Frequency converter

Abstract

The utility model belongs to the technical field of power equipment, and provides a frequency converter which comprises a frequency converter unit mechanism, a passive low-harmonic filtering mechanism and a sine filtering mechanism, the frequency converter unit mechanism comprises a frequency converter machine core, and the frequency converter machine core is connected with a direct-current reactor. The direct-current reactor is used for reducing main loop harmonic waves on the frequency converter machine core; the passive low-harmonic filtering mechanism comprises a three-phase input reactor and a three-phase filter reactor, the three-phase input reactor is electrically connected with external equipment, the three-phase filter reactor and the frequency converter machine core, and the three-phase filter reactor is used for reducing harmonic waves on an input line of the frequency converter; the sine wave filtering mechanism comprises a sine wave filter reactor used for reducing harmonic waves on an output line of the frequency converter, and the sine wave filter reactor is electrically connected with the frequency converter machine core and external equipment. Under the condition that the original specification is not changed, the technical problem that the harmonic wave of the frequency converter is too large is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of electric power equipment, and in particular relates to a frequency converter that meets low harmonic requirements. Background Art

[0002] Inverter harmonics are high-order harmonics generated in the input and output circuits during the inverter operation, when the input power needs to be inverted by a high-power diode rectifier (or transistor / inverter module). Inverter harmonics are likely to interfere with the power supply system, loads and other nearby electrical equipment, so they need to be reduced.

[0003] In traditional inverters, input reactors are usually installed on the input circuit of the inverter movement, and output reactors are installed on the output circuit. Harmonics on such inverters are not effectively processed, resulting in too large harmonics that cannot meet customer needs. Therefore, how to reduce harmonics without changing the original specifications is a difficult problem for power equipment manufacturers. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a frequency converter that solves the technical problem of excessive harmonics in the frequency converter without changing the original specifications.

[0005] To achieve the above object, the technical solution adopted in the present application is: to provide a frequency converter, including an input circuit and an output circuit connected to the frequency converter, and the frequency converter also includes:

[0006] The inverter unit mechanism comprises an inverter core, the inverter core is connected with a DC reactor, and the DC reactor is used to reduce the main circuit harmonics on the inverter core;

[0007] A passive low harmonic filtering mechanism, comprising a three-phase input reactor and a three-phase filter reactor, wherein the three-phase input reactor is electrically connected to an external device, the three-phase filter reactor and the inverter core respectively, and the three-phase filter reactor is used to reduce harmonics on the inverter input line;

[0008] The sine wave filtering mechanism comprises a sine wave filtering reactor for reducing harmonics on the output circuit of the frequency converter, and the sine wave filtering reactor is electrically connected to the frequency converter core and external equipment respectively.

[0009] The beneficial effect of the frequency converter provided by the present application is that: compared with the prior art, the frequency converter of the present application is provided with filtering mechanisms on the input line and the output line of the frequency converter respectively. Among them, a combination of a three-phase input reactor and a three-phase filter reactor is provided on the input line to reduce input harmonics, a sine wave filter reactor is provided on the output line to reduce output harmonics, and a DC reactor is connected to the frequency converter core, and the DC reactor is used to reduce the main circuit harmonics of the frequency converter core, thereby forming a triple harmonic reduction composite mechanism, maximizing the reduction of the frequency converter harmonics, and effectively reducing the interference of the frequency converter harmonics.

[0010] The structure of the frequency converter is improved. The frequency converter includes a first cabinet, a second cabinet and a third cabinet arranged in sequence. The passive low harmonic filter mechanism is arranged in the first cabinet, the frequency converter unit mechanism is arranged in the second cabinet, and the sine filter mechanism is arranged in the third cabinet. In this way, in order to solve the problem of heat generation of each electrical component for reducing harmonics on the frequency converter, three cabinets are used to separate and assemble the three major mechanisms respectively, which effectively reduces the electrical interference between each other, especially helps to reduce the heat accumulation that causes the whole machine to easily rise in temperature and affect the electrical components. In addition, the three major mechanisms can also be inspected and repaired separately to reduce maintenance costs.

[0011] In one embodiment, the first cabinet is divided into an upper area, a middle area, and a lower area in the height direction, and the three-phase filter reactor is electrically connected to a three-phase filter capacitor; the three-phase filter capacitor is arranged in the upper area, the three-phase filter reactor is arranged in the middle area, and the three-phase input reactor is arranged in the lower area. In this way, the various electrical components in the first cabinet are arranged in layers, and in particular, the three-phase filter capacitor with a larger heat generation is arranged in the upper area to reduce the impact on other electrical components.

[0012] In one embodiment, the three-phase filter capacitor includes a base and a capacitor group arranged on the base, the capacitor group is composed of a plurality of capacitor arrays, and the plurality of capacitors are evenly arranged on the base; the capacitor group is provided with a first electrode row for being electrically connected to the three-phase filter reactor. In this way, the plurality of capacitors in the capacitor group are evenly arranged on the base, so that heat dissipation gaps are formed between the capacitors, thereby improving the heat dissipation effect.

[0013] In one embodiment, the passive low harmonic filter mechanism further includes a contactor for power-off protection according to the heating temperature of the three-phase filter capacitor, the contactor being electrically connected between the three-phase input reactor and the three-phase filter reactor; the contactor being arranged in the middle area of ​​the first cabinet and spaced apart from the three-phase filter reactor. In this way, when the heating temperature of the three-phase filter capacitor reaches a threshold, the contactor can be powered off in time to play a role of power-off protection.

[0014] In one embodiment, the contactor includes a contactor body, a second electrode row, and a fixed substrate for fixing on the side wall of the first cabinet, and the fixed substrate and the second electrode row are respectively arranged on opposite sides of the contactor body. The contactor is suspended on the side wall of the first cabinet using the fixed substrate on one side, and the second electrode row on the other side of the contactor is conveniently connected to the three-phase filter reactor.

[0015] In one embodiment, the second electrode row includes an input row, an output row, and a protrusion extending outward from the contactor body, the input row is connected to the lower end surface of the protrusion for electrically connecting to the three-phase input inductor; the output row is connected to the upper end surface of the protrusion for electrically connecting to the three-phase filter inductor.

[0016] The internal structure of the second mechanism is improved. The second cabinet is divided into a first area and a second area in the height direction, and the first area is located above the second area; the inverter unit mechanism also includes a transformer electrically connected to the inverter movement, and the inverter movement is arranged in the first area. The transformer and the DC reactor are both arranged in the second area, and the transformer and the DC reactor are spaced apart in the second area, thereby forming a separation space to avoid mutual interference.

[0017] The heat dissipation structure of the inverter is improved, and fans are provided on the tops of the first cabinet, the second cabinet and the third cabinet, and air inlets are respectively opened on the side walls of the first cabinet, the second cabinet and the third cabinet close to the ground, so that independent air ducts are formed inside each cabinet.

[0018] The structure of the sine filter mechanism is improved, the sine wave filter reactor is electrically connected to a sine filter capacitor, and a heat insulation plate is provided between the sine wave filter reactor and the sine filter capacitor to prevent the heat generated by the sine filter capacitor from affecting the sine wave filter reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 It is a schematic diagram of the traditional inverter structure;

[0021] Figure 2 A schematic diagram of the overall structure of the frequency converter provided in the embodiment of the present application;

[0022] Figure 3 A schematic diagram of the structure of the frequency converter unit provided in an embodiment of the present application;

[0023] Figure 4 A schematic diagram of the passive low harmonic filtering mechanism structure provided in an embodiment of the present application;

[0024] Figure 5 A schematic diagram of the structure of a sinusoidal filter mechanism provided in an embodiment of the present application;

[0025] Figure 6 A side view of the internal structure of a first cabinet provided in an embodiment of the present application;

[0026] Figure 7 A schematic diagram of the three-phase filter capacitor provided in an embodiment of the present application;

[0027] Figure 8 A schematic diagram of the three-dimensional structure of a contactor provided in an embodiment of the present application;

[0028] Fig. 9 A schematic diagram of the three-phase input reactor provided in an embodiment of the present application;

[0029] Fig.10 A schematic diagram of the three-phase filter reactor provided in an embodiment of the present application;

[0030] Fig.11 A side view of the internal structure of a second cabinet provided in an embodiment of the present application;

[0031] Fig.12 A schematic diagram of the structure of the inverter movement provided in the embodiment of the present application;

[0032] Fig.13 A schematic diagram of the three-dimensional structure of a DC reactor provided in an embodiment of the present application;

[0033] Fig.14 A side view of the internal structure of a third cabinet provided in an embodiment of the present application;

[0034] Fig.15 A schematic diagram of the three-dimensional structure of a sinusoidal wave filter reactor provided in an embodiment of the present application.

[0035] Among them, the reference numerals in the figure are:

[0036] 100 - inverter unit mechanism; 101 - second cabinet; 102 - first area; 103 - second area;

[0037] 200- passive low harmonic filtering mechanism; 201- first cabinet; 202- upper area; 203- middle area; 204- lower area;

[0038] 300-sine filter mechanism; 301-third cabinet; 302-first space; 303-second space;

[0039] 400-fan; 401-air inlet;

[0040] 500- steps;

[0041] 1- inverter movement; 11- energy unit; 12- electrode unit; 13- bus bar; 131- first terminal group; 132- second terminal group; 133- third terminal group;

[0042] 2- Transformer;

[0043] 3-DC reactor; 31-DC reactor body; 311-electrode ear; 32-bracket;

[0044] 4-three-phase input reactor; 41-lower three-way connection bar; 42-upper three-way connection bar;

[0045] 5-three-phase filter reactor; 51-output three-way row; 52-input three-way row;

[0046] 6-sine wave filter reactor; 61-sine wave filter capacitor; 62-gap; 63-thermal insulation board; 64-upper terminal block; 65-lower terminal block;

[0047] 7-three-phase filter capacitor; 71-base; 72-capacitor group; 73-first electrode row;

[0048] 8-contactor; 81-contactor body; 82-second electrode row; 821-input row; 822-output row; 823-protrusion; 83-fixed substrate; 831-mounting hole. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0050] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0051] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0052] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0053] like Figure 1 The inverter shown is a dual-core inverter model. Two parallel cabinets X are each provided with a set of inverter cores. Input reactors Y and output reactors Z are respectively provided on the input and output lines of each set of inverter cores. The input harmonics of this specification inverter are at least 40%, which is very large and cannot meet customer needs.

[0054] Here, an embodiment of the present application provides a new type of inverter, which solves the technical problem of excessive harmonics of the inverter without changing the original specifications, and is now described in detail.

[0055] See also Figure 2 The inverter is electrically connected to an input line and an output line. The inverter includes an inverter unit mechanism 100, a passive low harmonic filter mechanism 200 and a sine filter mechanism 300, wherein the passive low harmonic filter mechanism 200 is connected to the input line of the inverter unit mechanism 100, and the sine filter mechanism 300 is connected to the output line of the inverter unit mechanism 100.

[0056] See also Figure 3 The inverter unit structure 100 includes an inverter core 1 and a transformer 2. The inverter core 1 is electrically connected to the transformer 2. A DC reactor 3 is connected to the inverter core 1. The DC reactor 3 is used to reduce the main circuit harmonics on the inverter core 1.

[0057] See also Figure 4 The passive low harmonic filter mechanism 200 includes a three-phase input reactor 4 and a three-phase filter reactor 5. The three-phase input reactor 4 is a main component on the inverter input line and is electrically connected to an external device (not shown), the three-phase filter reactor 5 and the inverter core 1. The three-phase filter reactor 5 is used to reduce the harmonics on the inverter input line. The external device can be understood as the client's access device.

[0058] See also Figure 5 The sinusoidal filter mechanism 300 includes a sinusoidal filter inductor 6, which is used to reduce harmonics on the inverter output line. The sinusoidal filter inductor 6 is a main component on the output line and is electrically connected to the inverter core 1 and external equipment respectively.

[0059] Compared with the prior art, the frequency converter provided in the embodiment of the present application is provided with filtering mechanisms on the input line and the output line of the frequency converter, respectively. Among them, a combination of a three-phase input reactor 4 and a three-phase filter reactor 5 is provided on the input line to reduce input harmonics, a sine wave filter reactor 6 is provided on the output line to reduce output harmonics, and a DC reactor 3 is connected to the frequency converter core 1, and the DC reactor 3 is used to reduce the main circuit harmonics of the frequency converter core 1, thereby forming a triple harmonic reduction composite mechanism, maximizing the reduction of the frequency converter harmonics, and effectively reducing the interference of the frequency converter harmonics.

[0060] Experiments have proved that, through the above-mentioned triple harmonic reduction, under the same inverter specifications, the harmonics of the inverter can be controlled from more than 40% to within 5%, greatly reducing the harmonics to meet customer requirements.

[0061] It should be noted that since the above-mentioned electrical components on the frequency converter of the present application are mainly used to reduce harmonics and generate a large amount of heat, from the perspective of the design of the machine body, it is also necessary to effectively control and deal with the heat generation temperature inside the machine body.

[0062] Here, for the overall structure of the inverter, please refer to Figure 2 , Figure 3 , Figure 4 and Figure 5The frequency converter of the present application includes a first cabinet 201, a second cabinet 101 and a third cabinet 301 arranged in sequence, and the above three mechanisms are respectively arranged in corresponding cabinets. Specifically, the passive low harmonic filter mechanism 200 is arranged in the first cabinet 201, the frequency converter unit mechanism 100 is arranged in the second cabinet 101, and the sine filter mechanism 300 is arranged in the third cabinet 301.

[0063] Compared with the structure in the related art in which various mechanisms are arranged in the same cabinet, the inverter of the present application adopts three independent cabinets to respectively arrange the above-mentioned passive low harmonic filtering mechanism 200, the inverter unit mechanism 100 and the sine filtering mechanism 300, thereby separating the three major mechanisms, effectively reducing the electrical interference between each other, and especially helping to reduce the heat accumulation caused by the operation of various electrical components, resulting in temperature rise affecting the normal operation of the whole machine, and even the risk of fire.

[0064] In addition, the above three major mechanisms are assembled and set up in their own independent cabinets, which is conducive to separate inspection and maintenance or direct replacement, effectively reducing maintenance costs and improving inspection efficiency.

[0065] Please also refer to Figure 4 and Figure 6 The first cabinet 201 is divided into an upper area 202, a middle area 203 and a lower area 204 in the height direction. The three-phase filter reactor 5 is electrically connected to the three-phase filter capacitor 7 to form a filter combination.

[0066] The three-phase filter capacitor 7 is arranged in the upper area 202 , the three-phase filter reactor 5 is arranged in the middle area 203 , and the three-phase input reactor 4 is arranged in the lower area 204 , so that the various electrical components in the first cabinet 201 are arranged in layers.

[0067] Since hot air rises, the three-phase filter capacitor 7 with a larger heat generation is arranged in the upper area 202 which is higher than the middle area 203 and the lower area 204, thereby reducing the influence of the heat generation temperature on other electrical components in the first cabinet 201.

[0068] In addition, in the first cabinet 201, the three-phase filter inductor 5 is arranged between the three-phase filter capacitor 7 and the three-phase input inductor 4, which is convenient for connecting the output and input ends of the three-phase filter inductor 5, thereby improving the rationality of the line layout and facilitating the routing of the lines in the first cabinet 201.

[0069] In this embodiment, please refer to Figure 6 and Figure 7The three-phase filter capacitor 7 includes a base 71 and a capacitor group 72 disposed on the base 71. The base 71 allows the three-phase filter capacitor 7 to be stably disposed in the first cabinet 201. The capacitor group 72 is composed of a plurality of capacitor arrays, and the plurality of capacitors are evenly arranged on the base 71, so that heat dissipation gaps are formed between the capacitors, thereby improving the heat dissipation effect.

[0070] A first electrode row 73 is provided on the capacitor group 72 . The first electrode row 73 electrically connects the capacitors in the capacitor group 72 and is used to electrically connect to the three-phase filter reactor 5 .

[0071] In order to solve the heating problem of the three-phase filter capacitor 7, a protection structure needs to be provided in the passive low harmonic filter mechanism 200. Figure 6 The passive low harmonic filter mechanism 200 further includes a contactor 8, which is used to perform power-off protection according to the heating temperature of the three-phase filter capacitor 7. Specifically, the contactor 8 is electrically connected between the three-phase input reactor 4 and the three-phase filter reactor 5, so that when the heating temperature of the three-phase filter capacitor 7 reaches a threshold, the contactor 8 can be powered off in time to play a role of power-off protection.

[0072] Preferably, if Figure 6 As shown, the contactor 8 is disposed in the middle area 203 of the first cabinet 201 and is spaced apart from the three-phase filter reactor 5 to form a spacing space, which is beneficial to heat dissipation and convenient for wiring processing.

[0073] In this embodiment, please refer to Figure 6 and Figure 8 The contactor 8 includes a contactor body 81, a second electrode row 82 and a fixed substrate 83. The fixed substrate 83 and the second electrode row 82 are respectively arranged on opposite sides of the contactor body 81. The fixed substrate 83 is used to fix the contactor 8 on the side wall of the first cabinet 201 so that the contactor 8 is suspended on the inner wall of the first cabinet 201.

[0074] Among them, the connection structure between the fixed base plate 83 and the side wall of the first cabinet 201, in this embodiment, adopts the method of opening a mounting hole 831 on the fixed base plate 83, and fixing it to the side wall of the first cabinet 201 by installing fasteners such as screws through the holes. In other embodiments, a buckle hook may also be provided on the fixed base plate 83 to buckle and fix it with the buckle connection part on the side wall of the first cabinet 201. Therefore, the fixing structure between the fixed base plate 83 and the side wall of the first cabinet 201 is not specifically limited here.

[0075] Since the contactor 8 and the three-phase filter inductor 5 are both arranged in the middle area 203 of the first cabinet 201, the contactor 8 is suspended on the side wall of the first cabinet 201 using a fixed base plate 83 on one side, and the second electrode row 82 on the other side of the contactor 8 is facing the three-phase filter inductor 5, so as to facilitate the wiring processing of the connection line between the three-phase filter inductor 5 and the second electrode row 82.

[0076] Please also read Figure 6 and Figure 8 The second electrode row 82 on the contactor 8 includes an input row 821, an output row 822, and a protrusion 823 extending outward from the contactor body 81. The output row 822 is connected to the upper end surface of the protrusion 823 and extends upward, and is used to be electrically connected to the three-phase filter reactor 5. The input row 821 is connected to the lower end surface of the protrusion 823 and extends downward, and is used to be electrically connected to the three-phase input reactor 4 set in the lower area 204 of the first cabinet 201.

[0077] In this embodiment, the contactor 8 and the three-phase filter inductor 5 are both arranged in the middle area 203 of the first cabinet 201, and the protrusion 823 on the contactor 8 extends toward the direction of the three-phase filter inductor 5, so as to facilitate the electrical connection between the output row 822 on the protrusion 823 and the three-phase filter inductor 5, and to facilitate the electrical connection between the input row 821 on the protrusion 823 and the three-phase input inductor 4.

[0078] like Figure 6 and Fig. 9 As shown, three connection rows extend from the upper and lower ends of the three-phase input inductor 4 respectively, the lower three-way connection row 41 at the lower end is used to connect to an external device, two of the upper three-way connection rows 42 at the upper end are used to electrically connect to the inverter movement 1, and the remaining one is used to electrically connect to the input row 821 of the above-mentioned contactor 8.

[0079] In addition, if Figure 6 and Fig.10 As shown, the upper and lower ends of the three-phase filter inductor 5 also have an output three-way row 51 and an input three-way row 52 extending outward, respectively, wherein the output three-way row 51 is used to be electrically connected to the first electrode row 73 on the above-mentioned three-phase filter capacitor 7, and the input three-way row 52 is used to be electrically connected to the input row 821 of the contactor 8.

[0080] For the internal structure of the second cabinet 101, please refer to Figure 3 and Fig.11The second cabinet 101 is divided into a first area 102 and a second area 103 in the height direction, and the first area 102 is located above the second area 103. The inverter core 1 is arranged in the first area 102, and the transformer 2 and the DC reactor 3 are both arranged in the second area 103, and the transformer 2 and the DC reactor 3 are arranged at intervals in the second area 103, thereby forming an interval space to avoid mutual interference.

[0081] Please also read Figure 3 and Fig.12 The inverter core 1 is provided with an energy unit 11 (POWER) and an electrode unit 12, wherein the electrode unit 12 includes three connection terminals P1, a positive electrode and a negative electrode.

[0082] Two rows of busbars 13 are provided below the energy unit 11 and the electrode unit 12, and the busbars 13 include a first terminal group 131, a second terminal group 132 and a third terminal group 133. The first terminal group 131 is used to be electrically connected to the output end of the three-phase input inductor 4, the second terminal group 132 is used to be electrically connected to the input end of the sine wave filter inductor 6, and the third terminal group 133 is used to be electrically connected to the DC inductor 3 and to short-circuit the positive and negative busbars with the inverter movement 1 of the parallel cabinet.

[0083] For the structure of the DC reactor 3, Fig.13 As shown, the DC reactor 3 includes a DC reactor body 31 and a bracket 32. The DC reactor body 31 is arranged on the bracket 32. A pair of electrode ears 311 extending in parallel are provided on the DC reactor body 31. One electrode ear 311 of the pair of electrode ears 311 is electrically connected to the terminal group where the positive pole on the above-mentioned inverter movement 1 is located, and the other electrode ear 311 is electrically connected to the terminal group where P1 on the above-mentioned inverter movement 1 is located.

[0084] For the structure of the sinusoidal filter mechanism 300, please refer to the embodiments of the present application. Fig.14 and Fig.15 The sine wave filter reactor 6 is electrically connected to a sine wave filter capacitor 61, thereby forming a filter combination.

[0085] Since the sine wave filter capacitor 61 generates a large amount of heat, a gap 62 is formed between the sine wave filter inductor 6 and the sine wave filter capacitor 61, and a heat insulation board 63 is provided in the gap 62. The heat insulation board 63 is used to prevent the heat generated by the sine wave filter capacitor 61 from directly affecting the sine wave filter inductor 6, thereby effectively ensuring the normal operation of the sine wave filter inductor 6.

[0086] Among them, Fig.15As shown, the upper and lower ends of the sine wave filter inductor 6 are respectively provided with an upper terminal block 64 and a lower terminal block 65 extending outward in parallel. The upper terminal block 64 is used for electrical connection with an external device, and the lower terminal block 65 is used for electrical connection with the inverter core 1, so that the external connection terminals on the sine wave filter inductor 6 are separated up and down to avoid mutual interference.

[0087] Regarding the heat dissipation structure of the inverter, in one embodiment of the present application, fans 400 are provided on the tops of the first cabinet 201, the second cabinet 101 and the third cabinet 301, and air inlet holes 401 are respectively opened on the side walls of the first cabinet 201, the second cabinet 101 and the third cabinet 301 close to the ground.

[0088] like Figure 3 As shown, taking the second cabinet 101 as an example, a fan 400 is disposed on the top of the second cabinet 101 , and an air inlet 401 is opened on the bottom side wall of the second cabinet 101 , so that an independent air duct is formed inside the second cabinet 101 .

[0089] In this embodiment, the fan 400 may be preferably configured to draw air to the outside of the cabinet, so that air enters the cabinet from the bottom of the cabinet and then is discharged from the top of the cabinet. The heat dissipation airflow can flow through the various electrical components inside the cabinet, and the heat generated by the electrical components is discharged from the top of the cabinet, thereby ensuring the heat dissipation effect.

[0090] Preferably, a plurality of air inlet holes 401 are provided at the bottom of each cabinet and are evenly distributed on the side wall of the cabinet close to the ground, thereby forming an air inlet grid, which is beneficial to increase the air flow and improve the heat dissipation effect.

[0091] Preferably, if Figure 3 , Figure 4 and Figure 5 As shown, steps 500 are provided at the bottom of the first cabinet 201 , the second cabinet 101 and the third cabinet 301 , so that the bottom of each cabinet is higher than the ground, which is helpful to reduce the risk of wading.

[0092] In the embodiments of this application, please refer to Figure 3 , Figure 4 and Figure 5 Since it is a frequency converter model with a dual frequency converter core 1, the frequency converter unit mechanism 100, the passive low harmonic filter mechanism 200 and the sine filter mechanism 300 mentioned above each have two groups. In coordination, each cabinet is also provided with a corresponding number of chambers according to the volume of each electrical component in the above three mechanisms, which is conducive to separate management.

[0093] In this embodiment, if Figure 3 As shown, the second cabinet 101 includes two chambers, each of which is provided with a set of inverter unit mechanisms 100. Figure 4 As shown, the first cabinet 201 also includes two chambers, and each chamber is respectively provided with a group of passive low harmonic filtering mechanisms 200.

[0094] Since the number and volume of electrical components in the sine filter mechanism 300 are relatively small, the third cabinet 301 can adopt a chamber structure. Figure 5 As shown, the inner chamber of the third cabinet 301 is divided into upper and lower parts, thereby forming a first space 302 and a second space 303 which are arranged upper and lower, and a group of sinusoidal filter mechanisms 300 are arranged in each of them.

[0095] Since the third cabinet 301 adopts a single-chamber design, the lines on the two sets of sine filter mechanisms 300 are easily confused. Figure 5 As shown, the wiring banks on the two groups of sine wave filter reactors 6 in the third cabinet 301 are staggered up and down so that the connection lines can avoid each other, effectively solving the problem of confusion in the connection lines of the electrical components inside the third cabinet 301.

[0096] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A frequency converter, comprising an input circuit and an output circuit connected to the frequency converter, characterized in that: The frequency converter also includes: The inverter unit mechanism comprises an inverter core, the inverter core is connected with a DC reactor, and the DC reactor is used to reduce the main circuit harmonics on the inverter core; A passive low harmonic filtering mechanism, comprising a three-phase input reactor and a three-phase filter reactor, wherein the three-phase input reactor is electrically connected to an external device, the three-phase filter reactor and the inverter core respectively, and the three-phase filter reactor is used to reduce harmonics on the inverter input line; The sine wave filtering mechanism comprises a sine wave filtering reactor for reducing harmonics on the output circuit of the frequency converter, and the sine wave filtering reactor is electrically connected to the frequency converter core and external equipment respectively.

2. The frequency converter according to claim 1, characterized in that: The frequency converter includes a first cabinet, a second cabinet and a third cabinet arranged in sequence, The passive low harmonic filtering mechanism is arranged in the first cabinet, The inverter unit mechanism is arranged in the second cabinet, The sinusoidal filtering mechanism is arranged in the third cabinet.

3. The frequency converter according to claim 2, characterized in that: The first cabinet is divided into an upper area, a middle area and a lower area in the height direction, and the three-phase filter inductor is electrically connected to a three-phase filter capacitor; the three-phase filter capacitor is arranged in the upper area, the three-phase filter inductor is arranged in the middle area, and the three-phase input inductor is arranged in the lower area.

4. The frequency converter according to claim 3, characterized in that: The three-phase filter capacitor includes a base and a capacitor group arranged on the base, the capacitor group is composed of a plurality of capacitor arrays, and the plurality of capacitors are evenly arranged on the base; the capacitor group is provided with a first electrode row for electrically connecting to the three-phase filter inductor.

5. The frequency converter according to claim 3, characterized in that: The passive low harmonic filtering mechanism also includes a contactor for performing power-off protection according to the heating temperature of the three-phase filter capacitor, and the contactor is electrically connected between the three-phase input inductor and the three-phase filter inductor; the contactor is arranged in the middle area of ​​the first cabinet and is spaced apart from the three-phase filter inductor.

6. The frequency converter according to claim 5, characterized in that: The contactor comprises a contactor body, a second electrode row and a fixing base plate for fixing on the side wall of the first cabinet, wherein the fixing base plate and the second electrode row are respectively arranged on two opposite sides of the contactor body.

7. The frequency converter according to claim 6, characterized in that: The second electrode row includes an input row, an output row and a protrusion extending outward from the contactor body, the input row is connected to the lower end surface of the protrusion for electrically connecting to the three-phase input inductor; the output row is connected to the upper end surface of the protrusion for electrically connecting to the three-phase filter inductor.

8. The frequency converter according to claim 2, characterized in that: The second cabinet is divided into a first area and a second area in the height direction, and the first area is located above the second area; the inverter unit mechanism also includes a transformer electrically connected to the inverter core, and the inverter core is arranged in the first area, and the transformer and the DC reactor are both arranged in the second area, and the transformer and the DC reactor are spaced apart in the second area.

9. The frequency converter according to claim 2, characterized in that: The tops of the first cabinet, the second cabinet and the third cabinet are all provided with fans, and the first cabinet, the second cabinet and the third cabinet are respectively provided with air inlets on the side walls close to the ground.

10. The frequency converter according to any one of claims 1 to 9, characterized in that: The sine wave filter reactor is electrically connected to a sine filter capacitor, and a heat insulation plate is provided between the sine wave filter reactor and the sine filter capacitor.

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