CN216929676U

CN216929676U - Power-off protection circuit of magnetic bearing controller

Info

Publication number: CN216929676U
Application number: CN202122572409.9U
Authority: CN
Inventors: 李永胜; 张海刚; 何小宏; 吕前阔; 李致宇; 张婕妤; 孙洪洋; 郑伟
Original assignee: Shandong Tianrui Heavy Industry Co Ltd
Current assignee: Shandong Tianrui Heavy Industry Co Ltd
Priority date: 2021-10-26
Filing date: 2021-10-26
Publication date: 2022-07-08
Anticipated expiration: 2031-10-26

Abstract

The utility model discloses a power-off protection circuit of a magnetic bearing controller, which comprises: the frequency converter is electrically connected with the first DC-DC converter; the frequency converter is used for converting alternating current generated between the stator and the rotor into direct current after power failure; and the first DC-DC converter is used for supplying the direct current to the magnetic bearing controller after DC-DC conversion. The protection circuit can continuously supply power to the magnetic bearing controller when the power supply is suddenly cut off, and avoids the phenomenon that the suspended rotor suddenly drops to damage a machine.

Description

Power-off protection circuit of magnetic bearing controller

Technical Field

The utility model relates to the technical field of magnetic suspension high-speed motors, in particular to a power-off protection circuit of a magnetic bearing controller.

Background

The magnetic suspension motor has the advantages of no abrasion, no pollution, low power consumption, low noise, high efficiency, no need of lubrication and reduced energy consumption, and can be used in vacuum and corrosive media for a long time due to no mechanical contact. Under the working state, the magnetic shaft of the magnetic suspension motor is controlled by the magnetic bearing controller, and when the magnetic bearing controller is electrified and works normally, the rotor is suspended in the air by the magnetic bearing and can rotate at high speed. However, if the power supply is suddenly cut off during high-speed rotation, the rotor directly falls off, and the rotor rotating at high speed does not stop rotating immediately after the power supply is cut off, so that the rotor which cannot be suspended and rotates at high speed and the auxiliary bearing and the bearing are subjected to strong friction, and finally the auxiliary bearing and the rotor are damaged.

In the prior art, a standby power supply is usually added to deal with the emergency situation of sudden power supply disconnection, but the method usually increases the cost for meeting the power supply requirement of the magnetic bearing, cannot judge whether the standby power supply can normally supply power, wastes resources, and also has the hidden danger of damaging equipment.

Disclosure of Invention

In order to solve the technical problems, the utility model provides a power-off protection circuit of a magnetic bearing controller, which is used for solving the problems that power is continuously supplied to the magnetic bearing controller when the power supply is suddenly cut off, a suspension rotor is prevented from suddenly dropping, resources are saved and waste is reduced.

According to one aspect of the present invention, there is provided a power-off protection circuit of a magnetic bearing controller, the power-off protection circuit including: the frequency converter is electrically connected with the first DC-DC converter; the frequency converter is used for converting alternating current generated between the stator and the rotor into direct current after power failure; and the first DC-DC converter is used for supplying the DC current to the magnetic bearing controller after the DC-DC conversion. Wherein the DC-DC converter is a DC-DC converter for regulating the current in response to the DC current supplied by the magnetic bearing controller.

The frequency converter comprises a first rectifier and a direct current bus, and the first rectifier is electrically connected with the direct current bus; the first rectifier is used for converting the alternating current into the direct current and feeding the direct current back to the direct current bus; the direct current bus transmits the direct current to the first DC-DC converter.

Wherein the protection circuit further comprises a UPS power supply; the UPS power supply is electrically connected with the magnetic bearing controller.

Wherein the protection circuit further comprises a second rectifier and a second DC-DC converter; the UPS is electrically connected with the second rectifier and the second DC-DC converter in sequence; the second DC-DC converter is electrically connected with the magnetic bearing controller.

Wherein the protection circuit further comprises a solid state relay; the first DC-DC converter and the second DC-DC converter are electrically connected with the magnetic bearing controller through the solid state relay.

Wherein the first rectifier is electrically connected with the motor.

The protection circuit of the utility model has the advantages that:

the protection circuit is a power-off protection circuit for the magnetic bearing controller, and can solve the problems that the power is continuously supplied to the magnetic bearing controller when the power supply is suddenly cut off, the suspension rotor is prevented from suddenly dropping, resources are saved, and waste is reduced.

Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the utility model, the objectives and other advantages of the application being realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the utility model and together with the description, serve to explain the principles of the utility model. In the drawings, like reference numerals are used to identify like elements. The drawings in the following description are directed to some, but not all embodiments of the utility model. For a person skilled in the art, other figures can be derived from these figures without inventive effort.

Fig. 1 is a schematic view of the present invention showing the normal operation of powering a magnetic bearing controller.

Fig. 2 is a schematic view of an embodiment of the present invention showing power supply to the magnetic bearing controller when power supply is disconnected.

Fig. 3 is a schematic diagram of an embodiment of the present invention showing power to a magnetic bearing controller.

Reference numerals

1. And a frequency converter.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention. It should be noted that, in the embodiments and examples of the present application, the feature vectors may be arbitrarily combined with each other without conflict.

The magnetic shaft of the magnetic suspension motor is controlled by a magnetic bearing controller, and when the magnetic bearing controller is powered and works normally, a rotor is suspended in air and rotates at a high speed under the action of the magnetic bearing. However, if the power supply is suddenly cut off during high-speed rotation, the rotor directly falls off, and the rotor rotating at high speed does not stop rotating immediately after the power supply is cut off, which causes strong friction between the rotor which cannot be suspended and rotates at high speed and the magnetic bearing, and causes damage to the magnetic bearing and damage to the rotor. In the related art, the emergency situation of sudden disconnection of power supply, such as commercial power, is usually dealt with only by adding a standby power supply, but this method increases the cost by meeting the power supply requirement of the magnetic bearing, but cannot judge whether the standby power supply can normally supply power, wastes resources, and still has the hidden trouble of damaging equipment.

In order to solve the above problems, the present invention provides a power-off protection circuit for a magnetic bearing controller, which is used for continuously supplying power to the magnetic bearing controller when the power supply is suddenly interrupted, so as to prevent a suspension rotor from suddenly dropping, and simultaneously save resources and reduce resource waste.

The following describes the power down protection circuit provided by the present invention in detail with reference to the accompanying drawings.

In the normal operation as shown in fig. 1, the magnetic bearing controller is powered by an external power source, and the rotor rotates at a high speed. After power is supplied to the motor, the alternating current is converted into direct current to a direct current bus through a rectifier, and on the one hand, the current on the direct current bus converts direct current voltage into alternating current voltage through an inverter so as to drive the motor. On the other hand, the bus voltage on the direct current bus is converted into direct current capable of supplying power to the magnetic bearing controller after passing through the DC-DC converter. If the power supply is suddenly cut off and is not supplied, the power supply process is cut off, the motor and the magnetic bearing controller are disabled at the moment, the rotor rotating at high speed still rotates at high speed based on inertia, but the rotor rotating at high speed directly falls off at the moment, and the magnetic bearing and the rotor are damaged.

A power down protection circuit for a magnetic bearing controller provided in the embodiment shown in fig. 2 includes: the frequency converter 1 is electrically connected with the first DC-DC converter; the frequency converter 1 is used for converting alternating current generated between the stator and the rotor into direct current after power failure; the first DC-DC converter is used for supplying the DC current to the magnetic bearing controller after DC-DC conversion. As shown in fig. 2, when the motor is suddenly powered off during high-speed rotation, the rotor of the motor continues to rotate under the action of inertia, and in the rotation process, the magnetic induction lines generated by the permanent magnets are continuously cut, so that electromotive force is generated, and the motor becomes a generator. The electromotive force is rectified by a rectifier and then fed back to a direct current bus, and the electromotive force generated by the motor based on inertia supplies power to the magnetic bearing controller through a power supply system shown in figure 2, so that the suspension of the rotor is ensured.

In an exemplary embodiment as shown in fig. 2, the frequency converter 1 includes a first rectifier and a DC bus, the first rectifier is electrically connected to the DC bus, the first rectifier is used for converting an ac current into a DC current and feeding the DC current back to the DC bus, and the DC bus transmits the DC current to the first DC-DC converter. When the motor normally rotates, direct-current voltage exists in the direct-current bus all the time, and the voltage is called as bus voltage. However, the bus voltage on the DC bus is much higher than the operating voltage of the magnetic bearing controller, so the bus voltage needs to be converted by the first DC-DC converter and reduced to the operating voltage of the magnetic bearing controller to power the magnetic bearing controller.

As an exemplary embodiment of the present invention, as shown in fig. 2, since the rotor of the motor is in decelerated rotation after the power supply is cut off, the voltage supplied to the magnetic bearing controller by the first DC-DC converter is fully satisfied for the normal operation of the magnetic bearing controller before the rotation speed of the rotor is reduced to the safe rotation speed. However, when the rotor is lowered to the safe rotation speed, the power supply for the magnetic bearing controller can not be continued, so that the magnetic bearing controller stops working and the rotor falls off, and the rotor of the motor is low in rotation speed and cannot damage the rotor and the magnetic bearing. But still can cause damage to the rotor and the magnetic bearings when damage occurs to the first DC-DC converter or to the frequency converter 1.

To address the above-mentioned issues, in an exemplary embodiment as shown in fig. 3, the power-off protection circuit of the magnetic bearing controller further comprises a UPS power source electrically connected to the magnetic bearing controller. In order to avoid the situation that the first DC-DC converter is damaged or the frequency converter 1 is damaged, a UPS power supply is added on the protection circuit, and when the output voltage of the first DC-DC converter is lower than the power supply voltage of the magnetic bearing controller, the UPS power supply is immediately switched to supply power to the magnetic bearing controller.

In an exemplary embodiment as shown in fig. 3, the power-off protection circuit of the magnetic bearing controller further includes a second rectifier and a second DC-DC converter, the UPS power source in turn electrically connected to the second rectifier and the second DC-DC converter, the second DC-DC converter electrically connected to the magnetic bearing controller. Because the output voltage of the UPS is alternating current voltage, the power supply voltage of the magnetic bearing controller is direct current voltage, and a second rectifier is added between the UPS and the magnetic bearing controller to convert the alternating current voltage into the direct current voltage. Since the rectified DC voltage is much higher than the operating voltage of the magnetic bearing controller, the DC voltage needs to be reduced to the operating voltage of the magnetic bearing controller through the second DC-DC converter to power the magnetic bearing controller, so a second DC-DC converter is added between the UPS power supply and the magnetic bearing controller.

As an exemplary embodiment of the present invention, the power-off protection circuit of the magnetic bearing controller further includes a solid-state relay, as shown in fig. 3. The first DC-DC converter and the second DC-DC converter are electrically connected with the magnetic bearing controller through a solid state relay. Switching to the second DC-DC converter is promptly performed when it is detected that the output voltage of the first DC-DC converter is lower than the operating voltage of the magnetic bearing controller. Because the UPS is in a normally open state, the output end of the second DC-DC converter outputs normal voltage constantly, and the power is supplied by the magnetic bearing controller through the solid-state relay.

As an exemplary embodiment of the present invention, the first rectifier is electrically connected to the motor. As shown in fig. 2, the motor is electrically connected to the first rectifier, the rotating motor rotor continuously cuts the permanent magnet to generate an electromotive force, and the electromotive force is rectified by the first rectifier and then fed back to the dc bus to realize the subsequent power supply process for the magnetic bearing controller.

The utility model greatly reduces the occurrence frequency of the failure event of the magnetic bearing controller caused by the power supply disconnection, and plays a role in protecting the rotor and the magnetic bearing. The rotor of the motor has inertia to generate back electromotive force after power failure, and the back electromotive force can be converted into a power supply of the equipment control device. Therefore, the power-off protection circuit can be used for power-off protection of the magnetic suspension controller and can also be applied to power-off protection of control devices of all equipment with motors. And the problem that the power supply network is paralyzed due to the fact that only the UPS is used as the only standby power supply is solved, because when the UPS is damaged, the standby power supply network is inevitably failed due to power supply failure. The utility model preferentially uses the self-generating function of the motor to supply power for the magnetic bearing controller when the power supply is disconnected, and the UPS is started when the self-generating function is abnormal, so the utility model is not limited by a standby power supply and can not cause the paralysis of the power supply network. And meanwhile, the resources are saved, the resource waste is reduced, and the method is more practical.

It is to be noted that, in this document, the terms "comprises", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion, so that an article or apparatus including a series of elements includes not only those elements but also other elements not explicitly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising.

The above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and the present invention has been described in detail with reference to the preferred embodiments only, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and shall be covered in the claims of the present invention.

Claims

1. A power-down protection circuit for a magnetic bearing controller, the power-down protection circuit comprising:

the frequency converter is electrically connected with the first DC-DC converter;

the input end of the frequency converter is electrically connected with the motor, and the frequency converter is used for converting alternating current generated between a stator and a rotor of the motor into direct current after power failure;

the first DC-DC converter is used for supplying power to the magnetic bearing controller after DC-DC conversion of direct current;

the power-off protection circuit further comprises a UPS power supply, a second rectifier and a second DC-DC converter;

the UPS is electrically connected with the second rectifier and the second DC-DC converter in sequence;

the second DC-DC converter is electrically connected with the magnetic bearing controller.

2. The outage protection circuit according to claim 1, wherein the frequency converter comprises a first rectifier and a direct current bus, the first rectifier being electrically connected with the direct current bus;

the first rectifier is used for converting the alternating current into the direct current and feeding the direct current back to the direct current bus;

the direct current bus transmits the direct current to the first DC-DC converter.

3. The power outage protection circuit of claim 1, wherein the protection circuit further comprises a solid state relay;

the first DC-DC converter and the second DC-DC converter are electrically connected with the magnetic bearing controller through the solid state relay.

4. The power failure protection circuit of claim 2, wherein the first rectifier is electrically connected to a motor.