A energy storage type large current rapid demagnetization device

Abstract

The embodiment of the present invention discloses an energy storage type large current rapid demagnetization device, comprising: a DC excitation power supply, a DC excitation winding, a demagnetization switch, an isolation transformer, a primary side directional diode, a secondary side directional diode, a capacitor, a first discharge switch and a discharge circuit; the demagnetization switch is connected in series between the DC excitation power supply and the DC excitation winding, and the demagnetization switch, the DC excitation power supply and the DC excitation winding constitute a first series circuit; the primary side directional diode is connected in series to the primary side of the isolation transformer, and the primary side directional diode is connected in parallel to both ends of the DC excitation winding; the secondary side of the isolation transformer, the secondary side directional diode and the capacitor are connected in series; the first discharge switch is connected in series with the discharge circuit and then connected in parallel with the capacitor to form a second series circuit. The functions of rapid demagnetization and energy transfer, storage and reuse are realized at the same time, and the isolation effect of the directional diode and the isolation transformer does not affect the access of the DC excitation power supply and the re-excitation process of the excitation winding.

Description

Technical Field

[0001] The invention relates to the technical field of rapid demagnetization, and in particular to an energy storage type large current rapid demagnetization device. Background Art

[0002] The DC excitation winding (also called the excitation winding) is a coil winding that can generate a constant DC magnetic field. DC excitation windings are generally used in motors and generators, and are divided into series excitation and parallel excitation. The use of excitation windings in generators can replace permanent magnets, generate a strong magnetic flux density that permanent magnets cannot generate, and is easy to adjust, thereby achieving high-power power generation. DC excitation windings are also commonly used in saturated iron core type current limiting reactors. Under normal operating conditions, a constant DC magnetic field is generated to keep the core of the current limiter in a saturated state, ensuring that the current limiter does not affect the power transmission of the line.

[0003] In recent years, the rated excitation current of DC excitation windings has gradually increased with the increase in the capacity of generators, motors and current limiters. When a synchronous generator fails, a large amount of energy in the magnetic field of the excitation winding must be quickly transferred or eliminated to reduce the expansion of the accident and protect the generator set; when a short circuit occurs in the power grid system, it is necessary to quickly disconnect the DC excitation power supply and transfer or eliminate a large amount of energy in the DC excitation winding so that the current limiter can be quickly put into use and limit the peak current to protect various equipment in the line. Since DC excitation windings usually have large inductance characteristics, it is difficult to quickly transfer or eliminate the energy therein. Therefore, it is very necessary to improve the performance of demagnetization protection devices. It is generally required that the demagnetization device can cope with different harsh working conditions while ensuring safety, and quickly and reliably transfer or consume the energy stored in the DC excitation winding. In addition, the demagnetization device should also be easy to operate and maintain.

[0004] For the fast demagnetization device of DC excitation winding, in addition to meeting the basic operating requirements of the demagnetization device, the following three basic requirements should also be met:

[0005] 1. The demagnetization speed should be as fast as possible, that is, the time should be shortened as much as possible.

[0006] 2. During the demagnetization process, the voltage across the DC excitation winding cannot exceed the specified limit.

[0007] 3. At the end of the demagnetization process, it must be ensured that the residual excitation current is lower than the limit.

[0008] Among the above three basic requirements, demagnetization time is the most important indicator for judging the performance of demagnetization device. It is usually defined as the time between the demagnetization device being activated and the demagnetization being completed. The rapidity of demagnetization device is related to the safety and stability of equipment and even the power grid system, so it is necessary to give priority to the demagnetization time indicator.

[0009] According to different principles, demagnetization can be divided into the following three types:

[0010] 1. Energy-consuming demagnetization

[0011] Early series demagnetization belongs to energy-consuming demagnetization. Its working principle is: using the demagnetization switch to consume the energy in the excitation winding. When the demagnetization switch jumps, the magnetic energy in the excitation circuit forms an arc in the combustion chamber. When the energy is exhausted, the arc extinguishes. Before the 1980s, since most excitation systems used direct current or multi-machine excitation methods, the demagnetization method basically chose the series demagnetization method. However, due to its poor switching reliability, high failure rate, low demagnetization efficiency, poor arc breaking ability and many other shortcomings, other countries in the world have not developed and applied this demagnetization system. At present, this type of demagnetization switch has been eliminated from the market.

[0012] 2. Energy transfer type demagnetization

[0013] With the emergence of thyristor self-shunt excitation system, the demagnetization method has also changed from energy-consuming type achieved by circuit breakers to energy-transfer type. The energy-transfer type refers to the method of using circuit breakers and jumpers to transfer the magnetic field energy in the excitation circuit during demagnetization. The working principle of this type of demagnetization method is: the demagnetization system connects the excitation winding to the demagnetization circuit by actuating the demagnetization switch. The demagnetization circuit is connected to an energy-consuming element, which consumes the energy in the excitation winding. Energy-consuming elements can be divided into linear resistors and nonlinear resistors, so energy-transfer demagnetization can be roughly divided into the following two forms:

[0014] (1) Energy transfer demagnetization switch and linear resistor combination

[0015] The demagnetization circuit of this demagnetization method is relatively simple, but it also has many disadvantages, such as long demagnetization time, serious tailing phenomenon, and failure to achieve rapid demagnetization when a fault occurs. In addition, this type of demagnetization switch often malfunctions, making maintenance difficult and threatening the safety of the equipment.

[0016] (2) Energy transfer demagnetization switch and nonlinear resistor combination

[0017] Since the 1980s, nonlinear resistor demagnetization has been increasingly widely used. Nonlinear resistor demagnetization can effectively increase the demagnetization speed, and common ones include zinc oxide (ZnO) and silicon carbide (SiC) resistors.

[0018] The demagnetization method commonly used now is the energy transfer demagnetization method that combines an energy transfer demagnetization switch with a nonlinear resistor. The energy in the excitation winding is transferred by the demagnetization switch, and the nonlinear resistor in the demagnetization circuit consumes this energy. Although this method can achieve rapid demagnetization, the energy in the DC excitation winding is consumed by the nonlinear resistor and cannot be reused, which will cause energy waste. Therefore, this method does not meet the needs of energy-saving development of the power system.

[0019] 3. Energy storage demagnetization

[0020] In order to utilize the large amount of energy stored in the DC excitation winding during demagnetization, some scholars have proposed energy storage demagnetization methods. Energy storage demagnetization methods mainly include the following two types:

[0021] (1) Battery Energy Storage

[0022] Connecting a battery to the demagnetization circuit can transfer the energy in the excitation winding to the battery during the demagnetization process, realizing energy storage and conversion. The advantage of battery demagnetization is that it can realize the reuse of excitation energy and the demagnetization speed is relatively stable; the disadvantage is that the demagnetization speed is slow and it is easy to cause damage to the battery, which in turn affects the reliability of the demagnetization circuit.

[0023] (2) Capacitor energy storage

[0024] By connecting a large capacitor to the demagnetization circuit, the energy in the excitation winding can be quickly transferred to the large capacitor during the demagnetization process. The advantage is that the demagnetization speed is fast, and the energy stored in the capacitor can be reused through the subsequent discharge step; the disadvantage is that during the rapid demagnetization process, the energy is quickly transferred to the capacitor. If the selected capacitor capacity is small, the terminal voltage at both ends of the capacitor will increase rapidly, which may cause damage to the capacitor; if the selected capacitor capacity is large, the demagnetization speed will be reduced. In addition, since there is no isolation equipment in the device, the presence of the capacitor may harm the re-excitation process of the DC excitation winding. Summary of the invention

[0025] An embodiment of the present invention provides an energy storage type large current rapid demagnetization device, which improves the capacitor energy storage type demagnetization device by adding an isolation transformer in the demagnetization circuit, and aims to realize the storage and reuse of energy in the excitation winding on the basis of giving priority to ensuring the rapidity of demagnetization. At the same time, the capacity of the capacitor can be increased to ensure the safety of the capacitor, and isolation equipment can be added in the demagnetization circuit to prevent the capacitor elements from endangering the re-excitation process of the DC excitation winding.

[0026] The first aspect of the present invention provides an energy storage type large current rapid demagnetization device, comprising:

[0027] A DC excitation power supply, a DC excitation winding, a demagnetization switch, an isolation transformer, a primary-side directional diode, a secondary-side directional diode, a capacitor, a first discharge switch and a discharge circuit;

[0028] The demagnetization switch is connected in series between the DC excitation power supply and the DC excitation winding, and the demagnetization switch, the DC excitation power supply and the DC excitation winding form a first series circuit;

[0029] The primary-side directional diode is connected in series to the primary side of the isolation transformer, and the primary-side directional diode is connected in parallel to both ends of the DC excitation winding;

[0030] The secondary side of the isolation transformer, the secondary side directional diode and the capacitor are connected in series;

[0031] The first discharge switch is connected in series with the discharge loop and then in parallel with the capacitor to form a second series loop.

[0032] Optionally, the device further comprises:

[0033] A second discharge switch and a discharge circuit;

[0034] The second discharge switch is connected in series with the discharge loop and then connected in parallel to both ends of the capacitor.

[0035] Optionally, the turns ratio of the isolation transformer is N:1, where N is greater than a first threshold.

[0036] Optionally, the demagnetization switch is used to connect the DC excitation power supply and the DC excitation winding during excitation, and disconnect the DC excitation power supply during demagnetization.

[0037] Optionally, the discharge switch is used to connect the capacitor to the discharge circuit after the demagnetization process is completed.

[0038] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0039] In an embodiment of the present invention, a storage type large current rapid demagnetization device is provided, including: a DC excitation power supply, a DC excitation winding, a demagnetization switch, an isolation transformer, a primary side directional diode, a secondary side directional diode, a capacitor, a first discharge switch and a discharge circuit; the demagnetization switch is connected in series between the DC excitation power supply and the DC excitation winding, and the demagnetization switch, the DC excitation power supply and the DC excitation winding constitute a first series circuit; the primary side directional diode is connected in series to the primary side of the isolation transformer, and the primary side directional diode is connected in parallel to both ends of the DC excitation winding; the secondary side of the isolation transformer, the secondary side directional diode and the capacitor are connected in series; the first discharge switch is connected in series with the discharge circuit and then connected in parallel with the capacitor to form a second series circuit. In the above manner, by introducing an isolation transformer to cooperate with the capacitor, the functions of rapid demagnetization and energy transfer, storage and reuse are realized at the same time, and the isolation effect of the directional diode and the isolation transformer does not affect the access to the DC excitation power supply and the re-excitation process of the excitation winding. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the structure of an energy storage type large current rapid demagnetization device in an embodiment of the present invention;

[0041] Figure 2 It is a schematic diagram of the equivalent circuit of the energy storage type large current rapid demagnetization device when it is in the DC excitation state;

[0042] Figure 3It is a schematic diagram of the equivalent circuit of the energy storage type large current rapid demagnetization device when it is in the demagnetization state;

[0043] Figure 4 It is a schematic diagram of the current curve of the DC excitation winding when the energy storage type large current rapid demagnetization device is demagnetized;

[0044] Figure 5 It is a schematic diagram of the equivalent circuit when the energy storage type large current rapid demagnetization device is in the capacitor discharge state. DETAILED DESCRIPTION

[0045] The embodiment of the present invention provides an energy storage type large current rapid demagnetization device, which simultaneously realizes the functions of rapid demagnetization and energy transfer, storage and reuse by introducing an isolation transformer and cooperating with a capacitor. Through the isolation effect of a directional diode and an isolation transformer, the access to a DC excitation power supply and the re-excitation process of an excitation winding are not affected.

[0046] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] See also Figure 1 In one embodiment of the present invention, an energy storage type large current rapid demagnetization device comprises:

[0048] A DC excitation power supply, a DC excitation winding, a demagnetization switch, an isolation transformer, a primary-side directional diode, a secondary-side directional diode, a capacitor, a first discharge switch and a discharge circuit;

[0049] The demagnetization switch is connected in series between the DC excitation power supply and the DC excitation winding, and the demagnetization switch, the DC excitation power supply and the DC excitation winding form a first series circuit;

[0050] The primary-side directional diode is connected in series to the primary side of the isolation transformer, and the primary-side directional diode is connected in parallel to both ends of the DC excitation winding;

[0051] The secondary side of the isolation transformer, the secondary side directional diode and the capacitor are connected in series;

[0052] The first discharge switch is connected in series with the discharge loop and then in parallel with the capacitor to form a second series loop.

[0053] Optionally, the device further comprises:

[0054] A second discharge switch and a discharge circuit;

[0055] The second discharge switch is connected in series with the discharge loop and then connected in parallel to both ends of the capacitor.

[0056] Optionally, the turns ratio of the isolation transformer is N:1, where N is greater than a first threshold.

[0057] Optionally, the demagnetization switch is used to connect the DC excitation power supply and the DC excitation winding during excitation, and disconnect the DC excitation power supply during demagnetization.

[0058] Optionally, the discharge switch is used to connect the capacitor to the discharge circuit after the demagnetization process is completed.

[0059] The demagnetization switch K1 is connected in series between the DC excitation power supply and the DC excitation winding. It is used to connect the DC excitation power supply and the DC excitation winding during excitation, disconnect the DC excitation power supply during demagnetization, and transfer energy to the demagnetization circuit. R and L are the equivalent resistance and equivalent inductance of the DC excitation winding. The primary side AX of the isolation transformer is connected in series with the primary side directional diode D1 and then connected in parallel to both ends of the DC excitation winding. The secondary side ax is connected in series with the secondary side directional diode D2 and capacitor C. The turns ratio of the primary side to the secondary side of the isolation transformer is N:1; diodes D1 and D2 determine the current flow direction of the primary and secondary sides of the isolation transformer. U L ,I L , U C They are the voltage across the DC excitation winding, the current across the DC excitation winding and the voltage across the capacitor, and their directions are specified as follows: Figure 1 The discharge switch K2 is connected in series with the discharge circuit and then in parallel with both ends of the capacitor C, so as to reuse the energy stored in the capacitor through the discharge circuit after the demagnetization process is completed.

[0060] The energy storage type large current rapid demagnetization device of the present invention has four states: DC excitation state, demagnetization state, capacitor discharge state and excitation winding re-excitation state. The various working states of the energy storage type large current rapid demagnetization device are analyzed below.

[0061] 1. DC excitation state

[0062] Figure 2 This is the equivalent circuit of the energy storage type large current rapid demagnetization device in the DC excitation state. At this time, the demagnetization switch K1 of the demagnetization device is closed, the DC excitation power supply supplies power to the DC excitation winding, and the DC excitation winding passes a constant current I LSince the primary-side directional diode D1 is subjected to reverse voltage at this time, the isolation transformer and the excitation winding are disconnected, and no energy flows.

[0063] 2. Demagnetization state

[0064] Figure 3 This is the equivalent circuit of the energy storage type large current rapid demagnetization device in the demagnetization state. When the DC excitation winding receives the command for rapid demagnetization, the demagnetization switch K1 of the demagnetization device is disconnected, and the discharge switch K2 is disconnected. Since the inductance L of the DC excitation winding has a freewheeling function, the diodes D1 and D2 are subjected to positive voltage and are turned on. The equivalent circuit is an RLC series circuit with an isolation transformer. From the second-order circuit analysis, it can be seen that the energy in the inductance L will be quickly transferred to the capacitor through the transformer, and the current I on the inductance L L From the initial value I L (0 + )=IL(0_) rapidly decreases to 0, I L (0_) is the current on the inductor L when the demagnetization switch K1 is turned off. L After decreasing to 0, since diodes D1 and D2 are turned off due to reverse voltage, the energy stored in capacitor C cannot return to inductor L. Therefore, when all the energy in the DC excitation winding is transferred to capacitor C, the demagnetization state ends, that is, the demagnetization device completes the demagnetization.

[0065] To simplify the analysis, the isolation transformer is regarded as an ideal transformer and can be described by the second-order differential equation (1): Figure 3 The equivalent circuit of . According to KVL and KCL theory, we can get:

[0066]

[0067] This equation is a homogeneous differential equation, and its characteristic equation is formula (2):

[0068]

[0069] The characteristic roots are:

[0070]

[0071] Where: β = R / 2L, For different circuit parameters R, L, C and turns ratio N, the characteristic roots have the following three different situations.

[0072] (1) When 2β>ω0, s1 and s2 are two unequal real roots

[0073]

[0074] The solution of the differential equation is formula (3):

[0075]

[0076] The unknown coefficients A1 and A2 can be obtained from I L and dI L / dt initial value is obtained. Finally, I L The expression of is formula (4):

[0077]

[0078] It can be seen from formula (4) that I L It decays exponentially and finally approaches 0. This is an overdamped non-oscillatory process.

[0079] (2) When 2β=ω0, s1 and s2 are multiple roots, that is,

[0080] s1=s2=-β

[0081] The solution of the differential equation is formula (5):

[0082] I L =I L (0 + )(1+βt)e -βt (t≥0) (5)

[0083] It can be seen from formula (5) that I L The change of is similar to that of the over-damped non-oscillatory process, but the decay speed is faster than that of the over-damped non-oscillatory process, that is, it is in a critical state.

[0084] (3) When 2β<ω0, s1 and s2 are a pair of conjugate complex roots. After further determining the unknown coefficients A1 and A2, we can get I L The expression of is formula (6):

[0085]

[0086] It can be seen from formula (6) that I L It is a sine wave whose amplitude decays exponentially, that is, an underdamped oscillation process.

[0087] According to equations (4)-(6) and the analysis of the demagnetization process, the current I of the inductor L can be obtained: L Schematic diagram of the curve changing with time. Figure 4 This is the current curve of the DC excitation winding when the energy storage type large current rapid demagnetization device is demagnetized, where:

[0088] ω0(4)>ω0(3)>2β=ω0(2)>ω0(1)

[0089] Depend on Figure 4 It can be seen that when β remains unchanged, the current I L From the initial value IL (0 + ) decreases to 0 as ω0 increases. Since β=R / 2L, Among them, R and L are equivalent parameters of the DC excitation winding and cannot be changed. Therefore, in a certain system, β remains unchanged. The factor affecting the demagnetization time is ω0, that is, increasing the turns ratio N of the isolation transformer or reducing the capacitance C can increase the demagnetization speed of the DC excitation winding and achieve rapid demagnetization.

[0090] Next, consider the energy transfer problem before and after demagnetization. At the beginning of demagnetization, all the energy is stored in the inductor L. After demagnetization is completed, except for a small amount of energy consumed by the resistor R, basically all the energy is transferred and stored in the capacitor C. The energy in the inductor L is W L =LI L 2 / 2, in a certain system, the initial energy in the equivalent inductance L is certain; the energy in the capacitor is W C =CU C 2 / 2, if the energy consumed by the equivalent resistance R is ignored, it can be approximately considered that W C =W L Therefore, the size of the capacitor C is not only related to the demagnetization time, but also to the energy stored in the capacitor. Although reducing the capacitor C can increase the demagnetization speed and achieve faster demagnetization, at the same time, the voltage U across the capacitor C C It must be increased accordingly to ensure that the same amount of energy can be stored. However, capacitors have a certain voltage tolerance level, and the voltage across them cannot be increased indefinitely, otherwise it may cause damage to the capacitor. This is a contradiction that ordinary capacitor energy storage demagnetization devices cannot solve.

[0091] The energy storage type large current rapid demagnetization device of the present invention introduces the turns ratio N of the isolation transformer to solve the above problem. According to the energy formula of the capacitor C and the inductor L, it can be obtained that the voltage across the capacitor C does not exceed the limit value U Cmax In the case of

[0092]

[0093] After determining the value of the capacitor C, the value of the turns ratio N of the isolation transformer can be determined according to the actual project's need for rapid demagnetization time. In this way, the functions of rapid demagnetization and energy transfer and storage can be achieved while ensuring that the voltage across the capacitor does not exceed the rated value and that the capacitor works safely and stably.

[0094] 3. Capacitor discharge state

[0095] Figure 5The figure is a schematic diagram of the equivalent circuit of the energy storage type large current rapid demagnetization device when it is in the capacitor discharge state. At this time, the discharge switch K2 is closed, the capacitor discharges to the discharge circuit, and the energy is transferred out for reuse. The discharge circuit is used to realize the reuse of electric energy, which can be an energy storage battery, device or system, or various current conversion equipment. Since the demagnetization is completed in this state, the isolation transformer and the isolation effect of diodes D1 and D2 ensure that the DC excitation winding will not be affected when the capacitor is discharged. In this way, the function of energy reuse is realized.

[0096] 4. Field winding re-excitation state

[0097] Equivalent circuit and diagram of energy storage type large current rapid demagnetization device in the DC excitation winding re-excitation state Figure 2 The same. At this time, the demagnetization switch K1 is closed, the DC excitation system is connected, and the DC excitation winding is re-excited. Due to the isolation effect of the isolation transformer and diodes D1 and D2, even if the energy on the capacitor has not been completely released at this time, it will not affect the re-excitation process of the excitation winding.

[0098] In an embodiment of the present invention, a storage type large current rapid demagnetization device is provided, including: a DC excitation power supply, a DC excitation winding, a demagnetization switch, an isolation transformer, a primary side directional diode, a secondary side directional diode, a capacitor, a first discharge switch and a discharge circuit; the demagnetization switch is connected in series between the DC excitation power supply and the DC excitation winding, and the demagnetization switch, the DC excitation power supply and the DC excitation winding constitute a first series circuit; the primary side directional diode is connected in series to the primary side of the isolation transformer, and the primary side directional diode is connected in parallel to both ends of the DC excitation winding; the secondary side of the isolation transformer, the secondary side directional diode and the capacitor are connected in series; the first discharge switch is connected in series with the discharge circuit and then connected in parallel with the capacitor to form a second series circuit. In the above manner, by introducing an isolation transformer to cooperate with the capacitor, the functions of rapid demagnetization and energy transfer, storage and reuse are realized at the same time, and the isolation effect of the directional diode and the isolation transformer does not affect the access to the DC excitation power supply and the re-excitation process of the excitation winding.

[0099] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0100] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0101] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0102] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0103] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0104] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy storage type large current rapid demagnetization device, characterized in that: include: A DC excitation power supply, a DC excitation winding, a demagnetization switch, an isolation transformer, a primary-side directional diode, a secondary-side directional diode, a capacitor, a first discharge switch and a discharge circuit; The demagnetization switch is connected in series between the DC excitation power supply and the DC excitation winding, and the demagnetization switch, the DC excitation power supply and the DC excitation winding form a first series circuit; The primary-side directional diode is connected in series to the primary side of the isolation transformer, and the primary-side directional diode is connected in parallel to both ends of the DC excitation winding; The secondary side of the isolation transformer, the secondary side directional diode and the capacitor are connected in series; The first discharge switch is connected in series with the discharge circuit and then connected in parallel to the two ends of the capacitor to form a second series circuit; The turns ratio of the isolation transformer is N:1, and N is greater than a first threshold; The demagnetization switch is used to connect the DC excitation power supply and the DC excitation winding during excitation, and disconnect the DC excitation power supply during demagnetization.

2. The demagnetization device according to claim 1, characterized in that: The first discharge switch is used to connect the capacitor to the discharge circuit after the demagnetization process is completed.

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