Control method of vacuum pump and electronic device

Abstract

The application discloses a kind of control method of vacuum pump and electronic equipment, with vacuum side pressure and target pressure are compared, and the running stage of multistage vacuum pump is divided, in loading stage, according to the preset order, gradually put into vacuum pump operation, make total pumping speed gradually improve with the change of pressure, avoid the pressure difference mutation caused by the simultaneous start of multiple vacuum pumps and electrical impact, while guaranteeing the efficiency of building pressure;In unloading stage, gradually reduce the frequency conversion of vacuum pump or exit operation according to the order opposite to loading, make total pumping speed gradually reduce and match with system actual pumping demand, to avoid the pressure fluctuation caused by direct pump stop and valve anomaly, while reducing the energy waste brought by pumping speed redundancy, realize the smooth transition and stable control of system pressure.Solve the technical problems of large pressure building impact and steady-state pumping speed redundancy of multiple vacuum pumps, achieve the technical effects of reducing energy consumption and improving pressure stability.

Description

Technical Field

[0001] This invention relates to the field of energy-saving control of multi-stage vacuum pumps, and particularly to a control method and electronic device for a vacuum pump. Background Technology

[0002] Vacuum pumps are typically used to evacuate gas tanks or chambers, reducing the pressure on the vacuum side and creating a pressure difference with the positive pressure side. When this pressure difference reaches a valve opening threshold, the valve opens to facilitate media transfer or process connection. In practical industrial applications, to balance evacuation efficiency and system stability, multiple vacuum pumps are usually used in combination, and control strategies are employed to adjust the operating status of each pump to complete the pressure build-up and stabilization process.

[0003] However, existing control methods for multiple vacuum pumps struggle to achieve a proper matching of pumping speed between the pressure build-up and steady-state phases. During the pressure build-up phase, insufficient pumping speed from a single vacuum pump leads to slow pressure differential establishment, while simultaneous operation of multiple vacuum pumps can easily cause sudden pressure differential changes and electrical surges. During the steady-state operation phase, directly stopping the pumps or maintaining multiple pumps at full load results in either large pressure fluctuations or pumping speed redundancy, making it difficult to maintain stable system pressure. Summary of the Invention

[0004] The purpose of this invention is to provide a control method and electronic device for a vacuum pump, which solves the technical problems of large pressure build-up impact and redundancy in steady-state pumping speed of multiple vacuum pumps, and achieves the technical effects of reducing energy consumption and improving pressure stability.

[0005] In a first aspect, the present invention provides a method for controlling a vacuum pump, applied to a system including multiple vacuum pumps, the method comprising: The operating stages of the multi-stage vacuum pump are determined based on the relationship between the vacuum side pressure and the target pressure. When the vacuum side pressure is greater than the target loading pressure, each vacuum pump is controlled to enter the stepped loading stage. The stepped loading stage is to put the vacuum pumps into operation one by one in a first preset order, so that the total pumping speed of the vacuum pumps is gradually increased. When the vacuum side pressure is less than the target unloading pressure, each vacuum pump is controlled to enter the reverse step unloading stage. The reverse step unloading stage is to reduce the speed of each vacuum pump by frequency conversion or to stop operation in a second preset order, so that the total pumping speed of the vacuum pump is reduced step by step.

[0006] Optionally, the stepped loading stage specifically includes: According to multiple starting pressure thresholds that correspond one-to-one with each of the vacuum pumps and decrease in value, each vacuum pump is put into operation in the first preset order, and each vacuum pump operates at full frequency after being put into operation. Specifically, when the vacuum side pressure is greater than the maximum start-up pressure threshold, the first vacuum pump in the first preset sequence is activated. Whenever the vacuum side pressure drops below the corresponding next start-up pressure threshold, the next vacuum pump in the first preset sequence is activated, until all the vacuum pumps are activated or the vacuum side pressure drops to the target loading pressure.

[0007] Optional, also includes: Obtain the real-time leak rate of the system and automatically adjust the startup pressure threshold based on the real-time leak rate; When the real-time leakage rate increases, the starting pressure threshold is increased to allow the next vacuum pump to be put into operation earlier; when the real-time leakage rate decreases, the starting pressure threshold is decreased to delay the operation of the next vacuum pump.

[0008] Optionally, the reverse ladder unloading phase specifically includes: According to multiple frequency reduction thresholds that correspond one-to-one with each of the vacuum pumps and whose values ​​increase sequentially, the frequency reduction of each of the vacuum pumps is performed in sequence according to the second preset order. Specifically, when the vacuum side pressure is less than the minimum frequency conversion speed reduction threshold, the last vacuum pump put into operation in the first preset sequence is subjected to frequency conversion speed reduction. Whenever the vacuum side pressure is still less than the corresponding next frequency conversion speed reduction threshold, the previous vacuum pump put into operation in the first preset sequence is subjected to frequency conversion speed reduction, until all vacuum pumps are running at their respective lowest frequencies or the vacuum side pressure rises back to the target unloading pressure. The first preset sequence is the opposite of the second preset sequence.

[0009] Optionally, the triggering method for frequency conversion speed reduction of each vacuum pump during the reverse step unloading stage includes: When the frequency converter corresponding to the vacuum pump currently undergoing frequency conversion speed reduction detects that the vacuum pump is running at its lowest frequency, it sends a trigger signal to the frequency converter corresponding to the previous vacuum pump in the first preset sequence, triggering the frequency converter corresponding to the previous vacuum pump to perform frequency conversion speed reduction on the previous vacuum pump according to the trigger signal.

[0010] Optionally, if the vacuum side pressure is still less than the target unloading pressure after any of the vacuum pumps has been frequency-reduced to the lowest frequency, the vacuum pump that has been frequency-reduced to the lowest frequency will be unloaded, and the frequency reduction of the next vacuum pump will continue.

[0011] Optional, also includes: If the vacuum side pressure is still less than the target unloading pressure after all vacuum pumps have been unloaded, a fault alarm indicating that the minimum frequency setting is unreasonable will be issued.

[0012] Optional, also includes: When a shutdown command is received, the vacuum pumps are stopped one by one in a second preset order; the first preset order is the reverse of the second preset order. The process involves first stopping the last vacuum pump to be put into operation, and then stopping the previous vacuum pump after the vacuum side pressure rises back to the pump stop threshold, until all vacuum pumps are stopped, and then closing the air inlet valve of the vacuum pump.

[0013] Optional, also includes: The order in which the vacuum pumps are put into operation is rotated periodically, so that different vacuum pumps take turns being the first vacuum pump to be put into operation.

[0014] Secondly, this application provides an electronic device, comprising: Memory, used to store computer programs; A processor is used to implement the steps of the vacuum pump control method as described above when executing a computer program.

[0015] This invention provides a control method and electronic device for a vacuum pump. By comparing the vacuum side pressure with the target pressure, the operation of the multi-stage vacuum pump is divided into stages. During the loading stage, the vacuum pumps are activated sequentially according to a preset order, allowing the total pumping speed to gradually increase with pressure changes. This avoids sudden pressure drops and electrical shocks caused by simultaneous startup of multiple vacuum pumps, while ensuring pressure build-up efficiency. During the unloading stage, the vacuum pumps are decelerated or shut down sequentially in the reverse order of loading, gradually reducing the total pumping speed to match the actual pumping demand of the system. This avoids pressure fluctuations and valve malfunctions caused by direct pump shutdown, while reducing energy waste from pumping speed redundancy, achieving a smooth transition and stable control of the system pressure. This invention solves the technical problems of large pressure build-up shocks from multiple vacuum pumps and steady-state pumping speed redundancy, achieving the technical effects of reducing energy consumption and improving pressure stability. Attached Figure Description

[0016] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart of a vacuum pump control method provided by the present invention; Figure 2 This is a schematic diagram of the structure of a vacuum pump system provided by the present invention; Figure 3 A schematic diagram of the structure of another vacuum pump system provided by the present invention; Figure 4A detailed flowchart of a vacuum pump control method provided by the present invention; Figure 5 This is a schematic diagram of an electronic device provided by the present invention. Detailed Implementation

[0018] The core of this invention is to provide a control method and electronic device for a vacuum pump, which solves the technical problems of large pressure build-up impact and redundancy in steady-state pumping speed of multiple vacuum pumps, and achieves the technical effects of reducing energy consumption and improving pressure stability.

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 In a first aspect, the present invention provides a method for controlling a vacuum pump, applicable to a system comprising multiple vacuum pumps, the method comprising: S11: Determine the operating stage of the multi-stage vacuum pump based on the relationship between the vacuum side pressure and the target pressure; In this embodiment, vacuum side pressure is used as the sole criterion. By comparing it with the target pressure, the judgment logic for the operation stage of the multi-stage vacuum pump is established. Vacuum side pressure is a continuously changing physical quantity during the pumping process. Its changes directly reflect the current pressure difference establishment degree and the system pumping status. Therefore, using it as the basis for stage switching can avoid misjudgment problems caused by relying on time or a fixed sequence. Specifically, this embodiment does not limit the specific value of the target pressure. The target pressure can be set to a range close to the valve opening critical pressure, such as 90% to 100% of the critical pressure, while the target pressure can be set to a range slightly lower than the critical pressure, such as 85% to 95% of the critical pressure. These two pressure thresholds form a judgment range with width, giving the switching of operation stages a certain buffer range. It is important to understand that the target loading pressure and target unloading pressure described in this application can be the same if they occur during the same startup process. That is, the target loading pressure and target unloading pressure are the same pre-set value, referred to as the target pressure for that stage. It can be understood that during this startup process, as the vacuum pump gradually loads and the pressure on the vacuum side fluctuates around the target pressure, there may be instances where the vacuum side pressure is lower than the target pressure. In such cases, a certain degree of unloading is required to stabilize at the target pressure. If different processes are described, such as a separate startup process and a separate unloading process, then the target loading pressure and target unloading pressure can be set separately, with their values ​​serving their respective startup loading or unloading processes.

[0021] Furthermore, this embodiment achieves segmented identification of the operating state by comparing the vacuum-side pressure with the target pressure. When the vacuum-side pressure is in a higher range, it indicates that the pressure difference has not yet reached the target level, and pumping needs to continue. When the vacuum-side pressure drops to near the target loading pressure, it indicates that the system is close to the pressure-building completion state. When the vacuum-side pressure further falls below the target unloading pressure, it indicates that the system has entered a steady state or an over-pumping state, and pumping speed adjustment is required. This determination method can be implemented, but is not limited to, by sampling the pressure signal in real time and performing continuous comparisons. It can also employ a method with filtering or hysteresis to avoid frequent switching of operating stages due to small pressure fluctuations.

[0022] In actual operating conditions, the rate of change of vacuum-side pressure is closely related to the system volume, the rated pumping speed of a single vacuum pump, and the actual leakage rate on site. For example, in a cavity with a volume of V, when the rated pumping speed of a single vacuum pump is S0, the pressure drop in the high-pressure section is relatively fast, while the pressure drop rate slows down significantly as it approaches the target pressure. Simultaneously, when an actual leakage rate Q exists, the pressure drop will plateau or change slowly. Therefore, this embodiment introduces target loading pressure and target unloading pressure to ensure that the stage division covers the high-pressure section, the intermediate transition section, and the low-pressure steady-state section, allowing different control strategies to correspond to different physical stages, rather than simply using a single threshold switching. This solves the technical problem in existing technologies where unclear division of operating stages leads to unreasonable control strategy switching, achieving the technical effect of accurate determination of operating stages.

[0023] S12: When the vacuum side pressure is greater than the target loading pressure, control each vacuum pump to enter the stepped loading stage. The stepped loading stage is to put the vacuum pumps into operation one by one in the first preset order, so that the total pumping speed of the vacuum pumps is gradually increased. First, it's important to understand that if the vacuum pump is not applied, the vacuum side pressure is at atmospheric pressure. During the evacuation process, the vacuum side pressure gradually decreases; that is, the pressure under vacuum is numerically lower than the pressure under atmospheric pressure. For example, if the atmospheric pressure is 0 and the target pressure is -100, then during the stepped loading phase, the vacuum side pressure gradually decreases from 0 to -100.

[0024] In this embodiment, when the vacuum side pressure is greater than the target loading pressure, the vacuum pumps are activated one by one in a first preset order, resulting in a step-like change in the total pumping speed rather than a sudden jump. Since the actual pumping speed of a single vacuum pump is limited, initially, only one pump is needed to cover the pumping demand in the high-pressure range. At this time, the vacuum side pressure drops rapidly and changes relatively smoothly, without sudden pressure drops. As the vacuum side pressure gradually decreases, the gas density decreases, and the amount of gas that can be pumped out per unit time decreases. A single vacuum pump gradually becomes unable to maintain its original pressure drop rate. At this point, the next vacuum pump is activated in the first preset order, increasing the total pumping speed from S0 to approximately 2S0, and the pressure drop rate is correspondingly improved. This step-by-step activation method can be implemented, but is not limited to, using a fixed sequence or a preset priority order, ensuring that each vacuum pump undertakes a suitable pumping task within its corresponding pressure range.

[0025] Furthermore, as the pressure approaches the target loading pressure, the vacuum side pressure enters the low-pressure range, and the pressure drop process slows down significantly. At this point, the remaining vacuum pumps are activated in the first preset sequence to further increase the total pumping speed, for example, from 2S0 to 3S0. This ensures that the pressure drop process maintains a controllable downward trend as it approaches the target loading pressure, rather than experiencing prolonged stagnation. It's important to understand that each activation of a vacuum pump is triggered based on the current vacuum side pressure state, not at a fixed time or simultaneously. Therefore, the change in total pumping speed is synchronized with the pressure change process, and can be understood, but is not limited to, as a segmented pumping speed process that dynamically unfolds with pressure. Compared to the situation where the total pumping speed instantly reaches its maximum when multiple vacuum pumps are started simultaneously, this step-by-step activation method makes the pressure differential establishment process exhibit an approximately linear trend, avoiding pressure differential overshoot in the critical valve opening range.

[0026] The following is combined with Figure 2 and Figure 3 The structural diagram shown and Figure 4 The flowchart shown explains the principle of the embodiment.

[0027] If there are three vacuum pumps, the pumping process during the stepped loading can be divided into a high-pressure section, a medium-pressure section, and a low-pressure sprint section. In the high-pressure section, from atmospheric pressure to the first starting pressure threshold, the initial gas density is relatively high, and the pumping speed of a single vacuum pump can meet the pressure drop requirement. At this time, only one vacuum pump is put into operation, so that the system can meet the pressure drop rate requirement while avoiding the pumping speed redundancy caused by multiple pumps operating simultaneously. As the vacuum side pressure decreases to the medium-pressure section between the first and second starting pressure thresholds, the pressure drop rate of a single vacuum pump gradually decreases. At this time, a second vacuum pump is put into operation, so that the total pumping speed is increased to a level that matches the current pressure drop requirement, ensuring the pressure difference establishment rate while avoiding excessive pumping speed. When the vacuum side pressure further decreases to below the second starting pressure threshold and enters the low-pressure sprint section, the pressure drop rate slows down due to the further decrease in gas molecule density. At this time, the next vacuum pump is put into operation to compensate for the pumping speed, so that the pressure difference quickly approaches the valve opening critical value, thereby shortening the duration of the low-pressure section. In the above process, since the energy consumption per unit pumping speed in the low-pressure section is higher than that in the high-pressure section, this embodiment matches the timing of the activation of multiple vacuum pumps with each starting pressure threshold, thereby compressing the duration of the high-energy-consumption range and reducing energy consumption in the low-pressure section from an operational mechanism perspective. Simultaneously, the stepped activation method avoids the superposition of instantaneous high currents generated by the simultaneous activation of multiple vacuum pumps, reducing the impact on the power grid, and makes the differential pressure establishment process gradual, reducing the impact of sudden differential pressure changes on the valve structure, resulting in a smoother valve opening process.

[0028] From a physical perspective, when the volume of the gas tank or cavity is V, the pumping process satisfies the relationship between the pressure drop rate and the total pumping speed. The pressure drop effect per unit pumping speed is higher in the high-pressure section, while the pressure drop effect per unit pumping speed decreases significantly in the low-pressure section. This embodiment utilizes this characteristic, using only a small number of vacuum pumps in the high-pressure section and gradually increasing the number of vacuum pumps in the medium and low-pressure sections. This ensures that the total pumping speed at different stages corresponds to the actual pressure drop requirement, avoiding excessive pumping speed in the high-pressure section and preventing pressure drop stagnation due to insufficient pumping speed in the low-pressure section. Furthermore, using a smaller number of vacuum pumps initially ensures that the pumping speed meets the pressure drop requirement while also reducing energy consumption. For example, starting only one vacuum pump in the initial stage consumes only 1 / N of the energy required to start all vacuum pumps simultaneously, where N is the total number of vacuum pumps. In summary, this embodiment solves the technical problems of sudden pressure difference changes caused by the simultaneous start-up of multiple vacuum pumps and slow pressure drop caused by the operation of a single pump in the prior art, achieving a stable pressure drop and matched pumping speed during the pressure build-up process.

[0029] S13: When the vacuum side pressure is less than the target unloading pressure, control each vacuum pump to enter the reverse step unloading stage. The reverse step unloading stage is to reduce the speed of each vacuum pump by frequency conversion or stop operation in the second preset order, so that the total pumping speed of the vacuum pump is reduced step by step.

[0030] It is also important to understand that when unloading is required, the vacuum side pressure is less than the corresponding target unloading pressure. For example, if the target unloading pressure is -100 and the vacuum side pressure is -120, the vacuum side pressure will continuously increase from -120 to -100 during the reverse step unloading phase.

[0031] In this embodiment, when the vacuum-side pressure is less than the target unloading pressure, the pumps are not directly stopped. Instead, the vacuum pumps are sequentially reduced in frequency or taken out of operation according to a second preset sequence, resulting in a step-like decrease in the total pumping speed. At this point, the vacuum side has entered a low-pressure or steady-state range, and the system's pumping demand mainly comes from micro-leakage or cavity venting, which is much lower than during the pressure build-up phase. If all vacuum pumps are kept running at full frequency, there will be significant pumping speed overrun, causing the pressure to continue to drop rapidly or even over-pump. This embodiment reduces the operating capacity of each pump sequentially, gradually lowering the total pumping speed from a higher value to a level close to the current pumping demand. This can be done, but is not limited to, first reducing the frequency of the last vacuum pump put into operation during the loading phase, gradually decreasing the total pumping speed from, for example, 3S0 to 2S0, and then further to S0, ensuring that the pumping speed change process corresponds to the pressure change process.

[0032] Furthermore, during the variable frequency speed reduction process, the adjustment of each vacuum pump is not completed all at once, but is continuously adjusted according to the vacuum side pressure. For example, after a vacuum pump is reduced to its lowest operating frequency, if the vacuum side pressure is still lower than the target unloading pressure, it indicates that the current total pumping speed is still higher than the system requirement. At this point, the next vacuum pump is reduced in speed or taken out of operation according to the second preset sequence. This sequence is the opposite of the loading phase and can be understood, but is not limited to, prioritizing the reduction of pumping speed sources introduced in the later stage of pressure build-up, so that the total pumping speed quickly falls back to a reasonable range, rather than prioritizing the adjustment of the initially introduced vacuum pumps. The result of this approach is that the pumping speed reduction process is continuous and will not experience a sharp drop, thereby avoiding pressure difference fluctuations caused by a rapid rise in vacuum side pressure.

[0033] From an operational perspective, once the system enters the steady-state range, the sensitivity of vacuum-side pressure changes to pumping speed becomes significantly enhanced. A sudden decrease in pumping speed can cause a rapid pressure rebound, potentially repeatedly exceeding the target unloading pressure. This embodiment addresses this by progressively reducing the pumping speed in a reverse stepwise manner, resulting in a slow recovery or stable fluctuation in pressure. This can, but is not limited to, controlling the pressure within a small range near the target unloading pressure, such as ±3%. Compared to directly stopping the pump or operating at full speed, this method avoids drastic pressure fluctuations and the energy consumption issues caused by frequent start-stop cycles. It truly achieves the goal of supplying only the required pumping speed, with zero excess pumping speed and zero ineffective energy consumption. It solves the technical problems of large pressure fluctuations and redundant pumping speeds during the unloading phase in existing technologies, achieving the technical effect of progressively matching pumping speed and maintaining pressure stability during the steady-state phase.

[0034] In one exemplary embodiment, before controlling the operation of the multi-stage vacuum pump, the vacuum-side pressure in the gas tank is acquired and compared with the target loading pressure and the target unloading pressure to determine the initial operating stage of the system. Specifically, when the vacuum-side pressure is higher than the target loading pressure, it indicates that pumping still needs to continue to reduce the pressure, and the system enters the stepped loading stage; when the vacuum-side pressure is lower than the target unloading pressure, it indicates that the current pumping speed has redundancy or has entered a steady-state maintenance stage, and the system enters the reverse stepped unloading stage. Through this method, the system can be initially segmented based on the relationship between the vacuum-side pressure and the target pressure, thereby determining the subsequent control direction.

[0035] Furthermore, after determining the initial stage, the pressure difference between the vacuum side pressure and the other side pressure can be used to determine the current pumping or pressure stabilization requirements, thereby controlling the frequency converter in the multi-stage vacuum pump to enter the corresponding operating state. By judging the relationship between the vacuum side pressure and the target loading pressure and target unloading pressure, the system can automatically switch to the stepped loading stage or the reverse stepped unloading stage under different operating conditions, realizing dynamic adjustment of the gas tank pressure. This process does not rely on manual intervention and can be applied, but is not limited to, scenarios that require frequent switching between pumping and pressure stabilization, thus ensuring the continuity and stability of the control process.

[0036] In one exemplary embodiment, the stepped loading phase specifically includes: According to multiple starting pressure thresholds that correspond one-to-one with each vacuum pump and decrease in value, each vacuum pump is put into operation in the first preset order, and each vacuum pump operates at full frequency after being put into operation. Specifically, when the vacuum side pressure is greater than the maximum start-up pressure threshold, the first vacuum pump in the first preset sequence is activated. Whenever the vacuum side pressure drops below the corresponding next start-up pressure threshold, the next vacuum pump in the first preset sequence is activated, until all vacuum pumps are activated or the vacuum side pressure drops to the target loading pressure.

[0037] In this embodiment, the stepped loading stage divides the entire pressure build-up process into multiple pressure intervals by setting multiple starting pressure thresholds corresponding to each vacuum pump, and gradually engages the vacuum pumps within each interval. The starting pressure thresholds are arranged in descending order of value, and can be segmented according to, but is not limited to, the valve opening critical pressure. For example, different thresholds can be assigned to the high-pressure section, the intermediate transition section, and the low-pressure section approaching the target loading pressure. When the vacuum side pressure is greater than the maximum starting pressure threshold, only the first vacuum pump in the first preset sequence is engaged. At this time, the gas density is high, and a single vacuum pump can achieve a relatively fast pressure drop. As the vacuum side pressure gradually decreases to below the next starting pressure threshold, the next vacuum pump is engaged, increasing the total pumping speed from the single pump speed to the combined pumping speed of multiple pumps, and the pressure drop rate increases synchronously.

[0038] Furthermore, each vacuum pump operates at full frequency after being put into operation. This ensures that each vacuum pump maintains a stable output state within its respective pressure range, rather than frequently adjusting its frequency. In this embodiment, by focusing the adjustment on whether the pump is in operation, rather than on continuous frequency changes, the control logic is clearer, and the response lag or instability caused by frequent frequency changes during the loading phase is avoided. This can be understood, but is not limited to, using different numbers of full-frequency vacuum pumps in different pressure ranges to correspond to the current pressure drop requirement. For example, one pump operates at full frequency in the high-pressure range, two pumps operate at full frequency in the intermediate range, and three pumps operate at full frequency when approaching the target loading pressure.

[0039] From a process perspective, during the vacuum-side pressure decrease, the pressure drop capacity per unit pumping speed gradually weakens. If a fixed pumping speed is consistently used, the pressure drop will become slow or even stagnant in the later stages. This embodiment sets multiple decreasing start-up pressure thresholds, ensuring that the vacuum pump's activation time corresponds to pressure change nodes, resulting in a step-like increase in the total pumping speed, consistent with the trend of pressure drop capacity changes. Simultaneously, since each vacuum pump is activated sequentially, the total pumping speed does not experience a sudden, large jump, avoiding abrupt pressure differential changes when approaching the target loading pressure. This solves the technical problems of insufficient pressure drop capacity of a single vacuum pump and excessively rapid pressure differential changes caused by multiple pumps operating simultaneously in existing technologies, achieving the technical effect of segmented matching of pumping speed and a stable pressure drop process during pressure build-up.

[0040] Furthermore, the implementation of the aforementioned stepped loading stage will be illustrated below with a specific example. In this embodiment, the system includes three vacuum pumps, driven by the main frequency converter, auxiliary frequency converter 1, and auxiliary frequency converter 2, respectively. Before system startup, the processor determines multiple startup pressure thresholds, target loading pressure, target unloading pressure, and the lower limit of the frequency converter based on the vacuum pump parameters. The determination process may utilize, but is not limited to, parameters such as the rated pumping speed S0 of a single vacuum pump, the total volume V of the cavity and pipeline, the critical pressure difference ΔP0 for valve opening, the local atmospheric pressure Pa, the process loss rate ε, the rated frequency fn, the system steady-state leakage rate Q, the actual pumping speed S, the current vacuum side pressure P, and the actual operating frequency f.

[0041] The critical vacuum pressure corresponding to valve opening can be expressed as: The voltage drop rate is The actual combined pumping speed of the two pumps is The actual combined pumping speed of the three pumps is The actual pumping speed of a variable frequency pump is directly proportional to the frequency. ; The pressure drop rate during pumping is related to the current pumping speed and pressure, and can be expressed as v=(S×P) / V. When multiple vacuum pumps are running simultaneously, the total pumping speed is the sum of the pumping speeds of each pump, taking into account losses. During variable frequency operation, the pumping speed is proportional to the frequency. Based on the above relationships, multiple starting pressure thresholds are determined to match the changes in pumping speed at each stage with the pressure drop requirements.

[0042] In this embodiment, the multiple start-up pressure thresholds include a first start-up pressure threshold and a second start-up pressure threshold, wherein the first start-up pressure threshold is greater than the second start-up pressure threshold, and both are greater than the target loading pressure. The first start-up pressure threshold can be set close to the boundary between the high-pressure section and the medium-pressure section, for example, as... A certain proportion (for example, the first starting pressure threshold can be) Second starting pressure threshold The first starting pressure threshold is set between the first starting pressure threshold and the target loading pressure to ensure that a single vacuum pump can cover the pressure drop requirement for that range. The second starting pressure threshold is set between the first starting pressure threshold and the target loading pressure to introduce the next vacuum pump when the pressure drop rate begins to decrease, thus maintaining the continuity of the pressure drop process. The specific values ​​of each starting pressure threshold can be adjusted according to the on-site operating conditions. For example, the starting pressure thresholds can be appropriately increased when the system leakage rate is high, and appropriately decreased when the system leakage rate is low.

[0043] Upon receiving the start command, the system reads the current vacuum-side pressure P and compares it with the target loading pressure and various start-up pressure thresholds. When P is greater than the target loading pressure, the system controls each vacuum pump to enter the stepped loading stage and starts operating one by one according to a first preset sequence. Specifically, when P is greater than the first start-up pressure threshold, the first vacuum pump in the first preset sequence starts operating; when P drops below the first start-up pressure threshold, the next vacuum pump in the first preset sequence starts operating; when P further drops below the second start-up pressure threshold, the next vacuum pump in the first preset sequence starts operating, until all vacuum pumps are in operation or the vacuum-side pressure drops to the target loading pressure. Each vacuum pump operates at full frequency after starting operation without frequency conversion adjustment, thus ensuring that the total pumping speed increases stepwise, allowing the pressure difference to gradually build up and approach the valve opening condition (i.e., after the first pump starts, the vacuum-side pressure rises from atmospheric pressure). Reduced to startup pressure Then start the secondary pump, and the vacuum side pressure rises from the starting pressure. Reduced to startup pressure Then start the pump before it starts, and the vacuum side pressure will rise from the starting pressure. Reduced to the critical pressure on the vacuum side ).

[0044] In another exemplary embodiment, each frequency converter may be configured with its own independent start-up pressure threshold. Each frequency converter acquires a vacuum-side pressure signal (which may be acquired through a shared pressure sensor or its own independent sensor) and compares the current vacuum-side pressure with its own preset start-up pressure threshold. As the vacuum-side pressure gradually decreases from atmospheric pressure, the frequency converter that first reaches the highest threshold (i.e., the main frequency converter) autonomously determines that the start-up conditions are met and triggers the corresponding first vacuum pump to start operation. As the pressure further decreases, when the vacuum-side pressure is lower than the threshold of the next frequency converter, that frequency converter autonomously triggers the corresponding vacuum pump to start operation, and so on, until all vacuum pumps are in operation or the vacuum-side pressure drops to the target pressure. For example, when the vacuum-side pressure is greater than the target pressure, the first pump corresponding to the main frequency converter starts operation; when the vacuum-side pressure decreases to the first start-up pressure threshold, auxiliary frequency converter 1 controls the corresponding second pump to start operation; when the vacuum-side pressure decreases to the second start-up pressure threshold, auxiliary frequency converter 2 controls the corresponding last pump to start operation. In this implementation, the entire stepped loading process does not require a central controller to issue commands to each inverter individually. It is completed automatically entirely based on the physical process of pressure drop and the threshold comparison logic of each inverter. The advantages of this approach are twofold: firstly, even if the central controller malfunctions, each inverter can still independently decide and complete the stepped loading based on the pressure signal, resulting in higher system reliability; secondly, the activation conditions of each inverter are bound to its own threshold, and the activation timing naturally corresponds to the pressure change node, preventing timing deviations due to communication delays or lost commands. In this embodiment, each inverter can integrate a comparator or processor to compare the pressure signal with the internally stored start-up pressure threshold in real time. Unlike the approach where all vacuum pumps or inverters use the same start-up conditions and are uniformly judged and commanded individually by the central control cabinet, this embodiment does not require the central control cabinet or host computer to participate in the pump activation decision. The differentiated design of the start-up thresholds of each inverter ensures that the activation sequence is naturally determined by its respective configured pressure value, rather than being forcibly stipulated by the timing logic of the control program. This technology is suitable for scenarios with monotonically changing pressure, such as vacuum systems, and can achieve automatic stepped loading of multiple pumps without relying on high-level controllers, offering higher fault tolerance and response speed.

[0045] In this embodiment, the timing of the activation of multiple vacuum pumps corresponds to the pressure change process. Only a small number of vacuum pumps are activated in the high-pressure range, and the number of pumps is gradually increased as the pressure drop rate decreases. This avoids pumping speed redundancy and the impact caused by the simultaneous start-up of multiple pumps, ensuring that the pressure difference establishment process remains continuously changing and that the pressure difference is quickly established when the target loading pressure is approached.

[0046] In one exemplary embodiment, it further includes: Obtain the real-time leak rate of the system and automatically adjust the startup pressure threshold based on the real-time leak rate; Specifically, when the real-time leakage rate increases, the starting pressure thresholds are increased to allow the next vacuum pump to be put into operation earlier; when the real-time leakage rate decreases, the starting pressure thresholds are decreased to delay the operation of the next vacuum pump.

[0047] In this embodiment, real-time leakage rate is introduced as the adjustment basis to dynamically correct the start-up pressure threshold, so that the timing of each vacuum pump's activation is no longer fixed but varies with the on-site operating conditions. In actual operation, the leakage rate is not a constant value and may be affected by factors such as pipeline sealing, valve status, and chamber venting. When the leakage rate increases, the amount of gas entering the system per unit time increases, and the rate of decrease in vacuum side pressure will be significantly slower. If the original start-up pressure threshold is still used, the activation time of the next vacuum pump will be delayed, and it is easy to remain in a certain pressure range for a long time. This embodiment increases the start-up pressure threshold when an increase in real-time leakage rate is detected, so that the next vacuum pump is triggered to start operation before the vacuum side pressure drops to the original threshold. This is equivalent to increasing the overall pumping speed in advance, which can be understood, but is not limited to, shifting the original pressure segments as a whole to the high-pressure side by a certain distance.

[0048] Conversely, when the real-time leakage rate decreases, it indicates that the system has better sealing or reduced venting, and the vacuum-side pressure drop process is smoother. If the next vacuum pump is then activated at the original starting pressure threshold, the pumping speed will increase prematurely, resulting in a temporary over-pumping speed. In this embodiment, by lowering the starting pressure thresholds, the activation of the next vacuum pump is delayed to a lower pressure range. This can be understood, but is not limited to, shifting the pressure segments towards the lower pressure side, thereby extending the duration of the current pumping speed level. With this approach, under conditions of low leakage rate, fewer vacuum pumps can complete a greater pressure drop process, avoiding unnecessary equipment activation.

[0049] Overall, the real-time leak rate reflects the combined effect of external gas intake and internal gas release, and is a crucial factor influencing the pressure drop process. This embodiment establishes a correlation between the real-time leak rate and the starting pressure threshold, making the threshold no longer a fixed parameter but adaptively adjusting with changes in the leak rate. This ensures that the vacuum pump's activation rhythm aligns with the actual pressure drop capacity. This can be achieved, but is not limited to, by using methods such as inferring the leak rate based on the pressure change rate or directly acquiring the leak rate through a flow sensor. This solves the technical problem of fixed starting pressure thresholds failing to adapt to different operating conditions, leading to unreasonable activation timing, and achieves the technical effect of dynamically matching pumping speed under different leak rate conditions.

[0050] In one exemplary embodiment, to adapt to different field conditions and avoid malfunctions in the control process, appropriate fine-tuning can be made based on the determined starting pressure thresholds, target unloading pressure, and lower limit of the variable frequency. Specifically, when the real-time leakage rate of the field pipeline is large or there is obvious venting, resulting in a slow decrease in vacuum side pressure, the starting pressure thresholds can be appropriately increased, for example, by 5% to 10%, to allow the next vacuum pump to be put into operation earlier, avoiding a prolonged pressure build-up process due to late activation. When there is vibration after the valve is opened, the target unloading pressure can be appropriately reduced, for example, by 3% to 5%, to increase the pressure differential margin and keep the valve in a stable open state. When the vacuum pump type is a Roots pump or a molecular pump, the lower limit of the variable frequency can be appropriately increased to its lowest effective operating frequency, for example, not lower than 15Hz, to avoid rotor jamming or equipment malfunctions under low-frequency operation. Through the above methods, the control parameters can be better matched to changes in actual operating conditions, improving the stability and reliability of system operation without changing the overall control logic.

[0051] In one exemplary embodiment, the reverse ladder unloading phase specifically includes: According to multiple variable frequency speed reduction thresholds that correspond one-to-one with each vacuum pump and whose values ​​increase sequentially, each vacuum pump is subjected to variable frequency speed reduction in sequence according to the second preset order. When the vacuum side pressure is less than the minimum frequency conversion speed reduction threshold, the last vacuum pump put into operation in the first preset sequence is subjected to frequency conversion speed reduction. Whenever the vacuum side pressure is still less than the corresponding next frequency conversion speed reduction threshold, the previous vacuum pump put into operation in the first preset sequence is subjected to frequency conversion speed reduction until all vacuum pumps are running at their respective minimum frequencies or the vacuum side pressure rises back to the target unloading pressure. The first preset sequence and the second preset sequence are reversed.

[0052] In this embodiment, the reverse stepped unloading stage divides the pumping speed reduction process into multiple continuous intervals by setting multiple variable frequency speed reduction thresholds that correspond one-to-one with each vacuum pump and whose values ​​increase sequentially. The vacuum pumps are then sequentially speed-reduced according to a second preset order. Unlike the pressure build-up stage, the vacuum side pressure has already entered a lower range at this point, and the system's main requirement is no longer to quickly establish a pressure difference, but rather to maintain the current pressure level. Therefore, when the vacuum side pressure is less than the minimum variable frequency speed reduction threshold, the last vacuum pump in the first preset order is preferentially speed-reduced (specifically through PID control). This can be understood, but is not limited to, preferentially reducing the pumping speed sources superimposed in the later stages of pressure build-up, causing the total pumping speed to gradually decrease from a higher value. For example, with three vacuum pumps operating, the total pumping speed can be gradually reduced from 3S0 to 2S0, and then further reduced to S0, corresponding to the actual needs of different pressure ranges.

[0053] Furthermore, after a vacuum pump slows down, if the vacuum-side pressure is still lower than the corresponding next frequency conversion speed reduction threshold, the frequency conversion speed reduction continues according to the second preset sequence for the vacuum pump that was previously put into operation in the first preset sequence. The second preset sequence is the reverse of the first preset sequence, and can be understood, but is not limited to, as reducing the pumping speed step by step in reverse order of the order of operation, so that the total pumping speed changes continuously rather than decreasing sharply all at once. This processing method ensures that the speed reduction action of each vacuum pump corresponds to the current pressure state. When a vacuum pump runs to its lowest frequency, if the pressure has not yet risen back to the target unloading pressure, it indicates that the current pumping speed is still too high, and it is necessary to continue to reduce the next part of the pumping speed source until all vacuum pumps run to their lowest frequency or the pressure rises back to the target unloading pressure.

[0054] It is important to understand that the vacuum pump put into operation last during the pressure build-up phase typically undertakes the sprint pumping task in the low-pressure range, and its pumping speed contributes the most to the total pumping speed. However, in the steady-state phase, this pumping speed is often redundant. This embodiment prioritizes frequency conversion speed reduction of this vacuum pump, reducing redundant pumping speed within the shortest path and shortening the duration of high pumping speed. If the adjustment order is reversed, and the vacuum pump put into operation first in the first preset order is slowed down, the remaining high pumping speed portion will still be retained, causing a lag in the overall pumping speed reduction and a lack of synchronization between the pressure recovery process and the pumping speed adjustment. By adopting a reverse stepwise approach, the pumping speed reduction process is kept consistent with the pressure change process, which can, but is not limited to, stabilize the pressure within a small range near the target unloading pressure. This solves the technical problems of delayed pumping speed reduction and long duration of redundant pumping speed in the unloading phase in the prior art, achieving the technical effect of quickly removing redundant pumping speed and smoothly adjusting pressure in the steady-state phase.

[0055] In one exemplary embodiment, the triggering method for frequency conversion speed reduction of each vacuum pump during the reverse step unloading phase includes: The frequency converter corresponding to the vacuum pump currently undergoing frequency conversion speed reduction sends a trigger signal to the frequency converter corresponding to the previous vacuum pump in the first preset sequence after detecting that the vacuum pump is running at its lowest frequency. The frequency converter corresponding to the previous vacuum pump is triggered to reduce the speed of the previous vacuum pump according to the trigger signal.

[0056] In this embodiment, during the reverse stepped unloading phase, the frequency conversion speed reduction between vacuum pumps is not centrally issued by a unified control unit, but rather achieved through trigger signals transmitted step-by-step between frequency converters. Specifically, when the vacuum pump currently undergoing frequency conversion speed reduction reaches its lowest frequency, its corresponding frequency converter detects this state and sends a trigger signal to the frequency converter corresponding to the previous vacuum pump in the first preset sequence. This trigger signal can be, but is not limited to, relay contact signals, digital input / output, or communication signals, and is used to indicate that the pumping speed in the current stage cannot be further reduced, and the next stage of pumping speed reduction process needs to be initiated. Upon receiving the trigger signal, the frequency converter corresponding to the previously activated vacuum pump begins to perform frequency conversion speed reduction operation on the corresponding vacuum pump, causing the pumping speed reduction process to proceed step-by-step in a predetermined sequence.

[0057] By employing this step-by-step triggering method, the deceleration of each vacuum pump is predicated on the previous pump already reaching its lowest frequency. This creates a sequential, interconnected structure for the entire reverse step unloading process, rather than multiple control actions occurring simultaneously. This avoids sudden changes in the overall pumping speed caused by multiple vacuum pumps decelerating at the same time, while ensuring that each pumping speed change corresponds to the actual requirements of the current pressure state. It can be understood, but is not limited to, as breaking down the overall pumping speed adjustment process into multiple sequentially triggered sub-processes, creating clear connections between each stage, reducing control conflicts, and making the adjustment process more controllable.

[0058] In one exemplary embodiment, if the vacuum side pressure is still less than the target unloading pressure after any vacuum pump frequency is reduced to the lowest frequency, the vacuum pump with the lowest frequency will be unloaded, and the frequency reduction of the next vacuum pump will continue.

[0059] In this embodiment, when any vacuum pump has been frequency-reduced to its lowest frequency, it indicates that the vacuum pump can no longer reduce its pumping speed output by decreasing its rotational speed under the current operating conditions. At this point, its contribution to the total pumping speed is minimal, but it still has a certain pumping capacity. If the vacuum side pressure is still less than the target unloading pressure in this state, it indicates that the current total pumping speed is still greater than the actual system requirement, and frequency adjustment alone is insufficient to achieve further matching. Therefore, in this embodiment, the vacuum pump is directly unloaded, causing it to stop operating. This is equivalent to removing a portion of the fixed pumping capacity from the total pumping speed, thereby resulting in a controllable step decrease in the total pumping speed.

[0060] After unloading the current vacuum pump, the next vacuum pump is subjected to frequency conversion speed reduction in a predetermined sequence, creating a seamless connection between unloading and frequency conversion adjustment. This can be understood, but is not limited to, as follows: when the adjustment range of a single vacuum pump is exhausted, the unloading action releases a larger adjustment range for the pumping speed, allowing the next vacuum pump to handle the finer adjustments. This ensures that the overall pumping speed change has sufficient amplitude while maintaining continuity. This approach allows the total pumping speed to gradually approach the actual pumping requirements of the system, while avoiding situations where a single adjustment method limits the pumping speed to an excessively high level or the pressure to continuously deviate from the target range.

[0061] In one exemplary embodiment, it further includes: If the vacuum side pressure is still lower than the target unloading pressure after all vacuum pumps have been unloaded, a fault alarm will be issued indicating that the minimum frequency setting is unreasonable.

[0062] In this embodiment, if the vacuum side pressure remains lower than the target unloading pressure after all vacuum pumps have been unloaded, it indicates that the reduction in the total pumping speed during the step-by-step speed reduction and unloading process has failed to raise the pressure back to the target range. In this case, it can be determined that the currently set minimum frequency is unreasonable. Specifically, during the reverse step-by-step unloading process, the minimum frequency corresponds to the minimum effective pumping speed of a single vacuum pump under variable frequency operation. If this pumping speed is still higher than the actual requirements of the system under the current operating conditions, even if all vacuum pumps are sequentially reduced in speed and eventually unloaded, the pressure may still remain below the target unloading pressure for an extended period. This embodiment identifies and alerts to such anomalies by setting this fault alarm logic. This can be used, but is not limited to, to alert users to situations such as an excessively high minimum frequency setting, a low system leak rate, or improper parameter matching, thereby guiding adjustments to relevant parameters and preventing the system from operating in an incompatible state for an extended period.

[0063] It's important to understand that during the above stepped unloading process, the target unloading pressure is the vacuum side pressure, which needs to be slightly lower than the critical pressure to ensure a stable pressure differential after the valve opens, preventing fluctuations that could cause valve shaking or closure. This also allows for adjustment space to be reserved for variable frequency unloading. The optimal engineering coefficient is 0.9, so the target unloading pressure can be... When the vacuum-side pressure drops to the target unloading pressure, the pressure difference... Slightly higher than the valve's critical pressure differential With the valve in a fully open and stable state, initiating the unloading procedure ensures that even a slight pressure rebound due to frequency conversion speed reduction will not fall below the critical pressure differential, posing no risk of valve closure. The lower limit of the frequency conversion is the minimum frequency (i.e., the pump's minimum effective operating frequency), which must meet the following requirements: when the frequency is adjusted to this minimum frequency, the pump's actual pumping speed must be sufficient to offset the system's steady-state leakage rate, maintaining the vacuum side pressure near the unloading pressure, ensuring a stable pressure differential, and preventing a rapid pressure rebound due to insufficient pumping speed. Simultaneously, the frequency must not be lower than 10Hz to avoid pump rotor jamming and motor overheating. To prevent pressure rebound, the leakage rate needs to be offset; therefore, the minimum pumping speed to offset the leakage rate can be... The lower limit of the frequency conversion can be: A lower frequency limit does not necessarily mean higher energy efficiency. Vacuum pumps operate in a high-efficiency range. Below 10Hz, the pump's volumetric efficiency drops sharply, and the energy consumption per unit pumping speed actually increases. It may seem that the frequency is lower, but the actual energy consumption is higher. When the frequency limit of a rotary vane pump is set to 10Hz or the frequency limit of a Roots pump is set to 15Hz, the frequency limit is exactly the inflection point of the pump's volumetric efficiency. This minimizes the operating frequency, ensures that the pump operates in the high-efficiency range, minimizes the energy consumption per unit pumping speed, and ensures that the effective pumping speed can cover the system leakage rate, avoiding repeated pressure build-up energy consumption caused by pressure rebound, thus forming a complete energy-saving closed loop.

[0064] In one exemplary embodiment, it further includes: When a shutdown command is received, the vacuum pumps are stopped one by one in the second preset sequence; the first preset sequence is the reverse of the second preset sequence. The process involves first stopping the last vacuum pump to be put into operation, and then stopping the previous vacuum pump after the vacuum side pressure rises back to the pump stop threshold, until all vacuum pumps are stopped, and then closing the air inlet valve of the vacuum pump.

[0065] This embodiment describes the orderly shutdown of multiple vacuum pumps when the system has completed its process and needs to be decommissioned. Instead of simply cutting power to all pumps simultaneously, this embodiment treats the shutdown process as a controlled reverse pumping process. It utilizes the natural recovery of vacuum side pressure to match the shutdown rhythm of each pump. Specifically, upon receiving a shutdown command, the system stops the pumps one by one according to a second preset order, which is the reverse of the first preset order during loading. Essentially, it involves reversing the pumping speed establishment path. This can be understood, but is not limited to, that the pump that last participated in establishing the pressure difference is prioritized for shutdown, thus avoiding disturbances to the pressure field caused by sudden changes in pumping speed.

[0066] In this embodiment, the last vacuum pump put into operation is stopped first. At this time, the total pumping speed of the system will decrease slightly, and the vacuum side pressure will begin to slowly recover. When the pressure recovers to the preset pump stop threshold, the previous vacuum pump is then stopped. The pump stop threshold can be set according to process requirements, for example, slightly lower than the pressure point corresponding to the critical differential pressure for valve closure, so that each pump stop occurs in a relatively gradual pressure change range, rather than in a range of sudden pressure changes. Through this step-by-step pump stop method, the withdrawal of each pump is embedded in the process of natural pressure change, avoiding rapid pressure rebound caused by a sudden drop in pumping speed, thereby avoiding valve vibration or instantaneous closure. Throughout the process, the vacuum side pressure shows a continuous and slow upward trend, rather than a step-like fluctuation.

[0067] Furthermore, after all vacuum pumps have stopped, this embodiment isolates the system by closing the vacuum pump inlet valves, keeping the vacuum side closed to maintain the current pressure level and prevent outside air from continuously entering and affecting the equipment. Under certain conditions, but not limited to, dry gas can be slowly introduced by opening the vent valve to gradually restore the vacuum side pressure to the atmospheric pressure side level, bringing the pressure difference to zero. This process is not instantaneous but rather involves gradually balancing the pressure through controlled flow, allowing the valves to return to a stable closed state without impact. With this treatment, the entire system's transition from operating to stationary state is continuous and controllable, without pressure or mechanical shocks, providing stable initial conditions for the next startup.

[0068] In one exemplary embodiment, it further includes: The order in which the vacuum pumps are put into operation is rotated periodically in the first preset sequence, so that different vacuum pumps take turns being the first vacuum pump to be put into operation.

[0069] This embodiment controls the periodic adjustment of the first preset sequence under the premise that multiple vacuum pumps repeatedly participate in stepped loading operation over a long period. The starting point of this embodiment is that the workload of different vacuum pumps during stepped loading is not uniform. Vacuum pumps at the front of the first preset sequence are often put into operation earlier, run for longer periods, and undertake the main pumping task in the high-pressure section, while vacuum pumps at the rear participate more in the low-pressure sprint phase, resulting in significantly different running times and load distributions. Maintaining a fixed sequence for a long time would cause some vacuum pumps to operate under continuous high load, leading to decreased volumetric efficiency and excessive temperature rise, while other vacuum pumps would have low utilization rates. This embodiment, by periodically rotating the first preset sequence, allows different vacuum pumps to alternate as the first to be put into operation, ensuring that each vacuum pump undertakes a relatively balanced pumping task over multiple operating cycles.

[0070] In this embodiment, the rotation of the first preset sequence can be triggered by, but is not limited to, time periods, cumulative running time, or number of starts. For example, the sequence can be switched after running for several hours, completing several batches of processes, or accumulating a set number of starts. Taking three vacuum pumps as an example, three rotation methods can be formed: Mode 1, Mode 2, and Mode 3. In each mode, the order of the first pump being put into operation and the subsequent pumps being put into operation changes, but the overall logic of stepped loading remains unchanged, that is, it still operates in the manner of putting into operation one pump at a time and gradually increasing the pumping speed. Through this rotation, each vacuum pump undertakes the pumping tasks of the high-pressure section, medium-pressure section, and low-pressure section in different cycles, so that the load is evenly distributed in the time dimension, rather than concentrated on a certain piece of equipment.

[0071] It is important to understand that this embodiment does not change the relationship between pumping speed and pressure matching during a single operation, nor does it change the triggering conditions for stepped loading; it only rearranges the order of participation, thus having no impact on control stability. It can be understood, but is not limited to, that the gradual establishment of pumping speed still holds true within each operating cycle, and that after multiple cycles are superimposed, the cumulative operating time, load curve, and energy consumption distribution of each vacuum pump tend to be consistent. This approach avoids performance degradation of a single vacuum pump due to long-term high-load operation, thereby enabling the entire system to maintain relatively stable pumping speed characteristics and energy consumption levels over a longer period, while reducing control deviations caused by uneven equipment performance.

[0072] like Figure 5 Secondly, this application provides an electronic device, comprising: Memory 11 is used to store computer programs; The processor 12 is used to implement the steps of the vacuum pump control method described above when executing a computer program.

[0073] For a description of the electronic equipment, please refer to the embodiments of the vacuum pump control method described above; this application will not repeat them here.

[0074] Thirdly, this application also provides a frequency converter, including a frequency converter body and the electronic equipment described above; the frequency converter body is connected to the control device of the vacuum pump. For a description of the frequency converter, please refer to the embodiments of the vacuum pump control method described above; this application will not repeat them here.

[0075] Fourthly, this application also provides a vacuum pump, including a vacuum pump body and a frequency converter as described above; the vacuum pump body is connected to the frequency converter. For a description of the vacuum pump, please refer to the embodiments of the vacuum pump control method described above; this application will not repeat them here.

[0076] In summary, the control method provided by this invention determines multiple start-up pressure thresholds, target unloading pressures, and frequency conversion lower limits based on vacuum pump parameters and on-site operating parameters. Upon receiving a start-up command, it controls multiple vacuum pumps to enter the stepped loading stage in a preset sequence. As the vacuum side pressure gradually changes, each vacuum pump is put into operation in turn, so that the total pumping speed of the system gradually increases and matches the pressure drop requirement, thereby stabilizing the pressure difference and reaching the valve opening condition. After reaching the target unloading pressure, it controls multiple vacuum pumps to enter the reverse stepped frequency conversion unloading stage, and performs frequency conversion speed reduction on each vacuum pump in the reverse order of the loading stage. After running to the frequency conversion lower limit, it gradually transitions to the next vacuum pump for adjustment, so that the total pumping speed of the system gradually decreases and matches the actual pumping demand.

[0077] Through the above control methods, this invention avoids sudden changes in pumping speed and current surges caused by the simultaneous start-up of multiple vacuum pumps during the loading phase, making the pressure differential establishment process smoother and more controllable. During the unloading phase, continuous frequency conversion regulation replaces traditional start-stop control, allowing the vacuum side pressure to change smoothly near the target unloading pressure, reducing pressure fluctuations and repeated pressure building processes. Overall, it achieves dynamic matching between pumping speed supply, pressure drop demand, and steady-state leakage rate, ensuring stable valve opening while reducing pumping speed redundancy during the pressure building phase and excessive pumping speed energy consumption during the pressure stabilization phase.

[0078] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0079] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling a vacuum pump, characterized in that, Applied to a system including multiple vacuum pumps, the method includes: The operating stages of the multi-stage vacuum pump are determined based on the relationship between the vacuum side pressure and the target pressure; the target pressure includes the target loading pressure or the target unloading pressure. When the vacuum side pressure is greater than the target loading pressure, each vacuum pump is controlled to enter the stepped loading stage. The stepped loading stage is to put the vacuum pumps into operation one by one in a first preset order, so that the total pumping speed of the vacuum pumps is gradually increased. When the vacuum side pressure is less than the target unloading pressure, each vacuum pump is controlled to enter the reverse step unloading stage. The reverse step unloading stage is to reduce the speed of each vacuum pump by frequency conversion or to stop operation in a second preset order, so that the total pumping speed of the vacuum pump is reduced step by step.

2. The vacuum pump control method as described in claim 1, characterized in that, The stepped loading stage specifically includes: According to multiple starting pressure thresholds that correspond one-to-one with each of the vacuum pumps and decrease in value, each vacuum pump is put into operation in the first preset order, and each vacuum pump operates at full frequency after being put into operation. Specifically, when the vacuum side pressure is greater than the maximum start-up pressure threshold, the first vacuum pump in the first preset sequence is activated. Whenever the vacuum side pressure drops below the corresponding next start-up pressure threshold, the next vacuum pump in the first preset sequence is activated, until all the vacuum pumps are activated or the vacuum side pressure drops to the target loading pressure.

3. The vacuum pump control method as described in claim 2, characterized in that, Also includes: Obtain the real-time leak rate of the system and automatically adjust the startup pressure threshold based on the real-time leak rate; When the real-time leakage rate increases, the starting pressure threshold is increased to allow the next vacuum pump to be put into operation earlier; when the real-time leakage rate decreases, the starting pressure threshold is decreased to delay the operation of the next vacuum pump.

4. The vacuum pump control method as described in claim 1, characterized in that, The reverse ladder unloading phase specifically includes: According to multiple frequency reduction thresholds that correspond one-to-one with each of the vacuum pumps and whose values ​​increase sequentially, the frequency reduction of each of the vacuum pumps is performed in sequence according to the second preset order. Specifically, when the vacuum side pressure is less than the minimum frequency conversion speed reduction threshold, the last vacuum pump put into operation in the first preset sequence is subjected to frequency conversion speed reduction. Whenever the vacuum side pressure is still less than the corresponding next frequency conversion speed reduction threshold, the previous vacuum pump put into operation in the first preset sequence is subjected to frequency conversion speed reduction, until all vacuum pumps are running at their respective lowest frequencies or the vacuum side pressure rises back to the target unloading pressure. The first preset sequence is the opposite of the second preset sequence.

5. The vacuum pump control method as described in claim 4, characterized in that, During the reverse stepped unloading phase, the triggering methods for frequency conversion speed reduction of each vacuum pump include: When the frequency converter corresponding to the vacuum pump currently undergoing frequency conversion speed reduction detects that the vacuum pump is running at its lowest frequency, it sends a trigger signal to the frequency converter corresponding to the previous vacuum pump in the first preset sequence, triggering the frequency converter corresponding to the previous vacuum pump to perform frequency conversion speed reduction on the previous vacuum pump according to the trigger signal.

6. The vacuum pump control method as described in claim 5, characterized in that, If the vacuum side pressure is still less than the target unloading pressure after any of the vacuum pumps is frequency-reduced to the lowest frequency, the vacuum pump that was frequency-reduced to the lowest frequency will be unloaded, and the frequency reduction of the next vacuum pump will continue.

7. The vacuum pump control method as described in claim 6, characterized in that, Also includes: If the vacuum side pressure is still less than the target unloading pressure after all vacuum pumps have been unloaded, a fault alarm indicating that the minimum frequency setting is unreasonable will be issued.

8. The method for controlling a vacuum pump as described in any one of claims 1-7, characterized in that, Also includes: When a shutdown command is received, the vacuum pumps are stopped one by one in a second preset order; the first preset order is the reverse of the second preset order. The process involves first stopping the last vacuum pump to be put into operation, and then stopping the previous vacuum pump after the vacuum side pressure rises back to the pump stop threshold, until all vacuum pumps are stopped, and then closing the air inlet valve of the vacuum pump.

9. The method for controlling a vacuum pump as described in any one of claims 1-7, characterized in that, Also includes: The order in which the vacuum pumps are put into operation is rotated periodically, so that different vacuum pumps take turns being the first vacuum pump to be put into operation.

10. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to, when executing a computer program, implement the steps of the control method for a vacuum pump as described in any one of claims 1-9.

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