Flexible direct current converter valve sub-module voltage-sharing resistor heat dissipation structure and flexible direct current converter valve sub-module voltage-sharing resistor heat dissipation method

Abstract

The invention belongs to the technical field of flexible direct-current power transmission and distribution, and discloses a flexible direct-current converter valve submodule voltage-sharing resistor heat dissipation structure and method.The flexible direct-current converter valve submodule voltage-sharing resistor heat dissipation structure comprises a heat dissipation device body, the heat dissipation device body is connected to the outermost side of a silicon stack of a flexible direct-current converter valve submodule, and a plurality of resistor slots are formed in the side wall of the body; a cooling flow channel is integrated in the radiator, and each resistor body is connected in series with a corresponding switch. By adopting the heat dissipation structure, the heat dissipation efficiency is remarkably improved, the resistance junction temperature is reduced, and the heat released to a valve hall is reduced, so that the load of an air-conditioning system is reduced; meanwhile, efficient heat dissipation allows reduction of the power margin design, the safety and adaptability of the system under the high voltage level are enhanced, the problems of high energy consumption and low efficiency in the prior art are solved, and the new requirements of high power density and temperature control are met.

Description

Technical Field

[0001] This invention belongs to the field of flexible DC power transmission and distribution technology, specifically to a flexible DC converter valve submodule voltage equalization resistor heat dissipation structure and method. Background Technology

[0002] Currently, driven by the global energy transition and the "dual carbon" goal, the penetration rate of renewable energy continues to increase. The large-scale grid connection of fluctuating power sources such as wind power and photovoltaics has created an urgent need for flexible and efficient power transmission technologies. Flexible DC transmission (VSC-HVDC) technology, with its core advantages such as four-quadrant operation capability and independent control of active and reactive power, has become a key technological path for solving cross-regional energy interconnection and large-scale renewable energy consumption. The performance of its core equipment, the flexible DC converter valve, directly determines the system reliability. With the iterative development of fully controlled power devices IGBTs and IGCTs, the operating voltage of the converter valve submodule is constantly increasing, further driving the upgrade requirements for the performance of supporting components.

[0003] The series sub-module structure of the flexible DC converter valve places stringent requirements on voltage equalization control. The equalizing resistor, as a core component, is responsible for static voltage equalization during valve lock-up and capacitor discharge before maintenance. In existing technologies, planar thick-film non-inductive resistors are typically fixed on one side of a silicon heat sink while the other side is directly exposed to air, resulting in significant heat loss to the valve chamber and increased load on the air conditioning system. Simultaneously, the low efficiency of single-sided heat dissipation leads to higher junction temperatures, necessitating a large power margin to ensure safe operation. This design is ill-suited to the new power and temperature requirements of the equalizing resistor under high voltage levels.

[0004] It is evident that the heat dissipation structure of the equalizing resistor in the existing flexible DC converter valve has problems of low efficiency and high energy consumption, and cannot meet the power and temperature requirements under high voltage levels. Summary of the Invention

[0005] This invention provides a heat dissipation structure and method for the voltage equalization resistor of a flexible DC converter valve submodule. This heat dissipation structure improves the heat dissipation efficiency of the voltage equalization resistor in the submodule, thereby improving the operational stability of the flexible DC converter valve during pre-charging and the capacitor discharge efficiency during maintenance.

[0006] To achieve the above objectives, the present invention employs the following technical content: A voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule, including a heat sink body; The heat sink body is connected to the outermost silicon stack of the flexible DC converter valve submodule; At least two resistor slots are provided on the side wall of the radiator body; the resistor slots are provided along the thickness direction of the radiator body. Each of the resistor slots is fitted with a rod-shaped resistor; the rod-shaped resistors are connected in parallel. The radiator body is provided with cooling channels; Each of the aforementioned rod-shaped resistors is connected in series with a corresponding switch.

[0007] Furthermore, a thermally conductive medium layer is provided between the surface of the rod-shaped resistor and the inner wall of the resistor slot.

[0008] Furthermore, the thermally conductive medium layer is a composite layer of liquid metal and boron nitride, or a composite layer of thermally conductive silicone grease and boron nitride.

[0009] Furthermore, the cooling medium in the cooling channel is deionized water, ethylene glycol-water mixture, or phase change coolant.

[0010] Furthermore, the rod-shaped resistor is a thick-film non-inductive resistor.

[0011] Furthermore, the radiator body is provided with heat pipe coupling fins; wherein, the evaporation section of the heat pipe is in contact with the slot wall, and the condensation section is connected to the fins.

[0012] Furthermore, the switch employs a vacuum contactor, a magnetic latching relay, or a gas-insulated relay.

[0013] Furthermore, it also includes a control unit; The control unit is connected to the switch and is used to control the insertion or removal of the rod-shaped resistor through the switch.

[0014] Furthermore, the cooling channels are arranged on both sides of the resistor slot or arranged around the resistor slot.

[0015] An operation method for a voltage equalization resistor heat dissipation structure of a flexible DC-DC converter valve submodule, based on the aforementioned voltage equalization resistor heat dissipation structure of the flexible DC-DC converter valve submodule, includes: The valve control system performs a power-on self-test to determine whether the flexible DC converter valve is in the pre-charging stage. If so, close the switch and engage the rod-shaped resistor; Determine whether the current capacitor voltage has reached the set value; If so, disconnect the switch, disconnect the rod-shaped resistor, and return to normal operation; After receiving the maintenance instruction, the switch is closed again, the rod resistor is put back in, and the capacitor discharge is started. Determine if the current capacitor voltage is less than the preset capacitor voltage; If so, disconnect the switch, re-disconnect the rod resistor, and issue a maintenance ready signal.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule. The structure includes a heat sink body connected to the outermost side of the silicon stack. Multiple resistor slots are formed on the sidewall of the heat sink body, and parallel rod-shaped resistors are inserted into each slot. Cooling channels are integrated inside the heat sink, and each resistor is connected in series with a corresponding switch. This design achieves efficient heat transfer to the cooling medium by directly embedding the resistors into the heat sink body and utilizing the cooling channels for forced heat dissipation, avoiding heat loss caused by one-sided air exposure. Simultaneously, the parallel distribution of resistors reduces the unit heat load, while the series connection of switches facilitates independent control of resistor on / off during interlocking or maintenance, optimizing energy management. This heat dissipation structure significantly improves heat dissipation efficiency, reduces resistor junction temperature, and minimizes heat release to the valve chamber, thereby reducing the load on the air conditioning system. Furthermore, efficient heat dissipation allows for a smaller power margin design, enhancing the system's safety and adaptability at high voltage levels. It solves the problems of high energy consumption and low efficiency in existing technologies, meeting the new requirements for high power density and temperature control.

[0017] Preferably, in this invention, a thermally conductive medium layer is added between the rod-shaped resistor and the inner wall of the slot, enhancing the thermal coupling between the resistor and the heat sink body. This design reduces contact thermal resistance, promoting rapid heat transfer from the resistor surface to the heat sink body, avoiding the formation of localized hot spots. This further improves heat dissipation uniformity and heat transfer efficiency, effectively suppressing resistor temperature rise, extending resistor lifespan, and ensuring stable operation of the heat dissipation system under high loads, meeting the temperature control requirements of high voltage levels.

[0018] Preferably, in this invention, the thermally conductive medium layer is a composite layer of liquid metal and boron nitride or a composite layer of thermally conductive silicone grease and boron nitride. This utilizes the high fluidity and thermal conductivity of liquid metal to fill microscopic gaps, combined with the insulating properties of boron nitride. This material combination maximizes thermal conductivity while ensuring electrical safety. Its beneficial effects include enhanced heat dissipation reliability, prevention of electrical breakdown risk between the resistor and the heat sink, significant improvement in heat transfer rate, reduction of overall system thermal resistance, and optimized adaptability of the heat dissipation structure under high power density.

[0019] Preferably, in this invention, the cooling medium in the cooling channel is deionized water, an ethylene glycol-water mixture, or a phase change coolant, providing a diverse selection of heat dissipation media. Deionized water ensures electrical insulation, the ethylene glycol mixture is suitable for low-temperature environments, and the phase change coolant efficiently dissipates heat through latent heat absorption. This enhances the flexibility and environmental compatibility of the heat dissipation system, adapts to different operating conditions, optimizes heat exchange efficiency, reduces cooling energy consumption, and strengthens the system's reliable operation under extreme conditions.

[0020] Preferably, in this invention, the rod-shaped resistor element is a thick-film non-inductive resistor, utilizing its low inductance and high power density advantages. This type of resistor maintains stable electrical performance under high voltage and high frequency environments, reducing electromagnetic interference. This improves the accuracy and response speed of voltage equalization control, ensures the reliability of the pre-charge and discharge functions of the converter valve, and, in conjunction with the heat dissipation structure, reduces heat loss, meeting the stringent requirements of high voltage levels for resistor performance.

[0021] Preferably, in this invention, heat pipe coupling fins are integrated within the radiator body. The evaporation section of the heat pipe contacts the slot wall to absorb heat, while the condensation section enhances heat dissipation through the fins. This passive heat dissipation mechanism enhances heat transfer and diffusion capabilities. It achieves redundant heat dissipation assurance, improves system thermal capacity and heat dissipation stability, especially reducing junction temperature risk when cooling channels are limited, extending equipment life and improving overall energy efficiency.

[0022] Preferably, in this invention, a vacuum contactor, magnetic latching relay, or gas-insulated relay is selected as the switch. These components possess excellent insulation and low arc characteristics under high voltage. This ensures the reliability and safety of the resistance switching control, reduces system risks caused by switch failures, adapts to high-voltage environments, and improves the stability and ease of maintenance of the converter valve.

[0023] Preferably, this invention incorporates a control unit that uses an intelligent control switch to precisely engage and disengage the rod-shaped resistor during pre-charging or maintenance phases. This design optimizes the resistor's operating sequence, preventing prolonged energization. It reduces ineffective heat generation, decreases the burden on the cooling system and energy consumption, while simultaneously improving automation and enhancing the system's economy and response efficiency in high-voltage applications.

[0024] Preferably, in this invention, the cooling channels are arranged on both sides of the resistor slot or in a surrounding layout to ensure that the cooling medium acts directly on the resistor heat source area. This compact design maximizes the heat exchange contact area, improves heat dissipation uniformity and efficiency, prevents local overheating, enhances the reliability of system thermal management, and simplifies structural design to meet high power density requirements.

[0025] This invention also provides an operation method for the voltage equalization resistor heat dissipation structure of the flexible DC converter valve submodule. Based on the aforementioned voltage equalization resistor heat dissipation structure of the flexible DC converter valve submodule, in this method, after the valve control system powers on and performs a self-test, the switch is closed only during the pre-charging stage and the maintenance discharge stage to engage the rod-shaped resistor. Once the capacitor voltage reaches the set value or discharges to a safe voltage, the switch is immediately disconnected to remove the resistor. At other times, the resistor remains in a power-off isolation state. This method, by precisely controlling the on / off sequence of the resistor, strictly limits the resistor to two necessary short-term operating conditions: capacitor pre-charging equalization (static voltage equalization) at the initial stage of converter valve startup and active discharge before maintenance, thus avoiding continuous power-on and heat generation during normal long-term operation of the equipment. On the one hand, it significantly shortens the actual energizing time of the resistor, greatly reduces the generation of ineffective heat energy, and directly reduces the burden on the heat dissipation system and the energy consumption of the valve hall air conditioning. On the other hand, combined with the embedded heat dissipation design, it further suppresses the steady-state temperature rise of the resistor, avoids performance degradation caused by long-term high temperature, and thus achieves overall energy consumption optimization and heat dissipation efficiency improvement while ensuring the reliability of voltage balance and discharge function, meeting the stringent requirements of high voltage level for temperature control and operating economy. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule provided in an embodiment of the present invention; Figure 2 This is a topology diagram of the flexible DC converter valve submodule provided in an embodiment of the present invention.

[0027] Figure label: 1. Heat sink body; 2. Power device; 3. Rod resistor; 4. Switch. Detailed Implementation

[0028] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0032] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0033] To further understand the technical solution of this invention, the following terms are explained: VSC-HVDC (Voltage Source Converter based High Voltage Direct Current Transmission) is a high-voltage direct current transmission technology based on voltage source converters. Its core is to achieve efficient conversion and control of AC and DC power through fully controlled power electronic devices and pulse width modulation technology.

[0034] IGBT (Insulated Gate Bipolar Transistor) is a composite fully controllable voltage-driven power semiconductor device that combines the characteristics of metal-oxide-semiconductor field-effect transistors and bipolar transistors.

[0035] IGCT (Integrated Gate-Commutated Thyristor) is a power electronic device that combines the characteristics of a gate-turn-off thyristor with a fully controllable device.

[0036] like Figure 1As shown, this embodiment provides a voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule. This heat dissipation structure uses a heat sink body 1 as its core component, which is precision-machined from aluminum alloy. The heat sink body 1 is bolted to the outermost side of the silicon stack of the flexible DC converter valve submodule. The flexible DC converter valve submodule is composed of multiple power devices 2 stacked together. A 0.1mm thick layer of thermally conductive grease is applied to the contact surface between the heat sink body 1 and the silicon stack to reduce contact thermal resistance.

[0037] In this embodiment, two resistor slots are horizontally spaced on the side wall of the heat sink body 1. The slots have a circular or elliptical cross-section and a depth consistent with the thickness of the heat sink body 1, thus achieving a structure similar to a blind hole by opening along the thickness direction.

[0038] Each resistor slot contains one rod-shaped resistor 3. This resistor is a thick-film non-inductive voltage equalizing resistor, with a precision of ±0.1% and a power rating greater than 300W. It features advantages such as heat resistance, moisture resistance, electrical pulse resistance, and stable long-term performance. Its surface is anodized to enhance wear resistance and thermal conductivity. The resistance value of the rod-shaped resistor 3 can be flexibly determined based on factors such as the module capacitor discharge time, the voltage equalizing effect of uncontrolled charging of the converter valve, and the operating losses of the converter valve. The two rod-shaped resistors 3 are connected in parallel, and each rod-shaped resistor 3 is connected in series with a mechanical switch. The switch is closed during pre-charging and maintenance discharge of the converter valve.

[0039] To further improve heat transfer efficiency, a thermally conductive medium layer is disposed between the surface of the rod-shaped resistor 3 and the inner wall of the resistor slot. The thermally conductive medium layer is a composite layer of liquid gallium indium tin alloy and boron nitride (BN) powder, wherein the volume percentage of BN powder is 30%, and the coating thickness is controlled within 0.2 mm ± 0.02 mm. Two rod-shaped resistors 3 are connected in parallel through copper busbars to form a resistor group, which meets the power requirements of the submodule during the pre-charging and discharging phases.

[0040] For example, the radiator body 1 integrates a cooling channel system, arranged around the resistor slot. The inlet and outlet of the channel are connected to external cooling pipes via DN10 quick-connect connectors. The cooling medium flowing in the cooling channel is deionized water with a conductivity ≤0.1μS / cm, the operating pressure is maintained at 0.3MPa±0.05MPa, and the flow rate is 2L / min. Furthermore, the radiator body 1 also features a heat pipe coupled fin structure. The heat pipe is a copper-water gravity heat pipe, with its evaporation section tightly fitted to the outer wall of the resistor slot for a contact length of 50mm. The condensation section is brazed to aluminum fins with a thickness of 0.3mm and a spacing of 2mm, further enhancing heat dissipation.

[0041] For example, such as Figure 2As shown, to achieve flexible switching of the rod-shaped resistors 3, each rod-shaped resistor 3 is connected in series with a switch 4. This switch is preferably a vacuum contactor, model CKJ5-160, with a rated current of 160A and a mechanical life ≥1 million cycles. Its control coil is connected to the control unit via a wire. The control unit uses an STM32H743 microprocessor as its core, integrating a voltage acquisition module (measurement range 0-1000V, accuracy ±0.5%), a switch drive module, and a communication module. It can receive commands from the valve control system in real time and provide feedback on the operating status. Switch 4 is open during normal operation of the converter valve, reducing operating losses.

[0042] Figure 2 In this circuit, two IGBTs (T1, T2) and anti-parallel diodes (D1, D2) form a series branch. T1 and T2 are fully controllable power semiconductor devices, which can be controlled to turn on and off via gate signals; D1 and D2 are freewheeling diodes, providing a freewheeling path for current when the IGBTs are off, preventing damage from overvoltage. Capacitor C is the DC-side energy storage element of the submodule, connected in parallel across the power device branch and the resistor branch.

[0043] This embodiment provides a voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule, the specific principle of which is as follows: The heat sink body 1, with resistor slots, is located on the outermost side of the submodule's press-fit silicon stack. One side houses press-fit fully controlled power devices 2 or diodes, while the other side is exposed to air. The rod-shaped resistor 3 slot is located near the air side of the heat sink; therefore, the heat generated by the rod-shaped resistor 3 will not affect other power devices 2 in the silicon stack. The heat sink optimizes its flow channel structure, causing the fluid to collide with the heat dissipation channels during flow, generating turbulence and scouring that breaks down the thermal film on the inner surface of the heat dissipation channels, thus improving the heat transfer efficiency of the heat sink. The high-power rod-shaped resistor 3 used with the heat sink has excellent heat dissipation performance, simultaneously meeting the voltage equalization requirements of the module capacitors during the pre-charging phase of the converter valve and the capacitor discharge requirements during maintenance. Under rated operating conditions, the rod-shaped resistor 3 has a junction temperature margin of over 30°C and a power margin of over 50%. The rod-shaped resistor 3 is connected in series with a switch 4, which closes during converter valve pre-charging and maintenance and opens during normal operation, reducing converter valve operating losses.

[0044] The voltage equalization resistor heat dissipation structure for the flexible DC converter valve submodule provided in this embodiment has the following advantages: First, by applying insertable rod resistors (rod-shaped resistor bodies) to the sub-module voltage equalization of the flexible DC converter valve, the heat dissipation performance of the voltage equalization resistor is improved, the power margin requirement of the voltage equalization resistor is reduced, and the reliability and stability of the flexible DC converter valve system are improved. Secondly, the rod-shaped resistor is located on the air side of the heat sink, and the heat it dissipates is directly carried away by the water cooling system. It does not affect other power devices in the silicon stack and will not affect the performance of other devices due to changes in junction temperature. Third, by switching on and off the rod resistor, the module voltage equalization requirements during pre-charging of the converter valve and the capacitor discharge requirements during maintenance can be met.

[0045] In this embodiment, based on the above-mentioned voltage equalization resistor heat dissipation structure of the flexible DC converter valve submodule, the specific operation method is as follows: S1. After the valve control system is powered on, the control unit first performs a self-test, including the status detection of switch 4, the resistance value detection of rod resistor 3, and the pressure detection of the cooling system. After passing the self-test, it enters the standby state. S2. When it is determined that the flexible DC converter valve is in the pre-charging stage, the control unit sends a drive signal to close all two switches 4 and engage all rod resistors 3. At this time, the total power of the resistor group reaches 400W, which meets the current limiting requirement during pre-charging. S3. The voltage acquisition module monitors the capacitor voltage of the submodule in real time. When the detected voltage reaches the set value, such as 800V, the control unit issues a disconnect command, and the two switches 4 are disconnected at the same time, cutting off the rod-shaped resistor 3, and the submodule enters the normal operation stage. S4. When the maintenance command of the valve control system is received, the control unit closes the switch 4 again, re-engages the rod resistor 3, and starts the capacitor discharge process. S5. Continuously monitor the capacitor voltage. When the voltage drops to a preset value such as below 50V, the control unit disconnects switch 4, cuts off the rod-shaped resistor 3, and sends a maintenance ready signal to the valve control system through the communication module. At this time, the capacitor discharge ends and maintenance operations can be safely carried out.

[0046] As can be seen, this embodiment optimizes the heat dissipation structure design and control logic, so that the operating temperature of the rod-shaped resistor 3 is controlled below 70°C and the ambient temperature is 40°C. The heat dissipation efficiency is improved by more than 30% compared with the traditional structure. At the same time, it realizes the intelligent switching of resistor elements, which significantly improves the operational reliability and safety of the flexible DC converter valve submodule.

[0047] In summary, the voltage equalization resistor heat dissipation structure and method for a flexible DC converter valve submodule provided by this invention have the following advantages compared to traditional heat dissipation structures: This invention integrates parallel rod-shaped resistors into slots within the radiator body, along with cooling channels and independent switch control, achieving a unified design of the resistor and heat dissipation structure. This heat dissipation structure utilizes a thermally conductive medium layer (such as a liquid metal composite layer) to enhance thermal coupling, combining a cooling channel (optionally a phase change coolant) and a heat pipe-fin composite heat dissipation path for efficient heat removal. Simultaneously, the control unit precisely controls the switch, engaging the resistor only during the pre-charging phase to achieve capacitor voltage equalization, and engaging it during maintenance to complete capacitor discharge; the resistor is disconnected at other times to avoid ineffective heat generation. This heat dissipation structure significantly improves heat dissipation efficiency, reduces resistor junction temperature and valve hall environmental heat load, decreases air conditioning system energy consumption, and avoids wasted power margin through optimized thermal management. Intelligent on / off control ensures voltage balance and discharge reliability, ultimately solving the problems of low efficiency and high energy consumption in existing heat dissipation structures at high voltage levels, meeting the requirements of high power density and stringent temperature control.

[0048] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule, characterized in that, Including the heat sink body (1); The heat sink body (1) is connected to the outermost silicon stack of the flexible DC converter valve submodule; At least two resistor slots are provided on the side wall of the radiator body (1); the resistor slots are provided along the thickness direction of the radiator body (1); Each of the resistor slots is fitted with a rod-shaped resistor (3); the rod-shaped resistors (3) are connected in parallel. The radiator body (1) is provided with a cooling channel; Each of the rod-shaped resistors (3) is connected in series with a corresponding switch (4).

2. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 1, characterized in that, A heat-conducting medium layer is provided between the surface of the rod-shaped resistor (3) and the inner wall of the resistor slot.

3. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 2, characterized in that, The thermally conductive medium layer is a composite layer of liquid metal and boron nitride, or a composite layer of thermally conductive silicone grease and boron nitride.

4. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 1, characterized in that, The cooling medium in the cooling channel is deionized water, ethylene glycol-water mixture, or phase change coolant.

5. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 1, characterized in that, The rod-shaped resistor (3) is a thick-film non-inductive resistor.

6. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 1, characterized in that, The heat sink body (1) is provided with heat pipe coupling fins; wherein, the evaporation section of the heat pipe is in contact with the slot wall and the condensation section is connected to the fins.

7. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 1, characterized in that, The switch (4) is a vacuum contactor, a magnetic latching relay or a gas-insulated relay.

8. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 1, characterized in that, It also includes a control unit; The control unit is connected to the switch (4) and is used to control the insertion or removal of the rod-shaped resistor (3) through the switch (4).

9. The voltage equalization resistor heat dissipation structure for a flexible DC converter valve submodule according to claim 1, characterized in that, The cooling channels are arranged on both sides of the resistor slot or around the resistor slot.

10. A method for operating a voltage-equalizing resistor heat dissipation structure for a flexible DC-DC converter valve submodule, based on the voltage-equalizing resistor heat dissipation structure for a flexible DC-DC converter valve submodule according to any one of claims 1-9, characterized in that, include: The valve control system performs a power-on self-test to determine whether the flexible DC converter valve is in the pre-charging stage. If so, close the switch (4) and insert the rod resistor (3). Determine whether the current capacitor voltage has reached the set value; If so, then disconnect the switch (4), cut off the rod-shaped resistor (3), and enter normal operation; After receiving the maintenance instruction, the switch (4) is closed again, the rod resistor (3) is put back in, and the capacitor discharge is started; Determine if the current capacitor voltage is less than the preset capacitor voltage; If so, disconnect the switch (4), re-disconnect the rod resistor (3), and issue a maintenance ready signal.

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