An integrated air-cooled rectifier module suitable for high-power industrial rectification applications

Abstract

This invention discloses an integrated air-cooled rectifier module suitable for high-power industrial rectification applications. The module includes input terminals, a reactor, a rectifier bridge, copper busbars, a power board mounted on a power backplane, a filter capacitor bank consisting of a secondary capacitor board and a main capacitor board, and a four-wire fan, all installed inside a sheet metal housing. This invention significantly improves power density, saves on processes and raw materials, and utilizes the copper busbars and heat sinks as a common heat sink for the electrical busbars, rectifier bridge, and braking resistor, eliminating the need for numerous connecting wires and individual heat sinks. The high degree of integration within the sheet metal housing enables modular assembly, reduces internal wiring processes, and saves copper and sheet metal volume.

Description

Technical Field

[0001] This invention relates to the field of rectifier module technology, specifically an integrated air-cooled rectifier module suitable for high-power industrial rectifier applications. Background Technology

[0002] In the existing technology, in the main circuit of a servo drive or frequency converter, the AC power input from the power grid is usually converted into DC power through a rectifier bridge to supply the inverter circuit in the next stage. When the motor is in braking condition and generates regenerative energy, the DC bus voltage rises, and the excess energy needs to be dissipated as heat through a braking resistor to protect the power devices.

[0003] In existing technologies, rectifier bridges, braking resistors and their drive circuits, DC bus capacitor banks (usually composed of multiple capacitor plates), and reactors for current sharing and filtering are often installed separately inside the sheet metal casing of the equipment. Each component is connected by copper busbars or large-section wires and is equipped with an independent fan for cooling. The main working principle is: AC power is converted into pulsating DC power by the rectifier bridge, and after being filtered by the reactor and capacitor bank, it forms smooth DC power. The braking resistor is switched on to release energy when the bus voltage exceeds the threshold.

[0004] The main problems and shortcomings of existing technologies are as follows: 1) Low integration and serious space waste: The rectifier bridge, braking resistor, capacitor board, reactor, etc. are all independent modules, which are scattered and installed in the sheet metal shell. The copper busbars connecting them are long and use a lot of materials, resulting in a large overall size and difficulty in increasing power density. 2) The heat dissipation path is unreasonable, resulting in frequent local hot spots. The rectifier bridge is usually installed on a regular heat sink, while the braking resistor is an independent heat-generating unit. The heat sources of the two interfere with each other, but there is no unified heat dissipation management. The capacitor board is in a high-temperature environment for a long time, which accelerates the drying of the electrolyte and significantly shortens its lifespan. The existing fan layout is often a single large fan with poor airflow targeting and obvious heat dissipation dead zones. 3) High parasitic inductance and high electrical stress. The distributed layout results in excessively long copper busbars connecting the rectifier bridge to the capacitor bank and the capacitor bank to the power board. The main circuit is stray and has high inductance. This causes the power devices to withstand higher peak voltage stress during switching, resulting in severe electromagnetic interference. Furthermore, the current sharing and filtering effects of the capacitor bank are greatly reduced.

[0005] To solve the above-mentioned technical problems, there is an urgent need for an integrated air-cooled rectifier module with a reasonable structure that is suitable for high-power industrial rectifier applications. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing an integrated air-cooled rectifier module suitable for high-power industrial rectifier applications; the technical solution is as follows: An integrated air-cooled rectifier module suitable for high-power industrial rectifier applications includes an input terminal, a reactor, a rectifier bridge, a copper busbar, a power board mounted on a power backplane, a filter capacitor bank consisting of a secondary capacitor board and a main capacitor board, and a four-wire fan, all installed inside a sheet metal housing. External three-phase AC power first passes through the inductive reactance filter of the reactor through the input terminal, and then is sent to the AC input terminal of the rectifier bridge. The rectifier bridge converts the AC power into pulsating DC power. The current is led out from the DC output terminal of the rectifier bridge through the copper busbar. The DC power is connected in parallel to the filter capacitor group consisting of the secondary capacitor board and two main capacitor boards. The filter capacitor group absorbs high-frequency ripple and smooths the voltage waveform, and supplies power to the power board mounted on the power backplane. When the DC bus is overvoltage, the control circuit on the power board drives the braking resistor to quickly switch in. The heat is dissipated through the braking resistor body and carried away by the forced air cooling generated by the four-wire fan. The four-wire fan draws air from the front of the sheet metal housing, forcing the cold air to sequentially sweep over the reactor, copper busbar, rectifier bridge, braking resistor and filter capacitor bank, and finally exhausts the heat to the outside of the module.

[0007] Furthermore, the rectifier bridge and the braking resistor share a set of heat sinks. The bottom plane of the heat sink is attached to the base plate of the rectifier bridge, and the other side is locked to the braking resistor. The heat generated by the rectifier bridge and the braking resistor is uniformly directed to the heat sink.

[0008] Furthermore, the sheet metal shell is made of 1.5mm thick SPCC cold-rolled steel sheet, which is laser-cut and CNC bent. The inner and outer surfaces of the sheet metal shell are treated with electrostatic powder coating, with a coating thickness of 60μm-80μm. During the sheet metal unfolding stage, the inner bottom plate of the sheet metal shell is pre-welded with M3 press-fit studs and mounting studs, which are positioned to correspond to the mounting holes of the reactor and the bottom fixing holes of the heat sink and power back plate. The front end of the sheet metal shell is provided with an air inlet louver, and the rear end is provided with an air outlet louver.

[0009] Furthermore, the reactor is fixed inside the sheet metal housing on the side near the AC input terminal, and the reactor's lead-out terminals are directly locked to the AC input terminals of the rectifier bridge. The reactor is selected as a 40A rated current, 5mH inductance iron-silicon-aluminum magnetic ring inductor, and the reactor is installed vertically. It is fastened to the corresponding studs on the front of the sheet metal housing base plate with M6 bolts. The position is directly opposite the air inlet louver at the front of the sheet metal housing. After the cold air enters from the air inlet louver, it first flows through the reactor and the reactor is initially cooled by the low temperature airflow.

[0010] Furthermore, the selected rectifier bridge is model M23GMDS250G, and the selected braking resistor is model GD400SGX120C2SA. The rectifier bridge and the braking resistor are installed side by side on the heat dissipation mounting surface of the heat sink, and are both locked onto the heat sink with a specified torque of 8 N·m using M5 stainless steel bolts with spring washers and flat washers.

[0011] Furthermore, the heat sink is a functional component specifically designed to dissipate heat from the rectifier bridge and braking resistor. The heat sink is made of T2 copper material and is integrally formed by CNC machining. The overall thickness is set to 10mm, and the surface is treated with nickel plating for anti-oxidation, with a plating thickness of 8μm-12μm. The front of the heat sink is a smooth device mounting plane with pre-drilled M3 threaded holes; the back is machined with multiple rectangular longitudinal channels along the air duct direction, with a channel depth of 35mm, a channel width of 2mm, and a channel spacing of 2.5mm. The heat sink is electrically insulated from the outer shell by the corresponding studs on the bottom plate of the sheet metal housing through the insulating pad and fasteners at the bottom.

[0012] Furthermore, the copper busbar is configured as an independent conductive busbar component, made of T2 copper sheet by stamping and bending, with a thickness of 1.5mm and nickel-plated surface for oxidation prevention; the copper busbar is fixed above or to the side of the heat sink by insulating support columns, and maintains an electrical clearance of not less than 6mm between it and the heat sink. The copper busbar includes a positive copper busbar and a negative copper busbar, which are arranged in a stacked busbar structure with a high-performance insulating film sandwiched in between. The input end of the copper busbar is fastened to the DC output terminal of the rectifier bridge through a flexible copper strip or short bolt assembly. The two ends of the copper busbar are bent to form DC output busbar interfaces, corresponding to positive and negative potentials respectively, for connection with subsequent filter capacitor banks and power boards.

[0013] Furthermore, the power backplate is made of FR-4 epoxy fiberglass board with a thickness of 2.0mm. The left and right edges of the power backplate are inserted into the positioning grooves of the sheet metal housing side plate to achieve vertical fixation, forming a physical isolation barrier between the control side and the power side. The power board is fixedly installed on the power backplate by nylon studs and isolation columns. The relays, drive circuits, detection circuits, and braking IGBT pins on the power board are directly soldered onto the pads of the power board using a reflow soldering process. The pads are connected to the terminals on the edge of the power board via thick copper traces. The leads of the terminals are connected to the corresponding potential points of the copper busbars and the power supply pins of the braking resistor, forming a braking energy discharge circuit.

[0014] Furthermore, the secondary capacitor board is configured as a non-inductive absorption film capacitor board with a capacity of 20μF and a withstand voltage of 1200V, using polypropylene film dielectric. The lead-out pins of the secondary capacitor board are directly soldered to the positive and negative power take-off points of the copper busbar on the DC output side of the rectifier bridge with the shortest distance. The main capacitor board consists of two boards, both of which are large-capacity aluminum electrolytic capacitor banks. Each main capacitor board is composed of several 680μF / 450V horn-shaped aluminum electrolytic capacitors connected in series and parallel. The two main capacitor boards are arranged side by side above the reactor. The positive and negative leads of each main capacitor board are fastened to the positive and negative busbar interfaces of the copper busbar by overlapping screw connections.

[0015] Furthermore, there are two four-wire fans, each with four leads: a positive power supply terminal, a negative power supply terminal, a speed feedback signal line, and a pulse width modulation speed control line. Two four-wire fans are mounted side by side at the air outlet louvers at the rear of the sheet metal housing. The power supply and signal sockets are integrated on the edge connector of the power board. The main control chip on the power board reads the temperature of the heat sink in real time through an NTC thermistor mounted on the surface of the heat sink, and outputs PWM signals with different duty cycles according to the preset temperature control curve to steplessly adjust the fan speed.

[0016] Beneficial effects: The present invention has the following beneficial effects: 1) The power density of this invention is greatly improved, saving processes and raw materials. The copper busbar and heat sink are used as a common heat sink for electrical busbar, rectifier bridge and braking resistor at the same time, eliminating a large number of connecting wires and independent heat sinks. The sheet metal shell is highly integrated, realizing modular assembly, reducing the internal wiring process of the system, and saving copper material and sheet metal volume. 2) The heat dissipation efficiency and device lifespan of the present invention are optimized by a factor of two. The present invention uses two four-wire fans to establish a forced straight air duct, and the cold air directly cools the high-heat copper busbar and heat sink, so that the heat generated by the braking resistor and rectifier bridge does not accumulate and heat is prevented from radiating to the capacitor board. The four-wire fans support temperature-adjustable speed, achieving quiet operation and energy saving under medium and low loads, avoiding capacitor board failure due to high temperature bulging, and eliminating the impact of environmental heat pollution on device lifespan. 3) The electrical performance of this invention is significantly improved, and the operation is simpler. By directly connecting the copper busbar heat sink in layers and absorbing the ripple on the secondary capacitor board nearby, the main circuit path is shortened to the maximum extent, stray inductance is reduced, the impact of peak voltage on the power board is reduced, and the overall accuracy of the machine is improved. The module is embedded in the sheet metal shell, with only the electrical interface and fan module exposed to the outside. External maintenance personnel can directly replace the entire module or replace the fan by plugging and unplugging, which makes it extremely easy to use. Attached Figure Description

[0017] Figure 1This is an overall block diagram of the present invention; Figure 2 This is a structural diagram of the present invention; Figure 3 for Figure 2 Vertical section view; Figure 4 for Figure 3 Mid-lateral cross-section view; The components include: sheet metal casing 1, reactor 2, rectifier bridge 3, braking resistor 4, heat sink 5, copper busbar 6, power backplate 7, power board 8, auxiliary capacitor board 9, main capacitor board 10, and four-wire fan 11. Detailed Implementation

[0018] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0019] like Figures 1 to 4 As shown, the overall working principle of this invention is as follows: External three-phase AC power enters the sheet metal housing 1 through the input terminal. It first passes through the reactor 2 for inductive filtering, and then is sent to the AC input terminal of the rectifier bridge 3. The rectifier bridge 3 converts the AC power into pulsating DC power. The current is led out from the DC output terminal of the rectifier bridge 3 through the copper busbar 6. The DC power is connected in parallel to the filter capacitor group composed of the auxiliary capacitor board 9 and two main capacitor boards 10 to absorb high-frequency ripple and smooth the voltage waveform, and supplies power to the power board 8 installed on the power backplate 7. When the DC bus is overvoltage, the control circuit on the power board 8 drives the braking resistor 4 to quickly switch in. The heat energy is dissipated through the braking resistor 4 and carried away by the forced air cooling system. Two four-wire fans 11 (supporting speed adjustment and status feedback) draw air from the front of the sheet metal housing 1, forcing the cold air to sequentially sweep over the reactor 2, copper busbar 6, heat sink 5 (carrying away the heat of the rectifier bridge 3 and braking resistor 4), and filter capacitor group, and finally exhausting the heat to the outside of the module.

[0020] like Figures 2 to 4 The diagram shows the overall structural design and specific connection relationships of this invention. This invention creates an assembly structure for an integrated braking rectifier module, which consists of the following components, with their specific locations and connection relationships as follows: Firstly, the sheet metal outer shell 1, serving as both the overall load-bearing and shielding structure, is made of cold-rolled steel sheet through stamping and bending. It contains internal rivet nuts and mounting studs, with an air inlet louver at the front and an air outlet louver at the rear. Specifically, it is made of 1.5mm thick SPCC cold-rolled steel sheet, laser-cut and CNC-bent. All inner and outer surfaces are treated with electrostatic powder coating, with a coating thickness of 60μm-80μm, providing both rust prevention and insulation. During the sheet metal unfolding stage, M3 rivet studs are pre-welded onto the inner bottom plate of the sheet metal outer shell 1, their locations corresponding to the mounting holes of the reactor 2 and the bottom fixing holes of the power backplate 7 of the heat sink 5.

[0021] The reactor 2 is fixed inside the sheet metal housing 1 on the side near the AC input terminal, and its lead-out end is directly locked to the AC input terminal of the rectifier bridge 3. The reactor 2 is specifically selected as an iron-silicon-aluminum magnetic ring inductor with a rated current of 40A and an inductance of 5mH. The reactor 2 is installed vertically and is fastened to the corresponding studs on the front of the bottom plate of the housing with M6 bolts. Its shape and position are directly opposite the air inlet louvers at the front of the sheet metal housing 1, ensuring that the cold air entering the module first flows through the reactor 2 body and is initially cooled by the low-temperature airflow.

[0022] The rectifier bridge 3 and the braking resistor 4 share a single heat sink 5. The bottom plane of the heat sink 5 is attached to the base plate of the rectifier bridge 3, and the other side of the same platform is locked to the aluminum alloy housing with the braking resistor 4 attached. The heat generated by both is uniformly transferred to the heat sink 5. The specific model of the rectifier bridge 3 is M23GMDS250G, while the specific model of the braking resistor 4 is GD400SGX120C2SA. The rectifier bridge 3 and the braking resistor 4 are installed side by side, on the same heat dissipation mounting surface of the heat sink 5. Both are locked onto the heat sink 5 with a specified torque of 8 N·m using M5 stainless steel bolts with spring washers and flat washers.

[0023] The heat sink 5 is a functional component specifically designed to dissipate heat from the rectifier bridge 3 and the braking resistor 4. It is made of T2 copper and is integrally formed by CNC machining, with an overall thickness of 10mm. The surface is treated with nickel plating for anti-oxidation (plating thickness 8μm-12μm). The front of the heat sink 5 is a smooth device mounting plane with pre-drilled M3 threaded holes. The back is machined with multiple rectangular longitudinal channels along the airflow direction, with a channel depth of 35mm, a channel width of 2mm, and a channel spacing of 2.5mm, to significantly increase the convection heat transfer area. The heat sink 5 is fixed to the corresponding studs on the bottom plate of the sheet metal housing 1 by the insulating pad and fasteners at its bottom, ensuring electrical insulation between the heat sink 5 and the housing.

[0024] The copper busbar 6 is independent of the heat sink 5. The base of the copper busbar 6 is directly connected to the DC output terminal of the rectifier bridge 3 by a flexible copper strip or short bolt. The copper busbar 6 itself does not perform the function of the heat sink 5, but only serves as a low-inductive conductivity path. The copper busbar 6 extends along the side wall of the sheet metal housing 1 and provides multiple power-taking contacts for connecting the capacitor board and the power board 8 at specific locations. In this invention, the copper busbar 6 is an independent conductive busbar component, made of T2 copper sheet by stamping and bending, with a thickness of 1.5mm and nickel-plated surface for oxidation prevention. The copper busbar 6 is fixed above or to the side of the heat sink 5 by insulating support columns, and maintains an electrical gap of not less than 6mm between it and the heat sink 5. The copper busbar 6 includes a positive copper busbar and a negative copper busbar, which can adopt a stacked busbar structure (with a high-performance insulating film sandwiched in the middle) to reduce parasitic inductance. The input end of the copper busbar 6 is fastened to the DC output terminal of the rectifier bridge 3 by a flexible copper strip or short bolt assembly to absorb thermal expansion stress. The two ends of the copper busbar 6 are bent to form DC output busbar interfaces, corresponding to positive and negative potentials respectively, for connection with the filter capacitor bank and power board 8.

[0025] In this invention, the power backplate 7 is an insulating board, fixed parallel to the sheet metal base plate and maintaining an air gap with the heat sink 5. The power board 8 is vertically inserted and fixed on the power backplate 7. The power backplate 7 is specifically made of FR-4 epoxy fiberglass board with a thickness of 2.0mm, possessing excellent mechanical strength and electrical insulation properties. Its left and right edges are inserted into the positioning grooves of the side plate of the sheet metal housing 1 to achieve vertical fixation, forming a physical isolation barrier between the control side and the power side. The power board 8 is fixedly mounted on the power backplate 7 using nylon studs and isolation posts. The relays, drive and detection circuits, and braking IGBT pins on the power board 8 are directly soldered to the pads on the power board 8 using a reflow soldering process. The pads are connected to the terminals on the edge of the power board 8 via thick copper traces. The leads of the terminals are respectively connected to the corresponding potential points of the copper busbar 6 and the power supply pins of the braking resistor 4, forming a braking energy discharge circuit.

[0026] In this invention, the secondary capacitor board 9 is configured as a polypropylene film capacitor group, with its leads directly and closely soldered to the power take-off points of the copper busbar 6 on the output side of the rectifier bridge 3, for absorbing commutation glitch. Specifically, the secondary capacitor board 9 is configured as a non-inductive absorption film capacitor board with a capacitance of 20μF and a withstand voltage of 1200V, using polypropylene film dielectric. Its leads are directly soldered to the positive and negative power take-off points of the copper busbar 6 on the DC output side of the rectifier bridge 3 with the shortest distance, realizing near-field bypass absorption of high-frequency ripple.

[0027] Two main capacitor boards 10 are configured as aluminum electrolytic capacitor banks, vertically and symmetrically attached to both sides of the copper busbar 6 at the far end of the rectifier bridge 3, and connected in parallel with extremely low parasitic inductance through the large-area stacking of the copper busbar 6. Both main capacitor boards 10 are configured as large-capacity aluminum electrolytic capacitor banks, each main capacitor board 10 is composed of multiple 680μF / 450V horn-shaped aluminum electrolytic capacitors connected in series and parallel. The two main capacitor boards 10 are arranged side by side above the reactor 2, and the positive and negative leads of each main capacitor board 10 are fastened to the positive and negative busbar interfaces of the copper busbar 6 by overlapping screw connections. The large-area bonding of the copper busbar 6, utilizing the low inductance characteristics of the stacked busbar, achieves extremely low parasitic inductance connection, effectively suppressing voltage spikes on the DC bus.

[0028] The present invention includes two four-wire fans 11, which are installed side-by-side at the rear exhaust port of the sheet metal housing 1. The intake end is aligned with the gap between the fins of the heat sink 5 and the reactor 2. The positive, negative, FG speed measurement line, and PWM speed control line of the fan are connected to the power board 8, forming a dual-redundant intelligent temperature control airflow. Specifically, the two four-wire fans 11 are San Ace 120 industrial fans with a rated operating voltage of DC 24V. The four leads are for the positive power supply (V+), negative power supply (GND), speed feedback signal line (FG), and pulse width modulation (PWM) control line. The two fans are installed side-by-side at the rear exhaust port of the sheet metal housing 1 and operate using an exhaust method. Their power supply and signal sockets are integrated on the edge connector of the power board 8. The main control chip on the power board 8 reads the temperature of the heat sink 5 in real time through an NTC thermistor mounted on the surface of the heat sink 5 and outputs PWM signals with different duty cycles according to a preset temperature control curve to steplessly adjust the fan speed, achieving an intelligent balance between heat dissipation efficiency, energy consumption, and noise.

[0029] When any of the four-wire fans 11 malfunctions due to foreign object blockage or bearing aging, its abnormal speed signal is detected in real time by the main control chip on the power board 8 via the FG feedback line. The main control chip then reports a fan fault alarm code or illuminates a local alarm indicator light through the communication interface. Upon receiving the alarm, the on-site maintenance engineer does not need to power off the entire module or disassemble the main circuit copper busbar 6 connection. They only need to open the inspection cover at the rear of the sheet metal casing 1, unplug the four-wire connector of the faulty fan, and insert a spare fan in its original position. The entire maintenance operation can be completed within 2 minutes, and the heat dissipation function is immediately restored. This design enables quick and power-free replacement of fan components, greatly improving the maintainability and operational continuity of the system.

[0030] The above-described specific embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation of the present invention or the scope of the claims. All equivalent changes and modifications made in accordance with the scope of patent protection of the present invention should be included within the scope of the present invention patent application.

Claims

1. An integrated air-cooled rectifier module suitable for high power industrial rectification applications, characterized in that: The system includes an input terminal installed inside the sheet metal housing (1), a reactor (2), a rectifier bridge (3), a copper busbar (6), a power board (8) installed on the power backplate (7), a filter capacitor bank consisting of a secondary capacitor board (9) and a main capacitor board (10), and a four-wire fan (11). The external three-phase AC power first passes through the reactor (2) for inductive filtering through the input terminal, and then is sent to the AC input terminal of the rectifier bridge (3). The rectifier bridge (3) converts the AC power into pulsating DC power. The current is led out from the DC output terminal of the rectifier bridge (3) through the copper busbar (6). The DC power after being led out is connected in parallel to the filter capacitor group composed of the secondary capacitor plate (9) and two main capacitor plates (10). The filter capacitor group absorbs high-frequency ripple and smooths the voltage waveform, and supplies power to the power board (8). When the DC bus is overvoltage, the control circuit on the power board (8) drives the braking resistor (4) to quickly switch in. The heat energy is dissipated through the braking resistor (4) and carried away by the forced air cooling generated by the four-wire fan (11). The four-wire fan (11) draws air from the front of the sheet metal shell (1), forcing the cold air to sequentially sweep over the reactor (2), copper busbar (6), rectifier bridge (3), braking resistor (4) and filter capacitor bank, and finally exhausts the heat outside the module.

2. The integrated air-cooled rectifier module according to claim 1, wherein: The rectifier bridge (3) and the braking resistor (4) share a set of heat sinks (5). The bottom plane of the heat sink (5) is attached to the bottom plate of the rectifier bridge (3), and the other side is attached to the braking resistor (4). The heat generated by the rectifier bridge (3) and the braking resistor (4) is uniformly directed to the heat sink (5).

3. The integrated air-cooled rectifier module of claim 2, wherein: The sheet metal shell (1) is made of 1.5mm thick SPCC cold-rolled steel plate, which is laser-cut and CNC bent. The inner and outer surfaces of the sheet metal shell (1) are electrostatically powder-coated with a coating thickness of 60μm-80μm. The inner bottom plate of the sheet metal shell (1) is pre-welded with M3 press-fit studs and mounting studs during the sheet metal unfolding stage. The positions are respectively corresponding to the mounting holes of the reactor (2) and the bottom fixing holes of the heat sink (5) and the power back plate (7). The front end of the sheet metal shell (1) is provided with an air inlet louver, and the rear end is provided with an air outlet louver.

4. The integrated air-cooled rectifier module of claim 2, wherein: The reactor (2) is fixed inside the sheet metal housing (1) on the side near the AC input terminal, and the lead-out terminals of the reactor (2) are directly locked to the AC input terminals of the rectifier bridge (3). The reactor (2) is selected as an iron-silicon-aluminum magnetic ring inductor with a rated current of 40A and an inductance of 5mH. The reactor (2) is installed vertically and is fastened to the corresponding studs on the front of the bottom plate of the sheet metal shell (1) by M6 bolts. The position is directly opposite the air inlet louver at the front end of the sheet metal shell (1). After the cold air enters from the air inlet louver, it first flows through the reactor (2) and the reactor (2) is initially cooled by the low temperature airflow.

5. The integrated air-cooled rectifier module of claim 2, wherein: The rectifier bridge (3) is selected as model M23GMDS250G, and the braking resistor (4) is selected as model GD400SGX120C2SA. The rectifier bridge (3) and the braking resistor (4) are installed side by side on the heat dissipation mounting surface of the heat sink (5), and are both locked on the heat sink (5) with a specified torque of 8 N·m by M5 stainless steel bolts in conjunction with spring washers and flat washers.

6. The integrated air-cooled rectifier module of claim 5, wherein: The heat sink (5) is a functional component specifically designed to dissipate the heat of the rectifier bridge (3) and the braking resistor (4). The heat sink (5) is made of T2 copper and is integrally formed by CNC machining. The overall thickness is 10mm, and the surface is treated with nickel plating for anti-oxidation. The plating thickness is 8μm-12μm. The front of the heat sink (5) is a smooth device mounting plane with pre-drilled M3 threaded holes; the back is machined with multiple rectangular longitudinal channels along the air duct direction, with a channel depth of 35mm, a channel width of 2mm, and a channel spacing of 2.5mm. The heat sink (5) is fixed to the corresponding studs on the bottom plate of the sheet metal shell (1) by the bottom insulating pad and fasteners and is electrically insulated from the shell.

7. An integrated air-cooled rectifier module suitable for high-power industrial rectifier applications according to claim 2, characterized in that: The copper busbar (6) is set as an independent conductive busbar component. It is made of T2 copper sheet by stamping and bending, with a thickness of 1.5mm and nickel plating on the surface to prevent oxidation. The copper busbar (6) is fixed above or to the side of the heat sink (5) by insulating support columns, and maintains an electrical gap of not less than 6mm between it and the heat sink (5). The copper busbar (6) includes a positive copper busbar and a negative copper busbar, which are arranged in a stacked busbar structure. The input end of the copper busbar (6) is fastened to the DC output terminal of the rectifier bridge (3) through a flexible copper strip or short bolt assembly. The two ends of the copper busbar (6) are bent to form a DC output busbar interface, which corresponds to the positive and negative potentials respectively, and is used to connect with the subsequent filter capacitor group and power board (8).

8. An integrated air-cooled rectifier module suitable for high-power industrial rectifier applications according to claim 1, characterized in that: The power backplate (7) is made of FR-4 epoxy fiberglass board with a thickness of 2.0mm. The left and right edges of the power backplate (7) are inserted into the positioning grooves of the side plate of the sheet metal shell (1) to achieve vertical fixation, forming a physical isolation barrier between the control side and the power side. The power plate (8) is fixedly installed on the power backplate (7) by nylon studs and isolation columns. The relays, drive circuits, detection circuits and the pins of the braking IGBT on the power board (8) are directly soldered onto the pads of the power board (8) using a reflow soldering process. The pads are connected to the terminals on the edge of the power board (8) through thick copper traces. The leads of the terminals are respectively connected to the corresponding potential points of the copper busbar (6) and the power supply pins of the braking resistor (4) to form a braking energy discharge circuit.

9. An integrated air-cooled rectifier module suitable for high-power industrial rectifier applications according to claim 1, characterized in that: The secondary capacitor board (9) is configured as a non-inductive absorption film capacitor board with a capacity of 20μF and a withstand voltage of 1200V, using polypropylene film dielectric. The lead-out pins of the secondary capacitor board (9) are directly soldered to the positive and negative terminals of the copper busbar (6) on the DC output side of the rectifier bridge (3) with the shortest distance. The main capacitor board (10) is set to two pieces. Both main capacitor boards (10) are large-capacity aluminum electrolytic capacitor groups. Each main capacitor board is composed of several 680μF / 450V horn-shaped aluminum electrolytic capacitors connected in series and parallel. The two main capacitor boards (10) are arranged above the reactor (2) and side by side. The positive and negative leads of each main capacitor board are fastened to the positive and negative busbar interfaces of the copper busbar (6) by overlapping screw connection.

10. An integrated air-cooled rectifier module suitable for high-power industrial rectifier applications according to claim 2, characterized in that: There are two four-wire fans (11). Each four-wire fan (11) has four wires leading out, namely the positive terminal of the power supply, the negative terminal of the power supply, the speed feedback signal line and the pulse width speed control line. Two four-wire fans (11) are installed side by side at the air outlet louvers at the rear of the sheet metal housing (1). The power supply and signal sockets are integrated on the edge connector of the power board (8). The main control chip on the power board (8) reads the temperature of the heat sink (5) in real time through the NTC thermistor mounted on the surface of the heat sink (5), and outputs PWM signals with different duty cycles according to the preset temperature control curve to steplessly adjust the fan speed.

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