A magnetic bearing system and a control method thereof

Abstract

The application provides a magnetic suspension bearing system and a control method thereof, and the magnetic suspension bearing system comprises a rotating shaft, an axial magnetic bearing and a radial magnetic bearing, the axial magnetic bearing and the radial magnetic bearing are sleeved on the outer periphery of the rotating shaft, the axial magnetic bearing comprises an axial magnetic bearing stator, the radial magnetic bearing comprises a radial magnetic bearing stator and a radial magnetic bearing rotor, the radial magnetic bearing rotor is sleeved on the outer periphery of the rotating shaft and can rotate together, the radial magnetic bearing stator is located on the outer periphery of the radial magnetic bearing rotor and can exert a radial electromagnetic force on the radial magnetic bearing rotor, at least part of the structure of the axial magnetic bearing stator is located on the axial end of the radial magnetic bearing rotor, and the axial magnetic bearing stator can exert an axial electromagnetic force on the radial magnetic bearing rotor. According to the application, the radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated shaft and a radial integrated magnetic bearing structure, so that the axial dimension of the rotor is reduced, and the problem of low fixed frequency deviation of the rotor is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnetic suspension technology, in particular to a magnetic suspension bearing system and a control method thereof. BACKGROUND

[0002] Magnetic suspension bearing has the characteristics of no mechanical friction, no lubrication, high critical speed, long service life and high reliability, and has been widely used in high speed, ultra-high speed and other fields. Displacement sensor is an important part of magnetic suspension system. Reasonable layout of magnetic suspension sensor and bearing can improve the reliability and stability of the magnetic suspension system.

[0003] As Figure 1 Generally, the existing magnetic suspension bearing system adopts the form of sensing and actuating separation. As shown in the prior art figure, the basic structure includes a rotating shaft 1', a radial displacement sensor 2', a radial bearing 3', a motor rotor 4', an axial bearing core 5', an axial bearing coil 6', a rotor thrust disc 7' and an axial displacement sensor 8'.

[0004] The axial bearing stator is arranged on both sides of the rotor thrust disc 7', the radial displacement sensor 2' for detecting the radial displacement of the rotor is arranged on one side of the radial bearing 3', and the axial displacement sensor 8' for detecting the axial displacement of the rotor is arranged on the left end face of the rotating shaft 1'. The sensor and the bearing are installed separately. When the rotating shaft 1' has radial or axial displacement, the sensor converts the detected displacement change into a signal and transmits it to the system, and then controls the bearing output to make the shaft return to the safe position.

[0005] This structure has the following disadvantages:

[0006] 1. The thrust bearing 7' occupies a certain length of the rotating shaft 1', resulting in a long axial size of the rotor, which is prone to the problem of low rotor fixed frequency deviation

[0007] 2. The detection value of the axial sensor and the actual axial gap data of the thrust bearing may not be consistent (mainly due to thermal expansion caused by stable rising of the optical axis during motor operation, which makes the data detected by the axial displacement sensor 8 actually the axial displacement of the rotor 1' plus the axial expansion of the rotating shaft, resulting in error or error), which will affect the control accuracy of the system;

[0008] 3. The sensor and the axial bearing are arranged separately, resulting in a large number of outgoing terminal ends of the entire system;

[0009] 4. Arranging the axial sensor requires a certain axial space of the rotating shaft, resulting in an increase in the length of the rotating shaft, a decrease in the dynamic performance of the rotating shaft and an increase in the cost of the entire system.

[0010] As Figure 2Patent No. CN110242670A discloses a magnetic suspension bearing system and a tool with the same, the magnetic suspension bearing system comprising: a rotating shaft 10', a thrust bearing 20', a first axial core assembly 30', a second axial core assembly 40', and a detection assembly 50'. The first axial core assembly 30' is sleeved on the rotating shaft 10' and located on the first side of the thrust bearing 20'; the second axial core 40' is sleeved on the rotating shaft 10' and located on the second side of the thrust bearing 20'; and the detection assembly 50' is integrated on the first axial core assembly 30' or the second axial core assembly 40'. The magnetic suspension bearing system integrates the detection assembly on the first bearing iron assembly or the second axial core assembly, which can improve the control accuracy of the magnetic suspension bearing system, reduce the length of the rotating shaft, and further improve the mechanical properties and quality of the rotating shaft. However, the thrust bearing 20' occupies a certain length of the rotating shaft 10', and the detection assembly 50' integrated on the first axial core assembly 30' or the second axial core assembly 40' cannot determine the rotor heating elongation.

[0011] Since the thrust bearing of the magnetic suspension bearing system in the prior art occupies a certain length of the rotating shaft, the rotor axial size is long, and technical problems such as low rotor fixed frequency deviation are prone to occur, the present application researches and designs a magnetic suspension bearing system and a control method thereof. SUMMARY

[0012] Therefore, the technical problem to be solved by the present application is to overcome the defects that the thrust bearing of the magnetic suspension bearing system in the prior art occupies a certain length of the rotating shaft, the rotor axial size is long, and low rotor fixed frequency deviation is prone to occur, thereby providing a magnetic suspension bearing system and a control method thereof.

[0013] To solve the above problems, the present application provides a magnetic suspension bearing system, which comprises:

[0014] A rotating shaft, an axial magnetic bearing, and a radial magnetic bearing, the axial magnetic bearing and the radial magnetic bearing are both sleeved on the outer periphery of the rotating shaft, the axial magnetic bearing comprises an axial magnetic bearing stator, the radial magnetic bearing comprises a radial magnetic bearing stator and a radial magnetic bearing rotor, the radial magnetic bearing rotor is sleeved on the outer periphery of the rotating shaft and can rotate with the rotating shaft, the radial magnetic bearing stator is located on the outer periphery of the radial magnetic bearing rotor and can exert a radial electromagnetic force on the radial magnetic bearing rotor, at least part of the structure of the axial magnetic bearing stator is located at one axial end of the radial magnetic bearing rotor in the axial direction of the rotating shaft, and the axial magnetic bearing stator can exert an axial electromagnetic force on the radial magnetic bearing rotor.

[0015] In some embodiments, the axial magnetic bearing stator comprises an axial magnetic bearing core and an axial magnetic bearing coil, the axial magnetic bearing core comprises a main body part, a first annular part and a second annular part, the main body part is a disc structure with a central hole, the central hole accommodates the rotating shaft therethrough, one end of the first annular part is connected with the radially inner end of the main body part and the other end extends towards the radial magnetic bearing rotor, one end of the second annular part is connected with the main body part and the other end extends towards the radial magnetic bearing rotor, and the second annular part is located radially outside the first annular part to form an accommodation groove between the radially outer side of the first annular part and the radially inner side of the second annular part, the axial magnetic bearing coil is arranged in the accommodation groove and wound around the outer periphery of the first annular part.

[0016] In some embodiments, the first annular part extends along the axial direction of the rotating shaft and is spaced apart from the radial magnetic bearing rotor by a first predetermined distance, and the second annular part also extends along the axial direction of the rotating shaft and is spaced apart from the radial magnetic bearing rotor by a second predetermined distance.

[0017] In some embodiments, the radial magnetic bearing further comprises a radial magnetic bearing rotor baffle, the radial magnetic bearing rotor baffle is sleeved on the rotating shaft, and the radial magnetic bearing rotor baffle has two, one of which is located at one axial end of the radial magnetic bearing rotor, and the other is located at the other axial end of the radial magnetic bearing rotor; the two radial magnetic bearing rotor baffles are fixedly connected with the radial magnetic bearing rotor and can rotate integrally with the radial magnetic bearing rotor.

[0018] In some embodiments, among the two radial magnetic bearing rotor baffles, the radial magnetic bearing rotor baffle relatively close to the first annular part and the second annular part is spaced apart from the first annular part and the second annular part by a third predetermined distance.

[0019] In some embodiments, the radial magnetic bearing stator comprises a radial magnetic bearing stator core and a radial magnetic bearing coil, the radial magnetic bearing stator core is also an annular structure, is sleeved on the radial outer periphery of the radial magnetic bearing rotor and is spaced apart from the radial magnetic bearing rotor.

[0020] In some embodiments, the axial magnetic bearing core further comprises a third annular part, one end of the third annular part is connected with the radially outer end of the main body part, and the other end of the third annular part extends to the radially outer side of the radial magnetic bearing stator core and is connected with the radial magnetic bearing stator core.

[0021] In some embodiments, a housing is further included, the housing is a cylindrical structure and is located at the outer periphery of the axial magnetic bearing and the radial magnetic bearing, one end of the third annular portion is located at one axial side of the radial magnetic bearing, the other end of the third annular portion is located at the other axial side of the radial magnetic bearing, so that part of the third annular portion is located at the radial outer periphery of the radial magnetic bearing stator core, the radial inner periphery of the third annular portion is fixedly connected with the radial magnetic bearing stator core, and the radial outer periphery of the third annular portion is fixedly connected with the housing.

[0022] In some embodiments, an axial displacement sensor and an axial displacement detection member are further included, the axial displacement sensor is arranged on the axial magnetic bearing, the axial displacement detection member is arranged on the rotating shaft and can move with the rotating shaft, and the axial displacement sensor can detect the axial movement of the axial displacement detection member.

[0023] In some embodiments, when the axial magnetic bearing stator includes an axial magnetic bearing core, the axial displacement sensor is a ring structure and is fixedly arranged on the axial magnetic bearing core, the axial displacement detection member is also a ring structure and is fixedly arranged on the rotating shaft, and the axial displacement detection member can also prevent oil from entering the axial magnetic bearing and the radial magnetic bearing.

[0024] In some embodiments, a magnetic bearing assembly and a motor assembly are further included, the magnetic bearing assembly includes the axial magnetic bearing, the radial magnetic bearing, the axial displacement sensor and the axial displacement detection member, and the magnetic bearing assembly is at least two, one of which is arranged at one axial side of the motor assembly, the other of which is arranged at the other axial side of the motor assembly, and the two magnetic bearing assemblies are symmetrically arranged relative to the motor assembly.

[0025] In some embodiments, the motor assembly includes a motor rotor and a motor stator.

[0026] In some embodiments, a cooling device is further included, the cooling device can input cooling fluid according to the axial movement data of the axial displacement detection member detected by the axial displacement sensor to cool the rotating shaft, the axial magnetic bearing and the radial magnetic bearing.

[0027] The application also provides a control method of the magnetic levitation bearing system as described in any one of the preceding embodiments, wherein: when the axial magnetic bearing stator includes an axial magnetic bearing core and an axial magnetic bearing coil, and when the magnetic levitation bearing system further includes a cooling device:

[0028] The control method includes:

[0029] detecting, by an axial displacement sensor on one axial side of the motor assembly, an axial displacement of the rotating shaft, and detecting, by an axial displacement sensor on the other axial side of the motor assembly, an axial displacement of the rotating shaft;

[0030] judging, according to the axial displacements detected by the axial displacement sensors on the two axial sides of the motor assembly, whether the rotating shaft is operating in a standard temperature range or a non-standard temperature range;

[0031] controlling, when the rotating shaft is operating in the standard temperature range, the energizing current of the axial magnetic bearing coil of the axial magnetic bearing to change to adjust the axial displacement of the rotating shaft, and at the same time, turning off the cooling device; and controlling, when the rotating shaft is operating in the non-standard temperature range, the cooling device to be turned on to cool the rotating shaft, and at the same time, controlling the axial magnetic bearing coil of the axial magnetic bearing to operate, and controlling the energizing current of the axial magnetic bearing coil to change or not to change;

[0032] wherein the standard temperature range is a temperature range in which the rotating shaft does not deform due to thermal expansion and contraction, and the non-standard temperature range is a temperature range in which the rotating shaft deforms due to thermal expansion and contraction.

[0033] In some embodiments, in the detecting step, a first gap between the axial displacement detection member corresponding to the axial displacement sensor on one axial side of the motor assembly is detected by the axial displacement sensor, and a second gap between the axial displacement detection member corresponding to the axial displacement sensor on the other axial side of the motor assembly is detected by the axial displacement sensor.

[0034] In the judging step, when the first gap decreases and the second gap increases, and the decrease amount of the first gap and the increase amount of the second gap are within an error range; or when the first gap increases and the second gap decreases, and the increase amount of the first gap and the decrease amount of the second gap are within an error range; it is judged that the rotating shaft is operating in the standard temperature range.

[0035] When the first gap decreases and the second gap increases, and the decrease amount of the first gap and the increase amount of the second gap are not within an error range; or when the first gap increases and the second gap decreases, and the increase amount of the first gap and the decrease amount of the second gap are not within an error range; or when the first gap and the second gap decrease or increase at the same time, it is judged that the rotating shaft is operating in the non-standard temperature range.

[0036] In the control step, when the rotating shaft operates in a standard temperature range, the energization current of the axial magnetic bearing coil of the axial magnetic bearing is controlled to change to adjust the first gap and the second gap, at this time the cooling device is closed; when the rotating shaft operates in a non-standard temperature range, the cooling device is controlled to be opened to cool the rotating shaft, and the axial magnetic bearing coil of the axial magnetic bearing is controlled to operate, the energization current of the axial magnetic bearing coil is controlled to change or not to change; and the cooling flow of the cooling device is controlled to be increased or decreased according to the first gap and the second gap.

[0037] The magnetic suspension bearing system and the control method thereof have the following beneficial effects:

[0038] 1. The axial magnetic bearing and the radial magnetic bearing are effectively arranged, the radial magnetic bearing stator is located at the outer periphery of the radial magnetic bearing rotor and can exert a radial electromagnetic force on the radial magnetic bearing rotor, at least part of the structure of the axial magnetic bearing stator is located at one axial end of the radial magnetic bearing rotor, and the axial magnetic bearing stator can exert an axial electromagnetic force on the radial magnetic bearing rotor, so that the radial magnetic bearing rotor can be adjusted by the radial electromagnetic force exerted by the radial magnetic bearing stator to adjust the radial deviation of the rotating shaft, and the radial magnetic bearing rotor can also be adjusted by the axial electromagnetic force exerted by the axial magnetic bearing stator to adjust the axial deviation of the rotating shaft, and finally the radial and axial support of the rotating shaft is achieved. The radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated shaft and a radial integrated magnetic bearing structure. Compared with the separate axial magnetic bearing and radial magnetic bearing in the prior art, the axial magnetic bearing needs to be provided with a thrust bearing to provide an axial force to the rotating shaft, and the radial magnetic bearing needs to be provided with a radial magnetic bearing rotor. The structure of the thrust bearing is effectively saved, the axial size of the rotor is effectively reduced and shortened, and the problem of low rotor fixed frequency deviation is effectively solved. At this time, the radial magnetic bearing rotor can be subjected to radial forces in the up, down, left and right directions exerted by the radial magnetic bearing stator, and can be subjected to an axial force exerted by the axial magnetic bearing stator, so that the magnetic suspension bearing (radial magnetic bearing rotor) of the present application is formed as a 5-degree-of-freedom magnetic suspension bearing, the use of parts is reduced, the axial size of the rotor is shortened, and the rotor fixed frequency is improved.

[0039] 2. The application also comprises at least two magnetic bearing assemblies, one of which is arranged on one axial side of the motor assembly, the other is arranged on the other axial side of the motor assembly, and the two magnetic bearing assemblies are symmetrically arranged relative to the motor assembly, which improves the universality of bearing parts and avoids the need for two sets of drawings for processing front and rear axial parts; and since the axial sensor structure is arranged on both sides of the front and rear axial bearings, in the case of rotor heating, the rotor axial position is calculated by differential form, the rotor is judged and adjusted to be located at the center position, avoiding the situation that the rotor axial position deviates from the center position due to rotor heating and elongation, and the rotor heating and elongation can be effectively detected, solving the problem that the heating and elongation cannot be detected and determined in the prior art;

[0040] 3. The application adopts the axial sensor structure arranged on both sides of the front and rear axial bearings, the shaft elongation when the rotor is in the standard temperature interval is set to determine the shaft elongation by calculation, the rotor elongation is stabilized in a certain interval by adjusting the cooling medium flowing into the magnetic bearing system to increase or decrease the bearing current, and the running precision is improved. That is, the application controls the flow of the cooling fluid according to the shaft elongation to avoid falling into a non-standard temperature interval, thereby avoiding the above-mentioned error (i.e. avoiding the detection error caused by axial expansion), and the rotor heating and elongation can be effectively detected by differential to determine whether it is in a standard temperature interval or a non-standard temperature interval, solving the problem that the axial sensor detection value and the actual axial gap data of the thrust bearing may not be consistent, which affects the control precision of the system;

[0041] 4. The application also arranges the axial displacement sensor on the axial magnetic bearing, so that the axial displacement sensor is integrated with the axial magnetic bearing, effectively solving the problem of separate arrangement of the existing sensor and the axial bearing, which causes the number of outgoing terminals of the entire system to be relatively large, and also solving the problem that arranging the axial sensor requires a certain amount of spindle axial space, causing the length of the spindle to increase, the dynamic performance of the spindle to decrease, and the cost of the entire system to increase. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a structure diagram of the magnetic suspension system of background technology 1;

[0043] Figure 2 is a structure diagram of the magnetic suspension system of background technology 2;

[0044] Figure 3 is a structure diagram of the magnetic suspension system of the application;

[0045] Figure 4 is Figure 3 is a partial enlarged structure diagram of the axial magnetic bearing core in

[0046] Figure 5 is a flow chart of a control method of a magnetic suspension system of the present application.

[0047] Reference signs are shown as follows:

[0048] 1, rotating shaft; 100, axial magnetic bearing; 101, axial magnetic bearing stator; 200, radial magnetic bearing; 201, radial magnetic bearing stator; 2, axial displacement detection member; 3, axial displacement sensor; 4, axial magnetic bearing coil; 5, radial magnetic bearing rotor baffle; 6, radial magnetic bearing rotor; 7, radial magnetic bearing stator core; 8, axial magnetic bearing core; 80, main body portion; 81, first annular portion; 82, second annular portion; 83, third annular portion; 84, accommodating groove; 9, radial magnetic bearing coil; 10, motor rotor; 11, motor stator; 12, housing; 13, cooling device. DETAILED DESCRIPTION

[0049] As shown in Figures 3-4 , the present application provides a magnetic suspension bearing system, which comprises:

[0050] A rotating shaft 1 (or rotating shaft), an axial magnetic bearing 100, and a radial magnetic bearing 200, the axial magnetic bearing 100 and the radial magnetic bearing 200 are sleeved on the outer periphery of the rotating shaft 1, the axial magnetic bearing 100 comprises an axial magnetic bearing stator 101, the radial magnetic bearing 200 comprises a radial magnetic bearing stator 201 and a radial magnetic bearing rotor 6, the radial magnetic bearing rotor 6 is sleeved on the outer periphery of the rotating shaft 1 and can rotate together with the rotating shaft 1, the radial magnetic bearing stator 201 is located on the outer periphery of the radial magnetic bearing rotor 6 and can exert a radial electromagnetic force on the radial magnetic bearing rotor 6, at least part of the structure of the axial magnetic bearing stator 101 in the axial direction of the rotating shaft 1 is located at one axial end of the radial magnetic bearing rotor 6, and the axial magnetic bearing stator 101 can exert an axial electromagnetic force on the radial magnetic bearing rotor 6.

[0051] The axial magnetic bearing and the radial magnetic bearing are effectively arranged, the radial magnetic bearing stator is located at the outer periphery of the radial magnetic bearing rotor and can exert radial electromagnetic force on the radial magnetic bearing rotor, at least part of the structure of the axial magnetic bearing stator is located at one axial end of the radial magnetic bearing rotor, the axial magnetic bearing stator can exert axial electromagnetic force on the radial magnetic bearing rotor, so that the radial magnetic bearing rotor can be adjusted in radial deviation of the rotating shaft by the radial electromagnetic force of the radial magnetic bearing stator, and the radial magnetic bearing rotor can also be adjusted in axial deviation of the rotating shaft by the axial electromagnetic force of the axial magnetic bearing stator, finally, the radial and axial support of the rotating shaft is realized, the radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated shaft and a radial integrated magnetic bearing structure, compared with the separate axial magnetic bearing and the radial magnetic bearing in the prior art, the structure of the thrust bearing for the axial magnetic bearing is effectively saved, the axial size of the rotor is effectively reduced and shortened, and the problem of low rotor fixed frequency deviation is effectively solved; at this time, the radial magnetic bearing rotor can be subjected to the radial force in the up, down, left and right directions respectively exerted by the radial magnetic bearing stator, and can be subjected to the axial force exerted by the axial magnetic bearing stator, so that the magnetic suspension bearing (the radial magnetic bearing rotor) of the application forms a 5-degree-of-freedom magnetic suspension bearing, the use of parts is reduced, the axial size of the rotor is shortened, and the rotor fixed frequency is improved.

[0052] BACKGROUND 1. Problems existing in the prior art:

[0053] 1. The radial magnetic bearing and the axial magnetic bearing are separately arranged, so that the axial magnetic bearing must adopt a thrust bearing (or an axial magnetic bearing rotor) to bear the axial electromagnetic force, and the problem of low rotor fixed frequency deviation occurs;

[0054] 2. The detection value of the axial sensor and the actual axial gap data of the thrust bearing can be inconsistent, which can affect the control accuracy of the system;

[0055] 3. The sensor and the axial bearing are separately arranged, so that the number of outgoing terminals of the entire system is relatively large; the axial sensor occupies a certain axial space of the main shaft, so that the length of the main shaft is increased, the dynamic performance of the main shaft is reduced, and the cost of the entire system is increased.

[0056] For the above problem 1, the radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated shaft and a radial integrated magnetic bearing structure, which effectively saves the structure of the thrust bearing, effectively reduces and shortens the axial size of the rotor, and effectively solves the problem of low rotor fixed frequency deviation.

[0057] For the above problem 2, the flow size of the cooling fluid is controlled according to the shaft elongation to avoid falling into a non-standard temperature range, thereby avoiding the above error (i.e., avoiding the detection error caused by axial expansion), and the difference is used to determine whether it is in a standard temperature range or a non-standard temperature range.

[0058] For the above problem 3, the axial displacement sensor is arranged on the axial magnetic bearing, so that the axial displacement sensor is integrated with the axial magnetic bearing, effectively solving the problem of the existing sensor and the axial bearing being arranged separately, causing the number of outlet terminals of the entire system to be large, and also solving the problem of the axial sensor occupying a certain spindle axial space, causing the length of the spindle to increase, the dynamic performance of the spindle to decrease, and the cost of the entire system to increase.

[0059] Problems existing in the background art 2:

[0060] 1. The radial magnetic bearing and the axial magnetic bearing are arranged separately, so that the axial magnetic bearing must use a thrust bearing (or an axial magnetic bearing rotor) to bear the axial electromagnetic force, causing the problem of low rotor fixed frequency deviation;

[0061] 2. The detection assembly 50' integrated on the first axial core assembly 30' or the second axial core assembly 40' cannot determine the rotor heating elongation, and only one end has a sensor, which cannot effectively detect the rotor heating elongation.

[0062] For the above problem 1, the radial magnetic bearing and the axial magnetic bearing are effectively combined together to form an integrated shaft and a radial integrated magnetic bearing structure, which effectively saves the structure of the thrust bearing, effectively reduces and shortens the axial size of the rotor, and effectively solves the problem of low rotor fixed frequency deviation;

[0063] For the above problem 2: the application adopts the structure that axial sensors are installed on both sides of the front and rear axial bearings, the axial extension amount is calculated when the standard temperature interval of the running rotor is set, the axial gap is determined according to the calculation result, the rotor extension amount is stabilized in a certain interval by adjusting the cooling medium flowing into the magnetic suspension bearing system, the bearing current is reduced, and the running precision is improved.

[0064] The application improvement points of the application are as follows:

[0065] 1. A 5-degree-of-freedom magnetic suspension bearing system structure with double axial detection. The axial bearings are placed on both sides of the front and rear radial bearings, the use of parts is reduced, the rotor axis size is shortened, the rotor fixed frequency is improved, and the universality of the magnetic suspension bearing parts is improved.

[0066] 2. A double axial detection control method. The rotor axial position is calculated by difference, the rotor is judged and adjusted to be located at the center position, and independent temperature compensation devices can be omitted; the layout form can be considered to write the control method

[0067] 3. A motor rotor axial extension amount calculation method and cooling medium flow control method. Axial sensors are installed on both sides of the front and rear axial bearings, the axial extension amount can be calculated through the axial sensors, and the rotor extension amount is stabilized in a certain interval by adjusting the cooling medium flowing into the magnetic suspension bearing system, the bearing current is reduced, and the rotor running precision is improved.

[0068] The application solves the following technical problems:

[0069] 1. The 5-degree-of-freedom magnetic suspension bearing with the axial bearings placed on both sides of the front and rear radial bearings cancels the thrust bearing parts, reduces the rotor axial size, avoids the problem of low rotor fixed frequency, the axial symmetric magnetic suspension bearing system structure improves the universality of the bearing parts, and avoids two sets of drawings processing of the front and rear axial parts.

[0070] 2. By installing axial sensors on both sides of the front and rear axial bearings, detecting the oil blocking sleeve on both sides, judging and adjusting the rotor to be located at the axial center position by difference, the situation that the rotor is heated and extended to cause the rotor to deviate from the center position is avoided (because the rotor has axial displacement sensors at both ends, the difference form is a way of processing two groups of data measured by the sensors, and this point mainly indicates that the 5-degree-of-freedom magnetic suspension bearing detects the axial deviation of the rotor by the difference form of double axial detection, and then adjusts the axial position of the rotor through the axial bearing.

[0071] 3. The axial dimension change of the rotor is determined by summing up the axial distances on both sides, which can be used to deduce the temperature of the motor rotor; by setting the shaft elongation amount when the standard temperature interval of the running rotor is set, the cooling medium flowing into the magnetic bearing system is adjusted to increase or decrease. Figure 3 This mainly explains that the 5-DOF magnetic bearing can determine the shaft elongation amount by summing up the axial distances on both sides, calculate whether the rotor is running in the standard temperature interval, and if not, the attached

[0072] Advantages:

[0073] 1. The 5-DOF magnetic bearing structure with axial magnetic bearings placed on both sides of the front and rear radial bearings reduces the use of parts, shortens the axial dimension of the rotor, and improves the rotor fixed frequency.

[0074] 2. The axial symmetric magnetic bearing system structure improves the universality of magnetic bearing parts (the magnetic bearings on both sides of the motor stator are symmetric about the motor stator, and the bearing parts on both sides can be universal).

[0075] 3. The structure of installing axial sensors on both sides of the front and rear axial bearings can calculate the axial position of the rotor by difference form in the case of rotor heating, judge and adjust the rotor to be located at the center position.

[0076] 4. The structure of installing axial sensors on both sides of the front and rear axial bearings can determine the shaft elongation by setting the shaft elongation amount when the standard temperature interval of the running rotor is set, and by adjusting the cooling medium flowing into the magnetic bearing system to increase or decrease to stabilize the rotor elongation in a certain interval, reduce the bearing current, and improve the running accuracy.

[0077] In some embodiments, the axial magnetic bearing stator 101 includes an axial magnetic bearing core 8 and an axial magnetic bearing coil 4, the axial magnetic bearing core 8 includes a main body part 80, a first annular part 81 and a second annular part 82, the main body part 80 is a disc structure with a central hole, the central hole accommodates the shaft 1 passing through, one end of the first annular part 81 is connected with the main body part 80 (preferably the radial inner side end) and the other end extends towards the direction of the radial magnetic bearing rotor 6, one end of the second annular part 82 is connected with the main body part 80 and the other end extends towards the direction of the radial magnetic bearing rotor 6, and the second annular part 82 is located radially outside the first annular part 81 to form an accommodation groove 84 between the radially outer side of the first annular part 81 and the radially inner side of the second annular part 82, the axial magnetic bearing coil 4 is arranged in the accommodation groove 84 and wound around the outer periphery of the first annular part 81.

[0078] This is the preferred structure of the axial magnetic bearing stator of the present application, through the cooperation of the axial magnetic bearing core and the axial magnetic bearing coil, the axial magnetic bearing coil can be energized to generate a magnetic field, thereby providing an axial electromagnetic force to the radial magnetic bearing rotor; and the axial magnetic bearing core includes a main body portion, a first and a second annular portion, which forms a receiving groove between the first and second annular portions for accommodating the winding of the axial magnetic bearing coil, providing a structural condition for the axial magnetic bearing coil, and enabling the axial electromagnetic force to act on the radial magnetic bearing rotor in the axial direction.

[0079] In some embodiments, the first annular portion 81 extends in the axial direction of the shaft 1 and is spaced apart from the radial magnetic bearing rotor 6 by a first predetermined distance, and the second annular portion 82 also extends in the axial direction of the shaft 1 and is spaced apart from the radial magnetic bearing rotor 6 by a second predetermined distance. This is the preferred structure of the first and second annular portions of the present application, which both extend in the axial direction and are spaced apart from the radial magnetic bearing rotor, can be opposite to the radial magnetic bearing rotor to provide an axial electromagnetic force to it, and do not contact the radial magnetic bearing rotor to avoid collision. The axial magnetic bearing of the present application is fixed opposite to the housing, only the radial magnetic bearing rotor and the radial magnetic bearing rotor baffle rotate with the shaft.

[0080] In some embodiments, the radial magnetic bearing 200 further comprises a radial magnetic bearing rotor baffle 5, which is sleeved on the shaft 1, and the radial magnetic bearing rotor baffle 5 has two, one of which is located at one axial end of the radial magnetic bearing rotor 6, and the other is located at the other axial end of the radial magnetic bearing rotor 6; two radial magnetic bearing rotor baffles 5 are fixed with the radial magnetic bearing rotor 6 and can rotate with the radial magnetic bearing rotor 6. This is a further preferred structure of the radial magnetic bearing of the present application, through the setting of the radial magnetic bearing rotor baffle, the axial ends of the radial magnetic bearing rotor can be limited and positioned, preventing the radial magnetic bearing rotor from moving axially.

[0081] In some embodiments, among the two radial magnetic bearing rotor baffles 5, the radial magnetic bearing rotor baffles 5 relatively close to the first annular portion 81 and the second annular portion 82 are spaced apart from the first annular portion 81 and the second annular portion 82 by a third predetermined distance. The present application sets the radial magnetic bearing rotor baffles between the first and second annular portions and the radial magnetic bearing rotor to be spaced apart from the two annular portions by a third predetermined distance, so that the radial magnetic bearing rotor baffles do not contact the axial magnetic bearing to prevent collision, and the rotor baffles can be integrated with the radial magnetic bearing rotor to withstand the axial electromagnetic force of the axial magnetic bearing, thereby improving the performance of the axial electromagnetic force.

[0082] In some embodiments, the radial magnetic bearing stator 201 comprises a radial magnetic bearing stator core 7 and a radial magnetic bearing coil 9, the radial magnetic bearing stator core 7 is also annular structure, which is sleeved on the radial outer periphery of the radial magnetic bearing rotor 6 and is spaced apart from the radial magnetic bearing rotor 6. Preferably, the radial magnetic bearing coil 9 is wound from the axial one end of the radial magnetic bearing stator core 7 to the axial other end thereof. This is the preferred structure of the radial magnetic bearing stator of the present application. By comprising a radial magnetic bearing stator core and a radial magnetic bearing coil, the radial magnetic bearing coil can be energized to generate a radial magnetic field through the radial magnetic bearing stator core, thereby generating a radial electromagnetic force on the radial magnetic bearing rotor. The radial magnetic bearing stator is spaced apart from the radial magnetic bearing rotor to avoid collision.

[0083] In some embodiments, when the axial magnetic bearing stator 101 comprises an axial magnetic bearing core 8, the axial magnetic bearing core 8 further comprises a third annular portion 83, one end of the third annular portion 83 is connected with the radially outer end of the main body portion 80, and the other end of the third annular portion 83 extends to the radially outer side of the radial magnetic bearing stator core 7 and is connected with the radial magnetic bearing stator core 7. This is the preferred structure of the axial magnetic bearing core of the present application. By comprising a third annular portion and extending the third annular portion to the radially outer side of the radial magnetic bearing stator core and connecting with the radial magnetic bearing stator core, the two can be fixed as a whole, thereby realizing the integrated structure design of the axial magnetic bearing and the radial magnetic bearing, making the structure more compact, and canceling the thrust bearing (or axial magnetic bearing rotor) in the axial magnetic bearing.

[0084] Further preferably, the third annular portion extends in the axial direction of the shaft 1.

[0085] In some embodiments, the machine shell 12 is a cylindrical structure and is located at the outer periphery of the axial magnetic bearing 100 and the radial magnetic bearing 200, one end of the third annular portion 83 is located at one axial side of the radial magnetic bearing 200, the other end of the third annular portion 83 is located at the other axial side of the radial magnetic bearing 200, so that part of the structure of the third annular portion 83 is located at the radial outer periphery of the radial magnetic bearing stator core 7, the radial inner periphery of the third annular portion 83 is fixedly connected with the radial magnetic bearing stator core 7, and the radial outer periphery of the third annular portion 83 is fixedly connected with the machine shell 12. The axial magnetic bearing and the radial magnetic bearing and other structures can be accommodated in the machine shell, and the radial outer periphery of the third annular portion is fixed with the machine shell, and the radial inner periphery is fixed with the radial magnetic bearing stator core, so that the radial magnetic bearing stator and the axial magnetic bearing are fixed as a whole by the structure design of the third annular portion, and are fixed to the machine shell, realizing the design of structural integration, and the structure is more compact.

[0086] In some embodiments, the axial displacement sensor 3 is arranged on the axial magnetic bearing 100, and the axial displacement detection member 2 is arranged on the rotating shaft 1 and can move with the movement of the rotating shaft 1, and the axial displacement sensor 3 can detect the axial displacement of the axial displacement detection member 2. The axial displacement sensor and the axial displacement detection member are designed, and the axial displacement of the axial displacement detection member on the rotating shaft can be detected by the axial displacement sensor, so that the degree of axial displacement of the rotating shaft or the thermal expansion and contraction can be effectively detected. By arranging the axial displacement sensor on the axial magnetic bearing, the axial displacement sensor and the axial magnetic bearing are integrated, effectively solving the problem of too many system terminal wires caused by the separate arrangement of the existing sensor and the axial bearing, and solving the problem of occupying a certain axial space of the main shaft, causing the length of the main shaft to increase, the kinetic performance of the main shaft to decrease, and the cost of the whole system to increase.

[0087] In some embodiments, when the axial magnetic bearing stator 101 includes an axial magnetic bearing core 8, the axial displacement sensor 3 is in a ring structure and is fixedly arranged on the axial magnetic bearing core 8, and the axial displacement detection member 2 is also in a ring structure and is fixedly sleeved on the rotating shaft 1, and the axial displacement detection member 2 can also block oil for the axial magnetic bearing 100 and the radial magnetic bearing 200. This is the preferred structure of the axial displacement sensor and the axial displacement detection member of the present application, both of which can be in a ring structure, and the axial displacement detection member can not only detect the axial displacement of the rotating shaft or the thermal expansion by cooperating with the axial displacement sensor, but also block oil for the axial magnetic bearing and the radial magnetic bearing, i.e., act as an oil blocking sleeve.

[0088] In some embodiments, the magnetic bearing assembly and the motor assembly are further included, the magnetic bearing assembly includes the axial magnetic bearing 100, the radial magnetic bearing 200, the axial displacement sensor 3 and the axial displacement detection piece 2, and the magnetic bearing assembly is at least two, and one of the magnetic bearing assemblies is arranged on one side of the motor assembly in the axial direction, the other magnetic bearing assembly is arranged on the other side of the motor assembly in the axial direction, and the two magnetic bearing assemblies are symmetrically arranged relative to the motor assembly. The present application further comprises at least two magnetic bearing assemblies, one of which is arranged on one side of the motor assembly in the axial direction, the other magnetic bearing assembly is arranged on the other side of the motor assembly in the axial direction, and the two magnetic bearing assemblies are symmetrically arranged relative to the motor assembly. The universality of the bearing parts is improved, and two sets of drawings for processing front and rear axial parts are avoided. And because the axial sensor structure is installed on both sides of the front and rear axial bearings, the rotor axial position is calculated by differential form when the rotor is heated, the rotor is judged and adjusted to be located at the center position, and the situation that the rotor is heated and elongated to cause the rotor to be separated from the center position is avoided. The rotor heating elongation can be effectively detected, and the problem that the heating elongation cannot be detected and determined in the prior art is solved.

[0089] The present application provides a 5-DOF magnetic suspension bearing system with double axial detection, as shown in Figure 3 The system includes a rotating shaft 1, an axial displacement detection piece 2, an axial displacement sensor 3, an axial magnetic bearing coil 4, a radial magnetic bearing rotor baffle 5, a radial magnetic bearing rotor 6 (preferably a silicon steel sheet), a radial magnetic bearing stator core 7, an axial magnetic bearing core 8, a radial magnetic bearing coil 9, a motor rotor 10, a motor stator 11, a machine shell 12 and a cooling device 13.

[0090] As shown in Figure 3 The front and rear radial bearings, the front and rear axial bearings and the front and rear displacement sensors are completely symmetrical, which improves the universality of the magnetic suspension bearing parts.

[0091] In some embodiments, the motor assembly includes a motor rotor 10 and a motor stator 11. This is the preferred structure of the motor assembly of the present application.

[0092] In some embodiments, a cooling device 13 is further included, which is capable of detecting axial movement data of the axial displacement detection member 2 according to the axial displacement sensor 3 and passing the cooling fluid to cool the shaft 1, the axial magnetic bearing 100 and the radial magnetic bearing 200. It is further preferred that the cooling device is arranged on the casing 12. The present application can cool the shaft in a non-standard temperature range through the cooling device, so as to effectively avoid the inaccuracy caused by thermal expansion; that is, the present application adopts the structure that the axial sensors are arranged on both sides of the front and rear axial bearings, the shaft elongation amount in the standard temperature range of the running rotor is set, the shaft elongation amount is determined according to the axial gap calculated, the cooling medium passing through the magnetic bearing system is adjusted to increase or decrease, so as to stabilize the rotor elongation amount in a certain range, reduce the bearing current and improve the running accuracy. That is, the present application controls the flow of the cooling fluid according to the shaft elongation amount to avoid falling into the non-standard temperature range, so as to avoid the above error (i.e. to avoid the detection error caused by the axial expansion), the difference is used to determine whether it is in the standard temperature range or the non-standard temperature range, the rotor heating elongation amount can be effectively detected, and the problem that the axial sensor detection value and the actual axial gap data of the thrust bearing may not be consistent, which affects the control accuracy of the system, is solved.

[0093] As Figure 5 The present application further provides a control method of the magnetic bearing system according to any one of the preceding, characterized in that: when the axial magnetic bearing stator 101 comprises an axial magnetic bearing core 8 and an axial magnetic bearing coil 4, and when the magnetic bearing system further comprises a cooling device 13:

[0094] The control method comprises:

[0095] a detection step of detecting the axial deviation of the shaft 1 through the axial displacement sensor 3 on the axial side of the motor assembly, and detecting the axial deviation of the shaft 1 through the axial displacement sensor 3 on the other axial side of the motor assembly;

[0096] a judgment step of judging whether the shaft is running in the standard temperature range or the non-standard temperature range according to the axial deviation detected by the axial displacement sensors on the two axial sides of the motor assembly;

[0097] a control step of changing the energizing current of the axial magnetic bearing coil 4 of the axial magnetic bearing to adjust the axial deviation of the shaft when the shaft is running in the standard temperature range, at which time the cooling device is closed; and opening the cooling device to cool the shaft when the shaft is running in the non-standard temperature range, while controlling the axial magnetic bearing coil 4 of the axial magnetic bearing to run, and controlling the change or invariability of the energizing current of the axial magnetic bearing coil 4;

[0098] Wherein, the standard temperature interval is a temperature interval in which the rotating shaft does not deform due to thermal expansion and contraction, and the non-standard temperature interval is a temperature interval in which the rotating shaft deforms due to thermal expansion and contraction.

[0099] The application installs axial sensors on both sides of the front and rear axial bearings, detects the axial displacement of the rotating shaft 1, and determines whether the rotating shaft is in the standard temperature interval or the non-standard temperature interval, so that the rotating shaft returns to the standard temperature interval by increasing or decreasing the cooling medium of the magnetic suspension bearing system in the non-standard temperature interval, and the elongation is stabilized in a certain interval, which can effectively reduce the use of bearing current, avoid the inaccuracy of axial displacement detection caused by thermal expansion and contraction, and effectively improve the detection accuracy and operation accuracy of axial displacement.

[0100] In some embodiments, in the detection step, the first gap between the axial displacement sensor 3 on one axial side of the motor assembly and the corresponding axial displacement detection member is detected, and the second gap between the axial displacement sensor 3 on the other axial side of the motor assembly and the corresponding axial displacement detection member is detected.

[0101] In the determination step, when the first gap decreases and the second gap increases, and the decrease of the first gap and the increase of the second gap are within an error range; or when the first gap increases and the second gap decreases, and the increase of the first gap and the decrease of the second gap are within an error range; it is determined that the rotating shaft is operating in the standard temperature interval.

[0102] When the first gap decreases and the second gap increases, and the decrease of the first gap and the increase of the second gap are not within an error range; or when the first gap increases and the second gap decreases, and the increase of the first gap and the decrease of the second gap are not within an error range; or when the first gap and the second gap decrease or increase at the same time; it is determined that the rotating shaft is operating in the non-standard temperature interval.

[0103] In the control step, when the rotating shaft is operating in the standard temperature interval, the energization current of the axial magnetic bearing coil 4 of the axial magnetic bearing is controlled to change to adjust the first gap and the second gap, and at this time the cooling device is closed; when the rotating shaft is operating in the non-standard temperature interval, the cooling device is controlled to be opened to cool the rotating shaft, and the axial magnetic bearing coil 4 of the axial magnetic bearing is controlled to operate, the energization current of the axial magnetic bearing coil 4 is controlled to change or not to change; and the cooling flow of the cooling device is controlled to increase or decrease according to the first gap and the second gap.

[0104] This is the preferred control form of the present application, that is, the differential comparison method is explained, which can effectively determine whether the rotating shaft is in the standard temperature interval or the non-standard temperature interval; that is, when the first gap decreases and the second gap increases, and the decrease amount of the first gap and the increase amount of the second gap are within the error range; or, when the first gap increases and the second gap decreases, and the increase amount of the first gap and the decrease amount of the second gap are within the error range; it is determined that the rotating shaft is running in the standard temperature interval.

[0105] When the first gap decreases and the second gap increases, and the decrease amount of the first gap and the increase amount of the second gap are not within the error range; or, when the first gap increases and the second gap decreases, and the increase amount of the first gap and the decrease amount of the second gap are not within the error range; or when the first gap and the second gap decrease at the same time or increase at the same time; it is determined that the rotating shaft is running in the non-standard temperature interval.

[0106] The present application compares the two ends of the rotating shaft to determine whether the rotating shaft is running in the standard temperature interval or the non-standard temperature interval. If it is in the standard temperature interval, it means that the rotating shaft has not deformed due to thermal expansion and contraction, so only the size of the current needs to be adjusted to adjust the axial displacement of the rotating shaft. If it is in the non-standard temperature interval, it means that the rotating shaft has deformed due to thermal expansion and contraction, so the cooling fluid should be supplied first to cool the rotating shaft, so that the temperature returns to the standard temperature interval, thereby effectively avoiding low detection accuracy due to thermal expansion and contraction, and reducing the use of bearing current.

[0107] The operating principle of the present application is preferably as follows:

[0108] The axial displacement sensor in the magnetic suspension bearing system is arranged at the two ends of the rotating shaft to detect the axial displacement of the axial displacement detection member 2 (preferably an axial displacement detection ring). When the system is normally running in the standard temperature interval, the rotating shaft 1 will have a certain elongation, and the predetermined gap between the axial detection ring at both ends and the axial displacement sensor is determined in combination with the elongation;

[0109] When the rotating shaft is running in the standard temperature interval, but the rotating shaft 1 has an axial displacement towards the front end, the gap between the front end axial detection ring and the front end axial displacement sensor increases, and the gap between the rear end axial detection ring and the rear end axial displacement sensor decreases. The axial displacement sensors at both ends transmit the axial displacement data detected at this time to the system controller, and the system controller adjusts the axial position of the main shaft by reducing the input current of the front end axial bearing and increasing the input current of the rear end axial bearing; (in the figure Figure 3It can be understood that both ends have axial bearing coils, which side the current of the rotating shaft 1 is offset to, the gap between the corresponding axial detection member 2 and the axial sensor 3 will also increase.

[0110] When the rotating shaft runs in the standard temperature interval, but the rotating shaft 1 has an axial displacement to the rear end, the gap between the front end axial detection ring and the front end axial displacement sensor decreases, the gap between the rear end axial detection ring and the rear end axial displacement sensor increases, the axial displacement sensors at both ends transmit the axial displacement data detected at this time to the system controller, and the system controller adjusts the axial position of the main shaft by increasing the input current of the front end axial bearing and reducing the input current of the rear end axial bearing, so that the rotating shaft returns to the original position as much as possible.

[0111] When the rotating shaft runs in the non-standard temperature interval, the rotor is elongated or shortened, the predetermined gap between the front and rear end axial detection rings and the front and rear end axial displacement sensors increases or decreases (that is, the rotor is deformed due to thermal expansion or cold contraction), the axial displacement sensors at both ends transmit the axial displacement data detected at this time to the system controller, and the system controller analyzes the displacement data obtained and outputs a control signal to adjust the flow of the cooling medium into the magnetic suspension bearing system to stabilize the elongation of the rotor in a certain interval, reduce the bearing current (that is, reduce the use of current to adjust the offset of the rotating shaft), and improve the operation accuracy.

[0112] The double-axial detection magnetic suspension system of the application has front and rear end bearings that are axially symmetrical, improving the universality of the magnetic suspension bearing parts; analyzing the measurement data of the front and rear end axial displacement sensors can not only adjust the input current of the front and rear axial bearings to adjust the axial position of the main shaft, but also analyze whether the motor rotor is running in the standard temperature interval, and then adjust the flow of the cooling medium into the magnetic suspension bearing system to stabilize the elongation of the rotor in a certain interval, reduce the bearing current (here, "reducing the bearing current" means that the axial length of the rotor can be controlled by using the cooling medium, thereby reducing the use of bearing current in the non-standard temperature interval), improve the operation accuracy, prevent axial collision, and improve the stability of the magnetic suspension system.

[0113] The above description is only the preferred embodiment of the application and is not intended to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application. The above description is only the preferred embodiment of the application, and it should be pointed out that those skilled in the art can make several improvements and modifications without departing from the technical principles of the application, and these improvements and modifications shall be regarded as the protection scope of the application.

Claims

1. A magnetic bearing system, characterized by: Comprise: The rotating shaft (1), axial magnetic bearing (100), radial magnetic bearing (200), the axial magnetic bearing (100) and the radial magnetic bearing (200) are all set in the outer periphery of the rotating shaft (1), the axial magnetic bearing (100) includes axial magnetic bearing stator (101), the radial magnetic bearing (200) includes radial magnetic bearing stator (201) and radial magnetic bearing rotor (6), the radial magnetic bearing rotor (6) is set in the outer periphery of the rotating shaft (1) and can rotate with the rotating shaft (1), the radial magnetic bearing stator (201) is located in the outer periphery of the radial magnetic bearing rotor (6) and can exert radial electromagnetic force on the radial magnetic bearing rotor (6), at least part of the structure of the axial magnetic bearing stator (101) is located in the axial one end of the radial magnetic bearing rotor (6) along the axial direction of the rotating shaft (1), the axial magnetic bearing stator (101) can exert axial electromagnetic force on the radial magnetic bearing rotor (6); The radial magnetic bearing rotor (6) can be subjected to the force in the radial direction, up, left and right four directions exerted by the radial magnetic bearing stator (201), and at the same time, the radial magnetic bearing rotor (6) can be subjected to the force in the axial direction exerted by the axial magnetic bearing stator (101), so that the radial magnetic bearing rotor (6) is formed into a 5-degree-of-freedom magnetic suspension bearing rotor.

2. The magnetic suspension bearing system according to claim 1, wherein: The axial magnetic bearing stator (101) includes an axial magnetic bearing core (8) and an axial magnetic bearing coil (4), the axial magnetic bearing core (8) includes a main body portion (80), a first annular portion (81) and a second annular portion (82), the main body portion (80) is a disc structure with a central hole, the central hole contains the rotating shaft (1) passing through, one end of the first annular portion (81) is connected with the main body portion (80) and the other end extends towards the radial magnetic bearing rotor (6), one end of the second annular portion (82) is connected with the main body portion (80) and the other end extends towards the radial magnetic bearing rotor (6), and the second annular portion (82) is located radially outside the first annular portion (81) to form a containing groove (84) between the radially outer side of the first annular portion (81) and the radially inner side of the second annular portion (82), the axial magnetic bearing coil (4) is arranged in the containing groove (84) and wound around the outer periphery of the first annular portion (81).

3. The magnetic suspension bearing system according to claim 2, wherein: The first annular portion (81) extends along the axial direction of the rotating shaft (1) and is spaced apart from the radial magnetic bearing rotor (6) by a first predetermined distance, and the second annular portion (82) also extends along the axial direction of the rotating shaft (1) and is spaced apart from the radial magnetic bearing rotor (6) by a second predetermined distance.

4. The magnetic suspension bearing system according to claim 2, wherein: The radial magnetic bearing (200) further comprises a radial magnetic bearing rotor baffle (5), the radial magnetic bearing rotor baffle (5) is sleeved on the rotating shaft (1), and the radial magnetic bearing rotor baffle (5) has two, one of which is located at one axial end of the radial magnetic bearing rotor (6), and the other is located at the other axial end of the radial magnetic bearing rotor (6); the two radial magnetic bearing rotor baffles (5) are fixedly connected with the radial magnetic bearing rotor (6) and can rotate integrally with the radial magnetic bearing rotor (6).

5. The magnetic bearing system of claim 4, wherein: The radial magnetic bearing rotor baffles (5) in the two radial magnetic bearing rotor baffles (5) are spaced apart from the first annular portion (81) and the second annular portion (82) by a third predetermined distance.

6. The magnetic bearing system of any one of claims 1-5, wherein: The radial magnetic bearing stator (201) comprises a radial magnetic bearing stator core (7) and a radial magnetic bearing coil (9), the radial magnetic bearing stator core (7) is also annular structure, sleeved on the radial outer periphery of the radial magnetic bearing rotor (6) and arranged spaced apart from the radial magnetic bearing rotor (6).

7. The magnetic bearing system of claim 6, wherein: When the axial magnetic bearing stator (101) comprises an axial magnetic bearing core (8), and the axial magnetic bearing core (8) comprises a main body portion (80), the axial magnetic bearing core (8) further comprises a third annular portion (83), one end of the third annular portion (83) is connected with the radial outer side end of the main body portion (80), and the other end of the third annular portion (83) extends to the radial outer side of the radial magnetic bearing stator core (7) and is connected with the radial magnetic bearing stator core (7).

8. The magnetic bearing system of claim 7, wherein: Further comprising a housing (12), the housing (12) is a cylindrical structure and is located at the outer periphery of the axial magnetic bearing (100) and the radial magnetic bearing (200), one end of the third annular portion (83) is located at one axial side of the radial magnetic bearing (200), the other end of the third annular portion (83) is located at the other axial side of the radial magnetic bearing (200), so that part of the structure of the third annular portion (83) is located at the radial outer periphery of the radial magnetic bearing stator core (7), the radial inner periphery of the third annular portion (83) is fixedly connected with the radial magnetic bearing stator core (7), and the radial outer periphery of the third annular portion (83) is fixedly connected with the housing (12).

9. The magnetic bearing system of any one of claims 1-5, wherein: Further comprising an axial displacement sensor (3) and an axial displacement detection piece (2), the axial displacement sensor (3) is arranged on the axial magnetic bearing (100), the axial displacement detection piece (2) is arranged on the rotating shaft (1) and can move with the movement of the rotating shaft (1), and the axial displacement sensor (3) can detect the axial movement of the axial displacement detection piece (2).

10. The magnetic bearing system of claim 9, wherein: When the axial magnetic bearing stator (101) comprises an axial magnetic bearing core (8), the axial displacement sensor (3) is of a ring structure and is fixedly arranged on the axial magnetic bearing core (8), and the axial displacement detection piece (2) is also of a ring structure and is fixedly sleeved on the rotating shaft (1), and the axial displacement detection piece (2) can also block oil for the axial magnetic bearing (100) and the radial magnetic bearing (200).

11. The magnetic bearing system of claim 9, wherein: Further comprising a magnetic bearing assembly and a motor assembly, the magnetic bearing assembly comprises the axial magnetic bearing (100), the radial magnetic bearing (200), the axial displacement sensor (3) and the axial displacement detection piece (2), and the magnetic bearing assembly is at least two, one of which is arranged on one side of the motor assembly in the axial direction, the other of which is arranged on the other side of the motor assembly in the axial direction, and the two magnetic bearing assemblies are symmetrically arranged relative to the motor assembly.

12. The magnetic bearing system of claim 11, wherein: The motor assembly comprises a motor rotor (10) and a motor stator (11).

13. The magnetic bearing system of claim 11, wherein: Further comprising a cooling device (13), which can pass cooling fluid according to the axial movement data of the axial displacement detection piece (2) detected by the axial displacement sensor (3) to cool the rotating shaft (1), the axial magnetic bearing (100) and the radial magnetic bearing (200).

14. A method of controlling a magnetic bearing system as claimed in any one of claims 11-13, characterized by: When the axial magnetic bearing stator (101) comprises an axial magnetic bearing core (8) and an axial magnetic bearing coil (4), and when the magnetic bearing system further comprises a cooling device (13): The control method comprises: The detection step detects the axial displacement of the rotating shaft (1) through the axial displacement sensor (3) on one side of the motor assembly in the axial direction, and also detects the axial displacement of the rotating shaft (1) through the axial displacement sensor (3) on the other side of the motor assembly in the axial direction; The judgment step judges whether the rotating shaft is running in a standard temperature range or a non-standard temperature range according to the axial displacement detected by the axial displacement sensors on both sides of the motor assembly in the axial direction; The control step is to control the current of the axial magnetic bearing coil (4) of the axial magnetic bearing to change to adjust the axial displacement of the rotating shaft when the rotating shaft operates in the standard temperature range, at which time the cooling device is closed; and to control the cooling device to open to cool the rotating shaft while controlling the axial magnetic bearing coil (4) of the axial magnetic bearing to operate, and controlling the current of the axial magnetic bearing coil (4) to change or not to change when the rotating shaft operates in the non-standard temperature range. The standard temperature range is a temperature range in which the rotating shaft does not deform due to thermal expansion and contraction, and the non-standard temperature range is a temperature range in which the rotating shaft deforms due to thermal expansion and contraction.

15. The control method according to claim 14, characterized in that: In the detection step, the first gap between the axial displacement detection member corresponding to the axial displacement sensor (3) on one axial side of the motor assembly is detected by the axial displacement sensor (3), and the second gap between the axial displacement detection member corresponding to the axial displacement sensor (3) on the other axial side of the motor assembly is detected by the axial displacement sensor (3); In the judgment step, when the first gap decreases and the second gap increases, and the decrease amount of the first gap and the increase amount of the second gap are within an error range; or when the first gap increases and the second gap decreases, and the increase amount of the first gap and the decrease amount of the second gap are within an error range; it is judged that the rotating shaft operates in the standard temperature range; When the first gap decreases and the second gap increases, and the decrease amount of the first gap and the increase amount of the second gap are not within an error range; or when the first gap increases and the second gap decreases, and the increase amount of the first gap and the decrease amount of the second gap are not within an error range; or when the first gap and the second gap decrease or increase at the same time; it is judged that the rotating shaft operates in the non-standard temperature range; In the control step, when the rotating shaft operates in the standard temperature range, the current of the axial magnetic bearing coil (4) of the axial magnetic bearing is controlled to change to adjust the first gap and the second gap, at which time the cooling device is closed; when the rotating shaft operates in the non-standard temperature range, the cooling device is controlled to open to cool the rotating shaft while controlling the axial magnetic bearing coil (4) of the axial magnetic bearing to operate, and the current of the axial magnetic bearing coil (4) is controlled to change or not to change; and the cooling flow of the cooling device is controlled to increase or decrease according to the first gap and the second gap.

Images