CN117167404A

CN117167404A - Magnetic suspension bearing, control method and device thereof, compressor and storage medium

Info

Publication number: CN117167404A
Application number: CN202311231582.XA
Authority: CN
Inventors: 林炀; 赵科杰; 陈澍国; 符尔铮
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2023-09-22
Filing date: 2023-09-22
Publication date: 2023-12-05

Abstract

The invention discloses a control method and device of a magnetic suspension bearing, the magnetic suspension bearing, a magnetic suspension compressor and a storage medium, wherein the method comprises the following steps: according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation, if the current reference current value of the current loop is determined to be required to be compensated, controlling a current compensation device to be started, and compensating the current reference current value of the current loop; and then, according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation, if the current reference current value of the current loop is determined to be required to be stopped, controlling the current compensation device to be closed so as to stop compensating the current reference current value of the current loop. According to the scheme, the reference current value of the current loop is compensated under the working condition that the current fluctuation is large, the current response speed of the current loop is prevented from being untimely, and the running stability of the magnetic suspension bearing is improved.

Description

Magnetic suspension bearing, control method and device thereof, compressor and storage medium

Technical Field

The invention belongs to the technical field of magnetic suspension, and particularly relates to a control method and device of a magnetic suspension bearing, the magnetic suspension bearing, a magnetic suspension compressor and a storage medium, in particular to a method and device for compensating and controlling the magnitude of bearing coil current of the magnetic suspension bearing by using a current compensation device, the magnetic suspension bearing, the magnetic suspension compressor and the storage medium.

Background

The magnetic bearing control system mainly comprises two major parts, namely a magnetic bearing and a bearing controller, wherein the magnetic bearing can be simplified into a coil (namely a bearing coil), and the bearing controller is simplified into a device for controlling the current of the bearing coil.

The control of the bearing coil current is controlled by a current loop, and the current loop changes the magnitude of the output current in real time through pulse width modulation. In the stable operation process of the magnetic suspension compressor, the current fluctuation is small, and the real-time performance of current control meets the operation requirement; however, in some severe cases, the response speed of the current may be poor, and pulse width modulation is not timely so as to cause instability of the magnetic suspension compressor after the magnetic suspension compressor receives impact force.

The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present invention and is not intended to represent an admission that the foregoing is prior art.

Disclosure of Invention

The invention aims to provide a control method and device for a magnetic suspension bearing, the magnetic suspension bearing, a magnetic suspension compressor and a storage medium, so as to solve the problem that in the current loop control of the bearing coil current of the magnetic suspension bearing, the current response speed of a current loop is not timely under the working condition of large current fluctuation, and the magnetic suspension compressor where the magnetic suspension bearing is positioned is unstable due to impact force, and achieve the effects of compensating the reference current value of the current loop under the working condition of large current fluctuation in the current loop control of the bearing coil current of the magnetic suspension bearing, avoiding the untimely current response speed of the current loop, improving the running stability of the magnetic suspension bearing and improving the running stability of the magnetic suspension compressor where the magnetic suspension bearing is positioned.

The invention provides a control method of a magnetic suspension bearing, which comprises the following steps of; the bearing controller of the magnetic suspension bearing performs displacement ring control based on the target displacement and the current detection displacement of the rotor, and performs current ring control based on a reference current value output by the displacement ring and the current detection current value of the bearing coil so as to control the working current of the bearing coil; a current compensation device is arranged in a bearing controller of the magnetic suspension bearing; the current compensation device can provide a set compensation current value; the control method of the magnetic suspension bearing comprises the following steps: detecting a reference current value output by the displacement ring in the running process of the magnetic suspension bearing, and recording the reference current value as a current reference current value of the current ring; detecting a detection current value of the magnetic bearing coil, and recording the detection current value as a current detection current value of the current loop; under the condition that the current compensation device is closed, determining whether to start to compensate the current reference current value of the current loop according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation; if the current reference current value of the current loop needs to be compensated, controlling the current compensation device to be started so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device; under the condition that the current compensation device is started, determining whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation; and if the current reference current value of the current loop is determined to be required to be stopped, controlling the current compensation device to be closed so as to stop the current compensation value provided by the current compensation device and compensate the current reference current value of the current loop.

In some embodiments, determining whether compensation of the current reference current value of the current loop needs to be started based on the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation includes: recording a current reference current value of the current loop before current compensation as a first reference current value of the current loop; recording the current value detected by the current loop before current compensation as a first current value detected by the current loop; determining whether a first reference current value of the current loop is greater than a sum of a first detected current value of the current loop and the compensation current value; if the first reference current value of the current loop is determined to be larger than the sum of the first detection current value of the current loop and the compensation current value, determining that the current reference current value of the current loop needs to be compensated.

In some embodiments, the current compensation device comprises: a compensation current supply module and a switching module; the compensation current providing module is used for providing the current compensation value; the switch module is arranged at the output end of the compensation current supply module and used for controlling the on-off of the output branch of the current compensation value provided by the compensation current supply module; controlling the current compensation device to be started so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device, wherein the method comprises the following steps: controlling the switch module in the current compensation device to be switched on so as to switch on an output branch of the current compensation value, enabling the compensation current supply module to start to supply the current compensation value, and compensating the current reference current value of the current loop; the current reference current value of the current loop after compensation is the current difference value between the current reference current value of the current loop before compensation and the current compensation value.

In some embodiments, determining whether compensation for the current reference current value of the current loop is needed to be stopped according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation comprises: recording the current reference value of the current loop after current compensation as a second reference current value of the current loop; recording the current detected current value of the current loop after current compensation as a second detected current value of the current loop; determining whether a second reference current value of the current loop is less than a second detected current value of the current loop; if the second reference current value of the current loop is smaller than the second detection current value of the current loop, determining that compensation of the current reference current value of the current loop is needed to be stopped.

In some embodiments, the current compensation device comprises: a compensation current supply module and a switching module; the compensation current providing module is used for providing the current compensation value; the switch module is arranged at the output end of the compensation current supply module and used for controlling the on-off of the output branch of the current compensation value provided by the compensation current supply module; controlling the current compensation device to be closed so as to stop using the current compensation value provided by the current compensation device to compensate the current reference current value of the current loop, wherein the method comprises the following steps: controlling the switch module in the current compensation device to be turned off so as to turn off an output branch of the current compensation value, and stopping the compensation current supply module from supplying the current compensation value and stopping compensating the current reference value of the current loop; the current reference current value of the current loop after stopping compensation is a current sum value between the current reference current value of the current loop before stopping compensation and the current compensation value.

In accordance with the above method, another aspect of the present invention provides a control device for a magnetic suspension bearing, where the magnetic suspension bearing has a bearing coil and a rotor; the bearing controller of the magnetic suspension bearing performs displacement ring control based on the target displacement and the current detection displacement of the rotor, and performs current ring control based on a reference current value output by the displacement ring and the current detection current value of the bearing coil so as to control the working current of the bearing coil; a current compensation device is arranged in a bearing controller of the magnetic suspension bearing; the current compensation device can provide a set compensation current value; the control device of the magnetic suspension bearing comprises: the detection unit is configured to detect a reference current value output by the displacement ring and record the reference current value as a current reference current value of the current ring in the running process of the magnetic suspension bearing; detecting a detection current value of the magnetic bearing coil, and recording the detection current value as a current detection current value of the current loop; a control unit configured to determine whether or not to start compensation of a current reference current value of the current loop according to a current reference current value of the current loop before current compensation and a current detection current value of the current loop before current compensation, in a case where the current compensation device is turned off; the control unit is further configured to control the current compensation device to be started to start to compensate the current reference current value of the current loop if the current reference current value of the current loop is determined to need to be compensated; the control unit is further configured to determine whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation under the condition that the current compensation device is started; the control unit is further configured to control the current compensation device to be turned off to stop compensating the current reference current value of the current loop by using the current compensation value provided by the current compensation device if it is determined that the compensation of the current reference current value of the current loop needs to be stopped.

In some embodiments, the control unit determines whether to start compensation of the current reference current value of the current loop according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation, including: recording a current reference current value of the current loop before current compensation as a first reference current value of the current loop; recording the current value detected by the current loop before current compensation as a first current value detected by the current loop; determining whether a first reference current value of the current loop is greater than a sum of a first detected current value of the current loop and the compensation current value; if the first reference current value of the current loop is determined to be larger than the sum of the first detection current value of the current loop and the compensation current value, determining that the current reference current value of the current loop needs to be compensated.

In some embodiments, the current compensation device comprises: a compensation current supply module and a switching module; the compensation current providing module is used for providing the current compensation value; the switch module is arranged at the output end of the compensation current supply module and used for controlling the on-off of the output branch of the current compensation value provided by the compensation current supply module; the control unit controls the current compensation device to be started so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device, and the control unit comprises the following steps: controlling the switch module in the current compensation device to be switched on so as to switch on an output branch of the current compensation value, enabling the compensation current supply module to start to supply the current compensation value, and compensating the current reference current value of the current loop; the current reference current value of the current loop after compensation is the current difference value between the current reference current value of the current loop before compensation and the current compensation value.

In some embodiments, the control unit determines whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation, including: recording the current reference value of the current loop after current compensation as a second reference current value of the current loop; recording the current detected current value of the current loop after current compensation as a second detected current value of the current loop; determining whether a second reference current value of the current loop is less than a second detected current value of the current loop; if the second reference current value of the current loop is smaller than the second detection current value of the current loop, determining that compensation of the current reference current value of the current loop is needed to be stopped.

In some embodiments, the current compensation device comprises: a compensation current supply module and a switching module; the compensation current providing module is used for providing the current compensation value; the switch module is arranged at the output end of the compensation current supply module and used for controlling the on-off of the output branch of the current compensation value provided by the compensation current supply module; the control unit controls the current compensation device to be closed so as to stop using the current compensation value provided by the current compensation device to compensate the current reference current value of the current loop, and the control unit comprises the following steps: controlling the switch module in the current compensation device to be turned off so as to turn off an output branch of the current compensation value, and stopping the compensation current supply module from supplying the current compensation value and stopping compensating the current reference value of the current loop; the current reference current value of the current loop after stopping compensation is a current sum value between the current reference current value of the current loop before stopping compensation and the current compensation value.

In accordance with another aspect of the present invention, there is provided a magnetic bearing comprising: the control device of the magnetic suspension bearing.

In accordance with another aspect of the present invention, there is provided a magnetic levitation compressor comprising: the magnetic suspension bearing is described above.

In accordance with the above method, the present invention further provides a storage medium, where the storage medium includes a stored program, and when the program runs, the device where the storage medium is controlled to execute the above method for controlling a magnetic suspension bearing.

Therefore, according to the scheme of the invention, the current compensation device is arranged, and the compensation current value of the current compensation device is set; under the condition that the magnetic suspension compressor with the magnetic suspension bearing is stably operated, namely under the condition that the magnetic suspension bearing is stably operated, detecting the current value of a bearing coil of the magnetic suspension bearing, detecting the current reference current value output by a displacement ring of the magnetic suspension bearing, and if the current reference current value is larger than the sum of the current value and a compensation current value, starting a current compensation device to negatively compensate the current reference current value by using the compensation current value; after negative compensation is carried out on the current reference current value by using the compensation current value, if the current reference current after negative compensation is detected to be smaller than the current value after negative compensation, the current compensation device is closed so as to stop continuous negative compensation on the current reference current value by using the compensation current value; therefore, in the control of the current loop of the bearing coil current of the magnetic suspension bearing, the reference current value of the current loop is compensated under the working condition of large current fluctuation, the untimely current response speed of the current loop is avoided, the running stability of the magnetic suspension bearing is improved, and the running stability of the magnetic suspension compressor where the magnetic suspension bearing is positioned is improved.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

FIG. 1 is a flow chart of a method of controlling a magnetic bearing according to an embodiment of the present invention;

FIG. 2 is a flow chart of an embodiment of the method of the present invention for determining whether to start compensating the present reference current value of the current loop;

FIG. 3 is a flow chart of an embodiment of the method of the present invention for determining whether to stop compensating the current reference current value of the current loop;

FIG. 4 is a schematic diagram illustrating a control device for a magnetic bearing according to an embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating a simplified power amplifier circuit in current loop control of a magnetic bearing;

FIG. 6 is a schematic diagram of an embodiment of adding a current compensation device to the current loop control of a magnetic bearing;

FIG. 7 is a schematic diagram of a configuration of an embodiment of a magnetic bearing and bearing controller;

FIG. 8 is a schematic diagram of a magnetic bearing and an embodiment of a bearing controller incorporating a current compensation device;

FIG. 9 is a schematic diagram of a control flow of an embodiment of a current compensation device in current loop control of a magnetic bearing;

FIG. 10 is a flow chart of an embodiment of a method for controlling current compensation of a magnetic bearing in current loop control of the magnetic bearing.

In the embodiment of the present invention, reference numerals are as follows, in combination with the accompanying drawings:

102-a detection unit; 104-a control unit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It is considered that in the current loop control of the bearing coil current of the magnetic suspension bearing, the magnitude of the bearing coil current at each moment is determined by the magnitude of the force required for returning the position of the rotor to the reference position at the previous moment. In the related scheme, in most control methods, the control of the bearing coil current is controlled by a current loop, and the current loop changes the magnitude of the output current in real time through pulse width modulation, which can be analogically a charging and discharging process. In the stable operation process of the magnetic suspension compressor, current fluctuation is small, the real-time performance of current control meets the operation requirement, but the response speed of current can be poor under certain severe conditions.

For example: when the magnetic suspension compressor is impacted by a certain degree, the rotor position deviates from the reference position to a great extent, the rotor returns to the reference position and needs a larger current value B relative to the current value A, the current ring increases the current from the current value A to the current value B in a certain period of time through pulse width modulation, the pulse width modulation is also a charging and discharging process, and if the current change is larger, the condition of untimely response can occur, and the magnetic suspension compressor is difficult to keep in a stable state after being impacted.

Specifically, fig. 5 is a schematic structural diagram of an embodiment of a simplified power amplifier circuit in current loop control of a magnetic bearing. As shown in fig. 5, in the current loop control of the magnetic suspension bearing, a power amplifier circuit is simplified, a reference value Ref is input to a first input end of a first comparator, and a current detection value of a magnetic bearing coil (such as an electromagnet coil) is fed back to a second input end of the first comparator; the output end of the first comparator is connected to the input end of the current controller; the output end of the current controller outputs control current to the electromagnet coil after passing through the PWM circuit and the power circuit. In the example shown in fig. 5, the reference value Ref of the current loop is derived from the value calculated by the displacement loop, and the output value of the displacement loop is mainly dependent on the size of the interval between the current time position of the rotor and the reference position. The current output of the power amplifier circuit is controlled by pulse width modulation.

FIG. 7 is a schematic diagram of a magnetic bearing and bearing controller configuration of an embodiment. As shown in fig. 7, the magnetic suspension bearing has a rotor, a forward bearing and a bearing are provided at the front end of the rotor, and a backward displacement sensor and a backward bearing are provided at the rear end of the rotor. The forward bearing and the backward bearing are respectively provided with a bearing coil, and a gap a is reserved between the bearing coils and the rotor. The controller (i.e., bearing controller) is capable of controlling each bearing via a current loop, such as controlling the magnitude of the coil current of the bearing coils in the forward bearing.

It can be seen that in actual situations, when the rotor position is greatly deviated from the reference position after the compressor is suddenly impacted by a certain force during stable operation, the reference current of the current loop will have a great change in the actual current of the current bearing coil, and if pulse width modulation is adopted to increase the current, the condition that the required current response is not timely may occur. Therefore, the scheme of the invention provides a control method of a magnetic suspension bearing, in particular to a method for carrying out compensation control on the magnitude of the current of a bearing coil of the magnetic suspension bearing by utilizing a current compensation device.

According to an embodiment of the present invention, there is provided a control method of a magnetic suspension bearing, as shown in fig. 1, which is a schematic flow chart of an embodiment of the method of the present invention. The magnetic suspension bearing is provided with a bearing coil and a rotor; the bearing controller of the magnetic suspension bearing performs displacement ring control based on the target displacement and the current detection displacement of the rotor, and performs current ring control based on a reference current value output by the displacement ring and the current detection current value of the bearing coil so as to control the working current of the bearing coil; a current compensation device is arranged in a bearing controller of the magnetic suspension bearing; the current compensation device can provide a set compensation current value; specifically, fig. 8 is a schematic structural diagram of an embodiment of a magnetic bearing and a bearing controller incorporating a current compensation device. As shown in fig. 8, the magnetic suspension bearing has a rotor, a forward bearing and a bearing are provided at the front end of the rotor, and a backward displacement sensor and a backward bearing are provided at the rear end of the rotor. The forward bearing and the backward bearing are respectively provided with a bearing coil, and a gap a is reserved between the bearing coils and the rotor. The controller (i.e., bearing controller) is capable of controlling each bearing via a current loop, such as controlling the magnitude of the coil current of the bearing coils in the forward bearing. The current compensation device can output a control current to the electromagnet coil together with the controller.

In the solution of the present invention, as shown in fig. 1, the control method of the magnetic suspension bearing includes: step S110 to step S150.

At step S110, during the operation of the magnetic suspension bearing, specifically during the steady operation of the magnetic suspension bearing, detecting a reference current value output by the displacement ring, and recording the reference current value as a current reference current value of the current ring; and detecting a detection current value of the magnetic bearing coil, and recording the detection current value as a current detection current value of the current loop.

At step S120, in the case where the current compensation device is turned off, it is determined whether or not the current reference current value of the current loop needs to be started to be compensated, based on the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation.

In some embodiments, in step S120, it is determined whether a specific process of compensating the current reference current value of the current loop needs to be started according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation, see the following exemplary description.

The following is a flowchart of an embodiment of the method of the present invention in conjunction with fig. 2 for determining whether to start compensating the current reference current value of the current loop, further describing the specific process of determining whether to start compensating the current reference current value of the current loop in step S120, including: step S210 to step S230.

Step S210, the current reference current value of the current loop before current compensation is recorded as a first reference current value of the current loop, such as reference current C; the current value detected by the current loop before current compensation is recorded as a first current value detected by the current loop, such as a coil current A.

Step S220, determining whether a first reference current value of the current loop is larger than the sum of a first detection current value of the current loop and the compensation current value; wherein the compensation current value is, for example, compensation current B.

Step S230, if it is determined that the first reference current value of the current loop is greater than the sum of the first detected current value of the current loop and the compensation current value, it is determined that the compensation of the current reference current value of the current loop needs to be started. Of course, if it is determined that the first reference current value of the current loop is not greater than the sum of the first detected current value of the current loop and the compensation current value, it is determined that it is not necessary to start compensating for the present reference current value of the current loop.

Specifically, fig. 6 is a schematic structural diagram of an embodiment of adding a current compensation device to the current loop control of the magnetic bearing. As shown in fig. 6, a current compensation device is added in the power amplifier circuit, and the current compensation device is controlled by a current controller (such as an MCU). As shown in fig. 6, in the current loop control of the magnetic suspension bearing, a power amplifier circuit is simplified, a reference value Ref is input to a first input end of a first comparator, and a current detection value of a magnetic bearing coil (such as an electromagnet coil) is fed back to a second input end of the first comparator; the output end of the first comparator is connected to the first input end of the second comparator, the compensation current of the current compensation device is input to the second input end of the second comparator, and the output end of the second comparator is connected to the input end of the current controller; the output end of the current controller outputs control current to the electromagnet coil together with the output end of the current compensation device after passing through the PWM circuit and the power circuit.

In the example shown in fig. 6, the logic unit (e.g., the first comparator and the second comparator) calculates and compares to determine whether the difference between the current loop reference value (e.g., the reference value Ref) and the current value (e.g., the current detection value of the electromagnet coil) exceeds the compensation current of the current compensation device, and if so, the control unit 104 (e.g., the current controller) activates the current compensation device, otherwise, does not activate the current compensation device.

FIG. 9 is a schematic diagram of a control flow of an embodiment of a current compensation device in current loop control of a magnetic bearing. As shown in fig. 9, a control flow of the current compensation device in the current loop control of the magnetic suspension bearing includes:

and step 11, when the magnetic suspension compressor is stably operated, a certain large impact is applied, the related sensor acquires current data of the magnetic suspension bearing and displacement data of the rotor, and then step 12 is executed.

Step 12, the control unit 104 determines that the current gain needs to turn on the current compensation device at this time, and the control unit 104 turns on the current compensation device to perform current compensation control, so as to perform current compensation control on the bearing coil current of the magnetic suspension bearing.

At step S130, if it is determined that the compensation of the current reference current value of the current loop needs to be started, the current compensation device is controlled to be turned on, so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device, thereby realizing control of the output current of the current loop, that is, the working current of the bearing coil.

In some embodiments, the current compensation device comprises: a compensation current supply module and a switching module; the compensation current providing module is used for providing the current compensation value; the switch module is arranged at the output end of the compensation current supply module and used for controlling the on-off of the output branch of the current compensation value provided by the compensation current supply module.

In step S130, the current compensation device is controlled to be turned on, so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device, including: controlling the switch module in the current compensation device to be switched on so as to switch on an output branch of the current compensation value, enabling the compensation current supply module to start to supply the current compensation value, and compensating the current reference current value of the current loop; the current reference current value of the current loop after compensation is the current difference value between the current reference current value of the current loop before compensation and the current compensation value.

Specifically, fig. 10 is a schematic flow chart of an embodiment of a current compensation control method of a magnetic bearing in current loop control of the magnetic bearing. As shown in fig. 10, the current compensation control method of the magnetic suspension bearing in the current loop control of the magnetic suspension bearing includes:

And 21, stably operating the magnetic suspension compressor, executing a program of a control module by the bearing controller, controlling the rotor to stably suspend in the operation process of the magnetic suspension compressor, and then executing step 22.

Step 22, if at a certain moment, the magnetic suspension compressor receives a certain impact force, for example, the compressor receives a certain impact force under the conditions of high-voltage ratio working condition, a moment when the magnetic suspension compressor is stopped, etc., the rotor suspension position deviates from the reference position to a great extent, and the following is set: the current of the current coil is a current value a, the compensation current of the current compensation device is a current value B, the reference current of the current loop after the rotor is impacted is a current value C (C > a+b), at this time, the logic unit determines that the current compensation device needs to be turned on, the reference current value C after the current compensation device is turned on=the reference current C-current compensation device of the current loop after the rotor is impacted compensates the current B, and the control unit 104 controls the switch to enable the current compensation device, and then step 23 is executed.

At step S140, under the condition that the current compensation device is turned on, determining whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation.

In some embodiments, in step S140, it is determined whether the specific process of compensating the current reference current value of the current loop needs to be stopped according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation, which is described in the following exemplary description.

The following is a flowchart of an embodiment of the method of the present invention in conjunction with fig. 3 for determining whether to stop compensating the current reference current value of the current loop, further describing the specific process of determining whether to stop compensating the current reference current value of the current loop in step S140, including: step S310 to step S330.

Step S310, the current reference current value of the current loop after current compensation is recorded as a second reference current value of the current loop, such as reference current C'; the current value detected by the current loop after current compensation is recorded as a second current value detected by the current loop, such as coil current C'.

Step S320, determining whether the second reference current value of the current loop is smaller than the second detection current value of the current loop.

Step S330, if it is determined that the second reference current value of the current loop is smaller than the second detection current value of the current loop, it is determined that compensation for the current reference current value of the current loop needs to be stopped. Of course, if it is determined that the second reference current value of the current loop is not smaller than the second detected current value of the current loop, it is determined that compensation for the current reference current value of the current loop does not need to be stopped, that is, compensation for the current reference current value of the current loop needs to be continued.

Referring to the example shown in fig. 6, after the current compensation means is enabled, the current compensation means may be turned off, where appropriate. The current compensation device is of a circuit structure, and the current controller can control the current compensation device to be turned on or off; the logic unit judges whether the current compensation device needs to be started or not; the control unit 104 can control the switching-on and switching-off of the current compensation device at any time. The current compensation device may include a relay that controls the one fixed current circuit to be turned on and off, and a one fixed current circuit (e.g., a circuit for providing a fixed current of 2A) that is connected in parallel with the PWM pulse width modulation circuit.

At step S150, if it is determined that the compensation of the current reference current value of the current loop needs to be stopped, the current compensation device is controlled to be turned off so as to stop the compensation of the current reference current value of the current loop by using the current compensation value provided by the current compensation device, and then, continuously detecting the reference current value output by the displacement loop and continuously detecting the detection current value of the magnetic bearing coil in the running process of the magnetic bearing, so as to dynamically compensate the reference current value output by the displacement loop, thereby realizing the circulation control of the output current of the current loop, that is, the working current of the bearing coil.

According to the scheme provided by the invention, the current compensation device is used for carrying out compensation control on the magnitude of the current of the bearing coil of the magnetic suspension bearing, and the problem of untimely response caused by large current abrupt change can be effectively solved by arranging the current compensation device; specifically, when the magnetic suspension compression of the magnetic suspension bearing is impacted by a certain degree, the current required value is changed greatly, the current compensation device is started to compensate the reference current value of the current loop in the control link of the current of the bearing coil, so that the reference current value of the current loop is reduced, the current value required to be achieved by pulse width modulation is further reduced, the problem that the magnetic suspension compressor is unstable due to the impact force of the magnetic suspension compressor is solved due to the fact that the pulse width modulation is not timely, the problem that the magnetic suspension compressor is unstable after the impact force is caused is solved, the operation stability of the magnetic suspension bearing is improved, and the operation stability of the magnetic suspension compressor of the magnetic suspension bearing is improved.

In step S150, the current compensation device is controlled to be turned off, so as to stop the compensation of the current reference value of the current loop by using the current compensation value provided by the current compensation device, including: controlling the switch module in the current compensation device to be turned off so as to turn off an output branch of the current compensation value, and stopping the compensation current supply module from supplying the current compensation value and stopping compensating the current reference value of the current loop; the current reference current value of the current loop after stopping compensation is a current sum value between the current reference current value of the current loop before stopping compensation and the current compensation value.

Specifically, as shown in fig. 10, the current compensation control method of the magnetic suspension bearing in the current loop control of the magnetic suspension bearing further includes: in step 23, after the current compensation device is started, the value of the current coil current C is recorded as C ', when the output value (reference current C ') of the following displacement loop is smaller than the value C ' of the current coil current C, at this time, the logic unit determines that the current compensation device needs to be turned off, and then the reference current C ' after the current compensation device is turned off = the reference current value C ' after the current compensation device is turned on and then the current compensation value B control unit 104 controls the switch to turn off the current compensation device. The compensation current B is determined according to a current compensation circuit, which is generally fixed after being designed. For example: in some cases, the current value a is 0.5, the current value B is 2, the current value C is 3, the current value C 'after turning on the current compensation device is 1, and the current value C' is 0.6; the current value C' after switching off the current compensation device is 2.6.

By adopting the technical scheme of the embodiment, the current compensation device is arranged, and the compensation current value of the current compensation device is set; under the condition that the magnetic suspension compressor with the magnetic suspension bearing is stably operated, namely under the condition that the magnetic suspension bearing is stably operated, detecting the current value of a bearing coil of the magnetic suspension bearing, detecting the current reference current value output by a displacement ring of the magnetic suspension bearing, and if the current reference current value is larger than the sum of the current value and a compensation current value, starting a current compensation device to negatively compensate the current reference current value by using the compensation current value; after negative compensation is carried out on the current reference current value by using the compensation current value, if the current reference current after negative compensation is detected to be smaller than the current value after negative compensation, the current compensation device is closed so as to stop continuous negative compensation on the current reference current value by using the compensation current value; therefore, in the control of the current loop of the bearing coil current of the magnetic suspension bearing, the reference current value of the current loop is compensated under the working condition of large current fluctuation, the untimely current response speed of the current loop is avoided, the running stability of the magnetic suspension bearing is improved, and the running stability of the magnetic suspension compressor where the magnetic suspension bearing is positioned is improved.

According to an embodiment of the present invention, there is also provided a control device of a magnetic suspension bearing corresponding to the control method of a magnetic suspension bearing. Referring to fig. 4, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The magnetic suspension bearing is provided with a bearing coil and a rotor; the bearing controller of the magnetic suspension bearing performs displacement ring control based on the target displacement and the current detection displacement of the rotor, and performs current ring control based on a reference current value output by the displacement ring and the current detection current value of the bearing coil so as to control the working current of the bearing coil; a current compensation device is arranged in a bearing controller of the magnetic suspension bearing; the current compensation device can provide a set compensation current value. Specifically, fig. 8 is a schematic structural diagram of an embodiment of a magnetic bearing and a bearing controller incorporating a current compensation device. As shown in fig. 8, the magnetic suspension bearing has a rotor, a forward bearing and a bearing are provided at the front end of the rotor, and a backward displacement sensor and a backward bearing are provided at the rear end of the rotor. The forward bearing and the backward bearing are respectively provided with a bearing coil, and a gap a is reserved between the bearing coils and the rotor. The controller (i.e., bearing controller) is capable of controlling each bearing via a current loop, such as controlling the magnitude of the coil current of the bearing coils in the forward bearing. The current compensation device can output a control current to the electromagnet coil together with the controller.

In an aspect of the present invention, as shown in fig. 4, the control device for a magnetic suspension bearing includes: a detection unit 102 and a control unit 104.

The detecting unit 102 is configured to detect a reference current value output by the displacement ring during the running process of the magnetic suspension bearing, specifically during the stable running process of the magnetic suspension bearing, and record the reference current value as a current reference current value of the current ring; and detecting a detection current value of the magnetic bearing coil, and recording the detection current value as a current detection current value of the current loop. The specific function and process of the detecting unit 102 refer to step S110.

The control unit 104 is configured to determine whether to start compensation of the current reference current value of the current loop according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation, in the case that the current compensation device is turned off. The specific function and process of the control unit 104 refer to step S120.

In some embodiments, the control unit 104 determines whether to start compensation of the current reference current value of the current loop according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation, including:

The control unit 104 is specifically further configured to record the present reference current value of the current loop before current compensation as a first reference current value of the current loop, such as reference current C; the current value detected by the current loop before current compensation is recorded as a first current value detected by the current loop, such as a coil current A. The specific function and process of the control unit 104 refer to step S210.

The control unit 104 is specifically further configured to determine whether the first reference current value of the current loop is greater than a sum of the first detected current value of the current loop and the compensation current value; wherein the compensation current value is, for example, compensation current B. The specific function and process of the control unit 104 refer to step S220.

The control unit 104 is specifically further configured to determine that compensation of the present reference current value of the current loop needs to be started if it is determined that the first reference current value of the current loop is greater than the sum of the first detected current value of the current loop and the compensation current value. Of course, if it is determined that the first reference current value of the current loop is not greater than the sum of the first detected current value of the current loop and the compensation current value, it is determined that it is not necessary to start compensating for the present reference current value of the current loop. The specific function and process of the control unit 104 refer to step S230.

The control unit 104 is further configured to control the current compensation device to be turned on if it is determined that the current reference current value of the current loop needs to be compensated, so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device, thereby realizing control of the output current of the current loop, that is, the working current of the bearing coil. The specific function and process of the control unit 104 refer to step S130.

The control unit 104 controls the current compensation device to be turned on to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device, and includes: the control unit 104 is specifically further configured to control the switching module in the current compensation device to be turned on, so as to turn on an output branch of the current compensation value, enable the compensation current providing module to start providing the current compensation value, and compensate the current reference current value of the current loop; the current reference current value of the current loop after compensation is the current difference value between the current reference current value of the current loop before compensation and the current compensation value.

The control unit 104 is further configured to determine whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation when the current compensation device is turned on. The specific function and process of the control unit 104 refer to step S140.

In some embodiments, the control unit 104 determines whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation, including:

the control unit 104 is specifically further configured to record the current compensated present reference current value of the current loop as a second reference current value of the current loop, such as reference current C'; the current value detected by the current loop after current compensation is recorded as a second current value detected by the current loop, such as coil current C'. The specific function and process of the control unit 104 refer to step S310.

The control unit 104 is in particular further configured to determine whether the second reference current value of the current loop is smaller than the second detected current value of the current loop. The specific function and process of the control unit 104 refer to step S320.

The control unit 104 is specifically further configured to determine that compensation of the present reference current value of the current loop needs to be stopped if it is determined that the second reference current value of the current loop is smaller than the second detected current value of the current loop. Of course, if it is determined that the second reference current value of the current loop is not smaller than the second detected current value of the current loop, it is determined that compensation for the current reference current value of the current loop does not need to be stopped, that is, compensation for the current reference current value of the current loop needs to be continued. The specific function and process of the control unit 104 refer to step S330.

Referring to the example shown in fig. 6, after the current compensation means is enabled, the current compensation means may be turned off, where appropriate. The current compensation device is of a circuit structure, and the current controller can control the current compensation device to be turned on or off; the logic unit judges whether the current compensation device needs to be started or not; the control unit 104 can control the switching-on and switching-off of the current compensation device at any time.

The control unit 104 is further configured to control the current compensation device to be turned off if it is determined that the compensation of the current reference current value of the current loop needs to be stopped, so as to stop the compensation of the current reference current value of the current loop by using the current compensation value provided by the current compensation device, and then, continuously detect the reference current value output by the displacement loop and continuously detect the detection current value of the magnetic bearing coil in the running process of the magnetic bearing, so as to dynamically compensate the reference current value output by the displacement loop, thereby realizing the circulation control of the output current of the current loop, that is, the working current of the bearing coil. The specific function and process of the control unit 104 refer to step S150.

The control unit 104 controls the current compensation device to be turned off to stop compensating the present reference current value of the current loop by using the current compensation value provided by the current compensation device, and includes: the control unit 104 is specifically further configured to control the switching module in the current compensation device to be turned off, so as to turn off an output branch of the current compensation value, and enable the compensation current providing module to stop providing the current compensation value and stop compensating the current reference current value of the current loop; the current reference current value of the current loop after stopping compensation is a current sum value between the current reference current value of the current loop before stopping compensation and the current compensation value.

Specifically, as shown in fig. 10, the current compensation control method of the magnetic suspension bearing in the current loop control of the magnetic suspension bearing further includes: in step 23, after the current compensation device is started, the value of the current coil current C is recorded as C ', when the output value (reference current C ') of the following displacement loop is smaller than the value C ' of the current coil current C, at this time, the logic unit determines that the current compensation device needs to be turned off, and then the reference current C ' after the current compensation device is turned off = the reference current value C ' after the current compensation device is turned on and then the current compensation value B control unit 104 controls the switch to turn off the current compensation device. The compensation current B is determined according to a current compensation circuit, which is generally fixed after being designed.

For example: in some cases, the current value a is 0.5, the current value B is 2, the current value C is 3, the current value C 'after turning on the current compensation device is 1, and the current value C' is 0.6; the current value C' after switching off the current compensation device is 2.6.

Since the processes and functions implemented by the apparatus of the present embodiment substantially correspond to the embodiments, principles and examples of the foregoing methods, the descriptions of the embodiments are not exhaustive, and reference may be made to the descriptions of the foregoing embodiments and their descriptions are omitted herein.

By adopting the technical scheme of the invention, the current compensation device is arranged, and the compensation current value of the current compensation device is set; under the condition that the magnetic suspension compressor with the magnetic suspension bearing is stably operated, namely under the condition that the magnetic suspension bearing is stably operated, detecting the current value of a bearing coil of the magnetic suspension bearing, detecting the current reference current value output by a displacement ring of the magnetic suspension bearing, and if the current reference current value is larger than the sum of the current value and a compensation current value, starting a current compensation device to negatively compensate the current reference current value by using the compensation current value; after negative compensation is carried out on the current reference current value by using the compensation current value, if the current reference current after negative compensation is detected to be smaller than the current value after negative compensation, the current compensation device is closed to stop continuously carrying out negative compensation on the current reference current value by using the compensation current value, so that the operation stability of the magnetic suspension bearing is improved, and the operation stability of the magnetic suspension compressor where the magnetic suspension bearing is positioned is improved.

According to an embodiment of the present invention, there is also provided a magnetic suspension bearing corresponding to the control device of the magnetic suspension bearing. The magnetic suspension bearing may include: the control device of the magnetic suspension bearing.

Since the processing and functions implemented by the magnetic suspension bearing of the present embodiment basically correspond to the embodiments, principles and examples of the foregoing apparatus, the description of the present embodiment is not exhaustive, and reference may be made to the related descriptions of the foregoing embodiments, which are not repeated herein.

By adopting the technical scheme of the invention, the current compensation device is arranged, and the compensation current value of the current compensation device is set; under the condition that the magnetic suspension compressor with the magnetic suspension bearing is stably operated, namely under the condition that the magnetic suspension bearing is stably operated, detecting the current value of a bearing coil of the magnetic suspension bearing, detecting the current reference current value output by a displacement ring of the magnetic suspension bearing, and if the current reference current value is larger than the sum of the current value and a compensation current value, starting a current compensation device to negatively compensate the current reference current value by using the compensation current value; after the current reference current value is subjected to negative compensation by using the compensation current value, if the current reference current after negative compensation is detected to be smaller than the current value after negative compensation, the current compensation device is turned off to stop continuously using the compensation current value to carry out negative compensation on the current reference current value, so that the problem that the magnetic suspension compressor where the magnetic suspension bearing is located is unstable due to impact force, and the problem that the pulse width modulation is not timely and then the magnetic suspension compressor is unstable after the impact force is received is solved.

According to an embodiment of the present invention, there is also provided a magnetic levitation compressor corresponding to the magnetic levitation bearing. The magnetic levitation compressor may include: the magnetic suspension bearing is described above.

Since the processing and functions implemented by the magnetic suspension compressor of the present embodiment basically correspond to the embodiments, principles and examples of the magnetic suspension bearing described above, the description of the present embodiment is not exhaustive, and reference may be made to the related description of the foregoing embodiment, which is not repeated herein.

By adopting the technical scheme of the invention, the current compensation device is arranged, and the compensation current value of the current compensation device is set; under the condition that the magnetic suspension compressor with the magnetic suspension bearing is stably operated, namely under the condition that the magnetic suspension bearing is stably operated, detecting the current value of a bearing coil of the magnetic suspension bearing, detecting the current reference current value output by a displacement ring of the magnetic suspension bearing, and if the current reference current value is larger than the sum of the current value and a compensation current value, starting a current compensation device to negatively compensate the current reference current value by using the compensation current value; after negative compensation is carried out on the current reference current value by using the compensation current value, if the current reference current after negative compensation is detected to be smaller than the current value after negative compensation, the current compensation device is turned off to stop continuously carrying out negative compensation on the current reference current value by using the compensation current value, so that instability caused by impact force on the magnetic suspension compressor is avoided, the problem that pulse width modulation is not timely and the magnetic suspension compressor is unstable after the impact force is caused is solved, and the running stability of the magnetic suspension compressor is improved.

According to an embodiment of the present invention, there is also provided a storage medium corresponding to a control method of a magnetic bearing, the storage medium including a stored program, wherein the device in which the storage medium is controlled to execute the above-described control method of a magnetic bearing when the program runs.

Since the processes and functions implemented by the storage medium of the present embodiment substantially correspond to the embodiments, principles and examples of the foregoing methods, the descriptions of the present embodiment are not exhaustive, and reference may be made to the related descriptions of the foregoing embodiments, which are not repeated herein.

By adopting the technical scheme of the invention, the current compensation device is arranged, and the compensation current value of the current compensation device is set; under the condition that the magnetic suspension compressor with the magnetic suspension bearing is stably operated, namely under the condition that the magnetic suspension bearing is stably operated, detecting the current value of a bearing coil of the magnetic suspension bearing, detecting the current reference current value output by a displacement ring of the magnetic suspension bearing, and if the current reference current value is larger than the sum of the current value and a compensation current value, starting a current compensation device to negatively compensate the current reference current value by using the compensation current value; after negative compensation is carried out on the current reference current value by using the compensation current value, if the current reference current after negative compensation is detected to be smaller than the current value after negative compensation, the current compensation device is closed to stop continuously carrying out negative compensation on the current reference current value by using the compensation current value, the reference current value of the current loop is reduced, the current value required to be reached by pulse width modulation is further reduced, and the instability caused by impact force of the magnetic suspension compressor where the magnetic suspension bearing is located is avoided.

In summary, it is readily understood by those skilled in the art that the above-described advantageous ways can be freely combined and superimposed without conflict.

The above description is only an example of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The control method of the magnetic suspension bearing is characterized in that the magnetic suspension bearing is provided with a bearing coil and a rotor; the bearing controller of the magnetic suspension bearing performs displacement ring control based on the target displacement and the current detection displacement of the rotor, and performs current ring control based on a reference current value output by the displacement ring and the current detection current value of the bearing coil so as to control the working current of the bearing coil; a current compensation device is arranged in a bearing controller of the magnetic suspension bearing; the current compensation device can provide a set compensation current value; the control method of the magnetic suspension bearing comprises the following steps:

Detecting a reference current value output by the displacement ring in the running process of the magnetic suspension bearing, and recording the reference current value as a current reference current value of the current ring; detecting a detection current value of the magnetic bearing coil, and recording the detection current value as a current detection current value of the current loop;

under the condition that the current compensation device is closed, determining whether to start to compensate the current reference current value of the current loop according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation;

if the current reference current value of the current loop needs to be compensated, controlling the current compensation device to be started so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device;

under the condition that the current compensation device is started, determining whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation;

and if the current reference current value of the current loop is determined to be required to be stopped, controlling the current compensation device to be closed so as to stop the current compensation value provided by the current compensation device and compensate the current reference current value of the current loop.

2. The method according to claim 1, wherein determining whether or not to start compensation of the current reference current value of the current loop is required based on the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation, comprises:

recording a current reference current value of the current loop before current compensation as a first reference current value of the current loop; recording the current value detected by the current loop before current compensation as a first current value detected by the current loop;

determining whether a first reference current value of the current loop is greater than a sum of a first detected current value of the current loop and the compensation current value;

if the first reference current value of the current loop is determined to be larger than the sum of the first detection current value of the current loop and the compensation current value, determining that the current reference current value of the current loop needs to be compensated.

3. A control method of a magnetic suspension bearing according to claim 1 or 2, characterized in that the current compensation means comprises: a compensation current supply module and a switching module; the compensation current providing module is used for providing the current compensation value; the switch module is arranged at the output end of the compensation current supply module and used for controlling the on-off of the output branch of the current compensation value provided by the compensation current supply module;

Controlling the current compensation device to be started so as to start to compensate the current reference current value of the current loop by using the current compensation value provided by the current compensation device, wherein the method comprises the following steps:

controlling the switch module in the current compensation device to be switched on so as to switch on an output branch of the current compensation value, enabling the compensation current supply module to start to supply the current compensation value, and compensating the current reference current value of the current loop; the current reference current value of the current loop after compensation is the current difference value between the current reference current value of the current loop before compensation and the current compensation value.

4. The method according to claim 1, wherein determining whether compensation of the current reference current value of the current loop is required based on the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation, comprises:

recording the current reference value of the current loop after current compensation as a second reference current value of the current loop; recording the current detected current value of the current loop after current compensation as a second detected current value of the current loop;

Determining whether a second reference current value of the current loop is less than a second detected current value of the current loop;

if the second reference current value of the current loop is smaller than the second detection current value of the current loop, determining that compensation of the current reference current value of the current loop is needed to be stopped.

5. The control method of a magnetic bearing according to claim 1 or 4, characterized in that the current compensation means comprises: a compensation current supply module and a switching module; the compensation current providing module is used for providing the current compensation value; the switch module is arranged at the output end of the compensation current supply module and used for controlling the on-off of the output branch of the current compensation value provided by the compensation current supply module;

controlling the current compensation device to be closed so as to stop using the current compensation value provided by the current compensation device to compensate the current reference current value of the current loop, wherein the method comprises the following steps:

controlling the switch module in the current compensation device to be turned off so as to turn off an output branch of the current compensation value, and stopping the compensation current supply module from supplying the current compensation value and stopping compensating the current reference value of the current loop; the current reference current value of the current loop after stopping compensation is a current sum value between the current reference current value of the current loop before stopping compensation and the current compensation value.

6. The control device of the magnetic suspension bearing is characterized by comprising a bearing coil and a rotor; the bearing controller of the magnetic suspension bearing performs displacement ring control based on the target displacement and the current detection displacement of the rotor, and performs current ring control based on a reference current value output by the displacement ring and the current detection current value of the bearing coil so as to control the working current of the bearing coil; a current compensation device is arranged in a bearing controller of the magnetic suspension bearing; the current compensation device can provide a set compensation current value; the control device of the magnetic suspension bearing comprises:

the detection unit is configured to detect a reference current value output by the displacement ring and record the reference current value as a current reference current value of the current ring in the running process of the magnetic suspension bearing; detecting a detection current value of the magnetic bearing coil, and recording the detection current value as a current detection current value of the current loop;

a control unit configured to determine whether or not to start compensation of a current reference current value of the current loop according to a current reference current value of the current loop before current compensation and a current detection current value of the current loop before current compensation, in a case where the current compensation device is turned off;

The control unit is further configured to control the current compensation device to be started to start to compensate the current reference current value of the current loop if the current reference current value of the current loop is determined to need to be compensated;

the control unit is further configured to determine whether to stop compensating the current reference current value of the current loop according to the current reference current value of the current loop after current compensation and the current detection current value of the current loop after current compensation under the condition that the current compensation device is started;

the control unit is further configured to control the current compensation device to be turned off to stop compensating the current reference current value of the current loop by using the current compensation value provided by the current compensation device if it is determined that the compensation of the current reference current value of the current loop needs to be stopped.

7. The control device of a magnetic levitation bearing according to claim 6, wherein the control unit determining whether to start compensation of the current reference current value of the current loop according to the current reference current value of the current loop before current compensation and the current detection current value of the current loop before current compensation, comprises:

8. A magnetic bearing, comprising: a control device for a magnetic bearing as claimed in any one of claims 6 to 7.

9. A magnetic levitation compressor, comprising: a magnetic suspension bearing as claimed in claim 8.

10. A storage medium comprising a stored program, wherein the program, when run, controls a device in which the storage medium is located to perform the method of controlling a magnetic bearing according to any one of claims 1 to 5.