Frequency converter cooling system and frequency converter air cooling control method

Abstract

The invention discloses a frequency converter cooling system and a frequency converter air cooling control method. The cooling system comprises an inner cavity, an air inlet pipeline, an air return pipeline, a first air draft branch, a second air draft branch, a first heat exchanger and a filtering module. A transformer and a plurality of power modules are arranged in the inner cavity; two opposite sides of the inner cavity are respectively connected with an air inlet pipeline and an air return pipeline; the first air draft branch and the second air draft branch are arranged in parallel, the air inlet end of the first air draft branch and the air inlet end of the second air draft branch are connected with the air return pipeline, the air outlet end of the first air draft branch and the air outlet end of the second air draft branch are connected with the input end of the first heat exchanger, and the output end of the first heat exchanger is connected with the air inlet pipeline through a cooling air pipe. Circulating cooling of the gas in the inner cavity is realized; and a first filtering module is arranged on the cooling air pipe. The cooling device has the characteristics of compact structure, simple principle, high cooling efficiency and the like, and the reliability of cooling operation of the frequency converter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of inverter cooling, and in particular to an inverter cooling system and an inverter air cooling control method. Background Art

[0002] In modern industrial production, frequency converters (VFDs), core devices for motor speed control, are widely used in drive systems across various production lines. In manufacturing workshops, in particular, to achieve centralized control and optimize space, large numbers of VFDs are often clustered within enclosures or racks. While this efficient equipment layout improves system integration, it also poses significant challenges to the equipment's operating environment. Currently, VFDs generally use an active cooling method with built-in cooling fans, removing heat generated by the power modules through air convection. However, the high concentrations of dust (such as metalworking debris and fibrous dust) and acidic and corrosive gases (such as sulfides and nitrogen oxides) commonly found in workshop environments present a major challenge to traditional cooling methods. The forced airflow generated by the fans during continuous operation continuously draws dust particles into the equipment, causing a layer of dust to accumulate on delicate components such as circuit boards and capacitors. Furthermore, the acidic gases cling to the dust particles, forming conductive and corrosive deposits. This can easily cause electrical faults such as circuit board creepage, short circuits, or intermittent voltage loss when humidity fluctuates or components heat up.

[0003] The prior art CN220118357U discloses a cooling fan control device for a high-voltage inverter, which uses multiple fans in parallel to achieve inverter cooling, but does not solve the pollution problem. Actual measurements show that when the dust concentration is greater than 150mg / m 3 In this environment, the dust accumulation on the circuit board increases by 2 to 3 mm per month, causing the insulation resistance to drop to a critical value (<2MΩ).

[0004] Prior art CN217976683U discloses a timed automatic switching control circuit for two fans, which switches via mechanical shutters but does not integrate sensor monitoring. When dust accumulation on the impeller of the internal circulation main fan causes the air volume to drop by 20%, the system still cannot trigger the switch, eventually causing an overheating shutdown. In addition, there is a 5-8 second airflow interruption when the mechanical shutters are switched, causing the inverter to instantaneously temperature rise by more than 5°C. In addition, relying solely on thermal relays to detect overloads cannot identify hidden faults such as bearing wear and impeller dust accumulation.

[0005] Existing technologies also mention multi-modal variable frequency control technology that uses fuzzy PID to adjust speed, but these technologies lack hardware redundancy. In practice, when the fan motor winding temperature suddenly rises (>120°C), the lack of an internal backup fan can cause the inverter power module to burn out. Furthermore, traditional PID control has a response time of >30 seconds to sudden load changes, resulting in temperature fluctuations of ±10°C in the inverter power module, accelerating insulation aging. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the existing inverter cooling system in dusty and corrosive industrial environments, such as circuit board dust accumulation and short circuit, low heat dissipation efficiency, and insufficient redundancy reliability, and to provide an inverter cooling system and inverter air cooling control method with simple principle, convenient operation, high operating stability and significant cooling effect.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A frequency converter cooling system includes an inner cavity, an air inlet duct, a return air duct, an exhaust branch 1, an exhaust branch 2, a first heat exchanger, and a first filter module; a transformer and multiple power modules are provided in the inner cavity, and opposite sides of the inner cavity are respectively connected to the air inlet duct and the return air duct; the exhaust branch 1 and the exhaust branch 2 are arranged in parallel, and the air inlet ends of the exhaust branch 1 and the exhaust branch 2 are connected to the return air duct, and the air outlet ends of the exhaust branch 1 and the exhaust branch 2 are connected to the input end of the first heat exchanger, and the output end of the first heat exchanger is connected to the air inlet duct through the cooling air duct to realize circulating cooling of the gas in the inner cavity; the cooling air duct is provided with a first filter module.

[0009] As a further improvement of the present invention, the exhaust branch one is provided with a damper, an internal circulation main fan, a magnetic check valve and an electric damper in sequence; the exhaust branch two is provided with a damper, an internal circulation backup fan, a magnetic check valve and an electric damper in sequence; when the internal circulation main fan and the internal circulation backup fan are switched, the magnetic check valve is used to block the countercurrent airflow.

[0010] As a further improvement of the present invention, the air inlet duct includes an air inlet main duct and multiple air inlet guide ducts, and the multiple air inlet guide ducts are arranged on one side of the inner cavity. The air inlet of the air inlet main duct is connected to the cooling air duct, and the air outlet of the air inlet main duct is connected to the air inlet guide duct; the return air duct includes a return air main duct and multiple return air guide ducts, and the multiple return air guide ducts are arranged on the other side of the inner cavity. The air inlet of the return air main duct is connected to the return air guide duct, and the air outlet of the return air main duct is connected to the air inlet ends of exhaust branch 1 and exhaust branch 2.

[0011] As a further improvement of the present invention, it also includes an outer cavity, and the inner cavity, air inlet duct, return air duct, exhaust branch one, exhaust branch two, the first heat exchanger and the first filter module are all located in the outer cavity, and the outer circulation return air duct and the outer circulation air inlet duct with an external circulation damper are respectively provided on opposite sides of the outer cavity, and the outer circulation return air duct and the outer circulation air inlet duct are respectively connected to the input port and output port of the second heat exchanger, and the outer circulation return air duct is sequentially provided with an external circulation fan, a magnetic check valve and an electric damper, and the outer circulation air inlet duct is provided with a second filter module; the hot air in the outer cavity flows through the external circulation damper, the external circulation fan, the magnetic check valve and the electric damper in the outer circulation return air duct in sequence, and then enters the second heat exchanger for heat exchange, and the cooled air enters the outer circulation air inlet duct, flows through the second filter module for filtration, and then circulates to the outer cavity.

[0012] As a further improvement of the present invention, the internal circulation main fan, the internal circulation backup fan and the external circulation fan are all provided with micro vibration sensors, the air inlet main duct is provided with a temperature sensor, a pressure sensor and a flow sensor, the return air main duct is provided with a temperature sensor, the first filter module and the second filter module are both provided with dust sensors, and temperature sensors are both provided on the power module and in the inner cavity.

[0013] As a further improvement of the present invention, it also includes a compressed air intake pipeline, which includes compressed air pipeline one, compressed air pipeline two and compressed air pipeline three in parallel, the compressed air pipeline three is connected to the second filter module, the compressed air pipeline two is connected to the outer cavity, and the compressed air pipeline one is respectively connected to the first filter module and the inner cavity.

[0014] As a general technical concept, the present invention also provides a frequency converter air cooling control method based on the above-mentioned frequency converter cooling system, comprising the following steps:

[0015] Step S1: Building a multi-dimensional environment-equipment status monitoring network based on temperature sensors, dust sensors, pressure sensors, flow sensors, micro vibration sensors, and the current sensor of the inverter;

[0016] Step S2: constructing an adaptive fuzzy PID control strategy based on the data information fed back by the environment-equipment status monitoring network to control the operation of the fan to achieve inverter cooling;

[0017] Step S3: construct an internal circulation fan fault prediction and redundant switching mechanism to achieve long-term cooling of the inverter.

[0018] As a further improvement of the present invention, in step S2, the adaptive fuzzy PID control strategy includes intelligent adjustment of basic working conditions, extreme working condition protection mechanism and low load energy saving mode;

[0019] The intelligent adjustment of basic working conditions includes dynamic speed matching and filter cleaning strategy; when the temperature difference between the return air main and the inlet air main duct ΔT>10°C and the inverter load rate P>70% of the rated power, the composite adjustment formula V=V0×(1+0.1×ΔT / 10+0.05×P / 70) is used to achieve a linear response of the internal circulation fan speed to the real-time heat load, where V0 is the reference value set at 50% of the rated speed; when the dust concentration D>80mg / m 3 When the filter is running, the cleaning cycle of the first filter module is automatically shortened;

[0020] In the extreme working condition protection mechanism, when the gas dust concentration G of the first filter module is detected to be greater than 5ppm or the vibration value Vib of the internal circulation fan bearing is detected to be greater than 2.5mm / s, a three-level protection response is initiated, including: physical isolation, closing the damper at the output end of the second heat exchanger, and cutting off the path for external polluted gas to enter the inner cavity;

[0021] Enhanced heat dissipation: Increase the internal circulation fan speed by 20%, and use the compressed air in compressed air line 1 to continuously backflush the first filter module to quickly remove corrosive pollutants attached to the filter surface of the first filter module;

[0022] Status lock: Trigger a device-level fault code, which is uploaded to the central control system via the MODBUS protocol. Manual intervention is prohibited until environmental parameters return to normal.

[0023] As a further improvement of the present invention, in step S3, the internal circulation fan fault prediction mechanism includes fan bearing vibration spectrum analysis and air inlet main pipe blockage diagnosis; when performing fan bearing vibration spectrum analysis, the rotation frequency, frequency multiplication and bearing characteristic frequency components are extracted by fast Fourier transform (FFT), and when the amplitude of the characteristic frequency of the bearing outer ring fault exceeds 3.5mm / s, the system issues an early warning; when performing air inlet main pipe blockage diagnosis, an air volume-pressure difference joint judgment model is established. When the measured air volume of the air inlet main pipe is less than 80% of the set value and the pressure difference of the first filter module is greater than 200Pa, it is determined that the first filter module is blocked, and the backwash program is automatically triggered. If the pressure difference still does not drop after backwashing, an alarm is triggered.

[0024] As a further improvement of the present invention, in step S3, a fourth-order state machine is used to implement fan switching control:

[0025] Fault capture: Real-time monitoring of the operating status signal of the internal circulation main fan through the hardware interrupt circuit, with a response time of less than 50ms;

[0026] Power switching: The internal circulation main fan contactor is disconnected and the internal circulation backup fan soft starter is started at the same time. The SVPWM control algorithm is used to suppress current shock during the ramp acceleration process.

[0027] Air duct reconstruction: After the internal circulation standby fan reaches the preset speed, the electric damper is switched and the magnetic check valve is synchronously closed on the exhaust branch 1. The air volume fluctuation during the switching process is less than 10%;

[0028] System self-healing: Automatically records fault codes and uploads them to the central control system, while generating maintenance work orders, automating the entire process from fault detection to operation and maintenance scheduling.

[0029] Compared with the prior art, the advantages of the present invention are:

[0030] 1. The inverter cooling system of the present invention avoids direct exposure of the transformer and the power modules to a harsh working environment by sealing them in an inner cavity. At the same time, the opposite sides of the inner cavity are respectively connected to the air inlet duct and the return air duct, the return air duct is connected to the air inlet ends of the parallel exhaust branch 1 and the exhaust branch 2, the air outlet ends of the exhaust branch 1 and the exhaust branch 2 are connected to the input end of the first heat exchanger, and finally the output end of the first heat exchanger is connected to the air inlet duct through the cooling air duct, thereby realizing circulating cooling of the gas in the inner cavity and improving the cooling efficiency of the inverter; and the two exhaust branches are arranged in parallel, which can achieve the effect of one backup and one use, thereby ensuring the cooling effect of the inverter; further, a filtering module is provided on the cooling air duct, and the cooling gas is first filtered before entering the inner cavity, thereby reducing the probability of corrosive particles adhering to the surface of electrical components and improving the operating safety of precision components such as circuit boards and capacitors.

[0031] 2. The inverter air cooling control method of the present invention first constructs a multi-dimensional environment-equipment status monitoring network through various types of sensors, and incorporates dust concentration, corrosive gas concentration, and fan vibration value into the control logic to achieve precise heat dissipation in complex environments. Compared with traditional solutions, the amount of dust accumulated on the circuit board is reduced by 90% and the number of failures is reduced by 75%; secondly, an adaptive fuzzy PID control strategy is constructed based on the environment-equipment status monitoring network to dynamically adjust the fan speed to achieve a balance between heat dissipation efficiency and energy consumption; thirdly, a dual-fan N+1 redundant architecture is constructed, combined with vibration spectrum analysis and real-time wind pressure monitoring to achieve seamless switching within 5 seconds of a fault, and warn of potential faults 72 hours in advance, thereby achieving long-term and stable operation of the inverter in harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structural principle of a frequency converter cooling system in a specific embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of hardware connections in a specific embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the intelligent wind control process in a specific embodiment of the present invention;

[0035] Legend: 1. Temperature sensor; 2. Dust sensor; 3. Pressure sensor; 4. Flow sensor; 5. Micro-vibration sensor; 6. Internal circulation main fan; 7. Internal circulation backup fan; 8. Magnetic check valve; 9. Electric damper; 10. First heat exchanger; 11. First filter module; 12. Solenoid valve; 13. Inlet air guide pipe; 14. Return air guide pipe; 15. Inlet main pipe; 16. Return air main pipe; 17. Exhaust branch 1; 18. Exhaust branch 2; 19. Cooling air duct; 20. Compressed air pipeline 1; 21. Compressed air pipeline 2; 22. Compressed air pipeline 3; 23. HVAC unit; 24. Second heat exchanger; 25. External circulation fan; 26. External circulation return air duct; 27. External circulation air inlet duct; 28. External circulation damper; 29. ​​Second filter module; 100. Transformer; 200. Inner cavity; 300. Power module; 400. External cavity. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby.

[0037] In the description of the present invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention 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 operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0039] Example 1

[0040] like Figure 1As shown, the inverter cooling system of the present invention includes an inner cavity 200, an air inlet duct, a return air duct, an exhaust branch 17, an exhaust branch 2 18, a first heat exchanger 10, and a first filter module 11. A transformer 100 and four power modules 300 are provided in the inner cavity 200, and opposite sides of the inner cavity 200 are connected to the air inlet duct and the return air duct respectively. The exhaust branch 17 and the exhaust branch 2 18 are arranged in parallel, and the air inlet ends of the exhaust branch 17 and the exhaust branch 2 18 are connected to the return air duct, and the air outlet ends of the exhaust branch 17 and the exhaust branch 2 18 are connected to the input end of the first heat exchanger 10. The output end of the first heat exchanger 10 is connected to the air inlet duct through the cooling air duct 19 to realize circulating cooling of the gas in the inner cavity 200; the cooling air duct 19 is provided with a first filter module 11.

[0041] In this embodiment, the first filter module 11 adopts an integrated G4 primary efficiency + F9 high efficiency composite filter module. The inner cavity 200 adopts an integrated sealed cabinet design, the main body is made of 304 stainless steel to construct a rigid frame, and the joints are filled with silicone rubber sealant with a Shore hardness of 70A for full perimeter filling. Verified by the air tightness test, the overall protection level of the inner cavity 200 meets the IP65 standard, which can effectively isolate dust particles with a particle size of ≥50μm and low-pressure water spray erosion. The inner surface of the inner cavity 200 is evenly sprayed with a nano-hydrophobic coating with a thickness of 20 to 30μm. The surface energy modification technology is used to increase the solid surface contact angle to 120°, forming a self-repelling effect of condensed water, fundamentally eliminating the risk of condensation on the circuit board caused by changes in environmental humidity.

[0042] In this embodiment, by sealing the transformer 100 and multiple power modules 300 in the inner cavity 200, the transformer and power modules are prevented from being directly exposed to the harsh working environment. At the same time, the opposite sides of the inner cavity are respectively connected to the air inlet duct and the return air duct, the return air duct is connected to the air inlet ends of the parallel exhaust branch 17 and the exhaust branch 2 18, and the air outlet ends of the exhaust branch 17 and the exhaust branch 2 18 are connected to the input end of the first heat exchanger. Finally, the output end of the first heat exchanger 10 is connected to the air inlet duct through the cooling air duct, so that the gas in the inner cavity 200 is circulated and cooled, thereby improving the cooling efficiency of the inverter; and the two exhaust branches are arranged in parallel, which can achieve the effect of one backup and one use, thereby ensuring the cooling effect of the inverter; further, a filter module is also provided on the cooling air duct, and the cooling gas is first filtered before entering the inner cavity 200, thereby reducing the probability of corrosive particles adhering to the surface of electrical components, thereby improving the operating safety of precision components such as circuit boards and capacitors.

[0043] like Figure 1As shown, the exhaust branch 17 is provided with a damper, an internal circulation main fan 6, a magnetic check valve 8 and an electric damper 9 in sequence; the exhaust branch 2 18 is provided with a damper, an internal circulation backup fan 7, a magnetic check valve 8 and an electric damper 9 in sequence. When the internal circulation main fan 6 and the internal circulation backup fan 7 are switched, the magnetic check valve 8 is used to block the reverse flow. It can be understood that both the internal circulation main fan 6 and the internal circulation backup fan 7 are centrifugal fans, with a rated air volume of 20,000 m3 per fan. 3 / h. When the internal circulation main fan 6 is running, the electric damper 9 (opening time < 1 second) of the air duct of the internal circulation backup fan 7 remains closed to reduce the system wind resistance; when fault signals such as overcurrent or excessive vibration of the internal circulation main fan 6 are detected, the soft start program of the internal circulation backup fan 7 is immediately started, and the damper switching mechanism is triggered at the same time. The magnetic check valve 8 on the air duct of the internal circulation main fan 6 is closed, and the magnetic check valve 8 on the air duct of the internal circulation backup fan 7 is opened, ensuring that the air duct switching is completed within 1.5 seconds.

[0044] In this embodiment, a parallel architecture with dual centrifugal fans (primary and secondary) is used in the internal circulation. A magnetic fast check valve (response time <0.1 seconds) is installed at the fan outlet to block reverse airflow at the instant the two fans switch. Furthermore, a micro vibration sensor 5 (sensitivity 10mV / mm / s) is integrated at the fan shaft end to collect bearing vibration signals in real time. Spectral analysis is performed using a built-in FFT (Fast Fourier Transform) algorithm to provide early warning of bearing failures. For example, an early warning is triggered when the characteristic frequency amplitude exceeds 3.5mm / s.

[0045] like Figure 1 As shown, the air inlet duct includes an air inlet main duct 15 and multiple air inlet guide tubes 13. The multiple air inlet guide tubes 13 are arranged on one side of the inner cavity 200. The air inlet of the air inlet main duct 15 is connected to the cooling air duct 19, and the air outlet of the air inlet main duct 15 is connected to the air inlet guide tube 13. The return air duct includes a return air main duct 16 and multiple return air guide tubes 14. The multiple return air guide tubes 14 are arranged on the other side of the inner cavity 200. The air inlet of the return air main duct 16 is connected to the return air guide tube 14, and the air outlet of the return air main duct 16 is connected to the air inlet ends of the exhaust branch 1 and the exhaust branch 2. Under the suction action of the internal circulation main fan 6 or the internal circulation backup fan 7, the hot air generated by the inverter in the inner cavity 200 is guided into the air inlet main duct 15 through the air inlet guide pipe 13, and then enters the exhaust branch 1 17 or the exhaust branch 2 18, and then enters the first heat exchanger 10 for heat exchange and cooling. The cooled air flows into the cooling air duct 19, and after being filtered by the first filter module 11, enters the return air main duct 16, and finally is guided into the inner cavity 200 by multiple return air guide pipes 14 to cool the inverter.

[0046] In this embodiment, a temperature sensor 1, a pressure sensor 3, and a flow sensor 4 are installed in the main air inlet pipe 15; a temperature sensor 1 is installed in the main air return pipe 16; a dust sensor 2 is installed in the first filter module 11; and temperature sensors 1 are installed on the power module 300 and within the inner cavity 200. A high-precision (±2%) flow sensor 4 installed in the main air inlet pipe 15 provides real-time feedback on total air volume data, which is linked to the data detected by the pressure sensor 3 to ensure that air volume fluctuations are less than 5% during fan switching, achieving a disturbance-free cooling capacity connection.

[0047] like Figure 1 As shown, it also includes an outer cavity 400, and the inner cavity 200, the air inlet duct, the return air duct, the exhaust branch 17, the exhaust branch 18, the first heat exchanger 10 and the first filter module 11 are all located in the outer cavity 400. That is, the inner cavity 200, the air inlet duct, the return air duct, the exhaust branch 17, the exhaust branch 18, the first heat exchanger 10 and the first filter module 11 together form an inner circulation unit, and multiple inner circulation units can be set up in the outer cavity 400 at the same time. An outer circulation return air duct 26 and an outer circulation air inlet duct 27 with an outer circulation damper 28 are respectively provided on opposite sides of the outer cavity 400. The outer circulation return air duct 26 and the outer circulation air inlet duct 27 are respectively connected to the input port and the output port of the second heat exchanger 24, and the outer circulation return air duct 26 is sequentially provided with an outer circulation fan 25, a magnetic check valve 8 and an electric damper 9, and the outer circulation air inlet duct 27 is provided with a second filter module 29. As shown Figure 1 As shown, the hot air in the outer cavity 400 flows through the outer circulation damper 28, the outer circulation fan 25, the magnetic check valve 8, and the electric damper 9 in the outer circulation return air duct 26, and then enters the second heat exchanger 24 for heat exchange. The cooled air enters the outer circulation air inlet duct 27, flows through the second filter module 29 for filtration, and then recirculates into the outer cavity 400. In this embodiment, the outer circulation fan 25 is provided with a micro vibration sensor 5 to monitor the operating status of the fan bearing in real time; the second filter module 29 is provided with a dust sensor 2, which can specifically be a laser dust sensor, to monitor the dust concentration in the filter element in real time; the first heat exchanger 10 and the second heat exchanger 24 are both plate heat exchangers, and both the first heat exchanger 10 and the second heat exchanger 24 exchange heat with the HVAC unit 23 to achieve hot air cooling.

[0048] like Figure 1As shown, the system also includes a compressed air intake pipeline, which includes a parallel compressed air pipeline 1 20, a compressed air pipeline 21, and a compressed air pipeline 3 22. Compressed air pipeline 3 22 is connected to the second filter module 29 for backwashing the second filter module 29. Compressed air pipeline 21 is connected to the outer cavity 400 and can directly deliver compressed air to the outer cavity 400. Compressed air pipeline 1 20 is connected to the first filter module 11 and the inner cavity 200 respectively, and can backwash the first filter module 10 or directly deliver compressed air to the inner cavity 200.

[0049] In this embodiment, the cross-sectional area of ​​the internal heat exchange unit is 0.05m 2 The closed-loop channel integrates G4 primary filter + F9 high-efficiency composite filter modules, with a single-pass filtration efficiency of over 99.9% for 0.3μm dust particles. The filter element assembly of the first filter module 11 is equipped with a pulse backwash cleaning mechanism, which uses 0.6MPa high-pressure airflow for periodic cleaning. The single pulse duration is 0.1 seconds. The backwash cycle is dynamically adjusted by the dust concentration monitored in real time by the built-in laser dust sensor (detection accuracy ±5%). When the dust concentration is greater than 80mg / m 3 When the filter element is running, the backflush cycle is automatically shortened to 10 minutes to ensure the pressure drop stability of the filter element during long-term operation.

[0050] The external circulation heat exchange unit uses a titanium alloy plate type second heat exchanger 24 as the core heat exchange unit, 2m 2 The effective heat exchange area, combined with the turbulent flow guide structure, achieves a heat exchange efficiency of over 85%. A high-precision pressure sensor (±0.5% FS) is integrated into the circulating air duct. A closed-loop control system maintains a slightly positive pressure of 50-100 Pa inside the cavity. This pressure range effectively prevents the infiltration of external contaminants and avoids seal fatigue caused by excessive pressure.

[0051] Example 2

[0052] The inverter air cooling control method of this embodiment is implemented based on the inverter cooling system in Example 1, and includes the following steps:

[0053] Step S1: Construct a multi-dimensional environment-equipment status monitoring network based on the temperature sensor 1, the dust sensor 2, the pressure sensor 3, the flow sensor 4, the micro vibration sensor 5 and the current sensor of the inverter.

[0054] Specifically, temperature field monitoring: 8 groups of PT100 platinum resistors (accuracy ±0.1°C) are arranged on the surface of the inverter power module 300 (4 points), the inlet and outlet of the internal circulation air duct (2 points), and inside the inner cavity 200 (2 points). Through distributed temperature measurement, the thermal distribution data of the equipment is obtained in real time, providing core temperature parameters for the heat dissipation strategy.

[0055] Dust concentration monitoring: using LD-3C laser scattering sensor (detection range 0 ~ 200mg / m 3 , response time 5 seconds), installed at the entrance of the internal circulation air duct, it monitors the dust mass concentration in real time through the Mie scattering principle, and provides a quantitative basis for the backflushing frequency of the filter element of the first filter module 11.

[0056] Corrosive gas detection: An electrochemical gas sensor (resolution 1ppm) is integrated in the first filter module 11 to monitor corrosive gases such as SO2 and Cl2 in real time. When the concentration exceeds the 5ppm threshold, the strong sealing protection mechanism is automatically triggered.

[0057] Power-heat consumption calculation: Use Hall effect current sensor (accuracy ±0.5%) to collect main circuit current data, combined with Q=I 2 The heat loss calculation formula of Rt×1.2 (1.2 is the safety factor) dynamically evaluates the real-time heat generation of the inverter and establishes a mathematical mapping relationship between heat load and heat dissipation requirements.

[0058] Step S2: constructing an adaptive fuzzy PID control strategy based on the data information fed back by the environment-equipment status monitoring network to control the operation of the fan to achieve inverter cooling.

[0059] Step S3: construct an internal circulation fan fault prediction and redundant switching mechanism to achieve long-term cooling of the inverter.

[0060] like Figure 2 and Figure 3 As shown in the example, the MCU collects sensor data via the SPI interface and controls the fan speed via PWM output. The relay module controls the main and auxiliary fan contactors, damper solenoid valve, and back-blow valve. The HMI displays system parameters and fault information in real time. In this embodiment, through the deep coupling of hardware architecture innovation and intelligent algorithms, an inverter cooling solution integrating environmental isolation, thermal management optimization, and fault self-healing has been constructed. Industrial field testing has shown that the dust accumulation rate of circuit boards can be reduced by 85%, the risk of corrosive gas erosion by 70%, and the mean time between failures (MTBF) of the equipment can be increased to over 100,000 hours, significantly improving system reliability in complex industrial environments.

[0061] In step S2 of this embodiment, the adaptive fuzzy PID control strategy includes intelligent adjustment of basic working conditions, protection mechanism for extreme working conditions and low-load energy-saving mode.

[0062] Intelligent adjustment of basic working conditions includes dynamic speed matching and filter cleaning strategy. When the temperature difference ΔT between the return air main 16 and the inlet air main 15 is greater than 10°C and the inverter load rate P is greater than 70% of the rated power, the composite adjustment formula V=V0×(1+0.1×ΔT / 10+0.05×P / 70) is used to achieve a linear response of the internal circulation fan speed to the real-time heat load, where V0 is the reference value set at 50% of the rated speed. The backwash cycle of the filter element defaults to 30 minutes. When the dust concentration D is greater than 80mg / m 3 When the filter element is cleaned, the cleaning cycle of the first filter module 11 is automatically shortened to 10 minutes. The filter element is gradient cleaned by pulse airflow to maintain the stability of the filtration efficiency.

[0063] In the extreme working condition protection mechanism, when it is detected that the gas dust concentration G of the first filter module 11 is greater than 5ppm or the vibration value Vib of the internal circulation fan bearing is greater than 2.5mm / s, the third-level protection response is initiated, including: physical isolation, closing the damper at the output end of the second heat exchanger 24, and cutting off the path for external polluted gas to invade the inner cavity 200.

[0064] Enhanced heat dissipation: Increase the speed of the internal circulation fan by 20%, and use the compressed air in the compressed air pipeline 1 20 to continuously backflush the first filter module 11 to quickly discharge the corrosive pollutants attached to the filter element surface of the first filter module 11.

[0065] Status lock: Trigger a device-level fault code, which is uploaded to the central control system via the MODBUS protocol. Manual intervention is prohibited until environmental parameters return to normal.

[0066] In low-load energy-saving mode, for light-load conditions with P < 30% and ΔT < 5°C, an intermittent operation strategy is adopted: the fan speed is reduced to 30% of the rated value, and a cyclic start-stop control of "2 minutes of operation + 8 minutes of sleep" is implemented. Field measurements show that this mode can reduce standby energy consumption by 60%. At the same time, a cavity thermal inertia analysis model ensures that the equipment temperature rise is less than 5°C per cycle.

[0067] In step S3 of this embodiment, the internal circulation fan fault prediction mechanism includes fan bearing vibration spectrum analysis and air inlet main pipe 15 blockage diagnosis; when performing fan bearing vibration spectrum analysis, 1x (rotation frequency), 2x (multiplication frequency), and 3x (bearing characteristic frequency) components are extracted through fast Fourier transform (FFT). When the amplitude of the characteristic frequency of the bearing outer ring fault exceeds 3.5 mm / s, the system issues an early warning 72 hours in advance, prompting the operation and maintenance personnel to lubricate or replace the bearing.

[0068] When diagnosing blockage of the air inlet main duct 15, an air volume-pressure difference joint judgment model is established. When the measured air volume of the air inlet main duct 15 is less than 80% of the set value and the pressure difference of the first filter module 11 is greater than 200Pa, it is determined that the first filter module 11 is blocked, and the three-stage backwash program is automatically triggered (the number of pulses is increased to 3 times). If the pressure difference still does not drop after 3 backwashes, an alarm is triggered.

[0069] Furthermore, in step S3, a fourth-order state machine is used to implement fan switching control:

[0070] Fault capture: Real-time monitoring of the operating status signal of the internal circulation main fan 6 through the hardware interrupt circuit, with a response time of less than 50ms;

[0071] Power switching: The contactor of the internal circulation main fan 6 is disconnected and the soft starter of the internal circulation backup fan 7 is started. The SVPWM control algorithm is used to suppress current shock during the ramp acceleration process;

[0072] Air duct reconstruction: After the internal circulation standby fan 7 reaches the preset speed, the electric damper 9 is switched, and the magnetic check valve 8 is synchronously closed to the exhaust branch 17. The air volume fluctuation during the switching process is less than 10%;

[0073] System self-healing: Automatically records fault codes and uploads them to the central control system, while generating maintenance work orders, automating the entire process from fault detection to operation and maintenance scheduling.

[0074] In this embodiment, first, a multi-dimensional environment-equipment status monitoring network is constructed through various types of sensors, and dust concentration, corrosive gas concentration, and fan vibration value are incorporated into the control logic to achieve precise heat dissipation in complex environments. Compared with traditional solutions, the amount of dust accumulated on the circuit board is reduced by 90% and the number of failures is reduced by 75%; secondly, an adaptive fuzzy PID control strategy is constructed based on the environment-equipment status monitoring network to dynamically adjust the fan speed to achieve a balance between heat dissipation efficiency and energy consumption; thirdly, a dual-fan N+1 redundant architecture is constructed, combined with vibration spectrum analysis and real-time wind pressure monitoring to achieve seamless switching within 5 seconds of a fault and provide 72 hours in advance warning of potential faults, thereby achieving long-term and stable operation of the inverter in harsh environments.

[0075] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A frequency converter cooling system, characterized in that: The invention comprises an inner cavity (200), an air inlet duct, a return air duct, an exhaust branch 1 (17), an exhaust branch 2 (18), a first heat exchanger (10), and a first filter module (11); a transformer (100) and a plurality of power modules (300) are arranged in the inner cavity (200); opposite sides of the inner cavity (200) are respectively connected to the air inlet duct and the return air duct; the exhaust branch 1 (17) and the exhaust branch 2 (18) are arranged in parallel, The air inlet ends of the exhaust branch one (17) and the exhaust branch two (18) are connected to the return air duct, and the air outlet ends of the exhaust branch one (17) and the exhaust branch two (18) are connected to the input end of the first heat exchanger (10). The output end of the first heat exchanger (10) is connected to the air inlet duct through the cooling air duct (19) to realize circulating cooling of the gas in the inner cavity (200); the cooling air duct (19) is provided with a first filter module (11).

2. The inverter cooling system according to claim 1, characterized in that: The first exhaust branch (17) is provided with an air damper, an internal circulation main fan (6), a magnetic check valve (8) and an electric air damper (9) in sequence; the second exhaust branch (18) is provided with an air damper, an internal circulation standby fan (7), a magnetic check valve (8) and an electric air damper (9) in sequence; when the internal circulation main fan (6) and the internal circulation standby fan (7) are switched, the magnetic check valve (8) is used to block the reverse flow.

3. The inverter cooling system according to claim 2, characterized in that: The air inlet duct includes an air inlet main duct (15) and a plurality of air inlet guide ducts (13), the plurality of air inlet guide ducts (13) are arranged on one side of the inner cavity (200), the air inlet of the air inlet main duct (15) is connected to the cooling air duct (19), and the air outlet of the air inlet main duct (15) is connected to the air inlet guide duct (13); the return air duct includes a return air main duct (16) and a plurality of return air guide ducts (14), the plurality of return air guide ducts (14) are arranged on the other side of the inner cavity (200), the air inlet of the return air main duct (16) is connected to the return air guide duct (14), and the air outlet of the return air main duct (16) is connected to the air inlet ends of the exhaust branch 1 (17) and the exhaust branch 2 (18).

4. The inverter cooling system according to claim 3, characterized in that: The invention also includes an outer cavity (400), wherein the inner cavity (200), the air inlet duct, the air return duct, the exhaust branch 1 (17), the exhaust branch 2 (18), the first heat exchanger (10) and the first filter module (11) are all located in the outer cavity (400), and the outer circulation return duct (26) and the outer circulation inlet duct (27) with the outer circulation damper (28) are respectively provided on opposite sides of the outer cavity (400), and the outer circulation return duct (26) and the outer circulation inlet duct (27) are respectively connected to the input port and the output port of the second heat exchanger (24), and the outer circulation return duct (2 6) is provided with an external circulation fan (25), a magnetic check valve (8) and an electric damper (9) in sequence, and a second filter module (29) is provided on the external circulation air inlet pipe (27); the hot air in the external cavity (400) flows through the external circulation damper (28), the external circulation fan (25), the magnetic check valve (8) and the electric damper (9) in sequence in the external circulation return air pipe (26) and then enters the second heat exchanger (24) for heat exchange; the cooled air enters the external circulation air inlet pipe (27), flows through the second filter module (29) for filtration, and then circulates to the external cavity (400).

5. The inverter cooling system according to claim 4, characterized in that: The internal circulation main fan (6), the internal circulation standby fan (7) and the external circulation fan (25) are all provided with a micro vibration sensor (5); the air inlet main pipe (15) is provided with a temperature sensor (1), a pressure sensor (3) and a flow sensor (4); the return air main pipe (16) is provided with a temperature sensor (1); the first filter module (11) and the second filter module (29) are both provided with a dust sensor (2); and the power module (300) and the inner cavity (200) are both provided with a temperature sensor (1).

6. The inverter cooling system according to claim 4, characterized in that: The invention also includes a compressed air intake pipeline, wherein the compressed air intake pipeline includes a compressed air pipeline 1 (20), a compressed air pipeline 2 (21) and a compressed air pipeline 3 (22) connected in parallel, wherein the compressed air pipeline 3 (22) is connected to the second filter module (29), the compressed air pipeline 2 (21) is connected to the outer cavity (400), and the compressed air pipeline 1 (20) is respectively connected to the first filter module (11) and the inner cavity (200).

7. A frequency converter air cooling control method based on the frequency converter cooling system according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1, constructing a multi-dimensional environment-equipment status monitoring network based on the temperature sensor (1), the dust sensor (2), the pressure sensor (3), the flow sensor (4), the micro vibration sensor (5) and the current sensor of the inverter; Step S2: constructing an adaptive fuzzy PID control strategy based on the data information fed back by the environment-equipment status monitoring network to control the operation of the fan to achieve inverter cooling; Step S3: construct an internal circulation fan fault prediction and redundant switching mechanism to achieve long-term cooling of the inverter.

8. The inverter air cooling control method according to claim 7, characterized in that: In step S2, the adaptive fuzzy PID control strategy includes intelligent adjustment of basic working conditions, protection mechanism for extreme working conditions and low-load energy-saving mode; The basic working condition intelligent adjustment includes dynamic speed matching and filter cleaning strategy; when the temperature difference ΔT between the return air main pipe (16) and the inlet air main pipe (15) is greater than 10°C and the inverter load rate P is greater than 70% of the rated power, a composite adjustment formula V=V0×(1+0.1×ΔT / 10+0.05×P / 70) is used to achieve a linear response of the internal circulation fan speed to the real-time heat load, wherein V0 is a reference value set at 50% of the rated speed; when the dust concentration D is greater than 80mg / m 3 When the cleaning cycle of the first filter module (11) is automatically shortened; In the extreme working condition protection mechanism, when it is detected that the gas dust concentration G of the first filter module (11) is greater than 5ppm or the vibration value Vib of the inner circulation fan bearing is greater than 2.5mm / s, a three-level protection response is initiated, including: physical isolation, closing the damper at the output end of the second heat exchanger (24), and cutting off the path for external polluted gas to invade the inner cavity (200); Enhanced heat dissipation: the speed of the internal circulation fan is increased by 20%, and the compressed air in the compressed air pipeline (20) is used to continuously back-blow the first filter module (11) to quickly discharge the corrosive pollutants attached to the surface of the filter element of the first filter module (11); Status lock: Trigger a device-level fault code, which is uploaded to the central control system via the MODBUS protocol. Manual intervention is prohibited until environmental parameters return to normal.

9. The inverter air cooling control method according to claim 7, characterized in that: In step S3, the internal circulation fan fault prejudgment mechanism includes fan bearing vibration spectrum analysis and air inlet main pipe (15) blockage diagnosis; when the fan bearing vibration spectrum analysis is performed, the rotation frequency, frequency multiplication and bearing characteristic frequency components are extracted by fast Fourier transform (FFT), and when the amplitude of the characteristic frequency of the bearing outer ring fault exceeds 3.5mm / s, the system issues an early warning; when the air inlet main pipe (15) blockage diagnosis is performed, an air volume-pressure difference combined judgment model is established, and when the measured air volume of the air inlet main pipe (15) is less than 80% of the set value and the pressure difference of the first filter module (11) is greater than 200Pa, it is determined that the first filter module (11) is blocked, and the backflush procedure is automatically triggered. If the pressure difference still does not drop after the backflush, an alarm is triggered.

10. The inverter air cooling control method according to claim 7, characterized in that: In step S3, a fourth-order state machine is used to implement fan switching control: Fault capture: Real-time monitoring of the operating status signal of the internal circulation main fan (6) through the hardware interrupt circuit, with a response time of less than 50ms; Power switching: disconnecting the contactor of the internal circulation main fan (6) and starting the soft starter of the internal circulation backup fan (7) at the same time, using the SVPWM control algorithm to suppress current shock during the ramp acceleration process; Air duct reconstruction: After the internal circulation standby fan (7) reaches the preset speed, the electric damper (9) is switched, and the magnetic check valve (8) is synchronously closed to the exhaust branch (17). The air volume fluctuation during the switching process is less than 10%; System self-healing: Automatically records fault codes and uploads them to the central control system, while generating maintenance work orders, automating the entire process from fault detection to operation and maintenance scheduling.

Images