Air-cooled four-quadrant frequency converter unit

Abstract

The invention relates to an air-cooled four-quadrant frequency converter unit, which comprises a shell, an air-cooled radiator, a unit control board, an IGBT (Insulated Gate Bipolar Translator) module, an IGBT driving board, a positive bus copper bar, a negative bus copper bar, a thin-film capacitor and a radiating air duct, the structure is characterized in that a straight line where a capacitor positive and negative terminal connection point is located is perpendicular to a straight line where an IGBT positive and negative terminal connection point is located; the IGBT driving board is arranged close to the IGBT module, an IGBT interface board is fixed on the IGBT module, and the IGBT driving board is connected with the IGBT interface board through a driving wire. According to the frequency converter unit, the straight line where the connection point of the positive and negative terminals of the capacitor is located is perpendicular to the straight line where the connection point of the positive and negative terminals of the IGBT is located, so that the area enveloped by the shortest path of the current flowing through the film capacitor terminal and the IGBT module terminal is minimum, the stray inductance is reduced, the voltage peak can be absorbed, and the electrical performance of the frequency converter unit is effectively improved.

Description

Technical Field

[0001] The present invention relates to a frequency converter unit, and more particularly to an air-cooled four-quadrant frequency converter unit. Background Art

[0002] In recent years, with the continuous increase in high-power loads, market demand for high-power, high-voltage inverters has gradually increased, and the application of high-power four-quadrant inverters has become increasingly widespread. Against this backdrop of the ever-expanding application scope of high-power four-quadrant inverters, competition among four-quadrant inverter suppliers has also become increasingly fierce. This competition is reflected not only in product quality, but also in product size and price competitiveness.

[0003] Since high-power inverters (IGBT modules) generate a lot of heat during operation, when traditional air cooling can no longer meet the product's heat dissipation needs, high-power and high-voltage inverter products on the market will use water cooling. However, high-power and high-voltage inverters using water cooling have natural disadvantages such as high cost, large space occupation, and risk of water leakage. Therefore, there is an urgent need to develop a new type of high-power air-cooled four-quadrant inverter unit to fill the gap in this field.

[0004] When designing an air-cooled inverter power unit, the first consideration is heat dissipation. This involves meeting the heat dissipation requirements of the rectifier IGBT module and inverter IGBT within the power unit, ensuring stable and long-term operation within the designed temperature range. The heat dissipation requirements of the inverter's remaining electronic components must also be considered. Secondly, the layout and connection of the positive and negative busbars, film capacitors, and IGBT modules must be properly configured to minimize circuit circulation and stray inductance. Furthermore, high-voltage, high-power inverters utilize a cascade of multiple power units to achieve high-voltage output. In the event of a power unit failure, this requires a bypass function to maintain continued operation. To address this issue, the present invention provides an air-cooled four-quadrant inverter unit. Summary of the Invention

[0005] In order to overcome the disadvantages of the above technical problems, the present invention provides an air-cooled four-quadrant inverter unit.

[0006] The air-cooled four-quadrant inverter unit of the present invention includes a housing and an air-cooled radiator disposed in the housing, a unit control board, an IGBT module, an IGBT driver board, a positive busbar copper bar, a negative busbar copper bar, and a film capacitor. An inner plate is disposed on the right side of the housing, and a heat dissipation duct is formed between the inner plate and the housing. The air-cooled radiator comprises a heat-absorbing base plate and heat dissipation fins fixed to the heat-absorbing base plate. The IGBT module is fixed to the outer surface of the heat-absorbing base plate, and the heat dissipation fins are located in the heat dissipation duct. The positive busbar copper bar and the negative busbar copper bar are located on the rear side of the IGBT module and are separated from the negative busbar copper bar by a busbar spacer (PET). The IGBT module includes a rectifier IGBT module and an inverter IGBT module. The front side of the housing is fixed with input copper bars R, S and T connected to the input end of the rectifier IGBT module. The front side of the housing is provided with output copper bars U and V connected to the output end of the inverter IGBT module. The characteristics are: The output end of the rectifier IGBT module and the input end of the inverter IGBT module are respectively connected to the positive bus copper bus and the negative bus copper bus through the IGBT positive and negative terminal connection points. The film capacitor is respectively connected to the positive bus copper bus and the negative bus copper bus through the capacitor positive and negative terminal connection points. The straight line where the capacitor positive and negative terminal connection points are located is perpendicular to the straight line where the IGBT positive and negative terminal connection points are located; the IGBT driver board is arranged close to the IGBT module, and an IGBT interface board is fixed on the IGBT module. The IGBT driver board is connected to the IGBT interface board through the drive line.

[0007] The air-cooled four-quadrant inverter unit of the present invention has three rectifier IGBT modules and two inverter IGBT modules. The distance between the two inverter IGBT modules and the distance between an inverter module and an adjacent rectifier IGBT module are both greater than the distance between two adjacent rectifier IGBT modules. A plurality of heat pipe placement grooves are provided on the heat absorption base plate below the inverter IGBT module. Heat absorption pipes are placed in the heat pipe placement grooves to increase the heat conduction performance between the inverter IGBT module and the heat absorption base plate.

[0008] In the air-cooled four-quadrant inverter unit of the present invention, the unit control board is located above the film capacitor, a plurality of rear through holes are opened on the rear wall of the shell, and a plurality of side through holes are opened on the side wall of the shell.

[0009] The air-cooled four-quadrant inverter unit of the present invention includes a mechanical bypass mechanism consisting of a mechanical bypass contactor, a mechanical bypass control board, a mechanical bypass step-down transformer, a mechanical bypass copper busbar A, and a mechanical bypass copper busbar B. The mechanical bypass control board is fixed to the outside of the front wall of the housing, the mechanical bypass step-down transformer is fixed to the inside of the front wall of the housing, and the mechanical bypass contactor is arranged to penetrate the front wall of the housing. The input and output ends of the mechanical bypass contactor are respectively connected to the output copper busbar U and the output copper busbar V via the mechanical bypass copper busbar A and the mechanical bypass copper busbar B. At least two of the input copper bars R, S, and T are connected in series with fuses. The input end of the mechanical bypass step-down transformer draws power from the input copper bar R, S, or T on the front side of the fuse. The output of the mechanical bypass step-down transformer supplies power to the mechanical bypass control board, which controls the on / off state of the mechanical bypass contactor.

[0010] In the air-cooled four-quadrant inverter unit of the present invention, the connection points of the positive and negative terminals of the IGBT are lower than the connection points of the positive and negative terminals of the capacitor. The positive and negative busbars are provided with downwardly bent positive and negative busbar bending portions on the side close to the IGBT module. The angle between the positive and negative busbar bending portions and the positive and negative busbar portions on both sides is 120°.

[0011] In the air-cooled four-quadrant inverter unit of the present invention, a temperature collection board for collecting the temperature of the IGBT module and a temperature relay for protecting the IGBT module are fixed on the heat-absorbing bottom plate of the air-cooled radiator.

[0012] The air-cooled four-quadrant inverter unit of the present invention has an insulating unit control board protection plate and an IGBT drive board protection plate respectively arranged between the unit control board and the IGBT drive board and the thin film capacitor, a mechanical bypass control protection plate PET and a fuse protection PET respectively arranged between the mechanical bypass control board and the fuse and the front wall of the shell, and a mechanical bypass shielding box is arranged on the periphery of the mechanical bypass control board to reduce electromagnetic interference in a strong electric environment.

[0013] The air-cooled four-quadrant inverter unit of the present invention has two long limit holes on the lower part of the rear wall of the shell that cooperate with the unit guide rail to limit the position, and a threaded hole on the lower part of the front wall of the shell that cooperates with the unit guide rail to be fixed, and the lower surface of the shell below the threaded hole is coated with conductive paint that contacts the unit guide rail.

[0014] In the air-cooled four-quadrant inverter unit of the present invention, the input copper bar R, input copper bar S, input copper bar T, output copper bar U and output copper bar V, as well as the connection between the fuse and the input copper bar are all fixed to the front wall of the shell via 30-height insulators; the upper wall of the shell adopts an upper sealing plate formed of insulating material.

[0015] The beneficial effects of the present invention are as follows: the air-cooled four-quadrant inverter unit of the present invention is provided with a shell and an air-cooled radiator located in the shell, an IGBT module, a unit control board, an IGBT drive board, positive and negative busbar copper bars, a film capacitor and a heat dissipation air duct, the IGBT module includes a rectifier and an inverter IGBT module and is fixed on the heat-absorbing bottom plate of the air-cooled radiator, three input copper bars (R, S, T) are connected to the input end of the rectifier IGBT module, the output copper bars (U, V) are connected to the output end of the inverter IGBT module, the output end of the rectifier IGBT module and the input of the inverter IGBT module are both connected to the positive and negative busbar copper bars, the film capacitor is also connected to the positive and negative busbar copper bars, and the input high-voltage AC power is rectified. After flow and inversion, it is converted into alternating current with controllable phase and frequency to achieve variable frequency output. The heat generated by the IGBT module is carried away by the air flowing through the heat dissipation duct. At the same time, since the straight line where the positive and negative terminals of the film capacitor are connected is perpendicular to the straight line where the positive and negative terminals of the IGBT are connected (that is, at a 90° angle), the area enclosed by the shortest path of current flowing through the film capacitor terminals and the IGBT module terminals is minimized. In this way, the circuit loop path between the positive and negative busbars and the IGBT module can be shortened, reducing stray inductance, and the film capacitor can absorb voltage spikes to the greatest extent, effectively improving the electrical performance of the inverter unit and ensuring the long-term and stable operation of the inverter unit.

[0016] Furthermore, the distance between the two inverter IGBT modules on the heat absorption base plate of the air-cooled radiator and the distance between adjacent inverter modules and the rectifier IGBT module are both greater than the distance between two adjacent rectifier IGBT modules, and a heat pipe placement groove for placing the heat absorption pipe is provided on the heat absorption base plate below the inverter IGBT module. In this way, the heat dissipation effect of the inverter IGBT module is better than that of the rectifier IGBT module. Under the action of air cooling, it is more conducive to dissipating the heat generated by the inverter IGBT module with greater heat generation, thereby ensuring the stability of the operation of the inverter unit.

[0017] Furthermore, by providing a mechanical bypass mechanism consisting of a mechanical bypass contactor, mechanical bypass copper bars A and B, a mechanical bypass control board and a mechanical bypass step-down transformer, the mechanical bypass step-down transformer draws power from the input copper bar at the front end of the fuse. In this way, when a fault such as a blown fuse occurs in the inverter unit, the mechanical bypass control board short-circuits the output copper bar U and the output copper bar V via the mechanical bypass contactor and the mechanical bypass copper bars A and B, thereby bypassing the faulty inverter unit. This allows the remaining inverter units to continue operating after the faulty inverter unit is bypassed, making it suitable for situations where irreparable losses will be caused after the inverter is shut down.

[0018] Furthermore, positive and negative busbar copper bars are provided with bent portions at positions near the IGBT modules of the positive and negative busbar copper bars. The angles formed between the bent portions and the positive and negative busbar copper bars on both sides are obtuse angles (e.g., 120°), so that the upper and lower non-overlapping areas of the positive and negative busbar copper bars are very small, further reducing the stray inductance of the inverter unit.

[0019] Furthermore, by opening a plurality of rear through holes and side through holes on the rear wall and side walls of the shell respectively, the air in the shell can circulate with the outside through the rear through holes and the side through holes, thereby accelerating the air circulation inside the thin film capacitor, so that the thin film capacitor has good heat dissipation efficiency, and at the same time ensures the heat dissipation of the heat-generating electronic components on the unit control board and the IGBT driver board in the shell, thereby improving the service life of the inverter unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a front view of the air-cooled four-quadrant inverter unit of the present invention; Figure 2 It is a rear view of the air-cooled four-quadrant inverter unit of the present invention; Figure 3 It is a left side view of the air-cooled four-quadrant inverter unit of the present invention; Figure 4 It is a right side view of the air-cooled four-quadrant inverter unit of the present invention; Figure 5 A top view of the air-cooled four-quadrant inverter unit of the present invention; Figure 6 、 Figure 7 They are all three-dimensional diagrams of the air-cooled four-quadrant inverter unit of the present invention; Figure 8 This is a three-dimensional diagram of the air-cooled four-quadrant inverter unit of the present invention with the housing removed; Figure 9 、 Figure 10 and Figure 11 They are all partial three-dimensional views of the air-cooled four-quadrant inverter unit of the present invention; Figure 12 This is a diagram showing the fixing structure of the IGBT module on the air-cooled radiator in the present invention; Figure 13 This is a diagram showing the structure of the film capacitor fixed on the positive and negative busbars in the present invention; Figure 14 This is a circuit diagram of the air-cooled four-quadrant inverter unit of the present invention.

[0021] In the figure: 1 housing, 2 air cooling radiator, 3 unit control board, 4 IGBT driver board, 5 IGBT module, 6 IGBT interface board, 7 positive busbar copper bus, 8 negative busbar copper bus, 9 film capacitor, 10 busbar spacer PET, 11 heat absorbing base plate, 12 heat dissipation fin, 13 heat dissipation duct, 14 input copper bus R, 15 input copper bus S, 16 input copper bus T, 17 current sensor, 18 fuse, 19 30 high insulator, 20 output copper bus U, 21 output copper bus V, 22 capacitor positive and negative terminal connection points, 23 IGBT positive and negative terminal connection points, 24 positive and negative copper busbar bending parts, 25 mechanical bypass contactor, 26 mechanical bypass copper busbar A, 27 mechanical bypass copper busbar B, 28 mechanical bypass control board, 29 mechanical bypass step-down transformer, 30 inner plate, 31 handle, 32 limit long hole, 33 rear through hole, 34 side through hole, 35 film capacitor positioning hole, 36 unit control board protection plate, 37 IGBT driver board protection plate, 38 mechanical bypass shielding box, 39 mechanical bypass control board protection PET, 40 heat pipe placement groove, 41 absorption capacitor, 42 fuse protection PET, 43 temperature acquisition board, 44 temperature relay, 45 rectifier IGBT module, 46 inverter IGBT module, 47 threaded hole. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] like Figures 1 to 5 As shown, the front view, rear view, left view, right view and top view of the air-cooled four-quadrant inverter unit of the present invention are respectively given, Figure 6 and Figure 7 Its stereogram is given, Figures 9 and 10 Its local stereogram is given, Figure 12 and Figure 13 The fixed structure diagrams of the IGBT module on the air-cooled radiator and the fixed structure diagrams of the film capacitor on the positive and negative busbars in the present invention are respectively given. Figure 14 The circuit schematic diagram is given.

[0024] The air-cooled four-quadrant inverter unit of the present invention is shown as comprising a housing 1 and an air-cooled heat sink 2, a unit control board 3, an IGBT driver board 4, an IGBT module 5, a positive busbar copper busbar 7, a negative busbar copper busbar 8, and a film capacitor 9, located within the housing 1. An inner panel 30 is provided on the right side of the interior of the housing 1. The air-cooled heat sink 2 comprises a heat-absorbing base plate 11 and heat-dissipating fins 12. The heat-dissipating fins 12 are fixed to one side of the heat-absorbing base plate 11, and the IGBT module 5 is fixed to the other side of the heat-absorbing base plate 11. A heat dissipation duct 13 is formed between the inner panel 30 and the heat-absorbing base plate 11 and the outer wall of the housing 1. The openings at both ends of the heat dissipation duct 13 are respectively an air inlet and an air outlet. The heat dissipating fins 12 are located within the heat dissipation duct 13. Thus, the heat generated by the IGBT module 5 during the rectification and inversion processes is conducted through the heat-absorbing base plate 11 to the heat dissipating fins 12, and then carried away by the air flowing through the heat dissipation duct 13, so that the IGBT devices in the IGBT module 5 operate within a suitable temperature range.

[0025] As shown ( Figure 12 The IGBT modules 5 fixed to the heat-absorbing baseplate 11 of the air-cooled heat sink 2 include a rectifier IGBT module 45 and an inverter IGBT module 46. Each IGBT module 5 houses two IGBT devices. The rectifier IGBT module 45 contains three IGBT modules 5, while the inverter IGBT module 46 contains two IGBT modules 5. Input copper bars R, S, and T extend through the front wall of the housing 1 and connect to the input terminals of the rectifier IGBT modules 45. The outer ends of the input copper bars R, S, and T are connected to the secondary winding of the phase-shifting transformer. The output terminals of the inverter IGBT module 46 are connected to output copper bars U and V, which extend through the front wall of the housing 1. In this way, the AC power output from the secondary winding of the phase-shifting transformer is rectified into DC power by the rectifier IGBT module 45. The inverter IGBT module 46 then inverts the rectified DC power, converting it into AC power with controllable frequency and phase for output.

[0026] The positive busbar copper bar 7 and the negative busbar copper bar 8 are shown as being arranged outside the IGBT driver board 4. The positive busbar copper bar 7 and the negative busbar copper bar 8 are stacked together and separated by a busbar spacer PET to achieve electrical isolation between the busbar copper bar 7 and the negative busbar copper bar 8. The output of the rectifier IGBT module 45, the input of the inverter IGBT module 46, and the film capacitor 9 are all connected to the positive busbar copper bar 7 and the negative busbar copper bar 8, as shown in FIG. Figure 13 As shown, the straight line where the positive and negative terminal connection points 22 of the thin film capacitor 9 are located is perpendicular to the straight line where the positive and negative terminal connection points of the IGBT are located (that is, the angle is 90°), that is, the straight line where the positive and negative terminal connection points 22 of the thin film capacitor 9 are located is perpendicular to the long side of the heat absorption base plate 11.

[0027] Since the straight line where the connection points 22 of the positive and negative terminals of the film capacitor 9 are located is perpendicular to the straight line where the connection points of the positive and negative terminals of the IGBT are located, the area enclosed by the shortest path through the terminals of the film capacitor 9 and the terminals of the IGBT module 5 is minimized. In this way, the circuit loop path between the positive and negative busbar copper bars (7, 8) and the IGBT module 5 can be shortened, reducing stray inductance, and the film capacitor 9 can absorb voltage spikes to the greatest extent, effectively improving the electrical performance of the inverter unit and ensuring the long-term and stable operation of the inverter unit.

[0028] The positive busbar copper busbar 7 and the negative busbar copper busbar 8 are shown as being positioned close to the IGBT module 5, thereby minimizing the distance between the thin-film capacitor 9 and the IGBT module 5. The IGBT positive and negative terminal connection points 23 are slightly lower than the capacitor positive and negative terminal connection points 22. Positive and negative busbar copper busbars 7 and 8 are provided with positive and negative busbar bends 24 at locations close to the IGBT module 5. The angles formed between the positive and negative busbar bends 24 and the positive and negative busbar portions on either side of them are obtuse, such as 120°. This minimizes the non-overlapping area between the positive busbar 7 and the negative busbar 8, further reducing the stray inductance of the air-cooled four-quadrant inverter unit.

[0029] In order to be compatible with inverters of different power sizes, improve the utilization rate of the film capacitors 9 and thus reduce the capacitor cost, the number of film capacitors 9 can be increased or decreased according to different powers, and respectively suitable for different powers.

[0030] The unit control board 3 is positioned above the thin-film capacitor 9, and the IGBT driver board 4 is positioned outside the IGBT module 5. An IGBT interface board 6 is affixed to each IGBT module 5. The IGBT driver board 4 is plugged into the IGBT interface board 6 via drive lines to control the on / off states of the IGBT devices in the IGBT module 5, achieving rectification and inversion. The close proximity of the IGBT driver board 4 to the IGBT interface board 6 minimizes drive line length, significantly reducing drive signal loss and improving signal response speed.

[0031] Since the heat generated by inversion is greater than the heat generated by rectification, that is, the heat generated by the inverter IGBT module 46 is greater than the heat generated by the rectifier IGBT module 45, in order to ensure that the heat generated by the inverter IGBT module 46 is dissipated in time, 5 heat pipe placement grooves 40 are opened on the heat absorption base plate 11 below the inverter IGBT module 46 shown, and heat absorption pipes with higher heat conduction efficiency are placed in the heat pipe placement grooves 40. In this way, the heat generated by the inverter IGBT module 46 can be timely conducted to the heat absorption base plate 11 and the heat dissipation fins 12, thereby realizing timely heat dissipation of the inverter IGBT module 46.

[0032] The distance between the two inverter IGBT modules 46 and the distance between the inverter module 46 and the adjacent rectifier IGBT module 45 are both greater than the distance between two adjacent rectifier IGBT modules 45, that is, the inverter IGBT modules 46 are sparsely distributed and the rectifier IGBT modules 45 are relatively densely distributed, which is further conducive to the heat dissipation of the inverter IGBT module 46 with higher heat generation.

[0033] A temperature acquisition board 43 and a temperature relay 44 are provided on the heat absorbing bottom plate 11 of the air-cooled radiator 2 shown. The unit control board 3 acquires the temperature of the IGBT module 5 through the temperature acquisition board 43 and protects the IGBT module 5 through the temperature relay 44, thereby improving the stability of the power unit.

[0034] The rear wall of the housing 1 is provided with a plurality of rear through-holes 33, the lower portion of the rear wall of the housing 1 is provided with two limiting elongated holes 32, the side wall of the housing 1 away from the air-cooled radiator 2 is provided with side through-holes 34 and a thin film capacitor positioning hole 35, and a threaded hole 47 is provided below the front wall of the housing 1. In this way, the internal cavity of the housing 1 is communicated with the outside world through the rear through-holes 33 and the side through-holes 34, which accelerates the air circulation inside the thin film capacitor 9, making the thin film capacitor 9 have good heat dissipation efficiency. At the same time, it also ensures the heat dissipation of the heat-generating electronic components on the unit control board 3 and the IGBT driver board 4 in the housing, thereby improving the stability of the inverter unit.

[0035] The two limiting elongated holes 32 allow the inverter unit to be directly positioned at the rear via the unit guide rail when installed in the complete machine, with threaded holes 47 used for final positioning. The film capacitor positioning holes 35 are used to secure the non-connecting terminals of the film capacitor 9. The lower surface of the housing 1 below the threaded holes 47 is coated with a conductive paint that contacts the unit guide rail. The conductive paint ensures direct contact between the housing 1 and the unit guide rail, preventing the housing 1 from having a floating potential and preventing the risk of discharge.

[0036] To detect the input current, current sensors 17 are installed around the periphery of the input copper bars R and T. Current sensors 17 are fixed to the front wall of the housing 1 via a current sensor mounting plate. Current sensors 17 are installed externally, directly threaded onto the input copper bars, ensuring that the sensor chip does not operate between the two live input copper bars. To protect the inverter unit, fuses 18 are connected in series to the input copper bars R and S. Fuses 18 are two fuses connected in parallel and mounted on the front wall of the housing 1 via support insulators. Fuse 18 and the housing 1 are protected by fuse protection PET42, which increases the electrical clearance between fuse 18 and the housing 1.

[0037] The input copper bar R, input copper bar S, input copper bar T, output copper bar U and output copper bar V, as well as the connection between the fuse 18 and the input copper bar are fixed to the front wall of the housing 1 via 30 high insulators 19 (i.e., insulators with a height of 30 mm) to ensure that the electrical clearance between the input and output copper bars and the housing 1 meets the requirements.

[0038] As shown, an insulating unit control board protection plate 36 and an IGBT driver board protection plate 37 are respectively provided between the unit control board 3 and the IGBT driver board 4 and the film capacitor 9. The protective plates can effectively protect the unit control board 3 and the IGBT driver board 4. A mechanical bypass control protection plate PET is provided between the mechanical bypass control board 28 and the front wall of the housing 1. The mechanical bypass control protection plate PET (39) can effectively protect the mechanical bypass control board 28 so that the electrical gap between the mechanical bypass control board 28 and the housing 1 meets the requirements. A mechanical bypass shielding box 38 is provided on the periphery of the mechanical bypass control board to reduce electromagnetic interference in a strong electric environment.

[0039] As shown, the upper wall of the housing 1 is formed of an insulating material. This insulating material effectively prevents the problem of electrical gaps between different phase units in the entire machine, which would require an increase in the overall size of the machine, further reducing the overall size. The front end of the housing 1 is provided with a handle 31, and openings can be added to the rear wall of the housing 1, diagonally arranged with the front handle 2, to facilitate unit installation and maintenance.

Claims

1. An air-cooled four-quadrant frequency converter unit, comprising a housing (1) and an air-cooled radiator (2) arranged in the housing, a unit control board (3), an IGBT module (5), an IGBT drive board (4), a positive busbar copper bar (7), a negative busbar copper bar (8) and a film capacitor (9), an inner plate (30) being arranged on the right side of the housing, a heat dissipation duct (13) being formed between the inner plate and the housing, the air-cooled radiator being composed of a heat-absorbing base plate (11) and heat-dissipating fins (12) fixed on the heat-absorbing base plate, the IGBT module being fixed on the outer surface of the heat-absorbing base plate, and the heat-dissipating fins being located in the heat-dissipating duct; the positive busbar copper bar and the negative busbar copper bar being located on the rear side of the IGBT module, and the positive busbar copper bar and the negative busbar copper bar being separated by a busbar spacer PET (10); The IGBT module includes a rectifier IGBT module (45) and an inverter IGBT module (46); an input copper busbar R (14), an input copper busbar S (15), and an input copper busbar T (16) connected to the input end of the rectifier IGBT module are fixed on the front side of the housing; an output copper busbar U (20) and an output copper busbar V (21) connected to the output end of the inverter IGBT module are provided on the front side of the housing; and the characteristics are: The output end of the rectifier IGBT module and the input end of the inverter IGBT module are respectively connected to the positive busbar copper bar and the negative busbar copper bar via the IGBT positive and negative terminal connection points (23), and the film capacitor is respectively connected to the positive busbar copper bar and the negative busbar copper bar via the capacitor positive and negative terminal connection points (22). The straight line where the capacitor positive and negative terminal connection points are located is perpendicular to the straight line where the IGBT positive and negative terminal connection points are located. The IGBT driver board is arranged close to the IGBT module, and an IGBT interface board (6) is fixed on the IGBT module. The IGBT driver board is connected to the IGBT interface board via the drive line.

2. The air-cooled four-quadrant inverter unit according to claim 1, characterized in that: The number of the rectifier IGBT modules (45) is 3, and the number of the inverter IGBT modules (46) is 2. The distance between the two inverter IGBT modules and the distance between the inverter module and the adjacent rectifier IGBT module are both greater than the distance between two adjacent rectifier IGBT modules. A plurality of heat pipe placement grooves (40) are provided on the heat absorption base plate (11) below the inverter IGBT module. Heat absorption pipes are placed in the heat pipe placement grooves to increase the heat conduction performance between the inverter IGBT module and the heat absorption base plate.

3. The air-cooled four-quadrant inverter unit according to claim 1 or 2, characterized in that: The unit control board (3) is located above the film capacitor (9), a plurality of rear through holes (33) are provided on the rear wall of the shell (1), and a plurality of side through holes (34) are provided on the side wall of the shell.

4. The air-cooled four-quadrant inverter unit according to claim 1 or 2, characterized in that: The invention comprises a mechanical bypass mechanism consisting of a mechanical bypass contactor (25), a mechanical bypass control panel (28), a mechanical bypass step-down transformer (29), a mechanical bypass copper bar A (26) and a mechanical bypass copper bar B (27), wherein the mechanical bypass control panel is fixed to the outside of the front wall of the housing (1), the mechanical bypass step-down transformer is fixed to the inside of the front wall of the housing, the mechanical bypass contactor is arranged through the front wall of the housing, and the input and output ends of the mechanical bypass contactor are connected to the output copper bar U (20) and the output copper bar V (21) via the mechanical bypass copper bar A and the mechanical bypass copper bar B respectively; At least two of the input copper bars R (14), the input copper bar S (15) and the input copper bar T (16) are connected in series with a fuse (18). The input end of the mechanical bypass step-down transformer draws power from the input copper bar R, the input copper bar S or the input copper bar T on the front side of the fuse. The output of the mechanical bypass step-down transformer supplies power to the mechanical bypass control board, and the mechanical bypass control board controls the on-off state of the mechanical bypass contactor.

5. The air-cooled four-quadrant inverter unit according to claim 1 or 2, characterized in that: The IGBT positive and negative terminal connection points (23) are lower than the capacitor positive and negative terminal connection points (22), and a positive and negative copper bar bending portion (24) bent downward is provided on one side of the positive busbar copper bar (7) and the negative busbar copper bar (8) close to the IGBT module (5), and the angle between the positive and negative copper bar bending portion and the positive busbar copper bar portion and the negative busbar copper bar portion on both sides thereof is 120°.

6. The air-cooled four-quadrant inverter unit according to claim 1 or 2, characterized in that: A temperature collection board for collecting the temperature of the IGBT module (5) and a temperature relay (44) for protecting the IGBT module are fixed on the heat absorbing bottom plate (11) of the air-cooled radiator (2).

7. The air-cooled four-quadrant inverter unit according to claim 4, characterized in that: An insulating unit control board protection plate (36) and an IGBT drive board protection plate (37) are respectively provided between the unit control board (3) and the IGBT drive board (4) and the film capacitor (9); a mechanical bypass control protection plate PET (39) and a fuse protection PET (42) are respectively provided between the mechanical bypass control board (28) and the fuse (18) and the front wall of the housing (1); and a mechanical bypass shielding box (38) is provided on the periphery of the mechanical bypass control board to reduce electromagnetic interference in a strong electric environment.

8. The air-cooled four-quadrant inverter unit according to claim 1 or 2, characterized in that: The lower portion of the rear wall of the housing (1) is provided with two limiting long holes (32) for cooperating with the unit guide rails, and the lower portion of the front wall of the housing is provided with threaded holes (47) for cooperating with the unit guide rails for fixing. The lower surface of the housing below the threaded holes is coated with conductive paint for contacting the unit guide rails.

9. The air-cooled four-quadrant inverter unit according to claim 4, characterized in that: The input copper bar R (14), input copper bar S (15), input copper bar T (16), output copper bar U (20), output copper bar V (21), and the connection between the fuse (18) and the input copper bar are all fixed to the front wall of the housing (1) via 30 high insulators (19); the upper wall of the housing (1) is formed of an upper sealing plate made of insulating material.

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