Frequency converter

Abstract

The invention discloses a frequency converter. The frequency converter comprises a first chamber, a second chamber and a third chamber which are sequentially arranged in a first direction, the protection device is arranged in the first cavity and comprises a plurality of main circuit breakers used for controlling on-off of the frequency converter and an external power source, all the main circuit breakers achieve synchronous opening and closing through a linkage mechanism, and the linkage mechanism comprises a support base, a lifting plate, a rotating rod and a connecting rod assembly. When the rotating rod rotates, the connecting rod assembly drives the lifting plate to ascend and descend along the support base so as to stir the operation handle. And the harmonic filtering device is arranged in the second cavity and is used for being electrically connected with the main circuit breaker. And the frequency conversion device is arranged in the third cavity and is electrically connected with the harmonic filtering device. The frequency converter is reasonable in layout, and the use safety of the frequency converter is improved.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment technology, and more particularly to a frequency converter. Background Technology

[0002] A frequency converter, also known as a variable frequency drive or drive controller, is a power control device that uses frequency conversion technology and microelectronics to control an AC motor by changing the frequency of the power supply. The frequency converter adjusts the voltage and frequency of the output power supply by switching its internal IGBTs, providing the required power voltage according to the actual needs of the motor, thereby achieving energy saving and speed regulation.

[0003] Inverters generate a significant amount of heat during operation, which can potentially cause malfunctions. Furthermore, because inverters are powered, electrical safety is paramount during operation. Therefore, inverters are typically equipped with protective devices to enhance their safety. A well-designed arrangement of these protective devices can greatly improve the safety of inverter operation. Summary of the Invention

[0004] To overcome the above-mentioned shortcomings, the purpose of this invention is to provide a frequency converter with a reasonable layout, which improves the safety of frequency converter use.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a frequency converter, comprising: The housing includes a first chamber, a second chamber, and a third chamber arranged sequentially in a first direction; A protection device is installed in the first chamber and includes multiple main circuit breakers for controlling the switching on and off of the frequency converter and external power supply. All the main circuit breakers are opened and closed synchronously through a linkage mechanism. The linkage mechanism includes a support base, a lifting plate, a rotating rod, and a connecting rod assembly. The support base is fixed in the first chamber. The lifting plate is provided with a through hole for the operating handle of the main circuit breaker to pass through. The rotating rod is rotatably connected to the support base and one end extends out of the housing and is fixed with a handle. The rotating rod is connected to the lifting plate through the connecting rod assembly. When the rotating rod rotates, the connecting rod assembly drives the lifting plate to rise and fall along the support base to actuate the operating handle. A harmonic filter device is disposed in the second chamber and is used to be electrically connected to the main circuit breaker. A frequency converter is disposed in the third chamber and electrically connected to the harmonic filter. The beneficial effects of this invention are as follows: The frequency converter forms an integrated cabinet for frequency conversion and harmonic filtering, with multiple chambers sharing a single main structure, eliminating the need for parallel cabinet splicing. By using a linkage mechanism operated from outside the casing, all main circuit breakers can be opened and closed synchronously through a mechanical structure. This allows for immediate power cut-off of the inverter in case of maintenance or malfunction, thereby improving the safety of inverter operation.

[0006] Furthermore, the linkage assembly is provided in two sets along the axial direction of the rotating rod. The two sets of linkage assemblies drive the lifting plate to move from both sides, thereby improving the stability of the lifting plate during lifting.

[0007] Each of the connecting rod assemblies includes a first connecting rod and a second connecting rod. One end of the first connecting rod is fixedly connected to the rotating rod, and the other end is hinged to one end of the second connecting rod. The other end of the second connecting rod is hinged to the lifting plate.

[0008] The support base has a guide hole extending vertically, and a guide component that slides within the guide hole is fixed on the lifting plate. The guide hole and the guide component cooperate to guide the movement of the lifting plate, ensuring that the lifting plate can only slide up and down along the Z-axis. Furthermore, the lifting plate is also equipped with an adjustment plate corresponding to the operating handle. The adjustment plate is used to adjust the size of the through hole. The adjustment plate can move up and down along the adjustment plate to partially block the through hole. After the adjustment plate is in place, it is fixed to the lifting plate by a locking member. The movement of the adjustment plate allows the through hole size to be smaller to fit the operating handle.

[0009] Furthermore, the protection device also includes a surge protector, which is connected to the input copper busbar of the main circuit breaker via a cable. Furthermore, the housing includes a housing body and switch doors corresponding to the first, second, and third chambers. Each switch door is equipped with an electromagnetic lock, which is only open when the main circuit breaker is tripped. Limit switches for detecting the position of the switch doors are also installed in the first, second, and third chambers. When any switch detects that a switch is open, it controls the main circuit breaker to trip. The electromagnetic locks and limit switches provide dual protection, ensuring that the inverter is de-energized when the switch doors are open, thus improving operator safety. Furthermore, the third chamber is divided into an upper chamber and a lower chamber by a placement plate. The upper chamber forms an air duct and placement cavity that are connected to the lower chamber by a partition. The harmonic filtering device includes a sine wave filter fixed in the lower chamber and an inverter, rectifier and busbar copper bus fixed in the upper chamber and located on the same vertical plane.

[0010] The housing has a first air inlet at a position corresponding to the lower cavity. The top of the air duct is provided with a first fan and a first air outlet corresponding to the first fan. The first fan draws in external air from the first air inlet, passes through the air duct, and blows it out from the first air outlet. The placement cavity is provided with an internal circulation fan for internal air circulation. The air outlet of the internal circulation fan is inclined toward the vertical surface that fixes the inverter.

[0011] The upper and lower chambers are designed based on the heat distribution during operation. External air enters the lower chamber through the first inlet, carries away the heat from the sine wave filter, and is then blown out through the first outlet. Inside the placement chamber, an internal circulation fan creates the airflow direction shown in the attached diagram, cooling the inverter, rectifier, and busbar copper busbars.

[0012] Furthermore, the inverter, rectifier, and busbar are respectively connected to an inverter heatsink, a rectifier heatsink, and a busbar capacitor. The heat dissipation fins of the inverter heatsink, the rectifier heatsink, and the busbar capacitor are located within the air duct. For the inverter, rectifier, and busbar, which operate at relatively high temperatures, a dual heat dissipation circuit—an internal circulation circuit and an external circulation circuit—is implemented, significantly improving heat dissipation and enabling safe and reliable operation under relatively high temperatures.

[0013] Furthermore, the housing has a second air inlet and a second air outlet at positions corresponding to the second chamber. The second air inlet and the second air outlet are spaced apart along a second direction, and the second air outlet and the second air inlet are vertically spaced apart. A second fan is installed at the second air outlet, and the outlet of the second fan faces the outside of the housing. This fully utilizes the space of the second chamber to perform external circulation cooling for the harmonic filter device.

[0014] Furthermore, the harmonic filtering device includes an input reactor, a harmonic filtering reactor, and a harmonic capacitor located between the second air inlet and the second air outlet and connected in sequence.

[0015] Furthermore, the housing also includes a fourth chamber located on the side of the third chamber away from the second chamber, and the fourth chamber is provided with a copper busbar that is electrically connected to the frequency converter. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention; Figure 2 This is a three-dimensional receiving diagram from another angle according to an embodiment of the present invention; Figure 3 This is a front view of the door after it has been opened and closed, as shown in an embodiment of the present invention. Figure 4This is a schematic diagram of the first chamber in an embodiment of the present invention; Figure 5 This is a side view of the linkage mechanism in an embodiment of the present invention; Figure 6 This is a three-dimensional structural diagram of the linkage mechanism in an embodiment of the present invention; Figure 7 for Figure 2 Enlarged view of point A; Figure 8 This is a cross-sectional view of the second chamber in an embodiment of the present invention; Figure 9 This is a cross-sectional view of the third chamber in an embodiment of the present invention.

[0017] In the picture: 1. Casing; 11. Casing body; 12. Door; 1a. First chamber; 1b, Second chamber; 11b, Second air inlet; 12b, Second air outlet; 13b, Second fan; 1c, Third chamber; 11c, Upper chamber; 111c, Air duct; 1111c, First air outlet; 1112c, First fan; 112c, Placement chamber; 1121c, Internal circulation fan; 12c, Lower chamber; 121c, First air inlet; 1d, Fourth Chamber; 2. Protective devices; 21. Main circuit breaker; 22. Linkage mechanism; 221. Bracket base; 2211. Guide hole; 222. Lifting plate; 2221. Through hole; 223. Rotating rod; 224. Linkage assembly; 2241. First link; 2242. Second link; 225. Handle; 226. Adjusting plate; 2261. Waist-shaped hole; 227. Limit bracket; 2271. Limit hole; 23. Limit switch; 24. Surge protector; 3. Harmonic filtering device; 31. Input reactor; 32. Harmonic filter reactor; 33. Harmonic capacitor; 34. Harmonic filter circuit breaker; 4. Frequency converter; 41. Sine wave filter; 42. Inverter; 421. Heat sink fins of inverter radiator; 43. Rectifier; 431. Heat sink fins of rectifier radiator; 44. Busbar copper bus; 441. Busbar capacitor; 5. Wiring copper busbar. Detailed Implementation The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0018] In each diagram, the first direction is the X direction, the second direction is the Y direction, the two directions are perpendicular in the horizontal plane, and the vertical direction is the Z direction.

[0019] See appendix Figure 1 As shown, a frequency converter of the present invention includes a housing 1. The cavity within the housing 1 includes a first chamber 1a, a second chamber 1b, and a third chamber 1c arranged sequentially in a first direction. A protection device 2 is installed in the first chamber 1a to protect the entire frequency converter; a harmonic filter device 3 is installed in the second chamber 1b to form a harmonic filter protection circuit; and a frequency converter 4 is installed in the third chamber 1c. In this embodiment, the frequency converter forms an integrated cabinet for frequency conversion and harmonic filtering, with multiple chambers sharing a single main structure, eliminating the need for cabinet splicing.

[0020] See appendix Figure 4 As shown, the protection device 2 includes multiple main circuit breakers 21 for controlling the switching on and off of the frequency converter and external power supply. For example, there are two main circuit breakers 21. Since multiple circuit breakers must be opened and closed synchronously, a linkage mechanism 22 is provided to drive all main circuit breakers 21 to open and close synchronously.

[0021] See appendix Figure 5 and attached Figure 6 As shown, the linkage mechanism 22 includes a support base 221, a lifting plate 222, a rotating rod 223, and a connecting rod assembly 224. The support base 221 is fixed in the first chamber 1a. The lifting plate 222 is provided with a through hole 2221 for the operating handle of the main circuit breaker 21 to pass through. The rotating rod 223 is rotatably connected to the support base 221 and one end extends out of the housing 1 and is fixed with a handle 225. The rotating rod 223 is connected to the lifting plate 222 through the connecting rod assembly 224. When the rotating rod 223 rotates, it drives the lifting plate 222 to rise and fall along the support base 221 through the connecting rod assembly 224 to move the operating handle.

[0022] The handle 225 is located outside the housing 1, allowing the operator to grip and operate it from the outside. By holding the handle 225 and rotating the rotating rod 223, the rotating rod 223 pulls the lifting plate 222 up and down via the linkage assembly 224. During the up and down movement of the lifting plate 222, the upper and lower walls of the through hole 2221 push the operating handle up and down, thereby opening and closing the main circuit breaker 21. In this embodiment, through the linkage mechanism 22, all main circuit breakers 21 can be opened and closed synchronously through the mechanical structure by operating outside the housing 1. In the event of inverter maintenance or abnormality, the power to the inverter can be cut off immediately, thereby improving the safety of inverter operation.

[0023] See appendix Figure 6As shown, the bracket 221 has a guide hole 2211 extending vertically, and the lifting plate 222 has a guide member (not shown) that slides within the guide hole 2211. The guide hole 2211 and the guide member cooperate to guide the movement of the lifting plate 222, ensuring that the lifting plate 222 can only slide up and down along the Z direction. The operating handle opens and closes the main circuit breaker 21 during the up-and-down swinging process. The linkage assembly 224 converts the rotation of the rotating shaft into the lifting motion of the lifting plate 222. Two sets of linkage assemblies 224 are arranged along the axial direction of the rotating rod 223. The two sets of linkage assemblies 224 are respectively connected to both ends of the lifting plate 222 in the length direction. The two sets of linkage assemblies 224 drive the lifting plate 222 to move from both sides, thereby improving the stability of the lifting plate 222 during lifting and lowering, and also making the force applied by the lifting plate 222 to the operating handle more even.

[0024] Each linkage assembly 224 includes a first linkage 2241 and a second linkage 2242. One end of the first linkage 2241 is fixedly connected to the rotating rod 223, and the other end is hinged to one end of the second linkage 2242. The other end of the second linkage 2242 is hinged to the lifting plate 222. When the rotating rod 223 rotates counterclockwise, the first linkage 2241 swings upward, causing the second linkage 2242 to move upward, thereby pushing the lifting plate 222 upward. When the rotating rod 223 rotates clockwise, the first linkage 2241 swings downward, causing the second linkage 2242 to move downward, thereby pushing the lifting plate 222 downward.

[0025] When the handle 225 is in a vertical position under the action of gravity, the lifting plate 222 is also in its limit state of downward movement, and the main circuit breaker 21 is in the open state. When it is necessary to close the main circuit breaker 21, hold the handle 225 and turn the handle 225.

[0026] See appendix Figure 7 As shown, a limiting bracket 227 located on one side of the handle 225 is fixed on the housing 1. The limiting bracket 227 has a limiting hole 2271, through which a limiting rod (not shown in the figure) can pass. The limiting bracket 227 can limit the movement direction of the handle 225, so that the handle 225 can only swing counterclockwise as shown by the arrow in the figure when it is in the vertical position. When the handle 225 swings to the second position, it pushes the lifting plate 222 to move upward and closes the main circuit breaker 21. At this time, the limiting rod can be inserted into the limiting hole 2271. The limiting rod and the handle 225 abut against each other to limit the handle 225 to this position and prevent the handle 225 from returning to its original position under the action of gravity.

[0027] The rotation angle of the handle 225 is less than 90°. Because the displacement that the lifting plate 222 needs to move is small, the length of the first link 2241 does not need to be too long and does not need to occupy too much space.

[0028] To allow the operating handle to pass through the through hole 2221 even with installation errors, the through hole 2221 is designed to be relatively large. However, because the lifting distance of the lifting plate 222 is small, a larger through hole 2221 may prevent the operating handle from moving within its range of motion. Therefore, an adjusting plate 226 corresponding to the operating handle is also provided on the lifting plate 222. The adjusting plate 226 is used to adjust the size of the through hole 2221. The adjusting plate 226 can move up and down along the lifting plate 2221 to partially block the through hole 2221. After the adjusting plate 226 is adjusted to the correct position, it is fixed to the lifting plate 222 by a locking device. The movement of the adjusting plate 226 allows the through hole 2221 to be smaller to fit the operating handle.

[0029] The adjusting plate 226 is provided with a waist-shaped hole 2261. The locking component includes a bolt that passes through the waist-shaped hole 2261. The bolt can slide in the waist-shaped hole 2261 and lock with the lifting plate 222 to press the adjusting plate 226 onto the lifting plate 222. At this time, the lifting plate 222 and the adjusting plate 226 are fixed.

[0030] See appendix Figure 2 As shown, the housing 1 includes a housing body 11 and a switch door 12. The switch door 12 corresponds one-to-one with the first chamber 1a, the second chamber 1b and the third chamber 1c. The switch door 12 can be opened and closed respectively to install and maintain the devices in the corresponding chambers.

[0031] An electromagnetic lock is installed on the switch door 12. The electromagnetic lock is only open when the main circuit breaker 21 is open. At this time, the frequency converter is de-energized and in a safe state, so the electromagnetic lock cylinder retracts, and the switch door 12 can be opened. Limit switches 23 are also installed in the first chamber 1a, the second chamber 1b, and the third chamber 1c to detect the position of the switch door 12. When the limit switch 23 detects that any switch door 12 is open, it controls the main circuit breaker 21 to open. The limit switches 23 and the electromagnetic lock provide dual protection, ensuring that the frequency converter is de-energized when the switch door 12 is open, improving the safety of personnel operation.

[0032] An indicator light is also installed on the door 12 to indicate whether the frequency converter has power.

[0033] See appendix Figure 4 As shown, the protection device 2 also includes a surge protector 24, which is connected to the input copper busbar of the main circuit breaker 21 via a cable. The surge protector 24 can conduct electricity when the frequency converter is struck by lightning, effectively protecting the frequency converter and improving its operational safety.

[0034] Harmonic filter 3 is used for electrical connection with main circuit breaker 21, see appendix. Figure 3As shown, the harmonic filtering device 3 includes an input reactor 31, a harmonic filtering reactor 32, a harmonic capacitor 33, and a harmonic filtering circuit breaker 34 connected in sequence. The harmonic filtering circuit breaker 34 draws power from the front end of the input reactor 31 through a copper busbar and is connected to the harmonic filtering reactor 32 and the harmonic capacitor 33 through the copper busbar to form a harmonic filtering protection circuit.

[0035] The frequency converter 4 is electrically connected to the harmonic filter 3. The frequency converter 4 includes a sine wave filter 41, an inverter 42, a rectifier 43, and a busbar copper bus 44.

[0036] When the frequency converter is connected, the external power supply cable enters the first chamber 1a and connects to the input copper busbar of the main circuit breaker 21. It then enters the second chamber 1b through the output copper busbar of the main circuit breaker 21. The output copper busbar of the circuit breaker connects to the input reactor 31 through its input copper busbar, and then to the third chamber 1c through the output copper busbar of the input reactor 31. The rectifier 43 in the third chamber 1c connects to the output copper busbar of the input reactor 31. The output of the rectifier 43 is sent to the bus copper busbar 44, which connects to the inverter 42. The inverter 42 outputs to the sine wave filter 41, and the output of the sine wave filter 41 is connected to the motor to supply power to it.

[0037] In this embodiment, the frequency converter 4 and the harmonic filter 3 generate a lot of heat when they are working. Therefore, the frequency converter 4 and the harmonic filter 3 are placed in two different chambers, and the second chamber 1b and the third chamber 1c are cooled by different heat dissipation circuits, so that the frequency converter 4 and the harmonic filter 3 do not easily affect each other and can be cooled down quickly.

[0038] See appendix Figure 8 As shown, a second air inlet 11b and a second air outlet 12b are provided at positions corresponding to the second chamber 1b in the housing 1. The second air inlet 11b and the second air outlet 12b are spaced apart along a second direction. The second air inlet 11b is located on the corresponding switch door 12, and the second air outlet 12b is located on the back plate of the housing body 11. The second air outlet 12b and the second air inlet 11b are spaced vertically apart. The second air inlet 11b is located in the area below the corresponding switch door 12. A second fan 13b is provided at the second air outlet 12b, and the air outlet of the second fan 13b faces the outside of the housing 1. A harmonic filter device 3 is located between the second air inlet 11b and the second air outlet 12b.

[0039] Because cold air is usually located at the bottom, the second air inlet 11b is positioned at the bottom. When the second fan 13b is working, it draws the cooler air from the lower position into the second chamber 1b, removing the heat from the harmonic filter 3, and then blows it out from the first air outlet 1111c located at the higher position. See the appendix for the airflow direction. Figure 8As indicated by the arrow in the diagram, the temperature generated by the harmonic filter device 3 can be met by the airflow between the second air inlet 11b and the second air outlet 12b to achieve cooling. In this embodiment, the space of the second chamber 1b is fully utilized to perform external circulation cooling of the harmonic filter device 3.

[0040] When the frequency converter is working, the frequency converter 4 generates the most heat. Therefore, in this embodiment, two heat dissipation loops, an internal circulation loop and an external circulation loop, are used to accelerate heat dissipation for the frequency converter 4.

[0041] See appendix Figure 9 As shown, the third chamber 1c is divided into an upper chamber 11c and a lower chamber 12c by a placement plate. The upper chamber 11c forms an air duct 111c and a placement chamber 112c by a partition, and the air duct 111c is connected to the lower chamber 12c. A sine wave filter 41 is fixed in the lower chamber 12c, and an inverter 42, a rectifier 43, and a busbar copper bus 44 located on the same vertical plane are fixed in the upper chamber 11c. A first air inlet 121c is provided at the position corresponding to the lower chamber 12c on the housing 1. A first fan 1112c and a first air outlet 1111c corresponding to the first fan 1112c are provided at the top of the air duct 111c. The first fan 1112c draws in external air from the first air inlet 121c, passes through the air duct 111c, and blows it out from the first air outlet 1111c. An internal circulation fan 1121c is installed inside the placement cavity 112c to circulate air inside. The air outlet of the internal circulation fan 1121c is tilted towards the vertical surface of the fixed inverter 42.

[0042] The upper cavity 11c and lower cavity 12c are designed based on the heat distribution during operation. External air enters the lower cavity 12c through the first inlet, carries away the heat from the sine wave filter 41, and is then blown out through the first air outlet 1111c. Inside the placement cavity 112c, the internal circulation fan 1121c creates the airflow direction shown in the attached diagram, thereby cooling the inverter 42, rectifier 43, and busbar copper bus 44 within the placement cavity 112c.

[0043] Inverter 42, rectifier 43, and busbar 44 are respectively connected to inverter heat sinks, rectifier heat sinks, and busbar capacitors 441. The heat dissipation fins 421 of the inverter heat sink, 431 of the rectifier heat sink, and busbar capacitor 441 are located within air duct 111c. Because inverter 42 and rectifier 43 generate significant heat, corresponding heat sinks are installed for cooling. The heat dissipation fins of these heat sinks are located within air duct 111c, where they are cooled. Busbar capacitor 441 is also cooled by the airflow within air duct 111c. Thus, for the high-temperature inverter 42, rectifier 43, and busbar 44, a dual cooling circuit of internal and external circulation is achieved, greatly improving heat dissipation and enabling safe and reliable operation under relatively high temperatures.

[0044] Filter cotton is also installed at the first air inlet 121c and the second air inlet 11b to filter the air entering the third chamber 1c and the second chamber 1b, so as to prevent dust or debris from entering and damaging the harmonic filter device 3 and the frequency converter 4.

[0045] The frequency converter 4 also includes a detection board and a control board fixedly placed inside the cavity 112c.

[0046] See appendix Figure 2 As shown, the housing 1 also includes a fourth chamber 1d located on the side of the third chamber 1c away from the second chamber 1b. The fourth chamber 1d is provided with a wiring copper busbar 5 that is electrically connected to the frequency converter 4, and the motor is connected to the wiring copper busbar 5.

[0047] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A frequency converter, characterized in that: include: The housing includes a first chamber, a second chamber, and a third chamber arranged sequentially in a first direction; A protection device is installed in the first chamber and includes multiple main circuit breakers for controlling the switching on and off of the frequency converter and external power supply. All the main circuit breakers are opened and closed synchronously through a linkage mechanism. The linkage mechanism includes a support base, a lifting plate, a rotating rod, and a connecting rod assembly. The support base is fixed in the first chamber. The lifting plate is provided with a through hole for the operating handle of the main circuit breaker to pass through. The rotating rod is rotatably connected to the support base and one end extends out of the housing and is fixed with a handle. The rotating rod is connected to the lifting plate through the connecting rod assembly. When the rotating rod rotates, the connecting rod assembly drives the lifting plate to rise and fall along the support base to actuate the operating handle. A harmonic filter device is disposed in the second chamber and is used to be electrically connected to the main circuit breaker. A frequency converter is disposed in the third chamber and electrically connected to the harmonic filter.

2. The frequency converter according to claim 1, characterized in that: The linkage assembly is arranged in two sets along the axial direction of the rotating rod. Each set of the linkage assembly includes a first linkage and a second linkage. One end of the first linkage is fixedly connected to the rotating rod, and the other end is hinged to one end of the second linkage. The other end of the second linkage is hinged to the lifting plate. The support base has a guide hole extending in the vertical direction, and the lifting plate has a guide component that slides within the guide hole.

3. The frequency converter according to claim 1, characterized in that: The lifting plate is also provided with an adjustment plate corresponding to the operating handle. The adjustment plate is used to adjust the size of the through hole. The adjustment plate can move up and down along the adjustment plate to block part of the through hole. After the adjustment plate is adjusted to the position, it is fixed to the lifting plate by a locking member.

4. The frequency converter according to claim 1, characterized in that: The protection device also includes a surge protector, which is connected to the input copper busbar of the main circuit breaker via a cable.

5. The frequency converter according to any one of claims 1-4, characterized in that: The housing includes a housing body and a switch door corresponding to the first chamber, the second chamber and the third chamber. The switch door is equipped with an electromagnetic lock, which is only in the open state when the main circuit breaker is disconnected. The first chamber, the second chamber, and the third chamber are also equipped with limit switches for detecting the position of the open / closed doors. When the limit switches detect that any open / closed door is open, they control the main circuit breaker to disconnect.

6. The frequency converter according to claim 1, characterized in that: The third chamber is divided into an upper chamber and a lower chamber by a placement plate. The upper chamber forms an air duct and placement cavity that are connected to the lower chamber by a partition. The harmonic filtering device includes a sine wave filter fixed in the lower chamber and an inverter, rectifier and busbar copper bus fixed in the upper chamber and located on the same vertical plane. The housing has a first air inlet at a position corresponding to the lower cavity. The top of the air duct is provided with a first fan and a first air outlet corresponding to the first fan. The first fan draws in external air from the first air inlet, passes through the air duct, and blows it out from the first air outlet. The placement cavity is equipped with an internal circulation fan for air circulation, and the air outlet of the internal circulation fan is tilted towards the vertical surface where the inverter is fixed.

7. The frequency converter according to claim 6, characterized in that: The inverter, the rectifier, and the busbar are respectively connected to the inverter heat sink, the rectifier heat sink, and the busbar capacitor. The heat dissipation fins of the inverter heat sink, the rectifier heat sink, and the busbar capacitor are located inside the air duct.

8. The frequency converter according to claim 1, characterized in that: The housing has a second air inlet and a second air outlet at the position corresponding to the second chamber. The second air inlet and the second air outlet are spaced apart along the second direction, and the second air outlet and the second air inlet are spaced apart vertically. A second fan is provided at the second air outlet, and the air outlet of the second fan faces the outside of the housing.

9. The frequency converter according to claim 8, characterized in that: The harmonic filtering device includes an input reactor, a harmonic filtering reactor, and a harmonic capacitor, which are located between the second air inlet and the second air outlet and connected in sequence.

10. The frequency converter according to claim 1, characterized in that: The housing also includes a fourth chamber located on the side of the third chamber away from the second chamber, and the fourth chamber is provided with a copper busbar that is electrically connected to the frequency converter.

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