A variable frequency drive liquid cooling system and water quality control method

Abstract

The present application relates to the technical fields of frequency converter cooling and water treatment, and particularly relates to a kind of frequency converter liquid cooling system and water quality control method, including heat exchanger, heat exchanger is communicated with frequency converter by liquid sending pipe and liquid return pipe and forms the circulation channel of cooling liquid;The power component is arranged on the liquid return pipe, deionization branch, pH adjustment branch and oxygen removal branch are arranged between the liquid sending pipe and liquid return pipe, and cooling liquid monitoring component is further arranged on the liquid sending pipe.The liquid cooling system disclosed in the present application can realize online monitoring of the cooling liquid, quickly determine the current state of the cooling liquid through the monitoring data, and ensure the cooling liquid in a good and stable state by timely regulating and processing the cooling liquid, thereby stably and reliably cooling the frequency converter.

Description

Technical Field

[0001] This invention relates to the field of inverter cooling and water treatment technology, specifically to an inverter liquid cooling system and a water quality control method. Background Technology

[0002] In inverter liquid cooling systems, water quality deterioration caused by factors such as decreased pH, increased dissolved oxygen concentration, and increased conductivity in the circulating medium accelerates corrosion of transformer copper tubes, stainless steel pipes, and other welded areas. This leads to reduced pipe structural strength, decreased insulation, pipe blockage by corrosion products, and scale buildup on heat exchangers, reducing the system's heat exchange capacity. Current treatment technologies include using hydrazine for deoxygenation, but this has low efficiency and hydrazine is highly toxic; setting up bypass treatment systems to control pH but not the dissolved oxygen content of the circulating medium; using deionized resin to reduce conductivity but not to adjust pH and dissolved oxygen; and using sodium sulfite and deionized resin together for control, but this method cannot control dissolved oxygen during continuous equipment operation and requires frequent chemical dosing and drainage by maintenance personnel. In summary, none of these methods can comprehensively regulate system water quality throughout its entire life cycle, thereby protecting transformer copper tubes and extending the service life of stainless steel pipes. Furthermore, current control systems operate at the same pH value across all temperatures, failing to consider the decrease in water's neutral point with increasing temperature—that is, the impact of temperature on pH control strategies. This leads to higher chemical dosages, faster deionization resin consumption and shorter lifespan, and more frequent system maintenance (preparing chemicals, draining water, replacing resin, etc.). Therefore, from an efficiency and environmental perspective, a water quality control method is needed to adjust the quality of the circulating medium in the inverter's liquid cooling system and extend the maintenance intervals.

[0003] It is evident that the current inverter liquid cooling system still has room for improvement and should be optimized. Therefore, it is necessary to propose more reasonable technical solutions to solve the technical problems existing in the current technology. Summary of the Invention

[0004] This invention discloses a liquid cooling system for frequency converters and a water quality control method. It enables synchronous monitoring and precise control of the liquid cooling system for frequency converters, improving the stability and reliability of the system's operation, thereby enhancing the flexibility, convenience, and lifespan of the liquid cooling system and reducing the frequency of maintenance.

[0005] To achieve the above objectives, the liquid cooling system disclosed in this invention can adopt the following solution:

[0006] A liquid cooling system for a frequency converter includes a heat exchanger, which is connected to the frequency converter through a supply pipe and a return pipe to form a circulation channel for coolant; a power component is installed on the return pipe, and a deionization branch, a pH adjustment branch and a deoxygenation branch are provided between the supply pipe and the return pipe; a coolant monitoring component is also installed on the supply pipe.

[0007] The aforementioned liquid cooling system uses a power component to enable the cooling medium to flow within the circulation channel, carrying heat from the frequency converter to the heat exchanger for exchange, thus achieving temperature control of the frequency converter. The coolant monitoring component monitors various indicators of the coolant to detect changes in the coolant in a timely manner, facilitating adjustments when quality deteriorates. The deionization branch, pH adjustment branch, and deoxygenation branch can appropriately adjust the coolant to maintain stable and reliable quality, reducing corrosion to the equipment while ensuring cooling capacity.

[0008] Furthermore, the deionization branch is used to regulate the coolant and reduce the conductivity of the system coolant. Its composition can adopt various schemes, and its structure is not uniquely limited. Here, we optimize and propose one feasible option: the deionization branch includes a branch pipe, the inlet of which is connected to the delivery pipe, and the outlet of which is connected to the return pipe. A first mixed-bed resin tank and a first regulating valve are sequentially arranged on the branch pipe along the flow direction of the coolant. When adopting the above scheme, the first regulating valve includes a regulating electric two-way valve.

[0009] Furthermore, the first mixed bed resin tank includes an H / OH type mixed bed resin tank.

[0010] Furthermore, the pH adjustment branch is used to regulate the acidity or alkalinity of the coolant to prevent acidity or alkalinity imbalance. Its structure is not uniquely limited; here, an optimization is proposed, and one feasible option is suggested: the pH adjustment branch includes a branch pipe, the inlet of which is connected to the delivery pipe, and the outlet of which is connected to the return pipe. A second mixed-bed resin tank and a second regulating valve are sequentially arranged on the branch pipe along the coolant flow direction. In this scheme, the second regulating valve is a regulating type electric two-way valve.

[0011] Furthermore, the second mixed bed resin tank includes a Na / OH type mixed bed resin tank.

[0012] Furthermore, the deoxygenation branch includes a branch pipe, the inlet of which is connected to the delivery pipe, and the outlet of which is connected to the return pipe. A deoxygenation resin tank and a third regulating valve are sequentially arranged on the branch pipe along the flow direction of the coolant.

[0013] Furthermore, a coolant monitoring component is used to monitor the quality of the coolant. Here, an optimization is proposed, and one feasible option is suggested: the coolant monitoring component includes a temperature sensor, a dissolved oxygen sensor, a pH sensor, and a conductivity sensor mounted on the delivery pipe. The monitoring component is connected to the system controller and sends the monitoring data to the system controller. With this solution, the system controller and the monitoring component can communicate via a network or a data cable.

[0014] Furthermore, the system controller can adopt various schemes. Here, we optimize and propose one feasible option: the system controller includes a PLC.

[0015] Furthermore, the power assembly can adopt various schemes. Here, we optimize and propose one feasible option: the power assembly includes a circulating medium pump installed on the return pipe.

[0016] Furthermore, in order to regulate and control the coolant flowing back through the frequency converter and facilitate its better return to the heat exchanger, an optimization is proposed here, and one feasible option is suggested: a degassing tank is also provided on the return pipe, a heater is provided inside the degassing tank, and the degassing tank is also connected to an expansion tank.

[0017] The above content discloses the composition of the variable frequency liquid cooling system. This invention also discloses a variable water quality treatment method:

[0018] A water quality control method, applied to the aforementioned inverter liquid cooling system, includes:

[0019] The coolant monitoring component monitors the temperature, conductivity, pH, and dissolved oxygen of the medium in the delivery pipe in real time and transmits the monitoring values ​​to the system controller.

[0020] The system controller controls the opening of the deionization branch, pH adjustment branch, and deoxygenation branch to adjust the conductivity, pH value, and dissolved oxygen of the medium water accordingly.

[0021] Furthermore, based on the temperature-compensated pH control strategy, the pH of the medium water is adjusted to the set range.

[0022] Compared with the prior art, some of the beneficial effects of the technical solution disclosed in this invention include:

[0023] The liquid cooling system disclosed in this invention can realize online monitoring of the coolant. By monitoring the data, the current state of the coolant can be quickly determined, and the coolant can be adjusted in a timely manner to ensure that the coolant is in a good and stable state, thereby providing stable and reliable cooling for the frequency converter. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a block diagram of the components of a liquid cooling system.

[0026] In the above attached figures, the meanings of each number are as follows:

[0027] 1. Liquid cooling system; 2. System controller; 3. Dissolved oxygen sensor; 4. pH sensor; 5. Conductivity sensor; 6. Circulating medium pump; 7. Heat exchanger; 8. Deionization branch; 9. pH adjustment branch; 10. Deoxygenation branch; 11. First mixed bed resin tank; 12. Second mixed bed resin tank; 13. Deoxygenation resin tank; 14. Third regulating valve; 15. Second regulating valve; 16. First regulating valve; 17. Degassing tank; 18. Heater; 19. Expansion tank; 20. Temperature sensor. Detailed Implementation

[0028] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates this embodiment.

[0029] To address the problems in existing inverter cooling systems, such as the inability to coordinate, accurately, and throughout the entire lifecycle control of conductivity, pH, and dissolved oxygen, and the fact that traditional pH setpoint control modes do not consider the impact of temperature changes, leading to rapid consumption of reagents or resins, uncontrollable dissolved oxygen during operation, frequent maintenance, heavy maintenance workload, and accelerated corrosion of the cooler, the following embodiments optimize and overcome the defects of the existing technology.

[0030] Example

[0031] like Figure 1 As shown, this embodiment provides a frequency converter liquid cooling system 1, including a heat exchanger 7. The heat exchanger 7 is connected to the frequency converter through a liquid delivery pipe and a liquid return pipe to form a circulation channel for the coolant. A power component is provided on the liquid return pipe. A deionization branch 8, a pH adjustment branch 9, and a deoxygenation branch 10 are provided between the liquid delivery pipe and the liquid return pipe. A coolant monitoring component is also provided on the liquid delivery pipe.

[0032] The liquid cooling system 1 disclosed in this embodiment uses a power component to enable the cooling medium to flow in the circulation channel, carrying the heat from the inverter to the heat exchanger 7 for exchange, thereby achieving temperature control of the inverter. The coolant monitoring component monitors various indicators of the coolant to detect changes in the coolant in a timely manner, facilitating adjustments when parameters change. The deionization branch 8, pH adjustment branch 9, and deoxygenation branch 10 can moderately adjust the coolant to maintain stable and reliable parameters. While ensuring cooling capacity, this system can delay corrosion of the inverter copper pipes and liquid cooling system pipes, extend the system's service life, reduce resin or chemical consumption, lower maintenance frequency, and reduce maintenance workload.

[0033] The deionization branch 8 is used to regulate the coolant and reduce the conductivity of the system coolant. Its composition can take various forms, and its structure is not uniquely limited. This embodiment optimizes and adopts one feasible option: the deionization branch 8 includes a branch pipe, the inlet of which is connected to the delivery pipe, and the outlet of which is connected to the return pipe. A first mixed-bed resin tank 11 and a first regulating valve 16 are sequentially arranged on the branch pipe along the coolant flow direction. When adopting the above scheme, the first regulating valve 16 includes a regulating electric two-way valve.

[0034] Preferably, the first mixed bed resin tank 11 includes an H / OH type mixed bed resin tank.

[0035] The pH adjustment branch 9 is used to adjust the pH of the coolant to prevent pH imbalance. Its structure is not uniquely limited; this embodiment optimizes and adopts one feasible option: the pH adjustment branch 9 includes a branch pipe, the inlet of which is connected to the delivery pipe, and the outlet of which is connected to the return pipe. A second mixed-bed resin tank 12 and a second regulating valve 15 are sequentially arranged on the branch pipe along the coolant flow direction. In this configuration, the second regulating valve 15 is a regulating electric two-way valve.

[0036] Preferably, the second mixed bed resin tank 12 includes a Na / OH type mixed bed resin tank.

[0037] The deoxygenation branch 10 is used to treat dissolved oxygen in the medium water to prevent dissolved oxygen from exceeding the set level. Its structure is not limited to one specific type. Here, we optimize it and propose one feasible option: the deoxygenation branch 10 includes a branch pipe. The inlet of the branch pipe is connected to the liquid delivery pipe, and the outlet of the branch pipe is connected to the liquid return pipe. A deoxygenation resin tank 13 and a third regulating valve 14 are arranged sequentially along the flow direction of the coolant on the branch pipe.

[0038] A coolant monitoring component is used to monitor the quality of the coolant. This embodiment optimizes and adopts one feasible option: the coolant monitoring component includes a temperature sensor 20, a dissolved oxygen sensor 3, a pH sensor 4, and a conductivity sensor 5 installed on the coolant delivery pipe. The monitoring component is connected to the system controller 2 and sends the monitoring data to the system controller 2. With the above solution, the system controller 2 and the monitoring component can communicate via a network or a data cable.

[0039] The system controller 2 can adopt various schemes. This embodiment optimizes and adopts one of the feasible options: the system controller 2 includes a PLC.

[0040] The power assembly can adopt various schemes. This embodiment optimizes and adopts one of the feasible options: the power assembly includes a circulating medium pump 6 installed on the return pipe.

[0041] To regulate and control the coolant returning from the frequency converter, and to better reduce the initial oxygen content of the medium and improve degassing, this embodiment optimizes and adopts one feasible option: a degassing tank 17 is also provided on the return pipe, and a heater 18 is installed inside the degassing tank 17. The heater 18 can heat the temperature of the medium inside the degassing tank 17, reduce the initial solubility of air in the medium, accelerate degassing, and reduce the consumption of deoxygenating resin.

[0042] The liquid cooling system 1 disclosed in this embodiment detects the state of the circulating medium through a pH sensor 4, a conductivity sensor 5, and a dissolved oxygen sensor 3. First, the dissolved oxygen is adjusted to <20 ppb via a deoxygenation branch 10. Then, the flow rate of the deoxygenation branch 10 is automatically controlled by the system controller 2 to reduce the dissolved oxygen level that may rise due to abnormal operation or water replenishment. Simultaneously, the system conductivity is automatically adjusted via a deionization branch 8 to maintain it within <1 μS / cm. Furthermore, the pH is automatically adjusted to the range of 7.0-8.5 via a pH adjustment branch 9 and a deionization branch 8.

[0043] The liquid cooling system provided in this embodiment effectively solves the problems of existing technologies being unable to coordinate, accurately, and throughout the entire life cycle control of conductivity, pH, and dissolved oxygen by online monitoring and dynamic adjustment of the system's conductivity, dissolved oxygen, and pH. It also addresses the issues of traditional pH setpoint control modes not considering the impact of temperature changes, which lead to rapid consumption of reagents or resins, frequent maintenance, large maintenance workload, uncontrollable dissolved oxygen during operation, and accelerated corrosion by the cooler. The system can delay the corrosion of the inverter copper tubes and liquid cooling system pipes, improve the system's service life, extend the maintenance (resin replacement) interval, and reduce the maintenance workload (eliminating the need for regular preparation of reagents and drainage).

[0044] Example 2

[0045] The above embodiments disclose a frequency converter liquid cooling system, and this embodiment discloses a water treatment method.

[0046] A water quality control method, applied to the aforementioned inverter liquid cooling system, includes:

[0047] The coolant monitoring component monitors the temperature, conductivity, pH, and dissolved oxygen of the medium in the delivery pipe in real time and transmits the monitoring values ​​to the system controller.

[0048] The system controller controls the opening of the deionization branch, pH adjustment branch, and deoxygenation branch to adjust the conductivity, pH value, and dissolved oxygen of the medium water accordingly.

[0049] Specifically, based on the temperature-compensated pH control strategy, the pH of the medium water is adjusted to within a set range. Based on the content of this embodiment, an example is provided here for illustration:

[0050] like Figure 1 As shown, a variable frequency drive liquid cooling system 1 is provided. The liquid cooling system 1 includes a PLC 2, a dissolved oxygen sensor 3, a pH sensor 4, a conductivity sensor 5, a circulating medium pump 6, a heat exchanger 7, a deionization branch 8, a pH adjustment branch 9, a deoxygenation branch 10, an H / OH type mixed bed resin tank, a Na / OH type mixed bed resin tank, a deoxygenation resin tank 13, regulating electric two-way valves 14-16, a degassing tank 17, a heater 18, an expansion tank 19, and a temperature sensor 20. The PLC 2 is a programmable logic controller that monitors and controls various parts of the system in real time. It receives signals from sensors such as the pH sensor 4, conductivity sensor 5, and dissolved oxygen sensor 3, and controls the regulating electric two-way valves 14-16 in the system according to set parameters and strategies to regulate the flow rate of each branch. The circulating medium pump 6, heat exchanger 7, degassing tank 17, and pipes constitute the main circuit. The circulating medium pump 6 provides power to the entire closed-loop system, the heat exchanger 7 performs secondary heat exchange, the dissolved oxygen sensor 3 detects the dissolved oxygen content of the system in real time, the pH sensor 4 monitors the acidity and alkalinity of the system, and the conductivity sensor 5 monitors the conductivity of the system in real time.

[0051] Three small streams of circulating medium are branched off downstream of heat exchanger 7, passing through deionization branch 8, pH adjustment branch 9, and deoxygenation branch 10 respectively, before returning to the circulating medium pump 6. The small stream of circulating medium branched off in deionization branch 8 experiences a decrease in conductivity after passing through an H / OH mixed-bed resin tank, and its flow merges with the circulating medium in the main loop, thus reducing the system's conductivity. The small stream of circulating medium branched off in pH adjustment branch 9 experiences a rise in pH after passing through a Na / OH mixed-bed resin tank, and its flow merges with the circulating medium in the main loop, thus increasing the pH. The small stream of circulating medium branched off in deoxygenation branch 10 experiences a decrease in oxygen content after passing through a deoxygenation resin tank 13, and its flow merges with the circulating medium in the main loop, thus reducing dissolved oxygen.

[0052] The flow rates of the three branches mentioned above are adjusted in real time by the PLC program based on the detected values ​​of conductivity, pH, and dissolved oxygen. This ensures that the water quality parameters of the liquid cooling system are within acceptable limits, thus delaying corrosion of the inverter copper pipes and liquid cooling system piping, extending the system's service life, and reducing resin or chemical consumption, maintenance frequency, and workload. Specific control strategy one: Taking 25℃ as an example, when the pH value of the system circulating medium drops to 7.0 (neutral point), the deionization branch is closed, and the pH adjustment branch is activated to increase the pH value of the circulating medium. At this time, the conductivity will also gradually increase. When the conductivity reaches a certain level (e.g., 0.5 μS / cm), the pH adjustment branch is closed. When the conductivity continues to rise to a certain level (e.g., 0.9 μS / cm), the deionization branch is activated to absorb anions and cations in the water. At this time, the conductivity of the circulating medium will gradually decrease, and the pH will also decrease accordingly. When the pH drops to a certain value (neutral point), the pH adjustment branch is opened again, and the deionization branch is closed, thus achieving automatic control.

[0053] The second optional control strategy is to simultaneously operate the deionization branch and the pH adjustment branch according to a certain flow ratio (e.g., 2:8) based on the actual operation of the liquid cooling system, so that the system conductivity and pH are stabilized within the required range.

[0054] More preferably, based on the optimized pH control logic and a pH control strategy that considers the change in water's neutral point with temperature, the circulating medium can be controlled to meet the weak alkalinity requirement by controlling the hydroxide concentration, thereby extending the maintenance (resin replacement) interval. Specific calculation values ​​are shown in the table below.

[0055]

[0056] For example, at 25℃, the target pH is controlled at 7.0-8.5; when the system temperature rises to 40℃, based on the change in the ion product constant of water, the target pH is automatically adjusted to 6.77-8.04 to maintain the system as slightly alkaline and meet corrosion prevention requirements. Specifically, the PLC monitors the system temperature T in real time through temperature sensor 20 and queries a preset table of pH target values ​​calculated according to the temperature gradient (temperature-pH correspondence table) to obtain the target pH setpoint pH_target at the current temperature. Then, the measured value of the pH sensor is compared with pH_target, and a signal is output to control the opening degree of the pH adjustment branch valve.

[0057] Meanwhile, the degassing tank's built-in heater design saves structural space and heats the internal medium, reducing the initial solubility of air and accelerating degassing. This further reduces the gas and oxygen content of the medium, minimizing the consumption of deoxygenating resin.

[0058] The above are the embodiments listed in this example; however, this example is not limited to the optional embodiments described above; those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments; anyone can derive other various forms of embodiments under the guidance of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example; the scope of protection of this example should be determined by the claims.

Claims

1. A liquid cooling system for a frequency converter, characterized in that: It includes a heat exchanger (7), which is connected to the frequency converter through a liquid delivery pipe and a liquid return pipe to form a circulation channel for coolant; a power assembly is provided on the liquid return pipe, and a deionization branch (8), a pH adjustment branch (9) and a deoxygenation branch (10) are provided between the liquid delivery pipe and the liquid return pipe; a coolant monitoring assembly is also provided on the liquid delivery pipe. The deionization branch (8) includes a branch pipe, the inlet of which is connected to the delivery pipe, and the outlet of which is connected to the return pipe. A first mixed bed resin tank (11) and a first regulating valve (16) are sequentially arranged on the branch pipe along the flow direction of the coolant. The first mixed bed resin tank (11) includes an H / OH type mixed bed resin tank; The pH adjustment branch (9) includes a branch pipe, the inlet of the branch pipe is connected to the delivery pipe, the outlet of the branch pipe is connected to the return pipe, and a second mixed bed resin tank (12) and a second regulating valve (15) are sequentially arranged on the branch pipe along the flow direction of the coolant. The second mixed bed resin tank (12) includes a Na / OH type mixed bed resin tank; The coolant monitoring component includes a temperature sensor (20), a dissolved oxygen sensor (3), a pH sensor (4), and a conductivity sensor (5) located downstream of the heat exchanger and on the liquid delivery pipe that will soon enter the frequency converter. The monitoring component is connected to the system controller (2) and sends the monitoring data to the system controller (2). The system controller (2) has a built-in preset temperature-pH correspondence table based on the constant concentration of hydroxide ions. The system controller (2) monitors the system temperature T in real time through the temperature sensor (20), queries the preset temperature-pH correspondence table to obtain the target pH setting value pH_target at the current temperature, compares the measured value of pH sensor (4) with pH, ​​and outputs a signal to control the opening degree of the second regulating valve (15) of the pH regulating branch (9). The system controller (2) executes the following coordinated control logic: when the pH value of the system circulating medium drops to the neutral point corresponding to the current temperature, the deionization branch (8) is closed and the pH adjustment branch (9) is activated; when the conductivity increases to 0.9 μS / cm, the pH adjustment branch (9) is closed and the deionization branch (8) is activated; or the deionization branch (8) and the pH adjustment branch (9) are activated simultaneously according to the preset flow ratio, so that the system conductivity and pH are stabilized within the set range.

2. The inverter liquid cooling system according to claim 1, characterized in that: The deoxygenation branch (10) includes a branch pipe, the inlet of which is connected to the delivery pipe, and the outlet of which is connected to the return pipe. A deoxygenation resin tank (13) and a third regulating valve (14) are sequentially arranged on the branch pipe along the flow direction of the coolant.

3. The inverter liquid cooling system according to claim 1, characterized in that: The return pipe is also equipped with a degassing tank (17), and a heater (18) is installed inside the degassing tank (17). The degassing tank (17) is also connected to an expansion tank (19).

4. A water quality control method, applied to the inverter liquid cooling system according to any one of claims 1 to 3, characterized in that, include: The coolant monitoring component detects the temperature, conductivity, pH and dissolved oxygen of the medium in the delivery pipe in real time and transmits the monitoring values ​​to the system controller (2). The system controller (2) controls the opening of the deionization branch (8), pH adjustment branch (9) and deoxygenation branch (10) to adjust the conductivity, pH value and dissolved oxygen of the medium water accordingly.

5. The water quality control method according to claim 4, characterized in that: According to the temperature-compensated pH control strategy, the acidity or alkalinity of the medium water is adjusted to the set range. As the coolant temperature rises, the upper and lower limits of the preset pH control target range are automatically reduced to cope with the characteristic that the neutral point of water decreases with increasing temperature.

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