WO2021077859A1

WO2021077859A1 - Magnetic suspension bearing control method and apparatus, storage medium, and magnetic suspension system

Info

Publication number: WO2021077859A1
Application number: PCT/CN2020/108144
Authority: WO
Inventors: 胡余生; 郭伟林; 孙建东; 贺永玲; 胡叨福
Original assignee: 珠海格力电器股份有限公司
Priority date: 2019-10-25
Filing date: 2020-08-10
Publication date: 2021-04-29
Also published as: CN110939654A; CN110939654B

Abstract

A magnetic suspension bearing control method, a magnetic suspension bearing control apparatus, a magnetic suspension system, and a computer readable storage medium. The magnetic suspension bearing control method comprises: determining whether the starting torque required when starting up a compressor in a magnetic suspension system exceeds a specified torque; and if the starting torque required when starting up the compressor exceeds the specified torque, increasing a control parameter of a magnetic suspension bearing in the magnetic suspension system so as to control the control parameter of the magnetic suspension bearing to adapt to the starting torque required for starting up the compressor. The described method can solve the problem in which the reliability of start-up is affected due to starting torque being uncertain, and achieve the effect of improving the reliability of start-up.

Description

Magnetic suspension bearing control method, device, storage medium and magnetic suspension system

Cross-references to related applications

This application is based on the application whose CN application number is CN 201911024767.7 and the application date is October 25, 2019, and its priority is claimed. The disclosure of this CN application is hereby incorporated into this application as a whole.

Technical field

The present disclosure belongs to the field of magnetic suspension technology, and specifically relates to a magnetic suspension bearing control method, device, storage medium and magnetic suspension system, and more particularly to a magnetic suspension bearing control method, device, storage medium and magnetic suspension system.

Background technique

Magnetic levitation technology can use magnetic force to overcome gravity to make objects levitate. The magnetic levitation shaft runs in a non-contact environment and can easily achieve high-speed rotation. Magnetic levitation compressor is a common magnetic levitation rotating machine, which has been applied in many occasions. The magnetic levitation compressor consists of two core components: the motor and the magnetic bearing. The bearing controller adjusts the current of the bearing coil in real time to realize the stable suspension of the motor rotor and keep the rotor and stator without mechanical contact. The system diagram is shown in Figure 5.

The foregoing content is only used to assist in understanding the technical solutions of the present disclosure, and does not mean that the foregoing content is recognized as prior art.

Summary of the invention

The purpose of the present disclosure is to provide a magnetic suspension bearing control method, device, storage medium, and magnetic suspension system in view of the above-mentioned defects, so as to solve the problem that the starting torque is unstable and affect the starting reliability, and to achieve the effect of improving the starting reliability.

The present disclosure provides a magnetic suspension bearing control method, which includes: determining whether the starting torque required when the compressor starts in the magnetic levitation system exceeds the set torque; if the starting torque required when the compressor starts exceeds the set torque, Then increase the control parameters of the magnetic suspension bearing in the magnetic suspension system to control the control parameters of the magnetic suspension bearing to adapt to the starting torque required when the compressor starts.

In some embodiments, determining whether the starting torque required to start the compressor in the magnetic levitation system exceeds the set torque includes: obtaining the starting parameters of the compressor in the magnetic levitation system; determining whether the starting parameters of the compressor are greater than or equal to the set torque. If the starting parameter of the compressor is greater than or equal to the set parameter, it is determined that the starting torque required when the compressor starts exceeds the set torque.

In some embodiments, the startup parameter of the compressor includes the startup current of the compressor; or, the set parameter includes a set voltage and the set voltage is less than the voltage corresponding to the minimum current that can trigger the bearing rotor displacement protection.

In some embodiments, determining whether the starting torque required to start the compressor in the magnetic levitation system exceeds the set torque includes: obtaining the starting current of the compressor in the magnetic levitation system; converting the starting current of the compressor to the starting voltage , To determine whether the starting voltage is greater than or equal to the set voltage; in the case that the starting voltage is greater than or equal to the set voltage, it is determined that the starting torque required to start the compressor in the magnetic levitation system exceeds the set torque.

In some embodiments, the control parameters of the magnetic bearing include: the control stiffness of the bearing controller of the magnetic bearing; increasing the control parameter of the magnetic bearing in the magnetic levitation system includes: The control stiffness of the controller is increased; among them, the set increase mode includes: linear increase, step increase, convex mirror arc increase, concave mirror arc increase Large way or any number of ways to increase.

In some embodiments, the method further includes: determining whether the levitation degree of the magnetic levitation rotor in the magnetic levitation system reaches the set level when the bearing controller and the inverter in the magnetic levitation system receive the start instruction; When the set level is reached, the inverter is controlled to start to run; after the inverter starts to run, it is determined whether the starting torque required for the compressor in the magnetic levitation system to start exceeds the set torque.

In some embodiments, the startup parameter of the compressor includes the startup current of the compressor, and the set parameter includes a set voltage, and the set voltage is less than the voltage corresponding to the minimum current that can trigger the bearing rotor displacement protection.

In accordance with the above method, another aspect of the present disclosure provides a magnetic suspension bearing control device, which includes: a determining unit configured to determine whether the starting torque required for starting the compressor in the magnetic levitation system exceeds a set torque; and a control unit , Is configured to increase the control parameters of the magnetic bearing in the magnetic levitation system if the required starting torque when the compressor starts exceeds the set torque, so as to control the control parameters of the magnetic bearing to adapt to the starting required when the compressor starts Torque.

In some embodiments, the determining unit determining whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque includes: obtaining the starting parameters of the compressor in the magnetic levitation system; determining whether the starting parameters of the compressor are Greater than or equal to the set parameter; if the compressor's starting parameter is greater than or equal to the set parameter, it is determined that the required starting torque when the compressor is started exceeds the set torque.

In some embodiments, the startup parameter of the compressor includes the startup current of the compressor or the set parameter includes a set voltage and the set voltage is less than the voltage corresponding to the minimum current that can trigger the bearing rotor displacement protection.

In some embodiments, the determining whether the starting torque required for the compressor in the magnetic levitation system to start exceeds the set torque includes: obtaining the starting current of the compressor in the magnetic levitation system; converting the starting current of the compressor into a starting voltage Then, it is determined whether the starting voltage is greater than or equal to the set voltage; in the case that the starting voltage is greater than or equal to the set voltage, it is determined that the starting torque required when the compressor in the magnetic levitation system starts exceeds the set torque.

In some embodiments, the control parameters of the magnetic bearing include: the control stiffness of the bearing controller of the magnetic bearing; the control unit increasing the control parameter of the magnetic bearing in the magnetic suspension system includes: The control stiffness of the bearing controller of the magnetic suspension bearing is increased; among them, the set increase methods include: linear increase, step increase, convex mirror arc increase, and concave mirror arc increase. Any increase method or any several increase methods.

In some embodiments, the determining unit is further configured to determine whether the levitation degree of the magnetic levitation rotor in the magnetic levitation system reaches a set level when the bearing controller and the frequency converter in the magnetic levitation system receive a start instruction; The control unit is also configured to control the frequency converter to start operation when the levitation degree of the magnetic levitation rotor reaches a set level; the determining unit is also configured to control the magnetic levitation system after the frequency converter starts to operate. It is determined whether the required starting torque of the middle compressor exceeds the set torque when starting.

Matching with the above-mentioned device, another aspect of the present disclosure provides a magnetic levitation system, which includes the above-mentioned magnetic levitation bearing control device.

In accordance with the above method, another aspect of the present disclosure provides a computer-readable storage medium, including: a plurality of instructions are stored in the computer-readable storage medium; the plurality of instructions are configured to be loaded and loaded by a processor Carry out the above-mentioned magnetic suspension bearing control method.

In accordance with the above method, another aspect of the present disclosure provides a magnetic levitation system, including: a processor configured to execute a plurality of instructions; a memory configured to store a plurality of instructions; wherein the plurality of instructions are configured It is stored by the memory, loaded by the processor and executed the above-mentioned magnetic suspension bearing control method.

The solution of the present disclosure adopts an adaptive control method of magnetic suspension bearing control stiffness, which can adapt to various starting torque conditions, can ensure bearing control accuracy, ensure that the magnetic suspension compressor can be reliably started under various conditions, and improve the starting reliability.

Furthermore, the solution of the present disclosure, by judging the compressor startup current during the compressor startup process, adjusts the bearing controller control stiffness of the magnetic levitation compressor in real time, ensuring bearing operation accuracy without triggering bearing protection, and avoiding the startup failure of the magnetic levitation compressor The problem.

Further, the solution of the present disclosure adjusts the control stiffness of the bearing controller of the magnetic levitation compressor according to the size of the compressor startup current to ensure the bearing operation accuracy without triggering the bearing protection, thereby improving the startup reliability.

Furthermore, the solution of the present disclosure detects the starting current I of the frequency converter in real time, and modulates it into a voltage signal. When the voltage signal is greater than or equal to the reference signal, the bearing control stiffness increases according to a certain rule to realize real-time adjustment of the bearing control stiffness , To ensure the accuracy of bearing operation and not trigger bearing protection.

Furthermore, the solution of the present disclosure determines whether the inverter starting current reaches the set value, and if it reaches the set value, the bearing control stiffness is increased, so that the rotor suspension accuracy is guaranteed, and the bearing protection is not triggered to cause starting failure, which improves the starting reliability.

Therefore, the solution of the present disclosure, by judging the compressor starting current, adjusts the control stiffness of the magnetic levitation compressor bearing controller in real time, guarantees the bearing operation accuracy without triggering bearing protection, and solves the problem that the starting reliability is affected by the unstable starting torque , To achieve the effect of improving the reliability of starting; in particular, it can solve the problem that the starting torque required by the compressor is different due to the unstable load when the compressor starts, which affects the reliability of the compressor, and achieve the effect of improving the reliability of the compressor.

Other features and advantages of the present disclosure will be described in the following specification, and partly become obvious from the specification, or understood by implementing the present disclosure.

The technical solutions of the present disclosure will be further described in detail below through the accompanying drawings and embodiments.

Description of the drawings

FIG. 1 is a schematic flowchart of some embodiments of the magnetic suspension bearing control method of the present disclosure;

2 is a schematic flowchart of some embodiments of the method of the present disclosure for determining whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque;

FIG. 3 is a schematic flowchart of some embodiments of determining the control timing of the magnetic bearing in the method of the present disclosure;

4 is a schematic structural diagram of some embodiments of the magnetic suspension bearing control device of the present disclosure;

Figure 5 is a simplified diagram of the operation control of the magnetic levitation compressor;

Figure 6 is a schematic diagram of the curve of starting failure caused by bearing protection caused by too low control stiffness, in which (a) is the schematic diagram of the motor starting current curve when the control stiffness is too small and the bearing protection causes starting failure, and (b) is the curve diagram of the motor starting failure caused by the too small control stiffness. The schematic diagram of the suspension displacement curve of the rotor caused by the protection to start failure, (c) is the schematic diagram of the control stiffness curve of the starting failure caused by the bearing protection caused by the control stiffness is too small;

FIG. 7 is a schematic structural diagram of some embodiments of the magnetic levitation control system in the magnetic levitation system of the present disclosure;

FIG. 8 is a schematic diagram of the control logic of some embodiments of the magnetic levitation system of the present disclosure;

Figure 9 is a structural schematic diagram of five bearing control stiffness increasing modes of some embodiments of the magnetic levitation system of the present disclosure, in which (a) is the first increasing mode, (b) is the second increasing mode, ( c) is the third increasing mode, (d) is the fourth increasing mode, and (e) is the fifth increasing mode.

With reference to the drawings, the reference signs in the embodiments of the present disclosure are as follows:

102-determining unit; 104-control unit.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the present disclosure clearer, the technical solutions of the present disclosure will be described clearly and completely in conjunction with specific embodiments of the present disclosure and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

Most of the drive mode of the inverter adopts the open-closed loop start mode. Because the load is not fixed when the compressor starts, the starting torque required by the compressor is also different. The larger the starting current, the larger the starting torque, and the easier the motor rotor starts; on the contrary, the motor The rotor is more likely to fail to start. At the same time, the greater the starting torque, the greater the impact on the bearing during starting. When the magnetic bearing control rigidity remains unchanged, the bearing rotor suspension accuracy will be worse; conversely, the smaller the starting torque, the higher the bearing rotor suspension accuracy.

In order to avoid the compressor starting failure, a larger starting current is usually selected; or the starting current is increased after the starting failure; if different bearing control is not performed for various starting torques, when the starting torque is large, the bearing control is adopted If the bearing control stiffness is too small, the suspension accuracy of the bearing rotor is likely to deteriorate, causing bearing protection and affecting the reliability of the compressor; on the contrary, it is easy to excite the bearing rotor vibration, which is easy to lose stability and affect the reliability of the compressor.

According to an embodiment of the present disclosure, a method for controlling a magnetic suspension bearing is provided, as shown in FIG. 1, a schematic flowchart of some embodiments of the method of the present disclosure. The magnetic suspension bearing control method includes: step S110 and step S120.

At step S110, it is determined whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque.

In some embodiments, in conjunction with the method of the present disclosure shown in FIG. 2 to determine whether the required starting torque of the compressor in the magnetic levitation system exceeds the set torque, the flow chart of some embodiments is further explained in step S110. The specific process of whether the starting torque required for starting the compressor in the system exceeds the set torque includes: step S210 to step S230.

Step S210: Acquire the starting parameters of the compressor in the magnetic levitation system.

Among them, the starting parameters of the compressor include: the starting current of the compressor.

For example: during the compressor startup process, by judging the compressor startup current, real-time adjustment of the magnetic levitation compressor bearing controller control stiffness to ensure bearing operation accuracy without triggering bearing protection, avoiding compressor startup failure due to bearing protection problems during startup .

Therefore, by taking the starting current of the compressor as the starting parameter of the compressor, the determination of the starting parameter of the compressor is simple and reliable.

In step S220, it is determined whether the startup parameter of the compressor is greater than or equal to the set parameter.

Wherein, the setting parameters include: a setting current, or a setting voltage corresponding to the setting current, and the setting voltage is less than the voltage corresponding to the minimum current that can cause the bearing rotor displacement protection.

For example: the value of the reference signal Vref is smaller than the voltage signal corresponding to the minimum current value that triggers the bearing rotor displacement protection.

Therefore, by using the setting voltage as the setting parameter that is less than the voltage corresponding to the minimum current that can cause the bearing rotor displacement protection, the determination of the starting current of the compressor is accurate and reliable.

In some embodiments, determining whether the startup parameter is greater than or equal to the set parameter in step S220 includes: when the startup parameter of the compressor includes the startup current of the compressor and the set parameter includes the set voltage, After the starting current of the compressor is converted into a starting voltage, it is determined whether the starting voltage is greater than or equal to the set voltage, so as to determine that the starting parameter of the compressor is greater than or equal to the set parameter when the starting voltage is greater than or equal to the set voltage. When the starting voltage is less than the set voltage, the control parameters of the magnetic bearing in the magnetic levitation system are maintained.

For example: the current comparison circuit detects the starting current I of the inverter in real time, and modulates it into a voltage signal Vcurrent. The voltage signal Vcurrent is compared with the reference signal Vref. When the voltage signal Vcurrent is less than the reference signal Vref, the comparator output is 0; When the voltage signal Vcurrent is greater than or equal to the reference signal Vref, the output of the comparator is 1. The output of the current comparison circuit is provided to the bearing controller.

Therefore, by converting the starting current of the compressor into the starting voltage, and then comparing the starting voltage with the set voltage, it is easier to determine whether the starting current of the compressor reaches the set parameters, and the accuracy can be ensured. .

In step S230, if the starting parameter of the compressor is greater than or equal to the set parameter, it is determined that the starting torque required for starting the compressor exceeds the set torque.

Therefore, by determining that the starting torque required to start the compressor exceeds the set torque when the starting parameter of the compressor is greater than or equal to the set parameter, it is easy to determine the starting torque required to start the compressor And precise.

At step S120, if the required starting torque at the start of the compressor exceeds the set torque, increase the control parameters of the magnetic bearing in the magnetic levitation system to control the control parameters of the magnetic bearing to meet the requirements when the compressor is started Starting torque.

For example: an adaptive control method of magnetic levitation bearing control stiffness, which can adapt to various starting torque conditions, ensure bearing control accuracy, and ensure that the magnetic levitation compressor can be reliably started under various conditions. In this way, the problem that the starting current of the inverter increases during the start of the magnetic levitation compressor, which causes the rotor suspension accuracy to deteriorate, triggers bearing protection, and causes the magnetic levitation compressor to fail to start.

In this way, when the starting torque required at the start of the compressor exceeds the set torque, by increasing the control parameters of the magnetic bearing, the reliability of starting the compressor can be improved.

Among them, the control parameters of the magnetic bearing include: the control stiffness of the bearing controller of the magnetic bearing.

For example: In bearings and bearing controllers, the bearing controller adjusts the current of the bearing coils in real time through the suspension displacement of the rotor, thereby adjusting the bearing output and realizing the stable suspension of the rotor near the center position. For example: the bearing controller adjusts the bearing control stiffness in real time according to the output of the current comparison circuit. For example, when the current comparison circuit output is 1, the bearing control stiffness increases according to certain rules; when the current comparison circuit output is 0, the bearing control stiffness remains constant.

In some embodiments, increasing the control parameter of the magnetic suspension bearing in the magnetic suspension system in step S120 includes: increasing the control stiffness of the bearing controller of the magnetic suspension bearing in a set increasing manner.

Among them, the set increase method includes: linear increase, step increase, convex mirror arc increase, concave mirror arc increase, any one of the increase methods or any number of increase methods .

For example, the control stiffness of the bearing is increased according to certain rules, but not limited to a specific way. Figure 9 shows five ways to increase the control stiffness of the bearing. For example: in Figure 9, the first increase method shown in (a) is stable first and then linearly increases, the second increase method shown in (b) is stepped increase, and the first increase method shown in (c) is Stable and then press the third increasing method of convex mirror arc increase, (d) shows the fourth increasing method of increasing the concave mirror arc first smoothly, and then press the convex mirror first smoothly as shown in (e) The fifth increasing method in which the mirror curve and the concave mirror curve increase alternately is similar to the sixth increasing method in which the concave mirror curve and the convex mirror curve increase alternately as shown in (e). and many more.

As a result, the control stiffness of the bearing controller of the magnetic suspension bearing is increased through a variety of increasing methods, so that the processing for increasing the control stiffness of the bearing controller is flexible and simple.

In some embodiments, it further includes a process of determining the control timing of the magnetic suspension bearing, specifically a process of determining whether the starting torque required when the compressor in the magnetic levitation system starts exceeds the set torque.

The following describes the specific process of determining the control timing of the magnetic bearing with reference to the schematic flow diagram of some embodiments of the method of the present disclosure shown in FIG. 3 for determining the control timing of the magnetic bearing, including: step S310 to step S330.

In step S310, when the bearing controller and the inverter in the magnetic levitation system receive the start instruction, it is determined whether the levitation degree of the magnetic levitation rotor in the magnetic levitation system reaches the set level, that is, it is determined whether the magnetic levitation bearing in the magnetic levitation system is stable in suspension. . Wherein, the start command is configured to start the compressor.

In step S320, when the levitation degree of the magnetic levitation rotor reaches the set level, that is, when the levitation of the magnetic levitation rotor is stable, the inverter is controlled to start operation.

In step S330, after the inverter starts to run, it is determined whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque.

For example: the inverter and the bearing controller receive the start command, and the inverter will start to run after the rotor has stabilized in suspension. After the inverter starts to run, first judge whether the inverter starting current reaches the set value. If it reaches the set value, increase the bearing control stiffness to ensure the rotor suspension accuracy. If the bearing protection is not triggered, the startup fails.

Therefore, after the inverter starts to run when the magnetic suspension rotor is determined to be stable, it can be determined whether the required starting torque at the start of the compressor exceeds the set torque, so that the required start at the start of the compressor The timing for determining whether the torque exceeds the set torque is accurate and reliable.

After a large number of tests and verifications, the technical solution of this embodiment is adopted to adapt to various starting torque conditions by adopting the magnetic suspension bearing control stiffness adaptive control method, which can ensure the bearing control accuracy and ensure that the magnetic suspension compressor can perform under various conditions. It can be started reliably, and the reliability of starting is improved.

According to some embodiments of the present disclosure, a magnetic suspension bearing control device corresponding to the magnetic suspension bearing control method is also provided. See FIG. 4 for a schematic structural diagram of some embodiments of the device of the present disclosure. The magnetic suspension bearing control device includes: a determination unit 102 and a control unit 104.

In an optional example, the determining unit 102 is configured to determine whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque. For specific functions and processing of the determining unit 102, refer to step S110.

In some embodiments, the determining unit 102 determines whether the starting torque required to start the compressor in the magnetic levitation system exceeds the set torque, including:

The determining unit 102 is specifically configured to obtain the startup parameters of the compressor in the magnetic levitation system. The specific function and processing of the determining unit 102 also refer to step S210.

For example: during the compressor startup process, by judging the compressor startup current, real-time adjustment of the magnetic levitation compressor bearing controller control stiffness can ensure bearing operation accuracy without triggering bearing protection, and avoiding the compressor startup due to bearing protection problems during startup failure.

The determining unit 102 is specifically configured to determine whether the starting parameter of the compressor is greater than or equal to the set parameter. For the specific function and processing of the determining unit 102, refer to step S220.

In some embodiments, the determining unit 102 determines whether the startup parameter is greater than or equal to a set parameter, and includes: the determining unit 102 is specifically configured to include the startup current of the compressor when the startup parameter of the compressor , And the setting parameter includes the setting voltage, after converting the starting current of the compressor to the starting voltage, determine whether the starting voltage is greater than or equal to the set voltage, so that when the starting voltage is greater than or equal to the set voltage Make sure that the compressor's starting parameter is greater than or equal to the set parameter. When the starting voltage is less than the set voltage, the control parameters of the magnetic bearing in the magnetic levitation system are maintained.

The determining unit 102 is specifically configured to determine that the starting torque required for starting the compressor exceeds the set torque if the starting parameter of the compressor is greater than or equal to the set parameter. For the specific function and processing of the determining unit 102, refer to step S230.

In some embodiments, the control unit 104 is configured to increase the control parameter of the magnetic bearing in the magnetic levitation system to control the adaptation of the control parameter of the magnetic bearing if the required starting torque when the compressor starts exceeds the set torque. The starting torque required when the compressor is started. For specific functions and processing of the control unit 104, refer to step S120.

In some embodiments, the control unit 104 increases the control parameters of the magnetic suspension bearing in the magnetic levitation system, including: the control unit 104 is specifically configured to control the bearing controller of the magnetic suspension bearing in a set increasing manner. The control stiffness is increased.

The determining unit 102 is further configured to determine whether the levitation degree of the magnetic levitation rotor in the magnetic levitation system reaches the set level when the bearing controller and the inverter in the magnetic levitation system receive the start instruction, that is, determine whether the magnetic levitation system Whether the magnetic bearing in the levitation is stable. Wherein, the start command is configured to start the compressor. For the specific function and processing of the determining unit 102, refer to step S310.

The control unit 104 is further configured to control the frequency converter to start operation when the levitation degree of the magnetic levitation rotor reaches a set level, that is, when the levitation of the magnetic levitation rotor is stable. For specific functions and processing of the control unit 104, refer to step S320.

The determining unit 102 is further configured to determine whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque after the inverter starts to run. For the specific function and processing of the determining unit 102, refer to step S330.

For example: the inverter and the bearing controller receive the start command, and the inverter will start to run after the rotor has stabilized. After the inverter starts to run, first judge whether the inverter starting current reaches the set value. If it reaches the set value, increase the bearing control stiffness to ensure the rotor suspension accuracy. If the bearing protection is not triggered, the startup fails.

Since the processing and functions implemented by the device of this embodiment basically correspond to the embodiments, principles, and examples of the methods shown in FIGS. 1 to 3, the description of this embodiment is not exhaustive, please refer to the foregoing embodiment The related description of, I won’t go into details here.

After a large number of experiments, the technical solution of the present disclosure is used to adjust the control stiffness of the magnetic levitation compressor bearing controller in real time by judging the compressor startup current during the compressor startup process to ensure the bearing operation accuracy without triggering bearing protection. Avoid the problem that the magnetic levitation compressor fails to start.

According to some embodiments of the present disclosure, a magnetic levitation system corresponding to the magnetic suspension bearing control device is also provided. The magnetic suspension system includes: the above-mentioned magnetic suspension bearing control device.

In some embodiments, the solution of the present disclosure proposes an adaptive control method of magnetic suspension bearing control stiffness, which can adapt to various starting torque conditions, ensure bearing control accuracy, and ensure that the magnetic suspension compressor can be reliable under various conditions. start up. In this way, the problem that the starting current of the frequency converter increases during the starting process of the magnetic levitation compressor, which causes the rotor suspension accuracy to deteriorate, triggers bearing protection, and causes the magnetic levitation compressor to fail to start.

In some embodiments, in the solution of the present disclosure, during the compressor startup process, by judging the compressor startup current, real-time adjustment of the bearing controller control stiffness of the magnetic levitation compressor can ensure bearing operation accuracy without triggering bearing protection, avoiding When starting, the compressor failed to start due to bearing protection.

It can be seen that the solution of the present disclosure is aimed at increasing the startup current of the inverter during the startup process of the magnetic levitation compressor (such as selecting a larger startup current to avoid startup failure, or increasing startup current after startup failure). The torque is controlled by different bearings. When the starting torque is large, the bearing control adopts a smaller bearing control stiffness, which causes the rotor suspension accuracy to deteriorate, triggers bearing protection, and causes the magnetic levitation compressor to fail to start; The current (that is, the starting current I of the inverter) adjusts the control stiffness of the bearing controller of the magnetic levitation compressor to ensure the accuracy of bearing operation and does not trigger bearing protection.

Among them, the supporting characteristics of the magnetic bearing are composed of the rigidity and damping of the magnetic bearing. Magnetic bearing stiffness: The support stiffness of a magnetic bearing in a certain direction refers to the increase in force along the direction of displacement required for a unit displacement in that direction. Magnetic bearing damping: The supporting damping of a magnetic bearing in a certain direction refers to the increase in force along the direction of the speed required by the unit speed change in that direction. The rigidity of the magnetic bearing is composed of the rigidity of the structural body and the control rigidity. The rigidity of the structural body is determined by the structural parameters of the magnetic bearing and is immutable; the control rigidity mainly refers to the proportional constant of the digital controller.

In some embodiments, referring to the examples shown in FIG. 6 to FIG. 9, the implementation process of the solution of the present disclosure is exemplified.

Figure 6 shows a schematic diagram of bearing protection and starting failure due to increased starting current and poor bearing rotor suspension accuracy under the condition that the bearing control stiffness remains unchanged.

In some embodiments, in order to avoid starting failure due to excessive starting current, the solution of the present disclosure proposes a solution for changing the control stiffness of the bearing according to the magnitude of the starting current.

Refer to the example shown in Figure 7 for the hardware structure. Figure 7 shows the control diagram. The main components are: bearing controller, bearing, motor, motor controller and current comparison circuit.

In some embodiments, the current comparison circuit detects the starting current I of the inverter in real time, and modulates it into a voltage signal Vcurrent. The voltage signal Vcurrent is compared with the reference signal Vref. When the voltage signal Vcurrent is less than the reference signal Vref, the comparator outputs When the voltage signal Vcurrent is greater than or equal to the reference signal Vref, the output of the comparator is 1. The output of the current comparison circuit is provided to the bearing controller.

Among them, the value of the reference signal Vref is smaller than the voltage signal corresponding to the minimum current value that triggers the bearing rotor displacement protection.

In some embodiments, in the motor and the frequency converter, the frequency converter controls the current of the motor so that the motor runs stably at the set speed.

In some embodiments, in the bearing and the bearing controller, the bearing controller adjusts the current of the bearing coil in real time through the suspension displacement of the rotor, so as to adjust the bearing output and realize the stable suspension of the rotor near the center position. For example: the bearing controller adjusts the bearing control stiffness in real time according to the output of the current comparison circuit. For example, when the current comparison circuit output is 1, the bearing control stiffness increases according to certain rules; when the current comparison circuit output is 0, the bearing control stiffness remains constant.

For the principle of software control, see the example shown in Figure 8. In the control logic shown in Figure 8, the process of changing the bearing control stiffness according to the starting current includes:

Step 1. The inverter and the bearing controller receive the start command, and after the rotor suspension stabilizes, the inverter starts to run.

For example: after the rotor is suspended, it is determined that the suspension accuracy is maintained within a certain accuracy range within T time. For example, if the suspension accuracy is kept within 1um within 1 minute, it is determined that the rotor suspension is stable. Among them, the judgment time and the judgment suspension accuracy are changed according to actual conditions.

Step 2. After the inverter starts to run, first judge whether the inverter starting current reaches the set value. If it reaches the set value, increase the bearing control stiffness to ensure the rotor suspension accuracy. If the bearing protection is not triggered, the startup fails.

In some embodiments, the control stiffness of the bearing is increased according to a certain rule, but not limited to a specific way. As shown in FIG. 9, there are five ways to increase the control stiffness of the bearing. For example: in Figure 9, the first increase method shown in (a) is stable first and then linearly increases, the second increase method shown in (b) is stepped increase, and the first increase method shown in (c) is Stable and then press the third increasing method of convex mirror arc increase, (d) shows the fourth increasing method of increasing the concave mirror arc first smoothly, and then press the convex mirror first smoothly as shown in (e) The fifth increasing method in which the mirror curve and the concave mirror curve increase alternately is similar to the sixth increasing method in which the concave mirror curve and the convex mirror curve increase alternately as shown in (e). and many more.

Since the processing and functions implemented by the magnetic levitation system of this embodiment basically correspond to the embodiment, principle, and example of the device shown in FIG. 4, the description of this embodiment is not exhaustive, please refer to the relevant information in the foregoing embodiment. Note, I won’t repeat it here.

A large number of experiments have verified that the technical solution of the present disclosure is adopted to adjust the control stiffness of the magnetic levitation compressor bearing controller according to the compressor starting current to ensure the bearing operation accuracy without triggering the bearing protection, which improves the starting reliability.

According to an embodiment of the present disclosure, a computer-readable storage medium corresponding to the magnetic suspension bearing control method is also provided. The computer-readable storage medium includes: the computer-readable storage medium stores a plurality of instructions; the plurality of instructions are configured to be loaded by a processor and execute the above-mentioned magnetic bearing control method.

Since the processing and functions implemented by the computer-readable storage medium of this embodiment basically correspond to the embodiments, principles, and examples of the methods shown in FIGS. 1 to 3, the description of this embodiment is not exhaustive, please refer to The related description in the foregoing embodiment will not be repeated here.

After a large number of experimental verifications, the technical solution of the present disclosure is adopted to detect the starting current I of the inverter in real time and convert it into a voltage signal through modulation. When the voltage signal is greater than or equal to the reference signal, the bearing control stiffness increases according to a certain rule. Realize real-time adjustment of bearing control stiffness to ensure bearing operation accuracy without triggering bearing protection.

According to the embodiment of the present disclosure, a magnetic levitation system corresponding to the magnetic suspension bearing control method is also provided. The magnetic levitation system includes: a processor configured to execute a plurality of instructions; a memory configured to store a plurality of instructions; wherein the plurality of instructions are configured to be stored by the memory and executed by the processor Load and execute the above-mentioned magnetic bearing control method.

Since the processing and functions implemented by the magnetic levitation system of this embodiment basically correspond to the embodiments, principles, and examples of the methods shown in FIGS. 1 to 3, the description of this embodiment is not exhaustive, please refer to the foregoing embodiment Relevant descriptions in, do not repeat them here.

After a large number of experiments, the technical solution of the present disclosure is adopted to determine whether the starting current of the inverter reaches the set value. If it reaches the set value, the bearing control stiffness is increased, so that the rotor suspension accuracy is guaranteed without triggering the bearing protection. The startup fails, which improves startup reliability.

In summary, it is easy for those skilled in the art to understand that the above advantageous methods can be freely combined and superimposed on the premise of no conflict.

The above are only the embodiments of the present disclosure and are not used to limit the present disclosure. For those skilled in the art, the present disclosure has various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the scope of the claims of the present disclosure.

Claims

A control method of a magnetic suspension bearing includes:

Determine whether the required starting torque when starting the compressor in the magnetic levitation system exceeds the set torque;

If the required starting torque when the compressor starts exceeds the set torque, increase the control parameters of the magnetic bearing in the magnetic suspension system to control the control parameters of the magnetic bearing to adapt to the starting torque required when the compressor starts.
The magnetic suspension bearing control method according to claim 1, wherein determining whether the starting torque required for starting the compressor in the magnetic suspension system exceeds the set torque includes:

Obtain the starting parameters of the compressor in the magnetic levitation system;

Determine whether the compressor startup parameter is greater than or equal to the set parameter;

If the starting parameter of the compressor is greater than or equal to the set parameter, it is determined that the starting torque required when the compressor is started exceeds the set torque.
The magnetic suspension bearing control method according to claim 2, wherein:

The starting parameters of the compressor include the starting current of the compressor;

or,

The setting parameters include a setting voltage, and the setting voltage is less than the voltage corresponding to the minimum current that can cause the bearing rotor displacement protection.
The magnetic suspension bearing control method according to claim 1, wherein determining whether the starting torque required for starting the compressor in the magnetic suspension system exceeds the set torque includes:

Obtain the starting current of the compressor in the magnetic levitation system; after converting the starting current of the compressor into a starting voltage, determine whether the starting voltage is greater than or equal to the set voltage;

In the case that the starting voltage is greater than or equal to the set voltage, it is determined that the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque.
The magnetic suspension bearing control method according to any one of claims 1 to 4, wherein the control parameter of the magnetic suspension bearing comprises: the control stiffness of the bearing controller of the magnetic suspension bearing;

Increase the control parameters of the magnetic bearing in the magnetic levitation system, including:

Increase the control stiffness of the bearing controller of the magnetic suspension bearing according to the set increase method;

Among them, the set increase method includes: linear increase, step increase, convex mirror arc increase, concave mirror arc increase, any one of the increase methods or any number of increase methods .
The magnetic suspension bearing control method according to any one of claims 1 to 4, further comprising:

When the bearing controller and inverter in the magnetic levitation system receive the start command, determine whether the levitation degree of the magnetic levitation rotor in the magnetic levitation system reaches the set level;

When the levitation degree of the magnetic levitation rotor reaches the set level, control the inverter to start operation;

After the inverter starts to run, it is determined whether the starting torque required by the compressor in the magnetic levitation system when starting exceeds the set torque.
The magnetic suspension bearing control method according to claim 2, wherein the starting parameter of the compressor includes the starting current of the compressor, the setting parameter includes a setting voltage, and the setting voltage is less than the minimum current that can cause the bearing rotor displacement protection The corresponding voltage.
A magnetic suspension bearing control device, which includes:

The determining unit is configured to determine whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque;

The control unit is configured to increase the control parameters of the magnetic bearing in the magnetic levitation system if the required starting torque when the compressor starts exceeds the set torque, so as to control the control parameters of the magnetic bearing to adapt to the requirements when the compressor starts The starting torque.
8. The magnetic suspension bearing control device according to claim 8, wherein the determining unit determines whether the starting torque required for starting the compressor in the magnetic levitation system exceeds a set torque, comprising:

Obtain the starting parameters of the compressor in the magnetic levitation system;

Determine whether the compressor startup parameter is greater than or equal to the set parameter;

If the starting parameter of the compressor is greater than or equal to the set parameter, it is determined that the starting torque required when the compressor is started exceeds the set torque.
The magnetic suspension bearing control device according to claim 9, wherein:

The starting parameter of the compressor includes the starting current of the compressor, or the setting parameter includes the setting voltage and the setting voltage is less than the voltage corresponding to the minimum current that can cause the bearing rotor displacement protection.
The magnetic suspension bearing control device according to claim 8, wherein said determining whether the starting torque required for starting the compressor in the magnetic levitation system exceeds a set torque comprises:

Obtain the starting current of the compressor in the magnetic levitation system;

After converting the starting current of the compressor into a starting voltage, determine whether the starting voltage is greater than or equal to the set voltage;

In the case that the starting voltage is greater than or equal to the set voltage, it is determined that the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque.
The magnetic suspension bearing control device according to any one of claims 8 to 11, wherein the control parameter of the magnetic suspension bearing comprises: the control stiffness of the bearing controller of the magnetic suspension bearing;

The control unit for increasing the control parameters of the magnetic suspension bearing in the magnetic suspension system includes:

Increase the control stiffness of the bearing controller of the magnetic suspension bearing according to the set increase method;

Among them, the set increase method includes: linear increase, step increase, convex mirror arc increase, concave mirror arc increase, any one of the increase methods or any number of increase methods .
The magnetic suspension bearing control device according to any one of claims 8 to 11, wherein:

The determining unit is further configured to determine whether the levitation degree of the magnetic levitation rotor in the magnetic levitation system reaches a set level when the bearing controller and the inverter in the magnetic levitation system receive a start instruction;

The control unit is further configured to control the frequency converter to start operation when the levitation degree of the magnetic levitation rotor reaches a set level;

The determining unit is also configured to determine whether the starting torque required for starting the compressor in the magnetic levitation system exceeds the set torque after the inverter starts to run.
The magnetic bearing control device according to claim 9, wherein the starting parameter of the compressor includes the starting current of the compressor, the setting parameter includes a setting voltage, and the setting voltage is less than the minimum current that can cause the bearing rotor displacement protection The corresponding voltage.
A magnetic levitation system, comprising: the magnetic levitation bearing control device according to any one of claims 8 to 14;

or,

The magnetic levitation system includes:

The processor is configured to execute multiple instructions;

The memory is configured to store multiple instructions;

Wherein, the multiple instructions are configured to be stored by the memory and loaded by the processor to execute the magnetic bearing control method according to any one of claims 1 to 7.
A computer-readable storage medium, wherein multiple instructions are stored in the computer-readable storage medium; the multiple instructions are configured to be loaded by a processor and executed as described in any one of claims 1 to 7 The magnetic suspension bearing control method described.