Capacitor breakdown protection structure for wind power generator frequency converter and control method thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANXI INT ENERGY GRP NEW ENERGY INVESTMENT MANAGEMENT CO LTD
- Filing Date
- 2026-06-10
- Publication Date
- 2026-07-10
Smart Images
Figure CN122370194A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of capacitor protection technology, and in particular to a capacitor breakdown protection structure and control method for wind turbine frequency converters. Background Technology
[0002] Wind turbine generators are often deployed in remote, harsh environments, and their core component, the converter, faces severe challenges from high loads and extreme conditions. Power modules and filter capacitors within the converter are key vulnerable components. Among them, filter capacitors are at risk of breakdown failure after prolonged exposure to high voltage, high current, and temperature cycling stress. A capacitor, also known as an electrochemical capacitor, is a power source with special properties, falling between traditional capacitors and power sources. It primarily relies on the electric double layer and redox pseudocapacitance to store electrical energy, achieving its ultra-large capacity through an electric double layer structure composed of porous activated carbon electrodes and an electrolyte.
[0003] In existing technologies, capacitor protection primarily focuses on overvoltage and overcurrent protection through circuit design, or early warning through condition monitoring. However, once a capacitor experiences a severe breakdown, the enormous energy stored within it is released instantaneously, potentially causing the capacitor casing to rupture, generating a high-temperature electric arc and high-speed flying metal fragments (sputterings). These sputterings can affect other precision components within the converter (such as IGBT modules, drive circuits, busbars, etc.), triggering secondary faults and causing catastrophic equipment damage and significant economic losses. Summary of the Invention
[0004] The purpose of this invention is to solve the problems existing in the prior art, and to propose a capacitor breakdown protection structure and control method for wind turbine frequency converters.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: A capacitor breakdown protection structure for a wind turbine frequency converter includes an explosion-proof housing with a top cover, and further includes: The capacitor body is fixed inside an explosion-proof housing and has terminals on it that are connected to the DC bus of the converter. The heat dissipation holes are formed on the explosion-proof housing, and a filter screen is fixed inside the heat dissipation holes; A partition, which is fixed inside the explosion-proof housing, is provided with a pressure-reducing component to buffer pressure; And a sealing component, which is disposed on the outside of the explosion-proof housing and is used to seal the heat dissipation holes in the event of an explosion of the capacitor body.
[0006] Preferably, the pressure relief assembly includes a fixed tube fixed between the top cover and the partition, a fixed rod disposed inside the fixed tube, a first piston slidably connected to the fixed rod, and a first elastic element disposed between the first piston and the inner wall of the fixed tube. The first piston is provided with a one-way valve, and a first air pipe is connected to the first piston at the one-way valve. The end of the first air pipe away from the first piston passes through the fixed tube and is connected to an airbag. The airbag is disposed on the partition.
[0007] Preferably, the sealing assembly includes a rotating ring rotatably connected to the outside of the explosion-proof housing, air holes formed on the rotating ring and corresponding one-to-one with the heat dissipation holes, an L-shaped rod fixed on the rotating ring, a gear ring fixedly connected to the end of the L-shaped rod away from the rotating ring, and a one-way gear set on the fixed rod and meshing with the gear ring. A fixing block is fixed on the inner sidewall of the first piston, and a spiral groove and a vertical groove that cooperate with the fixing block are formed on the fixed rod.
[0008] Preferably, the inner wall of the heat dissipation hole is fixedly provided with an upper baffle and a lower baffle that are spaced apart, and the inner wall of the heat dissipation hole is provided with a guide groove at the bottom of the lower baffle for guiding the flow to the bottom of the explosion-proof housing cavity.
[0009] Preferably, the terminal block includes a first terminal block fixedly connected to the capacitor body, a second terminal block fixedly mounted on the top cover, and a movable terminal block elastically disposed within the second terminal block and movingly abutting against the first terminal block. The first piston is provided with a connecting rod that movesly abuts against the outer support plate of the movable terminal block, and the second terminal block is elastically disposed with a locking block that engages with the movable terminal block.
[0010] Preferably, an exhaust device is fixedly provided on the top cover, a second air pipe is provided on the exhaust device, a telescopic pipe is connected to the end of the second air pipe away from the exhaust device, a rotating joint is fixedly provided at the bottom of the telescopic pipe, a spherical nozzle is fixedly provided at the bottom of the rotating joint, and the spherical nozzle is movably disposed within the partition.
[0011] Preferably, the exhaust device includes a gas storage shell fixed on the top cover for storing inert gas, a working shell fixed on the outside of the gas storage shell, a second piston slidably connected inside the working shell, and a second elastic element disposed between the second piston and the inner wall of the working shell. A sliding rod fixedly connected to the second piston is provided on the connecting rod. An air inlet valve is provided between the gas storage shell and the working shell. An air outlet valve connected to the second gas pipe is fixedly provided on the working shell.
[0012] Preferably, a mounting plate is fixedly provided on the partition plate, a reciprocating screw is rotatably connected to the mounting plate, a movable gear is fixedly provided on the reciprocating screw, a rack plate that meshes with the movable gear is provided on the connecting rod, a sleeve is threadedly connected to the reciprocating screw, and a push rod is movably provided between the sleeve and the telescopic tube.
[0013] Preferably, the end of the reciprocating screw is further provided with a main bevel gear, and the spherical nozzle is provided with a secondary bevel gear that meshes with the main bevel gear. The secondary bevel gear is rotatably mounted on the partition plate, and the spherical nozzle is rotatably connected to the secondary bevel gear by a pin.
[0014] This invention also discloses a control method for capacitor breakdown protection structure in wind turbine frequency converters, comprising the following steps: S1: Normal heat dissipation state: When the capacitor body is operating normally and generating heat, the air holes on the rotating ring are aligned with the heat dissipation holes on the explosion-proof housing. The hot air inside the explosion-proof housing is discharged through the heat dissipation holes by convection. The filter screen prevents external dust from entering. The pressure relief component and the sealing component are in the initial standby position. S2: Capacitor breakdown explosion and impact buffer: Energy absorption: The high-pressure shock wave generated by the explosion of the capacitor body first acts on the first piston. Due to the huge instantaneous pressure, most of the gas cannot pass through the one-way valve on the first piston in time. The shock wave pushes the first piston to compress the first elastic element and move upward. This process consumes a lot of impact energy. Gas storage: Some high-pressure gas enters the airbag through a one-way valve and the first air tube. The airbag expands to further absorb energy and store gas. The partition confines the explosion shock wave to the lower cavity. S3: Automatic sealing and electrical disconnection: During the upward movement of the first piston, the inner fixed block moves along the spiral groove on the fixed rod, forcing the fixed rod to rotate relative to the fixed tube. The one-way gear at the end of the fixed rod rotates accordingly, driving the gear ring meshing with it to rotate. The gear ring drives the rotating ring to rotate through the L-shaped rod, causing the air hole and the heat dissipation hole to be misaligned, thus achieving complete sealing of the heat dissipation hole. When the fixed block slides into the vertical groove, the fixed rod stops rotating, and the sealing state is locked. When the first piston moves upward, it pushes the movable terminal upward through the connecting rod, forcibly separating it from the first terminal on the capacitor body, thereby quickly cutting off the electrical path of the faulty capacitor. An electric arc will be generated at the separation point. When the first piston moves upward, it drives the slide rod to move upward through the connecting rod. The slide rod drives the second piston to move upward inside the working shell. The working shell draws inert gas from the gas storage shell through the air intake valve. S4: Automatic fire extinguishing, arc extinguishing, and cleaning: After the explosion shock wave, the first elastic element pushes the first piston to reset and move downward. The first piston drives the second piston to move downward through the connecting rod and slide rod, compressing the inert gas in the working shell. After being compressed, the inert gas passes through the gas outlet valve, the second gas pipe and the telescopic pipe, and is finally ejected at high speed from the spherical nozzle. The ejected inert gas directly acts on the separated terminal area, and through cooling and deionization, it quickly extinguishes the electric arc. At the same time, the inert gas blows away the electrolyte residue in the terminal and surrounding area. When the connecting rod moves down, the rack plate fixed on it drives the movable gear and the reciprocating screw to rotate. On the one hand, the sleeve moves along the axial direction of the reciprocating screw, and pushes the telescopic tube through the push rod, causing the spherical nozzle to swing left and right. On the other hand, the main bevel gear at the end of the reciprocating screw drives the secondary bevel gear to rotate, causing the spherical nozzle to rotate as a whole. The combination of these two movements allows the sprayed inert gas to cover the bottom of the entire cavity and key components, achieving cleaning and inerting without dead angles. S5: Maintenance Once the system is stable, maintenance personnel can safely open the top cover. At this point, there is no high voltage or electric arc inside the explosion-proof housing, harmful gases have been inertized, and the electrolyte has been blown to the bottom. Only the faulty capacitor body and the used airbag need to be replaced, and all mechanical mechanisms need to be reset.
[0015] Compared with the prior art, the present invention provides a capacitor breakdown protection structure and control method for wind turbine frequency converters, which has the following beneficial effects: 1. In this invention, by setting up pressure-reducing components and sealing components, the destructive energy of capacitor explosion is converted into power to drive the device to perform protection, isolation, fire extinguishing and cleaning actions, thereby achieving a highly efficient, reliable and fully automatic active safety protection, thus ensuring the safe use of the wind turbine frequency converter. This solves the problem in the prior art where the high-temperature and high-pressure airflow, metal sputterings and corrosive electrolyte generated by capacitor explosion are sprayed without restraint, causing a single capacitor failure to escalate into catastrophic damage to the entire machine.
[0016] 2. In this invention, the high-pressure shock wave generated by the explosion of the capacitor body first acts on the first piston. Due to the huge instantaneous pressure, most of the gas does not have time to pass through the one-way valve on the first piston. The shock wave pushes the first piston to compress the first elastic element and move upward. This process consumes a lot of impact energy. Some of the high-pressure gas enters the airbag through the one-way valve and the first air pipe. The airbag expands, further absorbs energy and stores gas. The partition restricts the explosion shock wave to the lower cavity, effectively weakening, buffering and isolating the high-pressure shock wave, greatly reducing the peak pressure of the shock wave and protecting the structural integrity of the explosion-proof shell.
[0017] 3. In this invention, by utilizing the explosive impact energy itself as a power source, during the upward movement of the first piston, the inner fixing block moves along the spiral groove on the fixing rod, forcing the fixing rod to rotate relative to the fixing tube. The one-way gear at the end of the fixing rod rotates accordingly, driving the gear ring meshing with it to rotate. The gear ring drives the rotating ring to rotate through the L-shaped rod, causing the air hole and the heat dissipation hole to be misaligned, thus achieving complete sealing of the heat dissipation hole. This realizes the passive and instantaneous switching from "heat dissipation state" to "sealed explosion-proof state," resolving the contradiction between heat dissipation and explosion-proof in the prior art.
[0018] 4. In this invention, when the first piston moves upward, the connecting rod pushes the movable terminal upward, forcibly separating it from the first terminal on the capacitor body, thereby quickly cutting off the electrical path of the faulty capacitor and achieving ultra-fast physical power-off. An electric arc will be generated at the separation point, and then inert gas will be automatically sprayed to precisely purge the electric arc and electrolyte, realizing continuous automated operation of "power-off-arc extinguishing-cleaning", fundamentally eliminating the risk of continuous electric arc hazards and secondary pollution existing in the prior art.
[0019] 5. In this invention, when the first piston moves upward, the connecting rod drives the sliding rod to move upward, and the sliding rod drives the second piston to move upward within the working shell. The working shell draws inert gas from the gas storage shell through the air inlet valve. After the explosion shock wave, the first elastic element pushes the first piston to reset and move downward. The first piston drives the second piston to move downward through the connecting rod and the sliding rod, compressing the inert gas in the working shell. After being compressed, the inert gas passes through the air outlet valve, the second air pipe, and the telescopic pipe, and is finally ejected at high speed from the spherical nozzle. The ejected inert gas directly acts on the separated terminal area, and through cooling and deionization, quickly extinguishes the electric arc. At the same time, the inert gas purges the electrolyte residue in the terminal and surrounding area, fundamentally eliminating the risk of continuous electric arc hazards and secondary pollution.
[0020] 6. In this invention, when the connecting rod moves downward, the rack plate moves downward and drives the movable gear and the reciprocating screw to rotate. On the one hand, the sleeve moves axially along the reciprocating screw, and pushes the telescopic tube through the push rod, causing the spherical nozzle to swing left and right. On the other hand, the main bevel gear at the end of the reciprocating screw drives the secondary bevel gear to rotate, causing the spherical nozzle to rotate as a whole. The combination of these two movements allows the sprayed inert gas to cover the entire bottom of the cavity and key components, achieving thorough cleaning and inertization, effectively blowing off the attached electrolyte and inertizing the atmosphere, creating safe and clean conditions for subsequent maintenance.
[0021] The linkage mechanism in this application is driven by a single shock wave generated by the capacitor explosion. This is a "one-time" safety protection that does not require repeated actions. Its reliability does not depend on the wear and tear of long-term use, but on whether it can respond and complete the preset action within milliseconds. Compared with active control systems (such as solenoid valves) that require continuous power supply and rely on sensors and software logic, this pure mechanical linkage has no aging of electronic components, no risk of electromagnetic interference, and no software crash problem. It is more reliable in extreme moments. The linkage design of the protective structure in this application is not to blindly increase complexity, but to make the optimal engineering trade-off for achieving multiple safety protections that are fast, reliable, and do not require external power in the specific high-risk scenario of capacitor explosion. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2This is a cross-sectional structural diagram of the present invention; Figure 3 For the present invention Figure 2 Enlarged structural diagram of section A in the middle; Figure 4 For the present invention Figure 2 Enlarged structural diagram of section B; Figure 5 For the present invention Figure 2 Enlarged structural diagram of section C; Figure 6 This is a cross-sectional structural diagram of the fixing tube of the present invention; Figure 7 This is a schematic diagram of the separation structure of the first piston and the fixed rod of the present invention; Figure 8 This is a partial cross-sectional structural diagram of the explosion-proof housing of the present invention; Figure 9 This is a schematic diagram of the external structure of the working shell of the present invention; Figure 10 This is a schematic diagram of the external structure of the reciprocating lead screw of the present invention; Figure 11 This is a cross-sectional structural diagram of the second connector of the present invention.
[0023] In the diagram: 1. Explosion-proof housing; 101. Top cover; 2. Capacitor body; 3. Terminal; 301. First terminal; 302. Second terminal; 3021. Locking block; 303. Movable terminal; 4. Heat dissipation hole; 401. Filter screen; 402. Upper baffle; 403. Lower baffle; 404. Guide channel; 5. Partition; 6. Fixing tube; 601. Fixing rod; 6011. Spiral groove; 6012. Vertical groove; 602. First piston; 6021. First air pipe; 6022. Fixing block; 603. First elastic element; 7. Rotating ring; 701. Air vent; 702. L-shaped rod; 703. Gear ring; 704. One-way gear; 8. Connecting rod; 801. Slide rod; 802. Rack plate; 9. Exhaust equipment; 901. Air storage shell; 902. Working shell; 903. Second piston; 904. Second elastic element; 10. Second air pipe; 11. Telescopic pipe; 111. Rotary joint; 112. Spherical nozzle; 12. Mounting plate; 121. Reciprocating screw; 122. Movable gear; 123. Main bevel gear; 124. Sleeve; 125. Push rod; 13. Secondary bevel gear. Detailed Implementation
[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0025] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0027] like Figures 1 to 3 As shown, this embodiment proposes a capacitor breakdown protection structure for a wind turbine inverter, including an explosion-proof housing 1 with a top cover 101. The explosion-proof housing 1 is a sealed container made of high-temperature resistant, high-strength, and insulating materials (such as ceramics, special engineering plastics, or metal materials with an insulating layer). It also includes: a capacitor body 2, heat dissipation holes 4, a partition 5, and a sealing assembly. The capacitor body 2 is fixed inside the explosion-proof housing 1, and a terminal 3 connected to the DC bus of the inverter is provided on the capacitor body 2. The capacitor body 2 contains an anode foil, a cathode foil, and electrolytic paper. The core package is wound and then sealed in the housing after being impregnated with electrolyte. Heat dissipation holes 4 are formed on the explosion-proof housing 1, and a filter screen 401 is fixed inside the heat dissipation holes 4, allowing for the cleaning of dust and impurities on the filter screen 401 during regular maintenance of the wind turbine. A partition 5 is fixed inside the explosion-proof housing 1, and a pressure-reducing component is installed on the partition 5 to buffer the explosion generated when the capacitor body 2 is punctured, preventing the explosion between the explosion-proof housing 1 and the partition 5. A sealing component is located on the outside of the explosion-proof housing 1 to seal the heat dissipation holes 4 in the event of an explosion of the capacitor body 2. Specifically, during normal operation, the capacitor body 2 generates heat, and the hot air inside the explosion-proof housing 1 is discharged through the heat dissipation holes 4 via convection. The filter screen 401 prevents external dust from entering, and the pressure relief component and the sealing component are in the initial standby position. When the capacitor body 2 breaks down, the high-voltage shock wave generated by the explosion of the capacitor body 2 acts on the pressure relief component to alleviate the impact force generated by the explosion inside the explosion-proof housing 1. When the pressure relief component is working, it drives the sealing component to close the heat dissipation holes 4, preventing the high-temperature gas mixed with electrolyte from splashing to the outside of the explosion-proof housing 1 through the heat dissipation holes 4 during the explosion and causing damage to other components. By incorporating pressure-reducing and sealing components, the destructive energy of a capacitor explosion is converted into power to drive the device's protective, isolation, fire-extinguishing, and cleaning actions. This achieves a highly efficient, reliable, and fully automatic active safety protection system, ensuring the safe operation of the wind turbine inverter. It also solves the problem in existing technologies where high-temperature, high-pressure airflow, metal sputterings, and corrosive electrolyte generated by a capacitor explosion can be sprayed without restraint, causing a single capacitor failure to escalate into catastrophic damage to the entire unit.
[0028] like Figure 2 , Figure 4 and Figure 6 As shown, in a preferred embodiment, based on the above method, the pressure relief component further includes a fixed tube 6 fixed between the top cover 101 and the partition 5, a fixed rod 601 disposed in the fixed tube 6, a first piston 602 slidably connected to the fixed rod 601, and a first elastic element 603 disposed between the first piston 602 and the inner wall of the fixed tube 6. A one-way valve is provided on the first piston 602, and a first air pipe 6021 is connected to the first piston 602 at the one-way valve. The end of the first air pipe 6021 away from the first piston 602 passes through the fixed tube 6 and is connected to an airbag. The airbag is disposed on the partition 5. The airbag can be made of a composite material of aramid fiber cloth and silicone rubber coating, so that it has high strength while being able to withstand high temperature and maintain airtightness. Specifically, the high-pressure shock wave generated by the explosion of capacitor body 2 will first act on the first piston 602. Due to the huge instantaneous pressure, most of the gas cannot pass through the one-way valve on the first piston 602 in time. The shock wave pushes the first piston 602 back to compress the first elastic element 603 and move upward. This process consumes a lot of shock energy and absorbs the energy of the shock wave. At the same time, other high-pressure gases enter the airbag through the one-way valve and the first air pipe 6021. The airbag expands, further absorbs energy and stores gas. The partition 5 restricts the explosion shock wave to the lower cavity, avoiding damage to the structural components on the upper side of the partition 5. It effectively weakens, buffers and isolates the high-pressure shock wave, greatly reduces the peak pressure of the shock wave and protects the structural integrity of the explosion-proof shell 1. It should be noted that the design of the airbag expansion volume is adapted to the reserved space in the upper cavity of the partition 5 to ensure that the airbag can fully expand when absorbing the explosion energy, while not compressing other key components, ensuring the normal operation of each linkage structure, and meeting the requirements of mechanical balance and motion continuity. The airbag receives and stores a portion of the high-pressure gas passing through the one-way valve on the first piston 602 at the moment of the explosion via the first air tube 6021. This not only absorbs the impact energy but, more importantly, helps maintain the inert atmosphere inside the explosion-proof housing 1, suppressing secondary combustion or arcing that may be caused by high-temperature fragments or residual electrolyte. The multi-layer spring shock absorber, which quickly resets after compression, cannot provide this continuous "occupancy" and "inertization" effect, which is something that a simple energy-consuming spring shock absorber cannot achieve.
[0029] like Figure 2 , Figure 4 , Figure 6 and Figure 7 As shown, in a preferred embodiment, based on the above method, the sealing assembly further includes a rotating ring 7 rotatably connected to the outside of the explosion-proof housing 1, an air hole 701 opened on the rotating ring 7 and corresponding to the heat dissipation hole 4, an L-shaped rod 702 fixed on the rotating ring 7, a gear ring 703 fixedly connected to the end of the L-shaped rod 702 away from the rotating ring 7, and a one-way gear 704 provided on the fixed rod 601 and meshing with the gear ring 703. The one-way gear 704 is the prior art, including a fixed wheel fixedly connected to the fixed rod 601 and a driven wheel rotatably connected to the outside of the fixed wheel and meshing with the gear ring 703. It will not be described in detail here. A fixed block 6022 is fixedly provided on the inner wall of the first piston 602. A spiral groove 6011 and a vertical groove 6012 that cooperate with the fixed block 6022 are opened on the fixed rod 601. Specifically, when the capacitor body 2 is operating normally, the air hole 701 on the rotating ring 7 is aligned with the heat dissipation hole 4 on the explosion-proof housing 1, and the hot air inside the explosion-proof housing 1 is discharged through the heat dissipation hole 4 by convection. When the capacitor body 2 breaks down and explodes, the high-voltage shock wave generated by the explosion first acts on the first piston 602. During the upward movement of the first piston 602, the inner fixing block 6022 moves along the spiral groove 6011 on the fixing rod 601, forcing the fixing rod 601 to rotate relative to the fixing tube 6. The one-way gear 704 at the end of the fixing rod 601 rotates accordingly, driving the meshing gear ring 703 to rotate. The gear ring 703, through the L-shaped rod 702, drives the rotating ring 7 to rotate, causing the vent 701 to misalign with the heat dissipation hole 4, thus completely sealing the heat dissipation hole 4. The inner fixing block 6022 of the first piston 602 moves along the spiral groove 6011 of the fixing rod 601, converting the linear impact into rotational motion, driving the gear ring 703 to drive the rotating ring 7 to seal the heat dissipation hole 4, ensuring that the sealing action and the impact energy are triggered synchronously. External signal detection or delayed response is required, avoiding potential malfunctions of pneumatic / electromagnetic systems due to pressure fluctuations or circuit failures. If simple alternatives such as pneumatic pistons or solenoid valves are used, an additional independent power source (such as a compressed air tank or circuit control) is required, which increases the complexity of the system and the potential for failure. Due to the use of a one-way gear 704, when the first piston 602 moves down and resets the first elastic element 603, the first piston 602 drives the fixed rod 601 to rotate through the spiral groove 6011. The fixed wheel connected to the fixed rod 601 does not drive the driven wheel to rotate, thus preventing the gear ring 703 from rotating. When the fixed block 6022 slides into the vertical groove 6012, the fixed rod 601 stops rotating, and the sealing state is locked. This achieves passive and instantaneous switching from "heat dissipation state" to "sealed explosion-proof state," resolving the contradiction between heat dissipation and explosion-proof.
[0030] like Figure 2 , Figure 4 and Figure 8 As shown, in a preferred embodiment, based on the above method, the inner wall of the heat dissipation hole 4 is further provided with an upper baffle 402 and a lower baffle 403 that are spaced apart. There is a sufficient gap between the upper baffle 402 and the lower baffle 403 to form an airflow channel, but it is sufficient to block the projectile multiple times. The inner wall of the heat dissipation hole 4 is provided with a guide groove 404 at the bottom of the lower baffle 403 for guiding the flow to the bottom of the cavity of the explosion-proof housing 1. Specifically, when the mixture of substances produced by the explosion, such as high-pressure gas, metal fragments, and liquid electrolyte, rushes towards the heat dissipation hole 4 at high speed, it first encounters the baffle. Solid metal fragments and other sputtering materials are directly blocked and collided with, and a large amount of kinetic energy is consumed. The airflow and some droplets are forced to change direction and pass through the gap between the upper baffle 402 and the lower baffle 403. The high-density droplets are more likely to adhere to the baffle and hole wall under the action of inertia, which limits the hazard to the inside of the shell. The liquid electrolyte adhering to the baffle and the lower wall of the heat dissipation hole 4 flows downward under the action of gravity. The guide channel 404, as a pre-set channel, guides the collected electrolyte to the bottom of the internal cavity of the explosion-proof shell 1 in an orderly manner, instead of letting it flow randomly. This fundamentally avoids the electrolyte causing local short circuits or corrosion damage, and collects the electrolyte in a specific area, which greatly facilitates subsequent maintenance and cleaning work.
[0031] like Figure 2 , Figure 6 and Figure 11 As shown, in a preferred embodiment, based on the above method, the terminal block 3 further includes a first terminal block 301 fixedly connected to the capacitor body 2, a second terminal block 302 fixedly mounted on the top cover 101, and a movable terminal block 303 elastically disposed within the second terminal block 302 and movingly abutting against the first terminal block 301. A connecting rod 8 is provided on the first piston 602 and movesly abutting against the outer support plate of the movable terminal block 303. A locking block 3021 elastically disposed within the second terminal block 302 and engaging with the movable terminal block 303 can be used. Springs can be used between the movable terminal block 303 and the second terminal block 302, as well as between the locking block 3021 and the movable terminal block 303. Specifically, during normal operation of the capacitor body 2, the first terminal 301 is connected to the second terminal 302 via the movable terminal 303 and is connected to the DC bus of the converter. When the capacitor body 2 experiences a breakdown, the high-voltage shock wave generated by the explosion first acts on the first piston 602. As the first piston 602 moves upward, it pushes the support plate via the connecting rod 8, thereby causing the movable terminal 303 to move upward, forcibly separating it from the first terminal 301 on the capacitor body 2. This quickly cuts off the electrical path of the faulty capacitor. After the movable terminal 303 moves upward, the elastically set locking block 3021 inside the second terminal 302 will lock the movable terminal 303. The spring force connected to the locking block 3021 is greater than the force exerted by the spring on the movable terminal within the second terminal 302. The elastic downward pressure of post 303 prevents the movable post 303 from moving down again and abutting against the first post 301 when the first piston 602 resets and moves down. At this time, since the circuit has not been repaired, the connection point of post 3 still has high voltage and is in a short circuit state. Any residual charge or induced current in the system will be released through this short circuit point, generating a huge short circuit current and arc. The huge short circuit current may burn out the busbar and damage the disconnecting switch or contactor that is performing the connection. When it is necessary to release the restriction of the movable post 303 by the locking block 3021, by applying a pulling force to the movable post 303, the movable post 303 squeezes the arc surface at the end of the locking block 3021, so that the slot of the movable post 303 moves down and resets over the locking block 3021.
[0032] like Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 9 and Figure 10 As shown, in a preferred embodiment, based on the above method, the top cover 101 is further provided with an exhaust device 9, the exhaust device 9 is provided with a second air pipe 10, the end of the second air pipe 10 away from the exhaust device 9 is connected to a telescopic pipe 11, the bottom of the telescopic pipe 11 is provided with a rotating joint 111, the bottom of the rotating joint 111 is provided with a spherical nozzle 112, and the spherical nozzle 112 is movably disposed in the partition 5. Furthermore, the exhaust device 9 includes a gas storage shell 901 fixed on the top cover 101 for storing inert gas, a working shell 902 fixed on the outside of the gas storage shell 901, a second piston 903 slidably connected inside the working shell 902, and a second elastic element 904 disposed between the second piston 903 and the inner wall of the working shell 902. A sliding rod 801 fixedly connected to the second piston 903 is fixed on the connecting rod 8. An air inlet valve is disposed between the gas storage shell 901 and the working shell 902. An air outlet valve connected to the second air pipe 10 is fixedly disposed on the working shell 902. Specifically, when the first piston 602 moves upward along the inner wall of the fixed tube 6 under the impact of the explosion, the first piston 602 drives the slide rod 801 to move upward through the connecting rod 8. The slide rod 801 drives the second piston 903 to move upward within the working shell 902. The working shell 902 draws inert gas from the gas storage shell 901 through the air intake valve. The inert gas can be nitrogen, which is an excellent insulating medium with a higher thermal conductivity than air. When the electric arc burns in nitrogen, the nitrogen can effectively carry away the heat of the arc column, enhance the cooling of the arc, and thus accelerate the extinction of the arc. After the explosion shock wave, the first elastic element 60... 3. Push the first piston 602 to reset and move downward. The first piston 602 drives the second piston 903 to move downward through the connecting rod 8 and the slide rod 801, compressing the inert gas in the working shell 902. After being compressed, the inert gas passes through the gas outlet valve, the second gas pipe 10 and the telescopic pipe 11, and is finally ejected at high speed from the spherical nozzle 112. The ejected inert gas directly acts on the separated terminal 3 area, and through cooling and deionization, quickly extinguishes the electric arc. At the same time, the inert gas blows away the electrolyte residue in the terminal 3 and the surrounding area, so that the electrolyte in the explosion-proof shell 1 quickly gathers for subsequent handling by the staff.
[0033] like Figure 2 , Figure 5 , Figure 6 , Figure 7 and Figure 10 As shown, in a preferred embodiment, based on the above method, a mounting plate 12 is fixedly provided on the partition 5, a reciprocating screw 121 is rotatably connected to the mounting plate 12, a movable gear 122 is fixedly provided on the reciprocating screw 121, a rack plate 802 that meshes with the movable gear 122 is provided on the connecting rod 8, a sleeve 124 is threadedly connected to the reciprocating screw 121, and a push rod 125 is movably provided between the sleeve 124 and the telescopic tube 11. Furthermore, a main bevel gear 123 is provided at the end of the reciprocating screw 121, and a secondary bevel gear 13 that meshes with the main bevel gear 123 is provided on the spherical nozzle 112. The secondary bevel gear 13 is rotatably mounted on the partition plate 5, and the spherical nozzle 112 is rotatably connected to the secondary bevel gear 13 by a pin. Specifically, after the explosion shock wave, the first piston 602 drives the connecting rod 8 to move down, and the rack plate 802 fixed on it drives the movable gear 122 and the reciprocating screw 121 to rotate. On the one hand, the sleeve 124 moves axially along the reciprocating screw 121, and pushes the telescopic tube 11 through the push rod 125, causing the spherical nozzle 112 to swing left and right. On the other hand, the main bevel gear 123 at the end of the reciprocating screw 121 drives the secondary bevel gear 13 to rotate, causing the spherical nozzle 112 to rotate as a whole. The rotating joint 111 connects the two motions, so that the sprayed inert gas can cover the bottom of the entire explosion-proof housing 1 cavity and key components, achieving thorough cleaning and inerting, effectively blowing off the attached electrolyte and inerting atmosphere, creating safe and clean conditions for subsequent maintenance. After a capacitor explosion, the splash trajectory and attachment points of contaminants such as electrolyte and metal fragments are random and unpredictable. No matter how optimized the angle of a fixed nozzle is, its coverage area is static and preset, which inevitably leads to problems such as cleaning dead zones and uneven coverage intensity. If critical parts (such as the arc area of a newly separated terminal) are not covered, the consequences will be secondary arcing or short circuit. However, the "swing + rotation" composite motion of the spherical nozzle 112 forms a dynamic and continuous scanning coverage area, ensuring that contaminants, whether attached to the side wall, bottom, or surface of the cavity, can be effectively swept away by the high-speed inertial airflow, which is something that a fixed nozzle cannot achieve.
[0034] This invention also discloses a control method for capacitor breakdown protection structure in wind turbine frequency converters, comprising the following steps: S1: Normal heat dissipation state: When the capacitor body 2 is running normally, it generates heat. At this time, the air hole 701 on the rotating ring 7 is aligned with the heat dissipation hole 4 on the explosion-proof housing 1. The hot air inside the explosion-proof housing 1 is discharged through the heat dissipation hole 4 by convection. The filter screen 401 prevents external dust from entering. The pressure relief component and the sealing component are in the initial standby position. S2: Capacitor breakdown explosion and impact buffer: Energy absorption: The high-pressure shock wave generated by the explosion of capacitor body 2 first acts on the first piston 602. Due to the huge instantaneous pressure, most of the gas cannot pass through the one-way valve on the first piston 602 in time. The shock wave pushes the first piston 602 to compress the first elastic element 603 and move upward. This process consumes a lot of impact energy. Gas storage: Some high-pressure gas enters the airbag through the one-way valve and the first air tube 6021. The airbag expands to further absorb energy and store gas. The partition 5 confines the explosion shock wave to the lower cavity. S3: Automatic sealing and electrical disconnection: During the upward movement of the first piston 602, the inner fixing block 6022 moves along the spiral groove 6011 on the fixing rod 601, forcing the fixing rod 601 to rotate relative to the fixing tube 6. The one-way gear 704 at the end of the fixing rod 601 rotates accordingly, driving the gear ring 703 meshing with it to rotate. The gear ring 703 drives the rotating ring 7 to rotate through the L-shaped rod 702, causing the air hole 701 to be misaligned with the heat dissipation hole 4, thus completely blocking the heat dissipation hole 4. When the fixing block 6022 slides into the vertical groove 6012, the fixing rod 601 stops rotating, and the blocking state is locked. When the first piston 602 moves upward, it pushes the movable terminal 303 upward through the connecting rod 8, forcibly separating it from the first terminal 301 on the capacitor body 2, thereby quickly cutting off the electrical path of the faulty capacitor. An electric arc will be generated at the separation point. When the first piston 602 moves upward, it drives the slide bar 801 to move upward through the connecting rod 8. The slide bar 801 drives the second piston 903 to move upward inside the working shell 902. The working shell 902 draws inert gas from the gas storage shell 901 through the air intake valve. S4: Automatic fire extinguishing, arc extinguishing, and cleaning: After the explosion shock wave, the first elastic element 603 pushes the first piston 602 to reset and move downward. The first piston 602 drives the second piston 903 to move downward through the connecting rod 8 and the slide rod 801, compressing the inert gas in the working shell 902. After being compressed, the inert gas passes through the gas outlet valve, the second gas pipe 10 and the telescopic pipe 11, and is finally ejected at high speed from the spherical nozzle 112. The ejected inert gas directly acts on the separated terminal 3 area, and through cooling and deionization, it quickly extinguishes the electric arc. At the same time, the inert gas blows away the electrolyte residue in the terminal 3 and the surrounding area. When the connecting rod 8 moves down, the rack plate 802 fixed on it drives the movable gear 122 and the reciprocating screw 121 to rotate. On the one hand, the sleeve 124 moves axially along the reciprocating screw 121, and pushes the telescopic tube 11 through the push rod 125, causing the spherical nozzle 112 to swing left and right. On the other hand, the main bevel gear 123 at the end of the reciprocating screw 121 drives the secondary bevel gear 13 to rotate, causing the spherical nozzle 112 to rotate as a whole. The combination of these two movements allows the sprayed inert gas to cover the entire bottom of the cavity and key components, achieving cleaning and inerting without dead angles. S5: Maintenance Once the system is stable, maintenance personnel can safely open the top cover 101. At this point, there is no high voltage or electric arc inside the explosion-proof housing 1, the harmful gases have been inertized, and the electrolyte has been blown to the bottom. Only the faulty capacitor body 2 and the used airbag need to be replaced, and all mechanical mechanisms need to be reset.
[0035] The accompanying drawings in this application are for illustrative purposes only. The dimensions and shapes of the components shown are not actual limitations but are merely schematic representations. In actual implementation, the components can be reasonably configured and adjusted according to specific needs and actual conditions.
[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A capacitor breakdown protection structure for a wind turbine frequency converter, comprising an explosion-proof housing (1) with a top cover (101) on top, characterized in that, Also includes: The capacitor body (2) is fixed inside the explosion-proof housing (1) and the capacitor body (2) is provided with a terminal (3) connected to the DC bus of the converter. Heat dissipation hole (4) is provided on the explosion-proof housing (1), and a filter screen (401) is fixed inside the heat dissipation hole (4). Partition (5), the partition (5) is fixed inside the explosion-proof housing (1), and the partition (5) is provided with a pressure-reducing component to buffer pressure; And a sealing component, which is disposed on the outside of the explosion-proof housing (1) and is used to seal the heat dissipation hole (4) when the capacitor body (2) explodes.
2. The capacitor breakdown protection structure for a wind turbine frequency converter according to claim 1, characterized in that, The pressure relief assembly includes a fixed tube (6) fixed between the top cover (101) and the partition (5), a fixed rod (601) disposed in the fixed tube (6), a first piston (602) slidably connected to the fixed rod (601), and a first elastic element (603) disposed between the first piston (602) and the inner wall of the fixed tube (6). A one-way valve is provided on the first piston (602), and a first air pipe (6021) is connected to the first piston (602) at the one-way valve. One end of the first air pipe (6021) away from the first piston (602) passes through the fixed tube (6) and is connected to an airbag. The airbag is disposed on the partition (5).
3. The capacitor breakdown protection structure for a wind turbine frequency converter according to claim 2, characterized in that, The sealing assembly includes a rotating ring (7) rotatably connected to the outside of the explosion-proof housing (1), an air hole (701) opened on the rotating ring (7) and corresponding to the heat dissipation hole (4), an L-shaped rod (702) fixed on the rotating ring (7), a gear ring (703) fixedly connected to the end of the L-shaped rod (702) away from the rotating ring (7), and a one-way gear (704) set on the fixed rod (601) and meshing with the gear ring (703). A fixed block (6022) is fixedly provided on the inner wall of the first piston (602). A spiral groove (6011) and a vertical groove (6012) that cooperate with the fixed block (6022) are opened on the fixed rod (601).
4. The capacitor breakdown protection structure for a wind turbine frequency converter according to claim 3, characterized in that, The inner wall of the heat dissipation hole (4) is fixed with an upper baffle (402) and a lower baffle (403) spaced apart. The inner wall of the heat dissipation hole (4) has a guide groove (404) at the bottom of the lower baffle (403) for guiding the flow to the bottom of the cavity of the explosion-proof housing (1).
5. The capacitor breakdown protection structure for a wind turbine frequency converter according to claim 4, characterized in that, The terminal block (3) includes a first terminal block (301) fixedly connected to the capacitor body (2), a second terminal block (302) fixedly mounted on the top cover (101), and a movable terminal block (303) elastically disposed in the second terminal block (302) and movingly abutting against the first terminal block (301). The first piston (602) is provided with a connecting rod (8) that moves against the outer support plate of the movable terminal block (303). The second terminal block (302) is elastically disposed with a locking block (3021) that engages with the movable terminal block (303).
6. The capacitor breakdown protection structure for a wind turbine frequency converter according to claim 5, characterized in that, An exhaust device (9) is fixedly installed on the top cover (101). A second air pipe (10) is provided on the exhaust device (9). A telescopic pipe (11) is connected to one end of the second air pipe (10) away from the exhaust device (9). A rotating joint (111) is fixedly installed at the bottom of the telescopic pipe (11). A spherical nozzle (112) is fixedly installed at the bottom of the rotating joint (111). The spherical nozzle (112) is movably installed inside the partition (5).
7. The capacitor breakdown protection structure for a wind turbine frequency converter according to claim 6, characterized in that, The exhaust device (9) includes a gas storage shell (901) fixed on the top cover (101) for storing inert gas, a working shell (902) fixed on the outside of the gas storage shell (901), a second piston (903) slidably connected inside the working shell (902), and a second elastic element (904) disposed between the second piston (903) and the inner wall of the working shell (902). A slide rod (801) fixedly connected to the second piston (903) is fixed on the connecting rod (8). An air inlet valve is provided between the gas storage shell (901) and the working shell (902). An air outlet valve connected to the second air pipe (10) is fixed on the working shell (902).
8. The capacitor breakdown protection structure for a wind turbine frequency converter according to claim 7, characterized in that, A mounting plate (12) is fixedly provided on the partition plate (5). A reciprocating screw (121) is rotatably connected to the mounting plate (12). A movable gear (122) is fixedly provided on the reciprocating screw (121). A rack plate (802) that meshes with the movable gear (122) is provided on the connecting rod (8). A sleeve (124) is threadedly connected to the reciprocating screw (121). A push rod (125) is movably provided between the sleeve (124) and the telescopic tube (11).
9. A capacitor breakdown protection structure for a wind turbine frequency converter according to claim 8, characterized in that, The end of the reciprocating screw (121) is also provided with a main bevel gear (123), and the spherical nozzle (112) is provided with a secondary bevel gear (13) that meshes with the main bevel gear (123). The secondary bevel gear (13) is rotatably mounted on the partition plate (5), and the spherical nozzle (112) is rotatably connected to the secondary bevel gear (13) by a pin.
10. A control method for a capacitor breakdown protection structure for a wind turbine frequency converter according to claim 9, characterized in that, Includes the following steps: S1: Normal heat dissipation state: When the capacitor body (2) generates heat during normal operation, the air hole (701) on the rotating ring (7) is aligned with the heat dissipation hole (4) on the explosion-proof housing (1). The hot air inside the explosion-proof housing (1) is discharged through the heat dissipation hole (4) by convection. The filter screen (401) prevents external dust from entering. The pressure relief component and the sealing component are in the initial standby position. S2: Capacitor breakdown explosion and impact buffer: Energy absorption: The high-pressure shock wave generated by the explosion of the capacitor body (2) first acts on the first piston (602). Due to the huge instantaneous pressure, most of the gas cannot pass through the one-way valve on the first piston (602) in time. The shock wave pushes the first piston (602) to compress the first elastic element (603) and move upward. This process consumes a lot of impact energy. Gas storage: Some high-pressure gas enters the airbag through the one-way valve and the first air tube (6021). The airbag expands, further absorbs energy and stores gas. The partition (5) confines the explosion shock wave to the lower cavity. S3: Automatic sealing and electrical disconnection: During the upward movement of the first piston (602), the inner fixing block (6022) moves along the spiral groove (6011) on the fixing rod (601), forcing the fixing rod (601) to rotate relative to the fixing tube (6). The one-way gear (704) at the end of the fixing rod (601) rotates accordingly, driving the gear ring (703) meshing with it to rotate. The gear ring (703) drives the rotating ring (7) to rotate through the L-shaped rod (702), causing the air hole (701) to be misaligned with the heat dissipation hole (4), thus completely sealing the heat dissipation hole (4). When the fixing block (6022) slides into the vertical groove (6012), the fixing rod (601) stops rotating, and the sealing state is locked. When the first piston (602) moves upward, it pushes the movable terminal (303) upward through the connecting rod (8), forcibly separating it from the first terminal (301) on the capacitor body (2), thereby quickly cutting off the electrical path of the faulty capacitor. An electric arc will be generated at the separation point. When the first piston (602) moves upward, it drives the slide rod (801) to move upward through the connecting rod (8). The slide rod (801) drives the second piston (903) to move upward inside the working shell (902). The working shell (902) draws inert gas from the gas storage shell (901) through the air intake valve. S4: Automatic fire extinguishing, arc extinguishing, and cleaning: After the explosion shock wave, the first elastic element (603) pushes the first piston (602) to reset and move down. The first piston (602) drives the second piston (903) to move down through the connecting rod (8) and the slide rod (801), compressing the inert gas in the working shell (902). After being compressed, the inert gas passes through the gas outlet valve, the second gas pipe (10) and the telescopic pipe (11), and is finally ejected at high speed from the spherical nozzle (112). The ejected inert gas directly acts on the separated terminal (3) area, and through cooling and deionization, it quickly extinguishes the electric arc. At the same time, the inert gas blows away the electrolyte residue in the terminal (3) and the surrounding area. When the connecting rod (8) moves down, the rack plate (802) fixed on it drives the movable gear (122) and the reciprocating screw (121) to rotate. On the one hand, the sleeve (124) moves axially along the reciprocating screw (121) and pushes the telescopic tube (11) through the push rod (125), causing the spherical nozzle (112) to swing left and right. On the other hand, the main bevel gear (123) at the end of the reciprocating screw (121) drives the secondary bevel gear (13) to rotate, causing the spherical nozzle (112) to rotate as a whole. The combination of these two movements allows the sprayed inert gas to cover the bottom of the entire cavity and key components, achieving cleaning and inertization without dead angles. S5: Maintenance Once the system is stable, maintenance personnel can safely open the top cover (101). At this time, there is no high voltage or electric arc inside the explosion-proof housing (1), the harmful gas has been inertized, and the electrolyte has been blown to the bottom. Only the faulty capacitor body (2) and the used airbag need to be replaced, and the mechanical mechanisms need to be reset.