the normal temperature power switch 9, and the other end of the second normal temperature capacitor 10 is connected to a load;

[0086] The second low-temperature power switch 11 is connected in series with the third low-temperature power switch 12, and the two are connected in series and then connected in parallel with the second normal temperature capacitor 10;

[0087] The fourth low-temperature power switch 13 is connected in series with the fifth low-temperature power switch 14, and the two are connected in series and then connected in parallel with the second normal temperature capacitor 10;

[0088] One end of the superconducting energy storage magnet 15 is connected to a common point between the second cryogenic power switch 11 and the third cryogenic power switch 12, and the other end is connected to a common point between the fourth cryogenic power switch 13 and the fifth cryogenic power switch 14;

[0089] The cathode of the third low-temperature diode 16 is connected to one end of the superconducting energy storage magnet 15, the anode of the third low-temperature diode 16 is connected to the third superconducting inductor 17, the other end of the third superconducting inductor 17 is connected to the superconducting current limiting resistor 18, the other end of the superconducting current limiting resistor 18 is connected to the positive electrode of the fuel cell 19, and the negative electrode of the fuel cell 19 is connected to the other end of the superconducting energy storage magnet 15;

[0090] One end of the sixth low-temperature power switch 20 is connected to the common point between the anodes of the third superconducting inductor 17 and the third low-temperature diode 16, and the other end is connected to the negative electrode of the fuel cell 19;

[0091] The working principle of the superconducting energy storage-fuel cell combined compensation submodule is as follows:

[0092] The driving signal of the second low-temperature power switch 11 is the same as that of the fifth low-temperature power switch 14; the driving signal of the third low-temperature power switch 12 is the same as that of the fourth low-temperature power switch 13, and the driving signal is complementary to the driving signal of the second low-temperature power switch 11 and the fifth low-temperature power switch 14;

[0093] By changing the duty ratio of the driving signals of the second cryogenic power switch 11 and the fifth cryogenic power switch 14, the superconducting energy storage magnet 15 absorbs the excess energy of the second normal temperature capacitor 10 or compensates for the insufficient energy;

[0094] The third low-temperature diode 12, the superconducting current limiting resistor 19, the third superconducting inductor 17, and the sixth low-temperature power switch 20 constitute a boost chopper circuit, and the charging power of the fuel cell 19 to the superconducting energy storage magnet is adjusted by changing the duty cycle of the driving signal of the sixth low-temperature power switch 20.

[0095] When the power supply voltage is equal to the rated voltage of the load, the power supply supplies power to the load through the superconducting DC circuit breaker module and the second normal temperature capacitor 10; the duty cycle of the drive signal of the second low temperature power switch 11 and the fifth low temperature power switch 14 is equal to 50%, so that the total energy interaction between the second normal temperature capacitor 10 and the superconducting energy storage magnet 15 in the positive and negative half cycles is zero;

[0096] When the power supply voltage is higher than the rated voltage of the load, by adjusting the duty cycle range of the driving signal of the second cryogenic power switch 11 and the fifth cryogenic power switch 14 to 50%-100%, the superconducting energy storage magnet 15 absorbs the excess energy of the second normal temperature capacitor 10 through the second cryogenic power switch 11 and the fifth cryogenic power switch 14, so that the output terminal voltage of the second normal temperature capacitor 10 is equal to the rated voltage of the load;

[0097] When the power supply voltage is lower than the rated voltage of the load, by adjusting the duty cycle range of the driving signals of the second cryogenic power switch 11 and the fifth cryogenic power switch 14 to 0%-50%, the superconducting energy storage magnet 15 compensates for the insufficient energy of the second normal temperature capacitor 10 through the third cryogenic power switch 12 and the fourth cryogenic power switch 13, so that the output terminal voltage of the second normal temperature capacitor 10 is equal to the rated voltage of the load;

[0098] When a short circuit fault occurs on the load side, by increasing the duty cycle of the driving signals of the second cryogenic power switch 11 and the fifth cryogenic power switch 14, the superconducting energy storage magnet 15 absorbs the power supply power through the second normal temperature capacitor 10, so that the second normal temperature capacitor 10 generates a voltage with the same amplitude and opposite direction as the power supply voltage, thereby realizing the short circuit fault current limiting operation of the load line;

[0099] When the duration of the short circuit fault on the load side reaches the upper limit threshold of the current limiting time, the normal temperature power switch 9 is closed, the superconducting DC circuit breaker submodule enters the circuit breaking mode, the first low temperature power switch 1 is turned off, and the circuit breaking operation on the load side is completed.

[0100] The superconducting energy storage magnet 15 discharges the second normal temperature capacitor 10 through the third low temperature power switch 12 and the second low temperature power switch 11 to compensate the normal temperature capacitor, and further includes:

[0101] When the current of the superconducting energy storage magnet 15 is lower than the rated operating current, the fuel cell 19 is started, the superconducting energy storage magnet 15 is charged through the superconducting current limiting resistor 18, the third superconducting inductor 17, and the third cryogenic diode 16, and the duty cycle of the driving signal of the sixth cryogenic power switch 20 is dynamically adjusted to maintain the current of the superconducting energy storage magnet 15 at the rated operating value;

[0102] When a short circuit fault occurs in the sixth cryogenic power switch 20 or / and the third superconducting inductor 17 or / and the third cryogenic diode 16 or / and the superconducting energy storage magnet 15, the superconducting current limiting resistor 18 increases its resistance from zero resistance to limit the short circuit fault current; when all short circuit faults are cleared, the superconducting current limiting resistor returns to the zero resistance state.

[0103] It also includes closing the normal temperature power switch 9 when a short circuit fault occurs on the power supply side, causing the superconducting DC circuit breaker submodule to enter the circuit breaking mode, turning off the first low temperature power switch 1, and realizing electrical isolation between the power supply side and the load side; at the same time, compensating for the insufficient energy on the load side through the superconducting energy storage-fuel cell combined compensation submodule to realize uninterrupted power supply to the load side.

[0104] The fuel cell uses hydrogen as fuel, and the fuel is stored in large capacity in the form of 20K liquid hydrogen. When the fuel cell is started, the liquid hydrogen first needs to be vaporized into low-temperature hydrogen, and then heated to 300K through a multi-stage heat exchange pipeline, and then input into the fuel cell to generate electricity. The superconducting energy storage magnet 15, the superconducting current limiting resistor 18, the first superconducting inductor 2, the second superconducting inductor 3, and the third superconducting inductor 17 are completely immersed in 20K low-temperature liquid hydrogen. The first low-temperature power switch 1, the second low-temperature power switch 11, the third low-temperature power switch 12, the fourth low-temperature power switch 13, the fifth low-temperature power switch 14, the sixth low-temperature power switch 20, the first low-temperature diode 5, the second low-temperature diode 7, and the third low-temperature diode 16 are installed in a multi-stage heat exchange pipeline, and the low-temperature operating environment is maintained by low-temperature hydrogen.

[0105] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. Superconducting circuit breaker-energy storage-fuel cell combined compensation DC customized power system, It is characterized in that It includes a superconducting DC circuit breaker submodule and a superconducting energy storage-fuel cell combined compensation submodule; The superconducting DC circuit breaker submodule includes a first low-temperature power switch, a first superconducting inductor, a second superconducting inductor, a first energy release resistor, a first low-temperature diode, a first normal-temperature capacitor, a second low-temperature diode, a second energy release resistor, and a normal-temperature power switch, wherein the first superconducting inductor and the second superconducting inductor form a pair of coupled inductors; The first cryogenic power switch is connected to the same-name end of the first superconducting inductor; the same-name end of the second superconducting inductor is connected to a common point between the first cryogenic power switch and the first superconducting inductor; The non-same-name end of the second superconducting inductor is connected to one end of the first normal-temperature capacitor, and the other end of the first normal-temperature capacitor is connected to the ground of the power supply; The non-same-name end of the first superconducting inductor is connected to one end of the normal-temperature power switch, and the other end of the normal-temperature power switch is connected to the ground of the power supply; One end of the first energy release resistor is connected to the anode of the first low-temperature diode, and the other end is connected to the same-name end of the second superconducting inductor, and the cathode of the first low-temperature diode is connected to the non-same-name end of the second superconducting inductor; The cathode of the second low-temperature diode is connected to the same-name end of the first superconducting inductor, the anode of the second low-temperature diode is connected to the second energy release resistor, and the other end of the second energy release resistor is connected to the non-same-name end of the first superconducting inductor; The superconducting energy storage-fuel cell joint compensation submodule includes a second normal temperature capacitor, a second low temperature power switch, a third low temperature power switch, a fourth low temperature power switch, a fifth low temperature power switch, a superconducting energy storage magnet, a third low temperature diode, a third superconducting inductor, a superconducting current limiting resistor, a fuel cell, and a sixth low temperature power switch; One end of the second normal temperature capacitor is connected to a common point between the first superconducting inductor and the normal temperature power switch, and the other end of the second normal temperature capacitor is connected to a load; The second low-temperature power switch is connected in series with the third low-temperature power switch, and the two are connected in series and then connected in parallel with the second normal temperature capacitor; The fourth low-temperature power switch is connected in series with the fifth low-temperature power switch, and the two are connected in series and then connected in parallel with the second normal temperature capacitor; One end of the superconducting energy storage magnet is connected to a common point between the second cryogenic power switch and the third cryogenic power switch, and the other end is connected to a common point between the fourth cryogenic power switch and the fifth cryogenic power switch; The cathode of the third low-temperature diode is connected to one end of the superconducting energy storage magnet, the anode of the third low-temperature diode is connected to one end of the third superconducting inductor, the other end of the third superconducting inductor is connected to one end of the superconducting current limiting resistor, the other end of the superconducting current limiting resistor is connected to the positive electrode of the fuel cell, and the negative electrode of the fuel cell is connected to the other end of the superconducting energy storage magnet; One end of the sixth low-temperature power switch is connected to a common point between the third superconducting inductor and the third low-temperature diode, and the other end is connected to the negative electrode of the fuel cell.

2. The DC customized power system of superconducting circuit breaker-energy storage-fuel cell combined compensation according to claim 1, It is characterized in that The working method of the superconducting DC circuit breaker submodule includes the following process: When the load side works normally, the superconducting DC circuit breaker submodule enters the steady-state mode; the power supply supplies power to the load side through the first low-temperature power switch, the first superconducting inductor, and the second normal temperature capacitor in sequence; the voltage of the first normal temperature capacitor is equal to the power supply voltage, and the current flowing through the first normal temperature capacitor and the second superconducting inductor is zero; When the load side needs to disconnect the power supply, the superconducting DC circuit breaker submodule enters the circuit breaking mode by closing the normal temperature power switch; the first normal temperature capacitor forms a closed discharge loop through the second superconducting inductor, the first superconducting inductor, and the normal temperature power switch; when the current of the second superconducting inductor flows out from the same-name end, the same-name end of the first superconducting inductor generates an induced current according to the inductive coupling ratio; when the current amplitude flowing out of the same-name end of the second superconducting inductor rises to be equal to the current of the first superconducting inductor, the current flowing through the first low-temperature power switch will drop to zero, and the first low-temperature power switch will be immediately shut down with zero current to complete the circuit breaking operation on the load side.

3. The DC customized power system of superconducting circuit breaker-energy storage-fuel cell combined compensation according to claim 1, It is characterized in that The working method of the superconducting energy storage-fuel cell joint compensation submodule includes the following process: The driving signal of the second low-temperature power switch is the same as that of the fifth low-temperature power switch; the driving signal of the third low-temperature power switch is the same as that of the fourth low-temperature power switch, and the driving signal is complementary to the driving signals of the second low-temperature power switch and the fifth low-temperature power switch; By changing the duty ratio of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch, the superconducting energy storage magnet absorbs excess energy of the second normal temperature capacitor or compensates for insufficient energy; The third low-temperature diode, the superconducting current limiting resistor, the third superconducting inductor, and the sixth low-temperature power switch constitute a boost chopper circuit, and the charging power of the fuel cell to the superconducting energy storage magnet is adjusted by changing the duty cycle of the sixth low-temperature power switch drive signal.

4. A superconducting circuit breaker-energy storage-fuel cell combined compensation method for a DC customized power system based on the superconducting circuit breaker-energy storage-fuel cell combined compensation of claim 1, It is characterized in that The process includes the following: When the power supply voltage is equal to the rated voltage of the load, the power supply supplies power to the load through the superconducting DC circuit breaker submodule and the second normal temperature capacitor; the duty cycle of the drive signal of the second low temperature power switch and the fifth low temperature power switch is equal to 50%, so that the total energy interaction between the second normal temperature capacitor and the superconducting energy storage magnet in the positive and negative half cycles is zero; When the power supply voltage is higher than the rated voltage of the load, by adjusting the duty cycle range of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch to 50%-100%, the superconducting energy storage magnet absorbs the excess energy of the second normal temperature capacitor through the second cryogenic power switch and the fifth cryogenic power switch, so that the output terminal voltage of the second normal temperature capacitor is equal to the rated voltage of the load; When the power supply voltage is lower than the rated voltage of the load, the duty cycle range of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch is adjusted to 0%-50%, and the superconducting energy storage magnet compensates for the insufficient energy of the second normal temperature capacitor through the third cryogenic power switch and the fourth cryogenic power switch, so that the output terminal voltage of the second normal temperature capacitor is equal to the rated voltage of the load; When a short circuit fault occurs on the load side, by increasing the duty cycle of the driving signals of the second cryogenic power switch and the fifth cryogenic power switch, the superconducting energy storage magnet absorbs the power supply power through the second normal temperature capacitor, so that the second normal temperature capacitor generates a voltage with the same amplitude and opposite direction as the power supply voltage, thereby realizing the short circuit fault current limiting operation of the load line; When the duration of the short-circuit fault on the load side reaches the upper limit threshold of the current limiting time, the room temperature power switch is closed, the superconducting DC circuit breaker submodule enters the circuit breaking mode, the first low temperature power switch is turned off, and the circuit breaking operation on the load side is completed.

5. The superconducting circuit breaker-energy storage-fuel cell combined compensation method according to claim 4, It is characterized in that The superconducting energy storage magnet discharges the second normal temperature capacitor through the third low temperature power switch and the second low temperature power switch to compensate the normal temperature capacitor, and further comprises: When the current of the superconducting energy storage magnet is lower than the rated operating current, the fuel cell is started, the superconducting energy storage magnet is charged through the superconducting current limiting resistor, the third superconducting inductor, and the third low-temperature diode, and the duty cycle of the driving signal of the sixth low-temperature power switch is dynamically adjusted to maintain the current of the superconducting energy storage magnet at the rated operating value; When a short circuit fault occurs in the sixth cryogenic power switch or / and the third superconducting inductor or / and the third cryogenic diode or / and the superconducting energy storage magnet, the superconducting current limiting resistor increases its resistance from zero resistance to limit the short circuit fault current; when all short circuit faults are cleared, the superconducting current limiting resistor returns to a zero resistance state.

6. The superconducting circuit breaker-energy storage-fuel cell combined compensation method according to claim 4, It is characterized in that It also includes closing the normal temperature power switch when a short circuit fault occurs on the power supply side, causing the superconducting DC circuit breaker submodule to enter the circuit breaking mode, turning off the first low temperature power switch, and realizing electrical isolation between the power supply side and the load side; at the same time, compensating for the insufficient energy on the load side through the superconducting energy storage-fuel cell combined compensation submodule to realize uninterrupted power supply to the load side.

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