A series winding controller and control method applied to a five-axis magnetic suspension bearing

Abstract

The application discloses a series winding controller and method applied to a hybrid five-axis magnetic suspension bearing, and belongs to the field of magnetic suspension bearing control, and comprises 12 controllable switches, 10 windings and a power supply. The application controls the current size passing through each winding by changing the conduction time of each controllable switch in a switching cycle, and divides the 10 windings into five groups in a parallel mode of using two windings for the same degree of freedom, so as to realize the control of the 10 winding currents for controlling five degrees of freedom in the magnetic suspension bearing. The series connection mode of the five degrees of freedom windings only needs six bridge arms for control, and only two bridge arms are needed for controlling a single coil in the common bridge circuit, so that the utilization rate of the device is effectively improved.

Description

A series winding controller and control method for a five-axis magnetic levitation bearing Technical Field

[0001] This invention belongs to the field of magnetic levitation bearing control, and more specifically, relates to a series winding controller and control method for a five-axis magnetic levitation bearing. Background Technology

[0002] A magnetic levitation bearing is a bearing device that uses electromagnetic force to levitate a rotor, thus replacing traditional mechanical bearings and achieving contactless operation between the rotor and stator. Because there is no mechanical contact between the rotor and stator, it features no need for lubrication, no mechanical friction, no pollution, high stability, and long service life. Magnetic levitation bearings are widely used in applications such as energy storage flywheels and aerospace equipment, where rotors need to rotate at high or ultra-high speeds or where the working environment requirements are high. As early as the 1940s, scholars abroad had already conducted in-depth research on magnetic levitation bearings, and in the 1970s, they entered the industrial application stage. The development of aerospace technology has greatly promoted the development of magnetic levitation bearings, resulting in many groundbreaking magnetic levitation devices. Domestic development in this field started relatively late, but in recent years many universities and enterprises have paid close attention to the latest research progress in magnetic levitation bearings, and some companies have already begun to produce related products. Magnetic levitation bearings still have broad development prospects in the coming decades.

[0003] A magnetic levitation bearing system mainly consists of a rotor, sensors, a controller, and electromagnetic actuators. The design of its control system has a significant impact on the performance of the entire device. The power amplifier, which converts the control signal into current in the windings to control the electromagnetic force of the magnetic bearing, is a crucial component of the magnetic levitation bearing system.

[0004] Currently, magnetic levitation bearings are mainly classified into active magnetic levitation bearings, passive magnetic levitation bearings, and hybrid magnetic levitation bearings. Hybrid magnetic levitation bearings, due to their low loss and small size, are widely used in magnetic levitation bearing systems. The main representatives of hybrid magnetic levitation bearings are a combination of permanent magnet biased magnetic levitation bearings and electromagnetic bearings, or a combination of a common-mode bias coil providing common-mode electromagnetic force and a coil providing differential-mode electromagnetic force. Regarding the control method of their winding current, the traditional full-bridge topology requires two bridge arms to control one winding, which complicates the system structure and increases the cost in magnetic levitation bearing systems. CN111894979B discloses a multi-bridge-arm switching power amplifier that connects all windings to the same bridge arm, increasing the current stress on that bridge arm and reducing safety, requiring additional fault-tolerant design. While this reduces device cost, the current stress on the common bridge arm is high, and the uneven distribution of current stress in the device increases the risk of failure. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a series winding controller and control method for hybrid magnetic levitation bearings, which aims to solve the problems of large number of components in existing hybrid magnetic levitation bearing systems and large common bridge arm current stress in five-phase six-bridge arm controllers.

[0006] To achieve the above objectives, the present invention first provides a series winding controller for a hybrid magnetic levitation bearing, comprising: a first controllable switch S1, a second controllable switch S2, a third controllable switch S3, a fourth controllable switch S4, a fifth controllable switch S5, a sixth controllable switch S6, a seventh controllable switch S7, an eighth controllable switch S8, a ninth controllable switch S9, and a tenth controllable switch S1. 10 Eleventh controllable switch S 11 The twelfth controllable switch S 12 Winding A1, Winding A2, Winding A3, Winding A4, Winding A5, Winding A6, Winding A7, Winding A8, Winding A9, Winding A10 10 And power supply; the hybrid magnetic levitation bearing is a five-axis magnetic levitation bearing, which has five degrees of freedom;

[0007] Specifically, the first controllable switch S1 and the second controllable switch S2 are connected in reverse parallel to form the first bridge arm, which is connected to the positive and negative terminals of the power supply; the third controllable switch S3 and the fourth controllable switch S4 are connected in reverse parallel to form the second bridge arm, which is connected to the positive and negative terminals of the power supply; the fifth controllable switch S5 and the sixth controllable switch S6 are connected in reverse parallel to form the third bridge arm, which is connected to the positive and negative terminals of the power supply; the seventh controllable switch S7 and the eighth controllable switch S8 are connected in reverse parallel to form the fourth bridge arm, which is connected to the positive and negative terminals of the power supply; the ninth controllable switch S9 and the tenth controllable switch S1 are connected in reverse parallel to form the fourth bridge arm, which is connected to the positive and negative terminals of the power supply; and the ninth controllable switch S9 and the tenth controllable switch S1 are connected in reverse parallel to form the fifth controllable switch S1 and the sixth controllable switch S2. 10 The fifth bridge arm, connected in reverse parallel, is connected to the positive and negative terminals of the power supply; the eleventh controllable switch S 11 With the twelfth controllable switch S 12 The sixth bridge arm is connected in reverse parallel to the positive and negative terminals of the power supply; the first winding A1 and the second winding A2 control the first degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the first and second bridge arms; the third winding A3 and the fourth winding A4 control the second degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the second and third bridge arms; the fifth winding A5 and the sixth winding A6 control the third degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the third and fourth bridge arms; the seventh winding A7 and the eighth winding A8 control the fourth degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the third and fourth bridge arms; the ninth winding A9 and the tenth winding A6... 10 The fifth degree of freedom of the magnetic levitation bearing is connected in reverse parallel between the fourth and fifth bridge arms; the controllable switch S1-S12 Used to control the magnitude of the currents i1, i2, i3, i4, and i5 through all windings;

[0008] Wherein, the sum of the currents in the first winding A1 and the second winding A2 corresponds to the first winding current i1; the sum of the currents in the third winding A3 and the fourth winding A4 corresponds to the second winding current i2; the sum of the currents in the fifth winding A5 and the sixth winding A6 corresponds to the third winding current i3; the sum of the currents in the seventh winding A7 and the eighth winding A8 corresponds to the fourth winding current i4; and the sum of the currents in the ninth winding A9 and the tenth winding A6 corresponds to the fourth winding current i4. 10 The sum of the currents corresponds to the fifth winding current i5. The first to fifth winding currents i1, i2, i3, i4, and i5 are used to generate the differential electromagnetic force required for the magnetic levitation bearing rotor to levitate.

[0009] According to one embodiment of the present invention, the controllable switches S1-S 12 All are insulated gate bipolar transistors.

[0010] According to one embodiment of the present invention, the five degrees of freedom are four degrees of freedom in the radial direction of the five-axis magnetic levitation bearing rotor and one degree of freedom in the axial direction of the five-axis magnetic levitation bearing rotor.

[0011] On the other hand, the present invention also provides a control method based on the above-mentioned series winding controller, comprising:

[0012] (1) By synchronously controlling the controllable switches S1-S 12 The on / off state of the controller switches its operating mode.

[0013] (2) By controlling the controllable switches S1-S 12 The conduction time controls the duration of each working mode of the series winding controller, thereby controlling the magnitude of the current in each winding.

[0014] Preferably, step (2) includes:

[0015] (2.1) The duration of each working mode of the controller is controlled by controlling the conduction time of each controllable switch;

[0016] (2.2) Obtain the voltage at adjacent winding nodes based on the duration of each working mode of the series winding controller;

[0017] (2.3) Calculate the current magnitude of each winding based on the voltage at adjacent winding nodes;

[0018] (2.4) By changing the magnitude of the current in the winding, the magnitude of the electromagnetic force in each degree of freedom direction in the magnetic levitation bearing is controlled, thereby levitizing the rotor of the magnetic levitation bearing.

[0019] Preferably, the controllable switches S1-S 12 Its on-time is controlled by changing its gate control signal.

[0020] Preferably, the controllable switches S1-S 12 The gate control signals are all pulse modulation signals with adjustable duty cycles.

[0021] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0022] (1) Compared with traditional hybrid magnetic levitation controllers, each winding requires two bridge arms to control simultaneously. The 10 windings used in this invention are connected in series, and the 10 windings only need 6 bridge arms to control. The current of each winding is controlled by the controllable switches on the two bridge arms adjacent to it, which greatly improves the utilization rate of the device and reduces the cost and volume of the controller.

[0023] (2) The control method of the present invention does not use the method of connecting one end of all windings to a common bridge arm, but adopts the form of series windings. Compared with the five-phase six-bridge arm topology, it evenly distributes the current stress of power devices and improves the reliability of the controller. Attached Figure Description

[0024] Figure 1 is a control structure diagram of the five-axis magnetic levitation bearing provided by the present invention.

[0025] Figure 2 is a topology diagram of the series winding provided by the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Figure 1 shows the control structure of a five-axis magnetic levitation bearing. Each degree of freedom includes two windings, which are connected in parallel in opposite directions for control. The two windings generate the differential electromagnetic force of the magnetic levitation bearing. The bias electromagnetic force is provided by a bias coil or permanent magnet structure. Magnetic levitation bearing control typically employs a dual-loop control system. The outer loop is a position loop, which compares the rotor's relative position signal fed back by a position sensor with a given position. The inner loop receives an excitation current command signal from the controller, and the current loop quickly tracks the position, achieving effective control of the electromagnetic force.

[0028] The following is a specific example 1:

[0029] As shown in Figure 2, this embodiment provides a series winding controller for a magnetic levitation bearing. The hybrid magnetic levitation bearing is a five-axis magnetic levitation bearing with five degrees of freedom, including four degrees of freedom in the radial direction of the magnetic levitation bearing rotor and one degree of freedom in the axial direction of the bearing rotor.

[0030] The series winding controller includes: 12 controllable switches S1-S 12 10 windings A1-A 10 And one DC voltage source; the first and second controllable switches S1 and S2 are connected in series to form the first bridge arm, which is connected to the positive and negative terminals of the power supply; the third and fourth controllable switches S3 and S4 are connected in reverse parallel to form the second bridge arm, which is connected to the positive and negative terminals of the power supply; the fifth and sixth controllable switches S5 and S6 are connected in reverse parallel to form the third bridge arm, which is connected to the positive and negative terminals of the power supply; the seventh and eighth controllable switches S7 and S8 are connected in reverse parallel to form the fourth bridge arm, which is connected to the positive and negative terminals of the power supply; the ninth and tenth controllable switches S9 and S1 are connected in reverse parallel to form the fourth bridge arm, which is connected to the positive and negative terminals of the power supply; and the tenth controllable switches S9 and S1 are connected in reverse parallel to form the fourth bridge arm, which is connected to the positive and negative terminals of the power supply. 10 The fifth bridge arm, connected in reverse parallel, is connected to the positive and negative terminals of the power supply; the eleventh and twelfth controllable switches S 11 With S 12 The sixth bridge arm is connected in reverse parallel to the positive and negative terminals of the power supply; the first and second windings A1 and A2 control the first degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the first and second bridge arms; the third and fourth windings A3 and A4 control the second degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the second and third bridge arms; the fifth and sixth windings A5 and A6 control the third degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the third and fourth bridge arms; the seventh and eighth windings A7 and A8 control the fourth degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the fourth and fifth bridge arms; the ninth and tenth windings A9 and A... 10 The fifth degree of freedom of the magnetic levitation bearing is connected in reverse parallel between the fifth and sixth bridge arms; all controllable switches are used to control the magnitude of the currents i1, i2, i3, i4, and i5 in the first to fifth windings; the first to tenth windings generate the electromagnetic force required by the magnetic levitation bearing through the corresponding winding currents.

[0031] Controllable switch S1-S 12 All are insulated gate bipolar transistors, and their conduction time is controlled by changing their gate control signals. The gate control signals are all pulse modulation signals with adjustable duty cycles.

[0032] The specific control method in this embodiment is as follows:

[0033] (1) The working mode of the controller is switched by synchronously controlling the on and off of each controllable switch;

[0034] (2) By controlling the conduction time of each controllable switch, the duration of each working mode of the controller is controlled, thereby realizing the control of the current of each winding.

[0035] Step (2) specifically includes:

[0036] (2.1) The duration of each working mode of the controller is controlled by controlling the conduction time of each controllable switch;

[0037] (2.2) Obtain the voltage at adjacent winding nodes based on the duration of each working mode of the controller;

[0038] (2.3) Calculate the current magnitude of each winding based on the voltage at adjacent winding nodes;

[0039] (2.4) By changing the magnitude of the current in the winding, the magnitude of the electromagnetic force in each degree of freedom direction in the magnetic levitation bearing is controlled, thereby levitizing the rotor of the magnetic levitation bearing.

[0040] In (2.4), the average voltage at the midpoint of the bridge arm containing the first and second controllable switches S1 and S2 is defined as u1, the average voltage at the midpoint of the bridge arm containing the third and fourth controllable switches S3 and S4 is defined as u2, the average voltage at the midpoint of the bridge arm containing the fifth and sixth controllable switches S5 and S6 is defined as u3, the average voltage at the midpoint of the bridge arm containing the seventh and eighth controllable switches S7 and S8 is defined as u4, and the average voltage at the midpoint of the bridge arm containing the ninth and tenth controllable switches S9 and S1 is defined as u4. 10 The average voltage at the midpoint of the bridge arm is u5, and the eleventh and twelfth controllable switches S 11 and S 12 The average voltage at the midpoint of the bridge arm is u6. This is achieved by controlling the insulated-gate bipolar transistors S1-S... 12 The duty cycle of the pulse width modulation signal of the gate control signal can control the average voltages u1, u2, u3, u4, u5 and u6 on the node;

[0041] Define the first to tenth windings as A1, A2, A3, A4, A5, A6, A7, A8, A9, A 10 The impedances are all ;

[0042] The current flowing through the first and second windings A1 and A2 is ;

[0043] The current flowing through the third and fourth windings A3 and A4 is ;

[0044] The current flowing through the fifth and sixth windings A5 and A6 is ;

[0045] The current flowing through the seventh and eighth windings A7 and A8 is ;

[0046] Ninth and tenth windings A9 and A 10 The current flowing through it is ;

[0047] Windings A1, A2, A3, A4, A5, A6, A7, A8, A9, A 10 The magnitude of the current in can be expressed as:

[0048] (Formula 1)

[0049] In this embodiment, the first and second windings A1 and A2 form a group, controlling the first degree of freedom; the third and fourth windings A3 and A4 form a group, controlling the second degree of freedom; the fifth and sixth windings A5 and A6 form a group, controlling the third degree of freedom; the seventh and eighth windings A7 and A8 form a group, controlling the fourth degree of freedom; and the ninth and tenth windings A9 and A6 form a group, controlling the fourth degree of freedom. 10 One group controls the fifth degree of freedom, using the current in each winding to levitate the five-axis magnetic levitation bearing.

[0050] In this embodiment, only the windings providing differential electromagnetic force to the magnetic levitation bearing are controlled. Each winding group controls the differential electromagnetic force in one degree of freedom of the magnetic levitation bearing, which meets the control requirements of the magnetic levitation bearing. Furthermore, through the above control method, various differential current changes required in the control of the magnetic levitation bearing can be realized, achieving the desired control effect. The current of 10 windings can be controlled using 12 controllable switches, improving the utilization rate of the components and saving the cost of the controller. At the same time, the current stress of each bridge arm is evenly distributed.

[0051] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A series winding controller for a hybrid magnetic levitation bearing, characterized in that, include: First controllable switch S1, second controllable switch S2, third controllable switch S3, fourth controllable switch S4, fifth controllable switch S5, sixth controllable switch S6, seventh controllable switch S7, eighth controllable switch S8, ninth controllable switch S9, tenth controllable switch S1 10 Eleventh controllable switch S 11 The twelfth controllable switch S 12 Winding A1, Winding A2, Winding A3, Winding A4, Winding A5, Winding A6, Winding A7, Winding A8, Winding A9, Winding A10 10 The hybrid magnetic levitation bearing is a five-axis magnetic levitation bearing with five degrees of freedom. Specifically, the first controllable switch S1 and the second controllable switch S2 are connected in reverse parallel to form the first bridge arm, which is connected to the positive and negative terminals of the power supply; the third controllable switch S3 and the fourth controllable switch S4 are connected in reverse parallel to form the second bridge arm, which is connected to the positive and negative terminals of the power supply; the fifth controllable switch S5 and the sixth controllable switch S6 are connected in reverse parallel to form the third bridge arm, which is connected to the positive and negative terminals of the power supply; the seventh controllable switch S7 and the eighth controllable switch S8 are connected in reverse parallel to form the fourth bridge arm, which is connected to the positive and negative terminals of the power supply; the ninth controllable switch S9 and the tenth controllable switch S1 are connected in reverse parallel to form the fourth bridge arm, which is connected to the positive and negative terminals of the power supply; and the ninth controllable switch S9 and the tenth controllable switch S1 are connected in reverse parallel to form the fifth controllable switch S1 and the sixth controllable switch S2. 10 The fifth bridge arm, connected in reverse parallel, is connected to the positive and negative terminals of the power supply; the eleventh controllable switch S 11 With the twelfth controllable switch S 12 The sixth bridge arm is connected in reverse parallel to the positive and negative terminals of the power supply; the first winding A1 and the second winding A2 control the first degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the first and second bridge arms; the third winding A3 and the fourth winding A4 control the second degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the second and third bridge arms; the fifth winding A5 and the sixth winding A6 control the third degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the third and fourth bridge arms; the seventh winding A7 and the eighth winding A8 control the fourth degree of freedom of the magnetic levitation bearing and are connected in reverse parallel between the fourth and fifth bridge arms; the ninth winding A9 and the tenth winding A6... 10 The fifth degree of freedom of the magnetic levitation bearing is connected in reverse parallel between the fifth and sixth bridge arms; the controllable switch S1-S 12 Used to control the magnitudes of the currents i1, i2, i3, i4, and i5 through all windings; wherein, the sum of the currents in the first winding A1 and the second winding A2 corresponds to the first winding current i1, the sum of the currents in the third winding A3 and the fourth winding A4 corresponds to the second winding current i2, the sum of the currents in the fifth winding A5 and the sixth winding A6 corresponds to the third winding current i3, the sum of the currents in the seventh winding A7 and the eighth winding A8 corresponds to the fourth winding current i4, and the sum of the currents in the ninth winding A9 and the tenth winding A5 corresponds to the fourth winding current i5. 10 The sum of the currents corresponds to the fifth winding current i5. The first to fifth winding currents i1, i2, i3, i4, and i5 are used to generate the differential electromagnetic force required for the magnetic levitation bearing rotor to levitate. The average voltage at the midpoint of the bridge arm containing the first and second controllable switches S1 and S2 is defined as u1, the average voltage at the midpoint of the bridge arm containing the third and fourth controllable switches S3 and S4 is defined as u2, the average voltage at the midpoint of the bridge arm containing the fifth and sixth controllable switches S5 and S6 is defined as u3, the average voltage at the midpoint of the bridge arm containing the seventh and eighth controllable switches S7 and S8 is defined as u4, and the average voltage at the midpoint of the bridge arm containing the ninth and tenth controllable switches S9 and S1 is defined as u4. 10 The average voltage at the midpoint of the bridge arm is u5, and the eleventh and twelfth controllable switches S 11 and S 12 The average voltage at the midpoint of the bridge arm is u6; by controlling S1-S 12 The duty cycle of the pulse width modulation signal of the gate control signal controls the average voltages u1, u2, u3, u4, u5, and u6 at the node; the first to tenth windings A1, A2, A3, A4, A5, A6, A7, A8, A9, and A 10 The impedances are all Then windings A1, A2, A3, A4, A5, A6, A7, A8, A9, A 10 The magnitude of the current in is expressed as: 。 2. The series winding controller according to claim 1, characterized in that, The controllable switches S1-S 12 All are insulated gate bipolar transistors.

3. The series winding controller according to claim 1 or 2, characterized in that, The five degrees of freedom are four in the radial direction of the five-axis magnetic levitation bearing rotor and one in the axial direction of the five-axis magnetic levitation bearing rotor.

4. A control method based on the series winding controller according to any one of claims 1-3, characterized in that, Includes the following steps: (1) By synchronously controlling the controllable switches S1-S 12 (2) By controlling the on and off of the controllable switches S1-S 12 The conduction time controls the duration of each working mode of the series winding controller, thereby controlling the magnitude of the current in each winding.

5. The control method according to claim 4, characterized in that, Step (2) includes the following steps: (2.1) Controlling the duration of each working mode of the controller by controlling the conduction time of each controllable switch; (2.2) Obtaining the voltage on the adjacent winding nodes according to the duration of each working mode of the series winding controller; (2.3) Calculating the current magnitude of each winding according to the voltage on the adjacent winding nodes; (2.4) Controlling the magnitude of the electromagnetic force in each degree of freedom direction of the magnetic levitation bearing by changing the magnitude of the current in the winding, thereby levitizing the rotor of the magnetic levitation bearing.

6. The control method according to claim 4 or 5, characterized in that, The controllable switches S1-S 12 Its on-time is controlled by changing its gate control signal.

7. The control method according to claim 6, characterized in that, The controllable switches S1-S 12 The gate control signals are all pulse modulation signals with adjustable duty cycles.

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