Cooling liquid distribution device control system and control method thereof

Abstract

A coolant distribution unit (CDU) system and a control method thereof are applied to a CDU control system in which at least a first CDU and a second CDU form a group, and include: detecting the second CDU in a stationary state; any CDU in the group outputs a low rotation speed instruction to the first CDU and the second CDU through the communication line so as to indicate the first CDU and the second CDU to operate at a second rotation speed, and the second rotation speed is lower than the first rotation speed of the first CDU originally operating; and when it is judged that both the first CDU and the second CDU operate at the second rotating speed for a preset time, any CDU in the group sends a target flow instruction to the first CDU and the second CDU through the communication line so as to instruct the first CDU and the second CDU to output the target flow respectively.

Description

Technical Field

[0001] This application relates to a coolant distribution device, and more particularly to a control system and control method for controlling the coolant distribution device. Background Technology

[0002] To help cool server racks, data centers typically deploy multiple Cooling Distribution Units (CDUs) to dissipate heat from the server racks through the delivery and recycling of coolant.

[0003] See Figure 1 This is a schematic diagram of an example cooling system. Figure 1 A cooling system consisting of a cooling tower 1 and two CDUs (including a first coolant distribution device 21 and a second coolant distribution device 22) is disclosed. The cooling system is connected to the server rack 3 via the first CDU 21 and the second CDU 22 to dissipate heat from the server rack 3. The multiple CDUs 21 and 22 in the cooling system not only distribute the coolant flow demand of the cooling system evenly, but also provide backup by increasing the output flow of the other CDUs when one CDU fails.

[0004] Please also refer to Figure 2 This is a schematic diagram of the coolant delivery system. (For example...) Figure 2 As shown, each CDU 2 has a pump assembly 20 consisting of multiple pumps, and a check valve 5 located after each pump. During operation, each CDU 2 performs PID control on its respective pump assembly 20 to maintain the CDU 2's output at the target flow rate specified by the cooling system. When any CDU 2 fails to operate, the cooling system increases the speed of the pump assemblies 20 of the other operating CDU 2s, thereby increasing the target flow rate output of the operating CDU 2s. This compensates for the flow rate that the non-operating CDU 2 should handle, ensuring that the overall cooling capacity of the cooling system is not affected by the non-operating CDU 2.

[0005] Generally, when a cooling system contains multiple CDUs 2, these CDUs 2 are connected in parallel. Each CDU 2 controls the speed of one or more pumps in the pump group 20 through its own internal CDU control unit, thereby controlling the coolant flow rate. A check valve 5 within the CDU 2 prevents coolant backflow. When a new CDU is added to the cooling system, or when a malfunctioning CDU recovers from a fault (hereinafter referred to as the new CDU), the new CDU must start operating from a standstill. At this time, the pressure generated by the other normally operating CDUs 2 will suppress the check valve 5 of the new CDU, preventing it from increasing its output flow rate. In this situation, the cooling system must allow the new CDU to operate at full speed to overcome the external pressure suppressing the check valve 5 and successfully output coolant.

[0006] However, as Figure 3 As shown, when the new CDU( Figure 3 Taking the second CDU as an example, after it runs at full speed (for example, the output flow rate scale rises rapidly to 1), other CDUs ( Figure 3 Taking the first CDU as an example, its flow rate will be instantly suppressed by the second CDU and drop rapidly (e.g., drop to flow rate scale 0). At this time, the cooling system needs to run the first CDU at full speed to increase its output flow rate (e.g., rapidly increase it to flow rate scale 1). Through such repeated control by the cooling system, multiple CDUs (such as...) will be affected. Figure 3 The pump unit 20 of the first CDU and the second CDU shown fluctuates in speed, causing instability in the cooling system and potentially damaging the CDU.

[0007] Therefore, how to control the cooling system so that new CDUs can be added quickly and stably has become a subject of in-depth research for those in this technical field. Summary of the Invention

[0008] The purpose of this application is to provide a CDU control system and control method that allows new CDUs to be stably added to an existing CDU group, thereby enabling all CDUs to operate stably.

[0009] In one embodiment, the coolant distribution device control system of this application includes:

[0010] A first CDU is configured to operate at a first rotational speed; and

[0011] A second CDU is configured to be in a static state, wherein the first CDU and the second CDU form a group;

[0012] In this group, any CDU is configured to issue a low speed command to the first CDU and the second CDU to instruct the first CDU and the second CDU to operate at a second speed, wherein the second speed is lower than the first speed;

[0013] In this group, any CDU is configured to issue a target flow command to the first CDU and the second CDU when the first CDU and the second CDU are both operating at the second rotation speed for a preset time, so as to instruct the first CDU and the second CDU to output a target flow respectively.

[0014] In one embodiment, the coolant distribution device control method of this application is applied to the above-mentioned CDU control system, and includes the following steps:

[0015] The second CDU, which was in a static state, is detected to be starting up;

[0016] The low-speed command is issued by any CDU in the group to the first CDU and the second CDU to instruct the first CDU and the second CDU to operate at the second speed, wherein the second speed is lower than the first speed; and

[0017] When it is determined that both the first CDU and the second CDU are operating at the second rotation speed for the preset time, any CDU in the group sends the target flow command to the first CDU and the second CDU to instruct the first CDU and the second CDU to output the target flow respectively.

[0018] Compared to related technologies, this application allows all CDUs to operate at low speeds initially, and only after the output flow of all CDUs has stabilized is the CDUs controlled to resume operation at the target flow rate. This overcomes the problem of unstable operation of the CDU group when a new CDU is added. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an example cooling system;

[0020] Figure 2 This is a schematic diagram of the coolant delivery system.

[0021] Figure 3 Waveform diagram for flow control of coolant distribution device;

[0022] Figure 4 This is an embodiment of a system schematic diagram of the coolant distribution device of this application;

[0023] Figure 5 This is an embodiment of the control flowchart of this application;

[0024] Figure 6An embodiment of the flow control waveform diagram of the coolant distribution device of this application;

[0025] Figure 7 This is another embodiment of the control flowchart of this application.

[0026] Explanation of reference numerals in the attached figures

[0027] 1: Cooling Tower

[0028] 2:CDU

[0029] 20: Pump set

[0030] 21: First CDU

[0031] 22: Second CDU

[0032] 3: Server rack

[0033] 5: Check valve

[0034] 6: Cooling Tower

[0035] 81: First CDU

[0036] 82: Second CDU

[0037] 9: Server rack

[0038] S51~S54: Control Steps

[0039] S71~S77: Control Steps Detailed Implementation

[0040] This application discloses a coolant distribution device control system and control method, which can be used to control a group of CDUs with multiple coolant distribution units (CDUs), so that the multiple CDUs in the CDU group can operate stably and the total output flow of the multiple CDUs can meet the heat dissipation requirements.

[0041] See Figure 4 This is an embodiment of the coolant distribution device system schematic diagram of this application. Figure 4 As shown, the control system of this application has a group consisting of multiple CDUs, the group including at least a first CDU 81 and a second CDU 82, wherein each CDU 81 and 82 is connected to each other in a masterless / slave communication manner. Thus, each CDU 81 and 82 in the group can communicate with each other via a communication line through an internal control unit (not shown) to control the output flow of the first CDU 81 and the second CDU 82.

[0042] More specifically, one side of the first CDU 81 and the second CDU 82 are respectively connected to the cooling tower 6, and the other side is respectively connected to the server rack 9. The first CDU 81 and the second CDU 82 each have a pump unit (e.g., Figure 2 The pump assembly 20 shown is an example. The pump assembly operates based on a preset duty cycle, causing the first CDU 81 and the second CDU 82 to receive coolant from the cooling tower 6 and output a specific flow rate of coolant to the server rack 9 to dissipate heat from the server rack 9. The coolant, having absorbed the heat, is then returned to the cooling tower 6 for further cooling, completing the heat dissipation cycle. In one embodiment, any CDU in the group can issue a speed command to the first CDU 81 and the second CDU 82 to control the speed of the pump assembly of the first CDU 81 and the second CDU 82, thereby adjusting the flow rate of coolant output to the server rack 9 by the first CDU 81 and the second CDU 82. In another embodiment, any CDU in the group can issue a flow rate command to the first CDU 81 and the second CDU 82 to automatically adjust the speed of the pump assembly so that the flow rate of coolant output to the server rack 9 conforms to the flow rate command.

[0043] As described above, any CDU in the group can act as a generator and sender of instructions to control other CDUs. Specifically, the CDU generates instructions through its internal CDU control unit and communicates with other CDUs via communication lines, sending the instructions to other CDUs. In one embodiment, the CDU control unit may be, for example, a Central Processing Unit (CPU), a Microcontroller Unit (MCU), a Programmable Logic Controller (PLC), a System-on-Chip (SoC), or a Field Programmable Gate Array (FPGA), but is not limited thereto.

[0044] At Figure 4 In the embodiments described, two CDUs are used as an example (i.e., a first CDU 81 and a second CDU 82). However, the control system of this application only needs to have multiple CDUs, but the number of CDUs is not limited to this. Figure 4The above is a limited description. More specifically, the technical solution of this application is that when one of the multiple CDUs in the control system starts from a static state, the CDU control unit inside any CDU in the group performs synchronous control of all CDUs, so that the multiple CDUs can operate stably, and ultimately all CDUs output a target flow rate of coolant.

[0045] For example, when the control system is operating stably, the first CDU 81 may operate at a first speed (i.e., the pump assembly of the first CDU 81 rotates at the first speed) and output a first flow rate of coolant. The second CDU 81 also operates at a first speed (i.e., the pump assembly of the second CDU 82 rotates at the first speed) and outputs a first flow rate of coolant. Furthermore, the total output flow rate of the first CDU 81 and the second CDU 82 (i.e., the first flow rate x 2) is equal to or very close to the required flow rate set by the administrator. It should be noted that the required flow rate refers to the flow rate set based on parameters such as the size of the data center, the size of the server rack 9, the performance of the first CDU 81 and the second CDU 82, the properties of the coolant, and the length or size of the piping, which meets the heat dissipation requirements of the server rack 9.

[0046] When the second CDU 82 fails, any CDU in the group (i.e., one of the remaining CDUs in the group excluding the failed CDU) will control the second CDU 82 to stop operating. At this time, the first CDU 81 needs to take over the flow originally handled by the second CDU 82, thereby providing backup for the second CDU 82. Therefore, the CDU control unit of the first CDU will issue a command to increase the rotational speed of the first CDU 81, so that the first CDU 81 operates at a speed greater than the first rotational speed, thereby ensuring that the output flow of the first CDU 81 meets the required flow.

[0047] When the second CDU 82 recovers from a fault, or when a new CDU is added to the control system to replace the old second CDU, the CDU control unit of the CDU can detect that the second CDU 82 has started from a standstill. At this time, because the speed of the first CDU 81 is too high and the speed of the second CDU 82 is too low, the check valve (e.g., the one used with the second CDU 82)... Figure 2The check valve 5 shown may be suppressed by the pressure of the first CDU 81, preventing the coolant output from the second CDU 82 from passing through the check valve. To solve this problem, when the CDU control unit inside any CDU in the group detects that the second CDU 82 is starting from a standstill, it will first control the first CDU 81 and the second CDU 82 to operate simultaneously at a second speed lower than the first speed. By reducing the current speed of the first CDU 81 and directly increasing the initial speed of the second CDU 82, the second CDU 82 can have sufficient force to overcome the pressure currently encountered by the check valve, allowing the coolant output by the second CDU 82 to pass through the check valve, thereby enabling the second CDU 82 to stably output the coolant flow rate corresponding to the second speed.

[0048] As described above, since the CDU control unit within any CDU in the group operates the first CDU 81 and the second CDU 82 at the same second speed, once both the first CDU 81 and the second CDU 82 are operating stably, they will output the same or similar flow rates of coolant. However, in order for the originally low-speed second CDU 82 to overcome the pressure of the originally high-speed first CDU 81, the CDU control unit within any CDU in the group operates the first CDU 81 and the second CDU 82 in a relatively low speed range. Therefore, the total output flow of the first CDU 81 and the second CDU 82 will be less than the flow rate required by the control system. Therefore, after both the first CDU 81 and the second CDU 82 have stably operated at the second speed, the CDU control unit again issues commands to the first CDU 81 and the second CDU 82 to increase the output flow rate of the first CDU 81 and the second CDU 82, so that the first CDU 81 and the second CDU 82 each output a target flow rate of coolant, and the sum of the target flow rates of the first CDU 81 and the second CDU 82 is equal to or very close to the required flow rate of the control system. That is,

[0049] By allowing all CDUs to operate stably first, and then increasing the output of each CDU to the target flow rate, the aforementioned instability problem caused by the check valve of one CDU being suppressed by the pressure of other CDUs, resulting in all CDUs being forced to continuously switch between high and low speeds, can be solved.

[0050] Please also refer to Figure 5 This is an embodiment of the control flowchart of this application. Figure 5 The specific steps of the control method disclosed in this application are mainly applicable to Figure 4The control system shown is a multi-processor control unit (CDU). Specifically, the control system includes multiple computer-executable programs (CDUs), each CDU containing a CDU control unit. In one embodiment, each CDU control unit stores firmware consisting of multiple computer-executable program codes. When the CDU control unit executes the firmware, it can... Figure 5 The steps shown control a group of CDUs consisting of multiple CDUs, thereby realizing the control method of this application. In other words, in this application, the CDU control unit inside each CDU can serve as the main control unit of the entire control system.

[0051] like Figure 5 As shown, during the continuous operation of one or more CDUs in the control system, the CDU control unit of any CDU in the group is configured to continuously monitor one or more CDUs and determine whether any stationary CDU needs to be started (step S51). When a stationary CDU is detected to be starting, the CDU control unit of that CDU generates a low-speed command and simultaneously sends the low-speed command to all CDUs in the control system via the communication line (step S52). For ease of understanding, the following will be combined with... Figure 4 The control system shown is illustrated by taking the example of any CDU in the group detecting that the second CDU 82, which is in a stationary state, needs to be started, and simultaneously sending a low speed command to the first CDU 81, which is currently operating at the first speed, and the second CDU 82, which is currently in a stationary state.

[0052] In one embodiment, the second CDU 82 in a static state refers to a new CDU newly added to the CDU group of the control system, and this new CDU is started from a static state. In another embodiment, the second CDU 82 in a static state refers to an existing CDU in the CDU group of the control system that has stopped operating due to a fault, and this CDU is started from a static state after recovering from the fault state. In yet another embodiment, the second CDU 82 in a static state refers to an existing but not operating backup CDU in the CDU group of the control system, and is started from a static state to replace the faulty CDU when any CDU in the CDU group fails. However, the above are only some specific embodiments of this application, and are not limited thereto.

[0053] In this application, the CDU control unit of any CDU in the group simultaneously sends a low speed command to the first CDU 81 at a first speed and the second CDU 82 at a stationary state, to instruct the first CDU 81 and the second CDU 82 to operate at a second speed, wherein the second speed is lower than the first speed at which the first CDU 81 originally operated.

[0054] Specifically, a check valve (e.g., a first check valve) is connected to the downstream end of the pump of the first CDU 81, and a check valve (e.g., a second check valve) is also connected to the downstream end of the pump of the second CDU 82. The first CDU 81 and the second CDU 82 are connected in parallel. As mentioned earlier, because the first CDU 81 originally operates at high speed and generates significant pressure, the output force of the second CDU 82 starting from a standstill is less than the force suppressed by the pressure of the first CDU 81 on the second check valve. This prevents the coolant output by the second CDU 82 from passing through the second check valve. Therefore, the control method of this application uses a low-speed command issued by the CDU control unit of any CDU in the group to control the first CDU 81 and the second CDU 82 to operate at a second speed. This is to reduce the current speed of the first CDU 81 and increase the initial speed of the second CDU 82, thereby allowing the output force of the second CDU 82 to overcome the force suppressed by the second check valve. This allows the coolant output by the second CDU 82 to pass through the second check valve, and the output flow rate to match the flow rate corresponding to the second speed. In other words, the second speed refers to the speed at which the coolant output by the first CDU 81 can pass through the first check valve, and the coolant output by the second CDU 82 can pass through the second check valve without being suppressed by the pressure generated by the first CDU 81. The low-speed command is the control command that controls the first CDU 81 and the second CDU 82 to operate at the second speed respectively.

[0055] In one embodiment, the first CDU 81 has a first pump group, and the second CDU 82 has a second pump group. The first and second pump groups rotate according to a pre-set working cycle of the control system to ensure that the first CDU 81 and the second CDU 82 stably output coolant at a target flow rate specified by the control system. In one embodiment, the working cycle may correspond to the rated frequency of the first and second pump groups, and the second rotational speed is 50% to 70% of the working cycle of the first and second pump groups. When the first CDU 81 and the second CDU 82 operate stably at the second rotational speed, the output flow rate of the first CDU 81 and the second CDU 82 is approximately 80% of the target flow rate, but is not limited thereto.

[0056] Back Figure 5After step S52, the first CDU 81 and the second CDU 82 will operate based on the low speed command. The CDU control unit of any CDU in the group will be set to continuously monitor the first CDU 81 and the second CDU 82 to determine whether the first CDU 81 and the second CDU 82 are both operating stably at the second speed and have reached the preset time (step S53). When the CDU control unit detects that the first CDU 81 and the second CDU 82 are both operating stably at the second speed and have reached the preset time, it will generate a target flow command and send the target flow command to the first CDU 81 and the second CDU 82 to instruct the first CDU 81 and the second CDU 82 to increase their speeds respectively in order to output the target flow rate of coolant (step S54).

[0057] Please also refer to Figure 6 This is an embodiment of the flow control waveform diagram of the coolant distribution device of this application. Figure 6 As shown, when the second CDU 82 starts from a standstill, the CDU control unit of any CDU in the group issues a low-speed command, causing the first CDU 81 and the second CDU 82 to operate at the same second speed. Upon receiving the low-speed command, the first CDU 81 decelerates (output flow gradually decreases), while the second CDU 82 accelerates (output flow gradually increases). When both the first CDU 81 and the second CDU 82 are operating stably at the same second speed, their output flow rates will be the same or very similar. Figure 6 In this embodiment, when both the first CDU 81 and the second CDU 82 are operating stably at the second speed, the output flow rate will approach 0.3 (a ratio, i.e., 30% of the flow rate required by the control system). When the CDU control unit detects that both the first CDU 81 and the second CDU 82 are operating stably at the second speed, it will begin recording the duration of stable operation of the first CDU 81 and the second CDU 82. Figure 6 In this embodiment, the CDU control unit will operate stably for 4 seconds after the first CDU 81 and the second CDU 82 have been operating (i.e., the output flow rate is continuously maintained at 30% of the required flow rate). Figure 6 When the ratio is 0.4 (for example), it is determined that both the first CDU 81 and the second CDU 82 are operating stably at the second speed and have reached the preset time. At this time, the CDU control unit will issue the target flow command to the first CDU 81 and the second CDU 82.

[0058] One objective of this application is to control multiple CDUs to provide cooling for server rack 9. Therefore, the control system must ensure that the total output flow of all CDUs meets the cooling requirements of the server rack. That is, the total output flow of all CDUs must be equal to or very close to the required flow preset by the administrator. Furthermore, the purpose of simultaneously setting up multiple CDUs in the control system, besides redundancy, is also to balance the output flow of the multiple CDUs so that the control system can operate stably. Therefore, in one embodiment, in step S54, the CDU control unit of any CDU in the group sends a target flow command, causing the first CDU 81 and the second CDU 82 to output the same target flow, and the sum of the target flow of the first CDU 81 and the target flow of the second CDU 82 must be equal to or very close to the required flow of the control system. Figure 6 In one embodiment, the control system has two CDUs. Therefore, when the first CDU 81 and the second CDU 82 receive the target flow command and operate according to the target flow command, the output flow of both the first CDU 81 and the second CDU 82 is 0.5 (a ratio, i.e. 50% of the required flow of the control system). Thus, the sum of the output flow of the first CDU 81 and the output flow of the second CDU 82 is equal to the required flow of the control system.

[0059] For example, if the control system includes five CDUs, then in step S54, the CDU control unit within any CDU in the group will also use a target flow command to make all five CDUs achieve the same target flow, and the sum of these five target flows is equal to or very close to the required flow of the control system. That is, the target flow output by each CDU is approximately 20% of the required flow of the control system. In other words, the target flow of each CDU is equal, and

[0060] It is worth mentioning that, Figure 5 The purpose of step S52 is to reduce the speed of the operating CDU so that the stationary CDU can start operating smoothly. Therefore, the CDU control unit issues a speed command that directly specifies the speed of the pump group. On the other hand, the purpose of step S54 is to enable the control system to provide the required flow rate for heat dissipation. Therefore, the CDU control unit issues a target flow rate command that directly specifies the target flow rate of each CDU, thereby ensuring that each CDU can output the target flow rate of coolant, so that the flow rate of coolant output by the entire control system meets the heat dissipation requirements.

[0061] It is worth noting that the multiple CDUs in the control system are configured in parallel, therefore the impedance encountered by each CDU on the pipeline may differ. When multiple CDUs stably output the target flow rate of coolant based on the target flow command, the pump speeds of each CDU may differ. More specifically, CDUs with higher pipeline impedance require their pumps to operate at higher speeds to achieve the same target flow rate; conversely, CDUs with lower pipeline impedance can use their pumps at lower speeds to achieve the same target flow rate. Therefore, in order to ensure that all CDUs in the CDU group of the control system can stably output the required flow rate of coolant, the CDU control unit generates and issues the target flow command, rather than instructing the speed of each CDU.

[0062] Please continue reading Figure 7 This is another embodiment of the control flowchart of this application. Figure 7 Another embodiment of the control method of this application is disclosed, and Figure 7 The control method shown is also applicable to, for example, Figure 4 The control system shown.

[0063] Specifically, after the control system starts operating, the CDU control unit of any CDU in the group is set to continuously detect whether any CDU among the multiple CDUs is faulty (step S71). When any CDU (e.g.) is detected... Figure 4 When the second CDU (82) shown malfunctions, the CDU control unit generates and issues flow commands to other CDUs (e.g., Figure 4 The first CDU 81 shown is used. Specifically, the CDU control unit increases the output flow of the first CDU 81 so that the overall output flow of the control system can be maintained at the required flow for heat dissipation (step S72).

[0064] After step S72, the control system provides heat dissipation through the first CDU 81, and the CDU control unit continuously detects whether a new CDU is added (step S73). The new CDU refers to a CDU that is stationary and can be activated to share the flow of the first CDU 81. If no new CDU is added, the control system continues to provide heat dissipation through the first CDU 81, and the CDU control unit continues to detect. If a new CDU is detected, in order for the new CDU to operate smoothly, the CDU control unit sends a low-speed command to reduce the speed of the first CDU 81 to a conditional speed, and allows the new CDU to operate at the same conditional speed as the reduced-speed first CDU 81 (step S74).

[0065] Next, the CDU control unit continuously determines whether the first CDU 81 and the new CDU are both operating stably at the conditional speed (step S75). For example, whether the first CDU 81 and the new CDU are both stably outputting a flow rate corresponding to the conditional speed, and whether the stabilization time reaches a preset length. When it is determined whether the first CDU 81 and the new CDU are both operating stably at the conditional speed, the CDU control unit then sets the target flow rate of all CDUs by sending a target flow rate command (step S76), so that all CDUs of the control system output the same target flow rate of coolant, and the sum of the target flow rates of all CDUs is equal to or very close to the required flow rate of the control system.

[0066] In this embodiment, the CDU control unit continuously executes steps S71 to S76. Therefore, the control system can continuously output coolant at the required flow rate to meet heat dissipation needs, increase the speed of other CDUs for backup in the event of a CDU failure, and adjust the speed and output flow of all CDUs when a new CDU is added, so that the new CDU can operate smoothly.

[0067] In summary, the technical solution of this application can synchronously control the speed and output flow of all CDUs based on the status of a CDU (fault, recovery from a fault, or addition to the control system), thereby ensuring that the CDU group will not experience operational instability when a CDU fails or a new CDU is added.

Claims

1. A coolant distribution device control system, comprising: The first coolant distribution device is configured to operate at the first rotational speed; and The second coolant distribution device is configured to be stationary, wherein the first coolant distribution device and the second coolant distribution device form a group; Wherein, any coolant distribution device in the group is configured to issue a low speed command to the first coolant distribution device and the second coolant distribution device to instruct the first coolant distribution device and the second coolant distribution device to operate at a second speed, wherein the second speed is lower than the first speed; In this configuration, any one of the coolant distribution devices in the group is configured to issue a target flow command to the first coolant distribution device and the second coolant distribution device when the first coolant distribution device and the second coolant distribution device are both operating at the second speed for a preset time, so as to instruct the first coolant distribution device and the second coolant distribution device to output the target flow respectively.

2. The control system according to claim 1, wherein the first coolant distribution device is connected to the first check valve, the second coolant distribution device is connected to the second check valve, and the second rotational speed is a rotational speed that allows the coolant output by the first coolant distribution device to pass through the first check valve and allows the coolant output by the second coolant distribution device to pass through the second check valve without being inhibited by the pressure generated by the first coolant distribution device.

3. The control system according to claim 1, wherein the first coolant distribution device has a first pump group, the second coolant distribution device has a second pump group, and the second rotation speed is 50% to 70% of the working cycle of the first pump group and the second pump group.

4. The control system of claim 1, wherein any coolant distribution device in the group is configured to issue the target flow command when it is detected that both the first coolant distribution device and the second coolant distribution device are operating stably at the second rotational speed for more than 4 seconds.

5. The control system of claim 1, wherein the control system is set to a required flow rate, and the sum of the target flow rate of the first coolant distribution device and the target flow rate of the second coolant distribution device is equal to the required flow rate.

6. The control system according to claim 1, wherein the second coolant distribution device is a new coolant distribution device newly added to the control system, or an old coolant distribution device in the control system that has recovered from a fault state.

7. A method for controlling a coolant distribution device, applied to a coolant distribution device control system, the coolant distribution device control system having a group including at least a first coolant distribution device and a second coolant distribution device, wherein the first coolant distribution device operates at a first rotational speed, and the control method includes: Step a) Detect the start-up of the second coolant distribution device, which is in a static state; Step b) A low-speed command is sent from any of the coolant distribution devices in the group to the first coolant distribution device and the second coolant distribution device to instruct the first coolant distribution device and the second coolant distribution device to operate at a second speed, wherein the second speed is lower than the first speed; and Step c) When it is determined that both the first coolant distribution device and the second coolant distribution device are operating at the second speed for a preset time, any one of the coolant distribution devices in the group sends a target flow command to the first coolant distribution device and the second coolant distribution device to instruct the first coolant distribution device and the second coolant distribution device to output the target flow respectively.

8. The control method according to claim 7, wherein the first coolant distribution device is connected to the first check valve, the second coolant distribution device is connected to the second check valve, and the second rotational speed issued in step b) is a rotational speed that allows the coolant output by the first coolant distribution device to pass through the first check valve, and allows the coolant output by the second coolant distribution device to pass through the second check valve without being inhibited by the pressure generated by the first coolant distribution device.

9. The control method according to claim 7, wherein the first coolant distribution device has a first pump group, the second coolant distribution device has a second pump group, and the second rotational speed issued in step b) is 50% to 70% of the working cycle of the first pump group and the second pump group.

10. The control method according to claim 7, wherein step c) is to issue the target flow command when it is detected that both the first coolant distribution device and the second coolant distribution device are operating stably at the second rotation speed for more than 4 seconds.

11. The control method of claim 7, wherein the control system has a demand flow rate, and step c) is to issue the target flow rate command such that the sum of the target flow rate of the first coolant distribution device and the target flow rate of the second coolant distribution device is equal to the demand flow rate.

12. The control method according to claim 7, wherein step a) is detecting a new coolant distribution device newly added to the control system, or detecting an old coolant distribution device in the control system that has recovered from a fault state.

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