A control method for a scroll dry pump

Abstract

The application discloses a control method of a scroll dry pump, which comprises the following steps: inputting a target vacuum value; acquiring a real-time vacuum value; calculating a vacuum difference value of the real-time vacuum value and the target vacuum value; if the vacuum difference value is greater than a preset difference value, controlling the scroll dry pump to execute first PID closed-loop adjustment to quickly reduce the difference between the real-time vacuum value and the target vacuum value; if the vacuum difference value is less than or equal to the preset difference value, controlling the scroll dry pump to execute second PID closed-loop adjustment to avoid causing large pressure fluctuation; wherein the P value of the first PID closed-loop adjustment is less than the P value of the second PID closed-loop adjustment. When the vacuum difference value is greater than the preset difference value, the running frequency of the scroll dry pump can be quickly adjusted to quickly reduce the difference between the real-time vacuum value and the target vacuum value; when the vacuum difference value is less than or equal to the preset difference value, the frequency is first quickly reduced, and then the speed is adjusted in a relatively slow mode, so that the problem of large pressure fluctuation range and instability can be avoided.

Description

Technical Field

[0001] This invention belongs to the field of vortex dry pump technology, and more specifically, relates to a control method for vortex dry pumps. Background Technology

[0002] Vortex vacuum pumps are a new generation of oil-free mechanical pumps, characterized by their simple structure, excellent sealing performance, and high ultimate vacuum. As a high-tech product, vortex dry vacuum pumps possess highly sophisticated design and manufacturing processes. They offer significant advantages in applications, including low operating costs, long service life, high reliability, and low noise, making them unparalleled in oil-free cleaning applications and thus highly favored by the market. For industries with highly complex processes, such as new energy, vortex vacuum pumps are required to operate at varying vacuum levels, placing extremely high demands on the pump's frequency adjustment flexibility.

[0003] However, traditional scroll dry pumps either operate at a fixed frequency or use a single P-value PID controller throughout the entire process. If the scroll dry pump operates at a fixed frequency, manual frequency adjustment is necessary to achieve different vacuum levels, which is time-consuming and inefficient. If the scroll dry pump uses a single P-value PID controller throughout the process, a small P-value results in slow speed adjustment without significant pressure fluctuations, but the system's sluggish response can cause the process cycle time to fail to meet requirements, affecting the process progress and slowing down efficiency. A large P-value allows for sensitive speed adjustment and rapid achievement of the target value, but it is prone to large pressure fluctuations, instability, and over-pumping of the chamber, leading to a higher product defect rate. Summary of the Invention

[0004] To address the problems of low production efficiency, large pressure fluctuations, and over-pumping of the cavity in related technologies where vortex dry pumps use a single P-value PID control throughout the entire process, the present invention aims to provide a control method for a vortex dry pump, comprising: inputting a target vacuum value; acquiring a real-time vacuum value; calculating the vacuum difference between the real-time vacuum value and the target vacuum value; if the vacuum difference is greater than a preset difference, controlling the vortex dry pump to perform a first PID closed-loop control to quickly reduce the gap between the real-time vacuum value and the target vacuum value; if the vacuum difference is less than or equal to the preset difference, controlling the vortex dry pump to perform a second PID closed-loop control to avoid large pressure fluctuations; wherein, the P-value of the first PID closed-loop control is less than the P-value of the second PID closed-loop control.

[0005] The technical effects achieved by this solution are as follows: By calculating the vacuum difference between the real-time vacuum value and the target vacuum value, the system can divide the vacuum difference into two ranges based on its relationship with a preset difference: a vacuum difference greater than the preset difference and a vacuum difference less than or equal to the preset difference. This allows for phased control of the scroll pump using different PID speed regulation modes within each range. Compared to traditional PID regulation using a single P value throughout the entire process, the control method provided in this application can quickly adjust the operating frequency of the scroll pump when the vacuum difference is greater than the preset difference, thereby rapidly reducing the gap between the real-time and target vacuum values. When the vacuum difference is less than or equal to the preset difference, a slower speed regulation mode is used to avoid large and unstable pressure fluctuations.

[0006] Furthermore, if the vacuum difference is less than or equal to the preset difference, the vortex dry pump is controlled to perform a second PID closed-loop regulation until the real-time vacuum value equals the target vacuum value.

[0007] The technical effect achieved by adopting this technical solution is as follows: If the vacuum difference is less than or equal to the preset difference, it means that the difference between the real-time vacuum value and the target vacuum value is relatively small. If the speed is adjusted quickly at this time, it is easy to cause large pressure fluctuations, instability, and over-pumping of the cavity, resulting in a large product defect rate. Therefore, a second PID closed-loop regulation with a slower speed adjustment is adopted at this time.

[0008] Furthermore, if the vacuum difference is greater than the preset difference, the scroll dry pump is first controlled to perform the first PID closed-loop regulation to reduce the vacuum difference to less than or equal to the preset difference, and then the scroll dry pump is controlled to perform the second PID closed-loop regulation.

[0009] The technical effects achieved by this solution are as follows: If the vacuum difference is greater than the preset difference, it indicates a significant gap between the real-time vacuum value and the target vacuum value. Slow speed adjustment would prevent the process cycle from meeting requirements, affecting the process progress and slowing down efficiency. Therefore, a first PID closed-loop control is used to quickly reduce the vacuum difference to less than or equal to the preset difference. Then, the scroll pump is controlled to execute a second PID closed-loop control for precise speed adjustment. This allows for rapid achievement of the target value while avoiding large pressure fluctuations and reducing product defect rates.

[0010] Furthermore, controlling the vortex dry pump to perform the first PID closed-loop regulation includes: increasing the operating frequency of the vortex dry pump according to the first PID closed-loop regulation.

[0011] Furthermore, after controlling the vortex dry pump to perform the first PID closed-loop regulation and reducing the vacuum difference to less than or equal to the preset difference, the operating frequency of the vortex dry pump is first reduced, and then the vortex dry pump is controlled to perform the second PID closed-loop regulation.

[0012] It should be noted that when controlling the scroll pump to perform the first PID closed-loop regulation, the operating frequency of the scroll pump is relatively high in order to achieve rapid speed regulation. If the frequency of the scroll pump is not reduced first, and the scroll pump is directly controlled to perform the second PID closed-loop regulation, it will cause the cavity to be over-pumped. Therefore, it is necessary to reduce the operating frequency of the scroll pump first, and then control the scroll pump to perform the second PID closed-loop regulation to avoid the problem of the cavity being over-pumped due to the scroll pump not being able to reduce its speed in time.

[0013] Furthermore, before acquiring the real-time vacuum value, the process includes: determining whether the target vacuum value is within a preset range; if the target vacuum value is within the preset range, acquiring the real-time vacuum value; if the target vacuum value is not within the preset range, prompting the user to re-enter the target vacuum value. This avoids prolonged extreme operation of the vortex dry pump due to unreasonable target vacuum value input, which could lead to the control system entering a dead loop, logical confusion, or reporting unpredictable faults. It prevents unnecessary hardware wear caused by unreasonable target vacuum value input from the source, extending equipment lifespan.

[0014] The technical effects and advantages of this invention are as follows: 1. By calculating the vacuum difference between the real-time vacuum value and the target vacuum value, the system can divide the vacuum difference into two ranges based on its relationship with a preset difference: a vacuum difference greater than the preset difference and a vacuum difference less than or equal to the preset difference. This allows for phased control of the scroll pump using different PID speed regulation modes within each range. Compared to traditional PID regulation using a single P value throughout the entire process, the control method provided in this application can quickly adjust the operating frequency of the scroll pump when the vacuum difference is greater than the preset difference, thereby rapidly narrowing the gap between the real-time and target vacuum values. When the vacuum difference is less than or equal to the preset difference, a slower speed regulation mode is used to avoid large and unstable pressure fluctuations.

[0015] 2. If the vacuum difference is less than or equal to the preset difference, it means that the difference between the real-time vacuum value and the target vacuum value is relatively small. If the speed is adjusted quickly at this time, it is easy to cause large pressure fluctuations, instability, and over-pumping of the cavity, resulting in a large product defect rate. Therefore, a second PID closed-loop regulation with a slower speed adjustment is adopted at this time.

[0016] 3. If the vacuum difference is greater than the preset difference, it indicates a significant gap between the real-time vacuum value and the target vacuum value. Slow speed adjustment in this case would prevent the process cycle from meeting requirements, impacting the process and slowing down efficiency. Therefore, in this situation, the first PID closed-loop control is used to quickly reduce the vacuum difference to less than or equal to the preset difference. Then, the scroll pump is controlled to execute the second PID closed-loop control for precise speed adjustment. This allows for rapid achievement of the target value while avoiding large pressure fluctuations and reducing product defect rates. Attached Figure Description

[0017] Figure 1 A flowchart illustrating a control method for a vortex pump provided by the present invention; Figure 2 A schematic diagram illustrating the process of allowing users to input target vacuum values; Figure 3 This table presents test data for the practical application of full-range PID voltage regulation. Figure 4 A table of test data for the practical application of the vortex pump control method provided by the present invention; Figure 5 This is a time comparison table before and after the solution was improved. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0019] Combination Figure 1 and Figure 2 This application provides a control method for a vortex pump, which includes the following steps: The process involves inputting a target vacuum value; acquiring a real-time vacuum value; calculating the vacuum difference between the real-time and target vacuum values; if the vacuum difference is greater than a preset difference, controlling the scroll pump to execute the first PID closed-loop regulation to quickly reduce the gap between the real-time and target vacuum values; if the vacuum difference is less than or equal to the preset difference, controlling the scroll pump to execute the second PID closed-loop regulation to avoid significant pressure fluctuations; wherein, the P value of the first PID closed-loop regulation is less than the P value of the second PID closed-loop regulation. For example, after the scroll pump is turned on, it draws air from the detection tank. The detection tank uses a vacuum diaphragm gauge to detect the pressure inside and returns the analog signal in real-time to the integrated drive unit inside the scroll pump for PID regulation. The pressure-stabilizing vacuum diaphragm gauge offers 1000 torr and 100 torr ranges, which users can switch between according to their needs, providing customized and precise pressure stabilization functions for different customer groups, with higher accuracy and a wider range. The Inforcom vacuum standard gauge is used for calibration with voltage regulator vacuum gauges. It performs 20 point selection and comparison calibrations throughout the entire range. By adjusting the gain parameters of the integrated machine, the accuracy of the voltage regulator vacuum level is made extremely high.

[0020] In one specific embodiment, the real-time vacuum value is calculated as follows: P = (P 满量程 *V out ) / 10. Where P is the real-time vacuum value; P 满量程 This is the full scale of the vacuum thin-film gauge, corresponding to 1000 torr and 100 torr mentioned above; V out The pressure value is obtained from a vacuum diaphragm gauge.

[0021] Understandably, by calculating the vacuum difference between the real-time vacuum value and the target vacuum value, the system can divide the vacuum difference into two ranges: one where the vacuum difference is greater than the preset difference, and the other where the vacuum difference is less than or equal to the preset difference. This allows for phased control of the scroll pump using different PID speed regulation modes based on these different ranges. Compared to the traditional method of using a single P-value for PID regulation throughout the entire process, the control method provided in this application can quickly adjust the operating frequency of the scroll pump when the vacuum difference is greater than the preset difference using a first PID closed-loop regulation with a large P-value to rapidly reduce the gap between the real-time and target vacuum values. When the vacuum difference is less than or equal to the preset difference, a slower speed regulation mode is used through a first PID closed-loop regulation with a small P-value to avoid large and unstable pressure fluctuations.

[0022] Specifically, if the vacuum difference is greater than the preset difference, the scroll dry pump is first controlled to perform the first PID closed-loop regulation to reduce the vacuum difference to less than or equal to the preset difference, and then the scroll dry pump is controlled to perform the second PID closed-loop regulation. If the vacuum difference is less than or equal to the preset difference, the scroll dry pump is controlled to perform the second PID closed-loop regulation until the real-time vacuum value equals the target vacuum value.

[0023] It is understandable that if the vacuum difference is less than or equal to the preset difference, it means that the difference between the real-time vacuum value and the target vacuum value is relatively small. If the speed is adjusted quickly at this time, it is easy to cause problems such as large pressure fluctuation range, instability, and over-pumping of the cavity, resulting in a large product defect rate. Therefore, a second PID closed-loop regulation with a slower speed adjustment is adopted at this time.

[0024] If the vacuum difference is greater than the preset difference, it indicates a significant gap between the real-time vacuum value and the target vacuum value. Slow speed adjustments would prevent the process cycle from meeting requirements, impacting the process and slowing down efficiency. Therefore, in this case, a first PID closed-loop control is used to quickly reduce the vacuum difference to less than or equal to the preset difference. Then, the scroll pump is controlled to execute a second PID closed-loop control for precise speed adjustment. This allows for rapid achievement of the target value while avoiding large pressure fluctuations and reducing product defect rates.

[0025] Furthermore, controlling the vortex dry pump to perform the first PID closed-loop regulation includes controlling the vortex dry pump to operate at a first operating frequency.

[0026] Furthermore, after controlling the scroll pump to perform the first PID closed-loop regulation and reducing the vacuum difference to less than or equal to the preset difference, the operating frequency of the scroll pump is first reduced, and then the scroll pump is controlled to perform the second PID closed-loop regulation. It should be noted that when controlling the scroll pump to perform the first PID closed-loop regulation, the operating frequency of the scroll pump is relatively high to achieve rapid speed adjustment. If the frequency of the scroll pump is not reduced first, and the second PID closed-loop regulation is performed directly, it will lead to over-pumping of the cavity. Therefore, it is necessary to first reduce the operating frequency of the scroll pump that increases during the first PID closed-loop regulation before controlling the scroll pump to perform the second PID closed-loop regulation to avoid the problem of over-pumping of the cavity due to the scroll pump not being able to reduce its speed in time.

[0027] In one specific embodiment, if the calculated vacuum difference is greater than a preset vacuum difference, the first PID closed-loop regulation is executed, which means controlling the pump to run at full speed to quickly reduce the difference from the target value until the vacuum difference is less than the preset vacuum difference. To avoid over-pumping of the cavity due to the scroll dry pump not slowing down in time, the pump frequency is reduced by 50% before the second PID closed-loop regulation is executed to make the pressure reach the target value and stabilize the pump speed.

[0028] Understandably, if the calculated vacuum difference is less than or equal to the preset vacuum difference, the second PID closed-loop regulation can be executed directly without reducing the speed of the vortex dry pump.

[0029] Preferably, before acquiring the real-time vacuum value, the method further includes: determining whether the target vacuum value is within a preset range; if the target vacuum value is within the preset range, acquiring the real-time vacuum value; if the target vacuum value is not within the preset range, prompting the user to re-enter the target vacuum value. In a specific embodiment, if the target vacuum value set by the user is negative or exceeds the range, indicating an unreasonable setting, the system will prompt the user to re-enter the target vacuum value. This avoids the control system from entering an infinite loop, experiencing logical confusion, or reporting unpredictable faults due to incorrect target vacuum value input, thus preventing unnecessary hardware damage caused by incorrect target vacuum value input and extending equipment lifespan.

[0030] Combination Figures 3 to 5Before using the vortex pump control method provided by this invention, under a fixed intake volume, full-range PID pressure regulation resulted in significant fluctuations in the pressure difference and frequency within each pressure regulation range. The pressure difference range varied to 50 Pa, 30 Pa, and 20 Pa, and the frequency fluctuation ranged to 4 Hz, 3 Hz, and 2 Hz; furthermore, the time taken was relatively long. After using the vortex pump control method provided by this invention, through two-stage PID closed-loop regulation, under the same intake volume, the fluctuation difference within each pressure regulation range can be kept constant at around 10 Pa, and the frequency is also very stable with almost no fluctuation, significantly reducing the time taken.

[0031] according to Figure 5 It can be seen that after using the control method of the vortex pump provided by the present invention, the cycle time is significantly reduced and the ratio is significant. While meeting the customer's pressure stabilization needs, it can also improve production efficiency and quickly reach the target value so that the product can react and be produced in advance within the specified pressure range.

[0032] In the description of this invention, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0033] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A control method for a vortex dry pump, characterized in that, The control methods for vortex dry pumps include: Input the target vacuum value; Obtain real-time vacuum value; Calculate the vacuum difference between the real-time vacuum value and the target vacuum value; If the vacuum difference is greater than the preset difference, the vortex dry pump is controlled to perform the first PID closed-loop regulation to quickly reduce the gap between the real-time vacuum value and the target vacuum value. If the vacuum difference is less than or equal to the preset difference, the vortex dry pump is controlled to perform the second PID closed-loop regulation to avoid large pressure fluctuations. Among them, the P value of the first PID closed-loop regulation is less than the P value of the second PID closed-loop regulation.

2. The control method for the vortex dry pump according to claim 1, characterized in that, If the vacuum difference is less than or equal to the preset difference, the vortex dry pump is controlled to perform the second PID closed-loop regulation until the real-time vacuum value equals the target vacuum value.

3. The control method for the vortex dry pump according to claim 1, characterized in that, If the vacuum difference is greater than the preset difference, the first control of the vortex dry pump to perform the first PID closed-loop regulation will reduce the vacuum difference to less than or equal to the preset difference, and then the second control of the vortex dry pump to perform the second PID closed-loop regulation will be performed.

4. The control method for the vortex dry pump according to claim 3, characterized in that, Controlling the vortex dry pump to perform the first PID closed-loop regulation includes: increasing the operating frequency of the vortex dry pump according to the first PID closed-loop regulation.

5. The control method for the vortex dry pump according to claim 4, characterized in that, After controlling the vortex dry pump to perform the first PID closed-loop regulation and reducing the vacuum difference to less than or equal to the preset difference, the operating frequency of the vortex dry pump is first reduced, and then the vortex dry pump is controlled to perform the second PID closed-loop regulation.

6. The control method for the vortex dry pump according to claim 1, characterized in that, Before obtaining the real-time vacuum value, the following is also included: Determine whether the target vacuum value is within the preset range; If the target vacuum value is within the preset range, the real-time vacuum value is obtained; If the target vacuum value is not within the preset range, the user will be prompted to re-enter the target vacuum value.

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