Quick excitation main circuit structure suitable for hybrid excitation synchronous generator

Abstract

The application belongs to the technical field of generator excitation control, and specifically discloses a quick excitation main circuit structure suitable for a hybrid excitation rectifier type synchronous generator, which comprises four IGBT switch tubes, two energy release IGBT switch tubes, six freewheeling diodes, two diodes, four energy release resistors, two energy release capacitors and an excitation winding. Under normal excitation working conditions, the excitation current controllable in both positive and negative directions can be output. In addition, under dynamic working conditions such as sudden addition and sudden removal of high-power loads of the generator, the quick release of the energy of the excitation winding can be realized, and the dynamic response speed of excitation control is improved.

Description

Technical Field

[0001] This application belongs to the field of generator excitation control technology, and more specifically, relates to a fast excitation main circuit structure suitable for hybrid excitation rectifier synchronous generators. Background Technology

[0002] The excitation source of the hybrid excitation rectifier synchronous generator is provided by permanent magnets in one part and by the ring-shaped electric excitation winding on the stator in the other part. This allows it to take advantage of the simple rotor structure, high-speed operation, high efficiency and high power density of permanent magnet motors. It can also achieve flexible adjustment of the air gap magnetic field through the stator electric excitation winding to meet the requirement of maintaining stable output voltage when the load or speed changes.

[0003] Hybrid-excitation rectifier synchronous generators have large transient reactance parameters and long voltage recovery times during sudden load increases and decreases. When this type of generator is used in a medium-voltage DC marine integrated power system, if a sudden unloading of the propulsion load occurs, the long voltage recovery time will trigger the inverter input capacitor overcurrent protection, potentially leading to a complete power outage. Therefore, whether this type of generator can quickly adjust the excitation current through a fast excitation regulation circuit to restore DC output voltage stability as soon as possible is a key problem that urgently needs to be solved. To achieve bidirectional fast regulation of the excitation current of this type of generator, if the traditional H-bridge excitation circuit topology is continued, the H-bridge input voltage needs to be significantly increased based on the rated excitation voltage and current. This results in a decrease in the accuracy of excitation current regulation under steady state, and at the same time, the capacitance of the switching transistors and the withstand voltage rating of the supporting capacitors need to be increased, which is not conducive to reducing the size and weight of the excitation device. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a fast excitation main circuit structure suitable for hybrid excitation rectifier synchronous generators, which aims to solve the problem of long voltage recovery time of hybrid excitation rectifier synchronous generators under dynamic operating conditions.

[0005] The first aspect of this application relates to a fast excitation main circuit structure suitable for a hybrid excitation rectifier synchronous generator, comprising: an excitation DC power supply, four IGBT switching transistors, two energy-discharging IGBT switching transistors, six freewheeling diodes, two diodes, four energy-discharging resistors, two energy-discharging capacitors, and an excitation winding. The positive terminal of the excitation DC power supply is connected to the collectors of the first and second IGBT switches, as well as the negative terminals of the first and second freewheeling diodes. The negative terminal of the excitation DC power supply is connected to the emitters of the third and fourth IGBT switches, as well as the positive terminals of the third and fourth freewheeling diodes. The emitter of the first IGBT switch is connected to the positive terminal of the first freewheeling diode, the collectors of the first and third IGBT switches, and the negative terminals of the fifth and third freewheeling diodes. The emitter of the second IGBT switch is connected to the positive terminal of the second freewheeling diode, the collectors of the second and fourth IGBT switches, and the negative terminals of the fifth and third freewheeling diodes. The collector of the first IGBT switch is connected to the cathodes of the sixth and fourth freewheeling diodes; the emitter of the first IGBT switch is connected to the anodes of the fifth and first freewheeling diodes, the positive terminal of the excitation winding, and the cathode of the second diode; the emitter of the second IGBT switch is connected to the anode of the sixth freewheeling diode, one end of the first and third leakage resistors, and the negative terminal of the excitation winding; the other end of the first leakage resistor is connected to the cathode of the first diode through the first leakage capacitor; the other end of the third leakage resistor is connected to the anode of the second diode through the second leakage capacitor; the second and fourth leakage resistors are connected in parallel with the first and second leakage capacitors, respectively.

[0006] In some implementations, the fast excitation main circuit structure is used to output a bidirectional controllable excitation current under normal excitation conditions.

[0007] In some implementations, the fast excitation main circuit structure is used to generate a positive excitation current flowing into the positive terminal and out the negative terminal of the excitation winding under normal excitation conditions; the operation mode of the fast excitation main circuit structure is as follows: The first IGBT switch remains on, while the second, third, and fourth IGBT switches remain off. The first and fourth IGBT switches are simultaneously on. The excitation DC power supply forms a path with the excitation winding through the first IGBT switch, the first IGBT switch, the sixth freewheeling diode, and the fourth IGBT switch. The positive and negative terminals of the excitation winding are directly connected to the positive and negative terminals of the excitation DC power supply, respectively, to generate a positive excitation current flowing in from the positive terminal and out from the negative terminal of the excitation winding. The first and fourth IGBT switches control the voltage input to the excitation winding from the excitation DC power supply by adjusting their duty cycles, thereby controlling the magnitude of the positive excitation current.

[0008] In some implementations, the fast excitation main circuit structure is used to generate a reverse excitation current flowing into the negative terminal and out the positive terminal of the excitation winding under normal excitation conditions. The operation mode of the fast excitation main circuit structure is as follows: The second IGBT switch remains on, while the first, third, and fourth IGBT switches remain off. The second and third IGBT switches are simultaneously on. The excitation DC power supply forms a path with the excitation winding through the second, third, and fourth IGBT switches. The positive and negative terminals of the excitation winding are directly connected to the negative and positive terminals of the excitation DC power supply, respectively, to generate a reverse excitation current flowing in from the negative terminal and out from the positive terminal of the excitation winding. The second and third IGBT switches are used to adjust the duty cycle to control the voltage input from the excitation DC power supply to the excitation winding, thereby controlling the magnitude of the reverse excitation current.

[0009] The fast excitation main circuit is the core power unit of the generator excitation system. Its function is to provide a continuously adjustable and fast-response excitation current to the generator rotor winding, thereby establishing and regulating the internal magnetic field of the generator, and realizing reliable voltage build-up, stable voltage regulation and dynamic voltage stabilization.

[0010] More specifically, when the generator is running under no-load or low-power load, the stator current armature response is weak and cannot counteract the permanent magnet magnetomotive force to stabilize the output voltage. In order to achieve demagnetization control of the permanent magnet field, the excitation current flows in from the negative end of the excitation winding and flows out from the positive end to form a reverse excitation current. When the generator suddenly increases the power load, the fast excitation main circuit is used to discharge the reverse excitation current and improve the excitation current response speed, thereby ensuring the generator's rapid dynamic voltage stabilization. When the generator is operating under high-power load, the stator current armature response is strong and cannot enhance the permanent magnet magnetomotive force to stabilize the output voltage. In order to achieve magnetization control of the permanent magnet magnetic field, the excitation current flows in from the positive end of the excitation winding and flows out from the negative end to form a positive excitation current. When the generator suddenly unloads a high-power load, the fast excitation main circuit is used to discharge the positive excitation current and improve the excitation current response speed, thereby ensuring the generator's rapid dynamic voltage stabilization.

[0011] In some implementations, the fast excitation main circuit is used to discharge the reverse excitation current in the following way: the second energy-discharging IGBT switch Q6 is turned off, the excitation current is freewheeled through the first diode, so that the excitation winding forms a circuit with the first energy-discharging capacitor, the first energy-discharging resistor and the second energy-discharging resistor, and the energy of the excitation winding is released through energy transfer and consumption.

[0012] In some implementations, the fast excitation main circuit is used to discharge the positive excitation current in the following way: the first energy-discharging IGBT switch Q5 is turned off, the excitation current is freewheeled through the second diode, so that the excitation winding forms a circuit with the second energy-discharging capacitor, the third energy-discharging resistor and the fourth energy-discharging resistor, and the energy of the excitation winding is released through energy transfer and consumption.

[0013] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: This application provides a fast excitation main circuit structure suitable for hybrid excitation rectifier synchronous generators. Addressing the large transient reactance parameters of hybrid excitation rectifier synchronous generators and to solve the inherent problem of long voltage recovery time under dynamic conditions, the fast excitation main circuit structure provided in this application can output a bidirectional controllable excitation current under normal excitation conditions. Furthermore, under dynamic conditions such as sudden application and removal of high-power loads, it can achieve rapid energy release of the excitation winding, improving the dynamic response speed of excitation control. The fast excitation main circuit structure provided in this application effectively solves the problem of input voltage limitations imposed by traditional H-bridge excitation circuit topologies on hybrid excitation rectifier synchronous generators under dynamic conditions. Additionally, the fast excitation main circuit structure provided in this application also solves the inherent problem of long voltage recovery time for this type of generator under dynamic conditions. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a fast excitation main circuit structure for a hybrid excitation rectifier synchronous generator provided in an embodiment of this application.

[0015] Figure 2 This is a schematic diagram of the working principle of the fast excitation main circuit structure provided in Embodiment 1 of this application when generating positive excitation current under normal excitation conditions.

[0016] Figure 3 This is a schematic diagram of the working principle of the fast excitation main circuit structure provided in Embodiment 2 of this application when generating reverse excitation current under normal excitation conditions.

[0017] Figure 4 This is a schematic diagram illustrating the working principle of the fast excitation main circuit structure provided in Embodiment 3 of this application, which rapidly releases the energy of the excitation winding L under dynamic operating conditions of a sudden increase in power load in the power generation system.

[0018] Figure 5 This is a schematic diagram illustrating the working principle of the fast excitation main circuit structure provided in Embodiment 4 of this application, which rapidly releases the energy of the excitation winding L under the dynamic operating condition of sudden unloading of a large power load in the power generation system. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. In this application, the symbol " / " indicates that the related objects are in an "or" relationship, for example, A / B means A or B.

[0021] In this application, the terms “first” and “second” are used to distinguish different objects, rather than to describe a specific order of objects.

[0022] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0023] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0024] The embodiments of this application are described below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, this application embodiment provides a fast excitation main circuit structure suitable for hybrid excitation rectifier synchronous generators, including: an excitation DC power supply, a first IGBT switch Q1, a second IGBT switch Q2, a third IGBT switch Q3, a fourth IGBT switch Q4, a first energy-discharging IGBT switch Q5, a second energy-discharging IGBT switch Q6, a first freewheeling diode D1, a second freewheeling diode D2, a third freewheeling diode D3, a fourth freewheeling diode D4, a fifth freewheeling diode D5, a sixth freewheeling diode D6, a first diode D7, a second diode D8, a first energy-discharging resistor R1, a second energy-discharging resistor R2, a third energy-discharging resistor R3, a fourth energy-discharging resistor R4, a first energy-discharging capacitor C1, a second energy-discharging capacitor C2, and an excitation winding L; like Figure 1In the fast excitation main circuit structure shown, the positive terminal DC+ of the excitation DC power supply is connected to the collector of the first IGBT switch Q1, the collector of the second IGBT switch Q2, the negative terminal of the first freewheeling diode D1, and the negative terminal of the second freewheeling diode D2, respectively; the negative terminal DC- of the excitation DC power supply is connected to the emitter of the third IGBT switch Q3, the emitter of the fourth IGBT switch Q4, the positive terminal of the third freewheeling diode D3, and the positive terminal of the fourth freewheeling diode D4, respectively; the emitter of the first IGBT switch Q1 is connected to the positive terminal of the first freewheeling diode D1, the collector of the first draining IGBT switch Q5, the negative terminal of the fifth freewheeling diode D5, the collector of the third IGBT switch Q3, and the negative terminal of the third freewheeling diode D3, respectively; the emitter of the second IGBT switch Q2 is connected to the positive terminal of the second freewheeling diode D2, the negative terminal of the second draining IGBT switch Q6, and the negative terminal of the second draining IGBT switch Q6, respectively. The collector, the negative terminal of the sixth freewheeling diode D6, the collector of the fourth IGBT switch Q4, and the negative terminal of the fourth freewheeling diode D4 are connected together; the emitter of the first discharge IGBT switch Q5 is connected to the positive terminal of the fifth freewheeling diode D5, the positive terminal of the first diode D7, the positive terminal F+ of the excitation winding L, and the negative terminal of the second diode D8, respectively; the emitter of the second discharge IGBT switch Q6 is connected to the positive terminal of the sixth freewheeling diode D6, one end of the first discharge resistor R1, the negative terminal F- of the excitation winding L, and one end of the third discharge resistor R3, respectively; the other end of the first discharge resistor R1 is connected to the negative terminal of the first diode D7 through the first discharge capacitor C1; the other end of the third discharge resistor R3 is connected to the positive terminal of the second diode D8 through the second discharge capacitor C2; the second discharge resistor R2 and the fourth discharge resistor R4 are connected in parallel with the first discharge capacitor C1 and the second discharge capacitor C2, respectively.

[0026] The following four embodiments illustrate the specific functions and working principles of the fast excitation main circuit structure for hybrid excitation rectifier synchronous generators provided in this application.

[0027] Example 1 The fast excitation main circuit structure of this application embodiment can generate a positive excitation current under normal excitation conditions. Embodiment 1 provides the working principle of the excitation main circuit generating a positive excitation current under normal excitation conditions. Specifically, such as Figure 2As shown, the first IGBT switch Q5 remains on, while the second IGBT switches Q6, Q2, and Q3 remain off. The first IGBT switch Q1 and the fourth IGBT switch Q4 are simultaneously turned on, allowing the excitation DC power supply to form a path with the excitation winding L through the first IGBT switch Q1, the first IGBT switch Q5, the sixth freewheeling diode D6, and the fourth IGBT switch Q4. At this time, the positive terminal F+ and the negative terminal F- of the excitation winding L are directly connected to the positive terminal DC+ and the negative terminal DC- of the excitation DC power supply, respectively, resulting in a positive excitation current flowing into the excitation winding L from the positive terminal F+ and out from the negative terminal F-. By adjusting the duty cycle of the first IGBT switch Q1 and the fourth IGBT switch Q4, the voltage input to the excitation winding L from the excitation DC power supply is controlled, thereby controlling the magnitude of the positive excitation current.

[0028] Example 2 The fast excitation main circuit structure of this application embodiment can generate reverse excitation current under normal excitation conditions. This embodiment 2 provides the working principle of the excitation main circuit generating reverse excitation current under normal excitation conditions. Specifically, such as Figure 3 As shown, the second IGBT switch Q6 remains on, while the first IGBT switches Q5, Q1, and Q4 remain off. The second and third IGBT switches Q2 and Q3 are simultaneously turned on, allowing the excitation DC power supply to form a path with the excitation winding L through the second IGBT switch Q2, the second IGBT switch Q6, the fifth freewheeling diode D5, and the third IGBT switch Q3. At this time, the positive terminal F+ and the negative terminal F- of the excitation winding L are directly connected to the negative terminal DC- and the positive terminal DC+ of the excitation DC power supply, respectively, resulting in a reverse excitation current flowing into the excitation winding L from the negative terminal F- and out from the positive terminal F+. By adjusting the duty cycle of the second and third IGBT switches Q2 and Q3, the voltage input to the excitation winding L from the excitation DC power supply is controlled, thereby controlling the magnitude of the reverse excitation current.

[0029] Example 3 The fast excitation main circuit structure of this application embodiment can realize the rapid release of the excitation winding L energy under the dynamic condition of sudden increase in power load when the generator is running under no-load or low-power load. This embodiment 3 provides the working principle of the excitation main circuit rapidly releasing the excitation winding L energy under the dynamic condition of sudden increase in power load in the power generation system. Specifically, when the generator system is operating under no-load or low-power load, the stator current armature response is weak and cannot counteract the permanent magnet magnetomotive force to stabilize the output voltage. To achieve demagnetization control of the permanent magnet field, the excitation current flows in from the negative terminal F- and out from the positive terminal F+ of the excitation winding L, forming a reverse excitation current. When the generator system suddenly experiences a high-power load, the reverse excitation current needs to be quickly discharged through the fast excitation main circuit to improve the excitation current response speed, thereby ensuring rapid dynamic voltage stabilization of the generator system. Figure 4 As shown, the second energy-discharging IGBT switch Q6 is turned off, and the excitation current freewheels through the first diode D7, so that the excitation winding L forms a circuit with the first energy-discharging capacitor C1, the first energy-discharging resistor R1, and the second energy-discharging resistor R2. The energy of the excitation winding L is quickly released through energy transfer and consumption.

[0030] Example 4 The fast excitation main circuit structure of this application embodiment can realize the rapid release of the excitation winding L energy under the dynamic condition of sudden unloading of high power load when the generator is running under high power load. This embodiment 4 provides the working principle of the excitation main circuit rapidly releasing the excitation winding L energy under the dynamic condition of sudden unloading of high power load in the power generation system. Specifically, when a generator system operates under high-power load, the stator current armature response is strong, failing to enhance the permanent magnet magnetomotive force to stabilize the output voltage. To achieve magnetization control of the permanent magnet field, the excitation current flows in from the positive terminal F+ of the excitation winding L and flows out from the negative terminal F-, forming a positive excitation current. After the generator system suddenly unloads a high-power load, the positive excitation current needs to be quickly discharged through the fast excitation main circuit to improve the excitation current response speed, thereby ensuring rapid dynamic voltage stabilization of the generator system. Figure 5 As shown, the first energy-discharging IGBT switch Q5 is turned off, and the excitation current freewheels through the second diode D8, so that the excitation winding L forms a circuit with the second energy-discharging capacitor C2, the third energy-discharging resistor R3, and the fourth energy-discharging resistor R4. The energy of the excitation winding L is quickly released through energy transfer and consumption.

[0031] In summary, this application has the following advantages compared with the prior art: This application proposes a fast excitation main circuit structure suitable for hybrid excitation rectifier synchronous generators. Addressing the issue of large transient reactance parameters in hybrid excitation rectifier synchronous generators and solving the inherent problem of long voltage recovery time under dynamic conditions, the fast excitation main circuit structure provided in this application can output a bidirectional controllable excitation current under normal excitation conditions. Furthermore, under dynamic conditions such as sudden application and removal of high-power loads, it can achieve rapid energy release of the excitation winding, improving the dynamic response speed of excitation control. The fast excitation main circuit structure provided in this application effectively solves the problem of input voltage limitations imposed by traditional H-bridge excitation circuit topologies on hybrid excitation rectifier synchronous generators under dynamic conditions. Additionally, the fast excitation main circuit structure provided in this application also solves the inherent problem of long voltage recovery time under dynamic conditions in this type of generator.

[0032] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0033] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0034] Furthermore, the mathematical concepts mentioned in the embodiments of this application, such as symmetry, equality, parallelism, and perpendicularity, are all limitations relative to the current technological level, rather than absolute and strict mathematical definitions. Slight deviations are allowed, and approximations of symmetry, equality, parallelism, and perpendicularity are all acceptable.

[0035] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A fast excitation main circuit structure suitable for a hybrid excitation synchronous generator of a rectifier type, characterized by, include: The system includes an excitation DC power supply, four IGBT switching transistors, two discharge IGBT switching transistors, six freewheeling diodes, two diodes, four discharge resistors, two discharge capacitors, and an excitation winding. The positive terminal of the excitation DC power supply is connected to the collectors of the first and second IGBT switches, as well as the negative terminals of the first and second freewheeling diodes. The negative terminal of the excitation DC power supply is connected to the emitters of the third and fourth IGBT switches, as well as the positive terminals of the third and fourth freewheeling diodes. The emitter of the first IGBT switch is connected to the positive terminal of the first freewheeling diode, the collectors of the first and third IGBT switches, and the negative terminals of the fifth and third freewheeling diodes. The emitter of the second IGBT switch is connected to the positive terminal of the second freewheeling diode, the collectors of the second and fourth IGBT switches, and the negative terminals of the fifth and third freewheeling diodes. The collector of the first IGBT switch is connected to the cathodes of the sixth and fourth freewheeling diodes; the emitter of the first IGBT switch is connected to the anodes of the fifth and first freewheeling diodes, the positive terminal of the excitation winding, and the cathode of the second diode; the emitter of the second IGBT switch is connected to the anode of the sixth freewheeling diode, one end of the first and third leakage resistors, and the negative terminal of the excitation winding; the other end of the first leakage resistor is connected to the cathode of the first diode through the first leakage capacitor; the other end of the third leakage resistor is connected to the anode of the second diode through the second leakage capacitor; the second and fourth leakage resistors are connected in parallel with the first and second leakage capacitors, respectively.

2. The quick excitation main circuit structure according to claim 1, characterized in that, The fast excitation main circuit structure is used to output a bidirectional controllable excitation current under normal excitation conditions.

3. The quick excitation main circuit structure according to claim 2, characterized in that, The fast excitation main circuit structure is used to generate a positive excitation current flowing into the positive terminal and outputting from the negative terminal of the excitation winding under normal excitation conditions. The working mode of the fast excitation main circuit structure is as follows: The first IGBT switch remains on, while the second, third, and fourth IGBT switches remain off. The first and fourth IGBT switches are simultaneously on. The excitation DC power supply forms a path with the excitation winding through the first IGBT switch, the first IGBT switch, the sixth freewheeling diode, and the fourth IGBT switch. The positive and negative terminals of the excitation winding are directly connected to the positive and negative terminals of the excitation DC power supply, respectively, to generate a positive excitation current flowing in from the positive terminal and out from the negative terminal of the excitation winding. The first and fourth IGBT switches control the voltage input to the excitation winding from the excitation DC power supply by adjusting their duty cycles, thereby controlling the magnitude of the positive excitation current.

4. The field excitation main circuit structure according to claim 2, characterized by The fast excitation main circuit structure is used to generate a reverse excitation current that flows into the negative terminal and out the positive terminal of the excitation winding under normal excitation conditions. The working mode of the fast excitation main circuit structure is as follows: The second IGBT switch remains on, while the first, third, and fourth IGBT switches remain off. The second and third IGBT switches are simultaneously on. The excitation DC power supply forms a path with the excitation winding through the second, third, and fourth IGBT switches. The positive and negative terminals of the excitation winding are directly connected to the negative and positive terminals of the excitation DC power supply, respectively, to generate a reverse excitation current flowing in from the negative terminal and out from the positive terminal of the excitation winding. The second and third IGBT switches are used to adjust the duty cycle to control the voltage input from the excitation DC power supply to the excitation winding, thereby controlling the magnitude of the reverse excitation current.

5. The fast excitation main circuit structure according to claim 1, characterized in that, When the generator is running under no-load or low-power load, in order to achieve demagnetization control of the permanent magnet field, the excitation current flows in from the negative end of the excitation winding and flows out from the positive end to form a reverse excitation current; when the generator suddenly increases the power load, the fast excitation main circuit is used to discharge the reverse excitation current. Or, when the generator is running under high power load, in order to achieve magnetization control of the permanent magnet field, the excitation current flows in from the positive end of the excitation winding and flows out from the negative end to form a positive excitation current; when the generator suddenly unloads the high power load, the fast excitation main circuit is used to discharge the positive excitation current.

6. The quick excitation main circuit structure according to claim 5, characterized in that, The specific working method of the fast excitation main circuit for discharging reverse excitation current is as follows: control the second energy dissipation IGBT switch Q6 to turn off, and the excitation current freewheels through the first diode, so that the excitation winding forms a circuit with the first energy dissipation capacitor, the first energy dissipation resistor, and the second energy dissipation resistor, and the energy of the excitation winding is released through energy transfer and consumption.

7. The quick excitation main circuit structure according to claim 5, characterized in that, The specific working method of the fast excitation main circuit for discharging the positive excitation current is as follows: the first energy dissipation IGBT switch Q5 is turned off, the excitation current is freewheeled through the second diode, so that the excitation winding forms a loop with the second energy dissipation capacitor, the third energy dissipation resistor and the fourth energy dissipation resistor, and the energy of the excitation winding is released through energy transfer and consumption.

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