Fault-tolerant control method and system for magnetic levitation expansion generator controller

Abstract

The application discloses a magnetic suspension expansion generator controller fault tolerance control method and system, belongs to the field of magnetic suspension bearing control, and the magnetic suspension bearing in the generator has N degrees of freedom and comprises 2N winding A1-A N and B1-B N ; the magnetic suspension bearing adopts a full-bridge type series winding topological structure; the method comprises the following steps: detecting currents i n and i n in the windings A an and B cn , n is an element in the set {1, 2, …, N}, if i an +i cn >i limiit ', it is determined that the upper switch tube of the bridge arm L n connected to A n , the lower switch tube of the bridge arm L n+1 , the upper switch tube of the bridge arm L n connected to B n+N , and the lower switch tube of the bridge arm L n+N+1 exist a short-circuit fault; the electromagnetic force resultant force generated by the windings on each degree of freedom is taken as a preset value as a target, the current size and the current direction of each winding are calculated, and a PWM signal for controlling each switch tube in each bridge arm is generated and applied to the corresponding switch tube. The application can realize short-circuit fault identification and fault tolerance for the magnetic suspension expansion generator controller based on the series winding topological structure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of magnetic suspension bearing control, and more particularly, to a magnetic suspension expansion generator controller fault-tolerant control method and system. BACKGROUND

[0002] As a device for efficiently utilizing low-temperature waste heat to generate power, the magnetic suspension expansion generator has the advantages of low loss, high efficiency, long service life, etc., and has been widely used in the industrial field in recent years.

[0003] As a core part of the magnetic suspension expansion generator, the magnetic suspension bearing is a device that suspends the rotor in the air by electromagnetic force, enabling the rotor to operate in a non-contact state, thereby realizing the working characteristics of no lubrication and no friction, and prolonging the service life of the equipment. This bearing is an excellent choice to replace traditional mechanical bearings and is widely used in centrifugal compressors, high-speed flywheels, vacuum molecular pumps and other equipment that require rotor high-speed operation or maintenance of a vacuum clean environment. The key components of the active magnetic suspension bearing system include the rotor, sensors, controllers and power amplifiers. Among them, the power amplifier, as the core component of electromechanical conversion, plays an indispensable role in the control of the entire magnetic suspension expansion generator.

[0004] The power amplifier converts the current command into the actual current of the winding in order to accurately regulate the electromagnetic attraction of the magnetic bearing. When a switching element in the power amplifier circuit fails, the control function of the bridge arm voltage will be lost, causing the winding current to deviate from the set value, further causing the rotor to be unstable, which may cause the rotor to fall and even cause the system to shut down and other serious failures. In response to this, in the patent document with the application publication number CN112901658A, a new fault-tolerant topology is disclosed for a magnetic suspension bearing switch open fault-tolerant control system. However, it can only solve the fault-tolerant problem of the open circuit fault of the switching device, and cannot cope with the short circuit fault of the switching device. When the switching element has a short circuit fault, the switching element is continuously turned on, and the winding current rises sharply. This fault will cause more serious harm to the magnetic suspension bearing and even the entire magnetic suspension expansion generator.

[0005] In the patent document with the application publication number CN116498651A, a switch short circuit fault-tolerant control method and system for a magnetic suspension bearing is disclosed. It proposes a method for identifying the short circuit fault of the switching device for a half-bridge topology structure, but cannot implement the corresponding fault-tolerant mechanism. In the patent document with the application publication number CN116857280A, a switch short circuit fault-tolerant topology circuit for a four-degree-of-freedom magnetic suspension bearing is disclosed. It proposes a method for identifying the short circuit fault of the switching device for a reverse common bridge arm topology structure and the corresponding short circuit fault-tolerant strategy.

[0006] In the field of electromagnetic bearings, series winding topology is a topology different from full-bridge topology and reverse common bridge arm topology, which can maximize the use of power supply voltage, make the output voltage amplitude reach the full DC voltage, match the open winding full-bridge inverter, and the speed range of the motor can exceed 70% of the conventional voltage source inverter (VSI) motor. The short-circuit fault tolerance strategy proposed for the reverse common bridge arm topology cannot be applied to the magnetic suspension bearing based on the series winding topology. SUMMARY

[0007] In view of the defects of the prior art and the need for improvement, the present application provides a magnetic suspension expansion generator controller fault tolerance control method and system, which aims to realize short-circuit fault identification and tolerance of the magnetic suspension expansion generator controller based on series winding topology, and improve the operation stability and safety of the magnetic suspension expansion generator.

[0008] To achieve the above-mentioned purpose, according to one aspect of the present application, a magnetic suspension expansion generator controller fault tolerance control method is provided, the magnetic suspension bearing in the magnetic suspension expansion generator has N degrees of freedom, and includes 2N windings A1-A N and B1-B N , the winding A n and the winding B n are used to control the nth degree of freedom, n∈{1,2,……,N}; the magnetic suspension bearing adopts full-bridge series winding topology, including 2N+1 bridge arms L1-L 2N+1 ; the 2N windings are sequentially connected in series in the order of A1-A N , B1-B N , the two ends of the winding A n are connected to the midpoints of the bridge arms L n and L n+1 , respectively, and the two ends of the winding B n are connected to the midpoints of the bridge arms L n+N and L n+N+1 , respectively; the fault tolerance control method includes: short-circuit fault identification and short-circuit fault tolerance;

[0009] The short-circuit fault identification includes: detecting the currents i n and i n in the windings A an and B cn , if the sum of the two currents is greater than a preset current threshold i limiit ', it is determined that a short-circuit fault exists in a group of switch tubes S n , S n , S 2n-1 and S 2n+2 used to control the windings A 2n+2N-1 and B 2n+2N+2 ; wherein, S2n-1 is the bridge arm L n The upper switch tube, S 2n+2 is the bridge arm L n+1 The lower switch tube, S 2n+2N-1 is the bridge arm L n+N The upper switch tube, S 2n+2N+2 is the bridge arm L n+N+1 The lower switch tube;

[0010] Short-circuit fault tolerance includes: after identifying a short-circuit fault, calculating the current magnitude and direction of each winding with the goal of making the resultant electromagnetic force generated by the two windings in each degree of freedom a preset value; based on the current magnitude and direction of each winding, generating a PWM signal for controlling the on and off of each switch tube in each bridge arm, and applying it to the corresponding switch tube.

[0011] Further, after identifying the control winding A n and B n A set of switching tubes S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 After a short circuit fault occurs, the current magnitude and current direction of each winding are calculated with the goal of making the resultant electromagnetic force generated by the two windings in each degree of freedom equal to a preset value, including the following steps:

[0012] S1: Positioning switch tube S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 There is a short circuit fault in the switch tube, if it is used to control winding A n If the switch tube is on, it switches to S2; otherwise, it switches to S3;

[0013] S2: Set winding A1~A n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding A is set n+1 ~A N The current magnitude is equal to the original current magnitude, the current direction is the same as the original current direction, and the electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings B1~B N The magnitude and direction of the current;

[0014] S3: Set winding B1~B n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding B is set n+1 ~B N The current magnitude is equal to the original current magnitude and the current direction is the same as the original current direction. The electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings A1~AN a current size and a current direction of the winding;

[0015] wherein the original current size and the original current direction of the winding represent a current size and a current direction of the winding in a normal working condition, respectively.

[0016] Further, in step S1, the switch tube S 2n-1 , S 2n+2 , S 2n+2N-1 and S 2n+2N+2 in which a short-circuit fault exists, includes:

[0017] monitoring a voltage instruction value of the bridge arm L n , L n+1 , L n+N and L n+N+1 ;

[0018] if the voltage instruction value of the bridge arm L n decreases and finally reaches negative saturation, it is judged that the short-circuit fault occurs in the switch tube S 2n-1 ;

[0019] if the voltage instruction value of the bridge arm L n+1 increases and finally reaches positive saturation, it is judged that the short-circuit fault occurs in the switch tube S 2n+2 ;

[0020] if the voltage instruction value of the bridge arm L n+N decreases and finally reaches negative saturation, it is judged that the short-circuit fault occurs in the switch tube S 2n+2N-1 ;

[0021] if the voltage instruction value of the bridge arm L n+N+1 increases and finally reaches positive saturation, it is judged that the short-circuit fault occurs in the switch tube S 2n+2N+2 .

[0022] Further, on the nth degree of freedom, the calculation expression of the resultant electromagnetic force generated by the two windings is:

[0023]

[0024] wherein F represents the resultant electromagnetic force generated by the two windings on the nth degree of freedom before the short-circuit fault occurs; μ0 represents the vacuum permeability, m represents the number of turns of the winding, A α represents the magnetic pole area, and α represents the included angle between the magnetic pole and the net force; dis0 represents twice the air gap of the magnetic suspension bearing, dis1 represents the distance from the center of the rotor to the magnetic pole corresponding to the coil A n ; I an and I cn represent the currents of the windings A n and B n , respectively.

[0025] Furthermore, the fault-tolerant control method for the magnetic levitation expansion generator controller provided by the present invention further includes: circuit breaker fault identification; circuit breaker fault identification includes:

[0026] Detection winding A n and B n The current i an and i cn , if the sum of the two is less than the preset current threshold i limiit ″, then it is determined that the winding A n and B n A set of switching tubes S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 There is a circuit breaker fault;

[0027] Among them, i limiit ″ limiit ′.

[0028] Furthermore, the fault-tolerant control method for the magnetic levitation expansion generator controller provided by the present invention further includes: circuit breaker fault location; circuit breaker fault location includes:

[0029] After identifying the control winding A n and B n A set of switching tubes S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 After a circuit breaker fault occurs, monitor the bridge arm L n 、L n+1 、L n+N and L n+N+1 Voltage command value;

[0030] If the bridge arm L n The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n-1 A circuit breaker fault occurs;

[0031] If the bridge arm L n+1 The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n+2 A short circuit fault occurs;

[0032] If the bridge arm L n+N The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n+2N-1 A circuit breaker fault occurs;

[0033] If the bridge arm L n+N+1 The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n+2N+2 A circuit breaker fault has occurred. ​

[0034] According to another aspect of the present invention, a fault-tolerant control system for a magnetic levitation expansion generator controller is provided. The magnetic bearing in the magnetic levitation expansion generator has N degrees of freedom and includes 2N windings A1 to A2. N and B1~B N , Winding A n and winding B n Used to control the nth degree of freedom, n∈{1,2,……,N}; the magnetic bearing adopts a full-bridge series winding topology, including 2N+1 bridge arms L1~L 2N+1 ; 2N windings according to A1~A N 、B1~B N The order of winding A is connected in series. n The two ends of the bridge arm L n and L n+1 The midpoint of winding B is connected n The two ends of the bridge arm L n+N and L n+N+1 The midpoints of are connected;

[0035] Fault-tolerant control systems include:

[0036] Short circuit fault identification module, used to detect winding A n and B n The current i an and i cn , and the sum of the two is greater than the preset current threshold i limiit ', it is determined that the winding A n and B n A set of switching tubes S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 There is a short circuit fault; where S 2n-1 is the bridge arm L n The upper switch tube, S 2n+2 is the bridge arm L n+1 The lower switch tube, S 2n+2N-1 is the bridge arm L n+N The upper switch tube, S 2n+2N+2 is the bridge arm L n+N+1 The lower switch tube;

[0037] And a short-circuit fault tolerance module is used to calculate the current magnitude and direction of each winding after identifying a short-circuit fault, with the goal of making the resultant electromagnetic force generated by the two windings on each degree of freedom a preset value; based on the current magnitude and direction of each winding, a PWM signal is generated to control the on and off of each switch tube in each bridge arm, and applied to the corresponding switch tube.

[0038] Further, the short-circuit fault tolerance module, after identifying that there is an open-circuit fault in the set of switch tubes S n , S n , S 2n-1 , S 2n+2 , S 2n+2N-1 and S 2n+2N+2 used for controlling the windings A 2n-1 and B 2n+2 , takes the resultant electromagnetic force generated by the two windings in each degree of freedom as a preset value as a target, and calculates the current size and current direction of each winding, including the following steps:

[0039] S1: locating the switch tube in which there is a short-circuit fault in the switch tubes S 2n+2N-1 , S 2n+2N+2 , S n and S n , if it is a switch tube used for controlling the winding A n+1 , then go to S2; otherwise, go to S3;

[0040] S2: setting the current size of the windings A N to be equal to the original current size and the current direction to be opposite to the original current direction, and setting the current size of the windings A N to be equal to the original current size and the current direction to be the same as the original current direction, taking the resultant electromagnetic force generated by the two windings in each degree of freedom as a preset value as a target, and calculating the current size and current direction of the windings B n ;

[0041] S3: setting the current size of the windings B n+1 to be equal to the original current size and the current direction to be opposite to the original current direction, and setting the current size of the windings B N to be equal to the original current size and the current direction to be the same as the original current direction, taking the resultant electromagnetic force generated by the two windings in each degree of freedom as a preset value as a target, and calculating the current size and current direction of the windings A N ;

[0042] Wherein, the original current size and the original current direction of the winding respectively represent the current size and the current direction of the winding under normal working conditions.

[0043] Further, in step S1, locating the switch tube in which there is a short-circuit fault in the switch tubes S 2n-1 , S 2n+2 , S 2n+2N-1 and S 2n+2N+2 , including:

[0044] Monitoring the voltage command value of the bridge arms L n , L n+1 , L n+N and L n+N+1 ;

[0045] If the bridge arm L n The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n-1 A short circuit fault occurs;

[0046] If the bridge arm L n+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n+2 A short circuit fault occurs;

[0047] If the bridge arm L n+N The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n+2N-1 A short circuit fault occurs;

[0048] If the bridge arm L n+N+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n+2N+2 A short circuit fault has occurred.

[0049] Furthermore, the magnetic levitation expansion generator controller fault-tolerant control system provided by the present invention further includes:

[0050] Open circuit fault identification module, used to detect winding A n and B n The current i an and i cn , and the sum of the two is less than the preset current threshold i limiit ″, it is determined that the winding A is used to control n and B n A set of switching tubes S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 There is a circuit breaker fault;

[0051] Among them, i limiit ″ limiit ′.

[0052] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0053] (1) Based on the working characteristics of the magnetic levitation bearing with a full-bridge series winding topology, the present invention proposes a corresponding short-circuit fault identification method and short-circuit fault fault tolerance strategy, which can effectively identify the short-circuit fault of the switching tube and perform fault tolerance in a timely manner, effectively improving the operating safety and stability of the magnetic levitation bearing and the entire magnetic levitation expansion motor.

[0054] (2) The present invention further proposes a method for identifying a circuit breaker fault and a corresponding method for locating a faulty switch tube, thereby further improving the operational safety and stability of the magnetic levitation bearing and the entire magnetic levitation expansion motor.​ BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The topology diagram of the five-degree-of-freedom magnetic bearing based on the full-bridge series winding topology;

[0056] Figure 2 for Figure 1 Schematic diagram of the symbols representing each bridge arm, switch tube and bridge arm;

[0057] Figure 3 for Figure 2 , a schematic diagram of winding A1 and the bridge arm to which it is connected in normal working mode;

[0058] Figure 4 for Figure 2 , a schematic diagram of the current change of winding A1 when the switch tube S1 used to control winding A1 has a short circuit fault;

[0059] Figure 5 for Figure 2 Control block diagram of the topology shown;

[0060] Figure 6 This is a flow chart of a fault-tolerant control method for a magnetic levitation expansion generator controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is 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 for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0062] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0063] The magnetic bearing system is the core component of a magnetic expansion generator. Accurately detecting short-circuit faults in the switching devices within its power amplifier and implementing appropriate fault tolerance are crucial for the control and safe operation of the entire magnetic expansion generator. Before explaining the technical solution of the present invention in detail, a brief introduction to the magnetic bearing topology involved in the present invention is provided.

[0064] The magnetic bearing has multiple degrees of freedom, and N represents the number of its degrees of freedom. Accordingly, the magnetic bearing has 2N windings, each in a group of two, for realizing the control of one degree of freedom. When a full-bridge series winding topology is adopted, the 2N windings are connected in series in sequence, and each winding is connected to the midpoint of the two bridge arms of an H-bridge. Adjacent windings share one bridge arm, so there are a total of 2N+1 bridge arms (2N-1 common bridge arms and 2 non-common bridge arms). The upper and lower tubes in each bridge arm are switching devices, and the upper and lower ends of each bridge arm are respectively connected to the positive and negative poles of the DC power supply. In practical applications, the more typical one is a 5-degree-of-freedom magnetic bearing, whose 5 degrees of freedom specifically refer to 4 degrees of freedom in the radial direction and 1 degree of freedom in the axial direction. Accordingly, the topological structure includes 10 windings, 9 common bridge arms and 2 non-common bridge arms, such as Figure 1 shown.

[0065] A1~A N 、B1~B N Represents 2N windings, where A n and B n Represents a pair of windings used to control the nth degree of freedom, n∈{1,2,……,N}; L1~L 2N+1 Represents 2N+1 bridge arms, then winding A n The bridge arm connected is L n and L n+1 , winding B n The bridge arm connected is L n+N and L n+N+1 , with S 2x-1 and S 2x Represents bridge arm L x The upper switch and lower switch tube, x∈{1,2,……,2N+1} is used to control the winding A n The switch tube is S 2n-1 and S 2n+2 , that is, bridge arm L n The upper switch tube and bridge arm L n+1 The lower switch tube is used to control winding B n The switch tube is S 2n+2N-1 and S 2n+2N+2 , that is, bridge arm L n+N The upper switch tube and bridge arm L n+N+1 The lower switch tube. Refer to this symbolic representation, Figure 1 In the diagram, the symbols for each winding, bridge arm, and switch tube are as follows: Figure 2 shown.

[0066] For any winding, by controlling the on-off state of the switch tube that controls the winding, the corresponding winding current can be in different states. nFor example, the state of the winding current is as follows:

[0067] When the switch tube S 2n-1 and S 2n+2 are both turned on (11 mode), the winding voltage is equal to the DC voltage source voltage V dc , the winding current increases, and at this time, it is in the charging mode;

[0068] When the switch tube S 2n-1 and S 2n+2 are turned on and turned off (10 mode or 01 mode), the winding voltage is close to 0, and at this time, it is in the freewheeling mode;

[0069] When the switch device S 2n-1 and S 2n+2 are both turned off (00 mode), the winding voltage is equal to -V dc , the winding current increases, and at this time, it is in the discharging mode.

[0070] In the normal working mode, when the current directions of adjacent windings are consistent, the winding bias currents cancel each other out, the current stress on the common bridge arm is small, the conduction loss and switching loss during switching are reduced, and the sum of the two winding currents on the same degree of freedom is equal to twice the bias current when the winding currents are normally controlled;

[0071] i an +i cn =2i0

[0072] Where i an and i cn represent the currents of windings A n and B n , and i0 represents the bias current.

[0073] In the normal working mode, all winding currents are in the same direction, and optionally, the currents in each winding are set from left to right. By controlling the driving signals of the switching devices in each bridge arm, the midpoint voltage of each bridge arm can be adjusted, and thus the winding currents can be controlled. The control method of pulse width modulation (PWM) is used, so that the duty cycle signals of the upper and lower switch tubes on each bridge arm are complementary. To prevent bridge arm shoot-through, the upper and lower switches of each bridge arm cannot be turned on at the same time; according to the reference current signal, the reference differential current and the bias current are obtained through the PI controller, and then the adjacent bridge arm voltage difference and the bridge arm reference voltage are obtained, and the corresponding bridge arm duty cycle is adjusted.

[0074] Taking winding A1 in Figure 2 as an example, in the normal working mode, the state of the switch tube of winding A1 and the current in winding A1 are as shown in Figure 3 . After a short circuit fault occurs, the winding with the faulty switch cannot continue to control the dynamic current, as shown in Figure 4As shown. Due to the existence of short circuit fault, the mode of S1 and S4 being off is blocked (00 mode), only charging mode and freewheeling mode exist, and there is no discharging mode, so that the winding current i1 will increase, and cannot maintain the original constant current value.

[0075] Based on this, the application proposes a basis for identifying short circuit faults of switches in magnetic suspension bearings based on series winding topology, that is, detecting the sum of winding currents of two windings corresponding to each degree of freedom to obtain winding bias current, if the winding bias current increases and the sum of currents of the two windings is greater than threshold i limiit , it is indicated that one of the four switch devices used to control the two windings corresponding to the degree of freedom has a short circuit fault.

[0076] In order to ensure the safe and stable operation of the magnetic suspension bearing and even the entire magnetic suspension expansion generator when a short circuit fault occurs, the application further proposes a corresponding short circuit fault tolerance mechanism in combination with the working mode of the series winding topology. The specific analysis is as follows:

[0077] In the normal working mode, the current of each winding is determined by the voltage difference of the bridge arm connected to it and the winding impedance, denoted as Z, and U x represents the output voltage of the bridge arm L x , then taking winding A n as an example, its current i an can be represented as:

[0078]

[0079] During the suspension process of the magnetic suspension bearing, the common-mode current is constant, and the bridge arm voltages U1 and U 2N+1 are equal, then correspondingly, the duty cycles of the switch devices in the two non-common bridge arms L1 and L 2N+1 need to be kept consistent, so at this time, the only independent bridge arm voltage variable is U1-U 2N .

[0080] Taking U Figure 1 as an example, at this time, set the bias currents of each winding to be equal, then the sum of the currents of the two windings corresponding to the five degrees of freedom can be set to the same size:

[0081] I a1 +I c1 =I a2 +I c2 =…=I a5 +I c5

[0082] At the same time, the relationship between the winding current and the bridge arm voltage can be represented as follows:

[0083]

[0084] In the normal working mode, based on the change relationship between the winding current and the bridge arm voltage, the average value of all independent bridge arm voltages can be U dc / 2, based on the change matrix, the instruction value of each bridge arm voltage is obtained, and the duty cycle of the corresponding switching device is adjusted according to the bridge arm voltage instruction value, so that the control of each winding current can be realized. The corresponding control block diagram is shown in Figure 5 .

[0085] Compared with the half-bridge topology, in the full-bridge winding series topology, the number of switching devices is more, the direction of each winding current can be independently changed, there are more kinds of topology operation modes, and part of the operation modes can be used as fault-tolerant operation modes; based on this, in the short-circuit fault tolerance mechanism proposed in the application, it is considered that the winding with the faulty switching device cannot continue to control the dynamic current, and only the current can be kept constant, at this time, the current in the opposite winding is controlled through the PID controller, power amplifier and PI controller, so that the resultant force of the electromagnetic force acting on the rotor is the same as before the fault occurs, so that the rotor in the magnetic suspension bearing can still be suspended in this fault state, and the control failure and rotor falling caused by the short-circuit fault of the switching device are avoided.

[0086] Specifically, if the winding with the faulty switching device is A n , the current of the winding with the faulty switching device and the windings A1-A n before it is kept constant, the direction of the current is opposite to the original state (the state in the normal working mode), the current of the remaining windings A n+1 -A N is kept constant, and the direction of the current is the same as the original state. B1-B N are opposite windings of A1-A N , and the entire dynamic change is borne by the opposite windings. Conversely, if the winding with the faulty switching device is B n , the current of the winding with the faulty switching device and the windings B1-B n before it is kept constant, the direction of the current is opposite to the original state (the state in the normal working mode), the current of the remaining windings B n+1 -B N is kept constant, and the direction of the current is the same as the original state. A1-A N are opposite windings of B1-B N , and the entire dynamic change is borne by the opposite windings.

[0087] After the size and direction of the current in each winding are determined, the drive signal for controlling the switching device in each bridge arm can be generated, the midpoint voltage of each bridge arm is adjusted, and the control of the winding current is realized.

[0088] The power amplifier and the winding generate electromagnetic force, and when single-axis control is performed, a pair of coils with current generate a pair of forces in opposite directions to suspend the rotor. At this time, the relationship between the resultant force of a pair of forces in opposite directions and the differential current and the bias current of the corresponding winding is as follows:

[0089]

[0090] where F is the resultant force of the electromagnetic force generated by the two windings in the nth degree of freedom before the short-circuit fault occurs, μ0 represents the magnetic permeability of vacuum, m represents the number of turns of the winding, A α represents the magnetic pole area, and α represents the angle between the magnetic pole and the net force; dis1 represents the distance from the center of the rotor to the corresponding magnetic pole of the coil A n , and dis2 represents the distance from the center of the rotor to the corresponding magnetic pole of the coil B n ; I an and I cn respectively represent the currents of the windings A n and B n calculated according to the above fault-tolerant mechanism.

[0091] The above calculation expression can be further represented as follows:

[0092]

[0093] where dis0 represents twice the air gap of the magnetic suspension bearing.

[0094] At this time, there are various methods of distributing the currents of the two windings. As long as the currents of the two windings satisfy the following formula, the performance of the rotor will not change, and the reference current of the opposite winding can be calculated by the formula:

[0095]

[0096] where i bias represents the input bias current, i ref represents the differential current, i a|ref represents the bias current of the winding A n in the normal working state, and i c|ref represents the bias current of the winding B n in the normal working state.

[0097] The following is an embodiment.

[0098] Embodiment 1

[0099] A fault-tolerant control method for a magnetic suspension expansion generator controller.

[0100] In this embodiment, the magnetic suspension bearing in the magnetic suspension expansion generator has N degrees of freedom and includes 2N windings A1-A Nand B1~B N , winding A n and winding B n for controlling the nth degree of freedom, n∈{1,2,……,N}; the magnetic suspension bearing adopts a full-bridge type series winding topology, including 2N+1 bridge arms L1~L 2N+1 ; 2N windings are sequentially connected in series in the order of A1~A N , B1~B N , two ends of winding A n are connected to the midpoints of bridge arms L n and L n+1 , and two ends of winding B n are connected to the midpoints of bridge arms L n+N and L n+N+1 .

[0101] As Figure 6 described, the magnetic suspension expansion generator controller fault-tolerant control method provided by the embodiment includes short-circuit fault identification and short-circuit fault tolerance.

[0102] The short-circuit fault identification includes detecting currents i n and i n in windings A an and B cn , and if the sum of the two currents is greater than a preset current threshold i limiit ', it is determined that a group of switch tubes S n , S n , S 2n-1 and S 2n+2 for controlling windings A 2n+2N-1 and B 2n+2N+2 have a short-circuit fault; wherein S 2n-1 is an upper switch tube of bridge arm L n , S 2n+2 is a lower switch tube of bridge arm L n+1 , S 2n+2N-1 is an upper switch tube of bridge arm L n+N , and S 2n+2N+2 is a lower switch tube of bridge arm L n+N+1 .

[0103] The short-circuit fault tolerance includes, after identifying the short-circuit fault, calculating the current size and current direction of each winding with the goal that the resultant force of the electromagnetic force generated by the two windings in each degree of freedom is a preset value, generating PWM signals for controlling the conduction and turn-off of each switch tube in each bridge arm according to the current size and current direction of each winding, and applying the PWM signals to the corresponding switch tubes.

[0104] The embodiment identifies a group of switch tubes S n , S n , S 2n-1, S 2n+2 , S 2n+2N-1 and S 2n+2N+2 After the short-circuit fault exists, the current size and the current direction of each winding are calculated with the resultant electromagnetic force generated by the two windings in each degree of freedom as a preset value as a target, and specifically includes the following steps:

[0105] S1: positioning the switch tube S 2n-1 , S 2n+2 , S 2n+2N-1 and S 2n+2N+2 The switch tube in which the short-circuit fault exists, if it is a switch tube for controlling the winding A n , turns to S2; otherwise, turns to S3;

[0106] S2: setting the current size of the windings A1-A n equal to the original current size and the current direction opposite to the original current direction, and setting the current size of the windings A n+1 -A N equal to the original current size and the current direction same as the original current direction, calculating the current size and the current direction of the windings B1-B N with the resultant electromagnetic force generated by the two windings in each degree of freedom as a preset value as a target;

[0107] S3: setting the current size of the windings B1-B n equal to the original current size and the current direction opposite to the original current direction, and setting the current size of the windings B n+1 -B N equal to the original current size and the current direction same as the original current direction, calculating the current size and the current direction of the windings A1-A N with the resultant electromagnetic force generated by the two windings in each degree of freedom as a preset value as a target;

[0108] Wherein, the original current size and the original current direction of the winding respectively represent the current size and the current direction of the winding under normal working condition.

[0109] After the switch device group in which the short-circuit fault occurs is determined, the specific faulty switch can be positioned according to the bridge arm voltage instruction. When the switch device of the upper bridge arm is short-circuited, the bridge arm voltage is always higher than the instruction value, and the instruction value of the bridge arm voltage will decrease and quickly reach negative saturation under the action of the current loop PI controller; similarly, when the switch device of the lower bridge arm is short-circuited, the corresponding bridge arm voltage instruction value will increase and quickly reach positive saturation. Based on this, in step S1 of the embodiment, the switch tube S 2n-1 , S 2n+2 , S 2n+2N-1 and S 2n+2N+2 in which the short-circuit fault exists, includes:

[0110] monitoring the bridge arm Ln , L n+1 , L n+N and L n+N+1 voltage command value;

[0111] If the voltage command value of bridge arm L n decreases and eventually reaches negative saturation, it is judged that short-circuit fault occurs in switch tube S 2n-1 ;

[0112] If the voltage command value of bridge arm L n+1 increases and eventually reaches positive saturation, it is judged that short-circuit fault occurs in switch tube S 2n+2 ;

[0113] If the voltage command value of bridge arm L n+N decreases and eventually reaches negative saturation, it is judged that short-circuit fault occurs in switch tube S 2n+2N-1 ;

[0114] If the voltage command value of bridge arm L n+N+1 increases and eventually reaches positive saturation, it is judged that short-circuit fault occurs in switch tube S 2n+2N+2 .

[0115] If short-circuit fault occurs in switch tube S 2n-1 or S 2n+2 , winding A n is the winding with the faulty switch tube, and if short-circuit fault occurs in switch tube S 2n+2N-1 or S 2n+2N+2 , winding B n is the winding with the faulty switch tube.

[0116] The identification result of the short-circuit fault switch tube provides a reliable basis for the replacement or repair of the subsequent faulty switch device.

[0117] The calculation expression of the resultant electromagnetic force generated by the two windings on the nth degree of freedom is:

[0118]

[0119] wherein F is the resultant electromagnetic force generated by the two windings on the nth degree of freedom before the short-circuit fault occurs; μ0 represents the vacuum permeability, m represents the number of turns of the winding, a α represents the magnetic pole area, and α represents the included angle between the magnetic pole and the net force; dis0 represents twice the air gap of the magnetic suspension bearing, and dis1 represents the distance from the center of the rotor to the corresponding magnetic pole of winding A n ; I an and I cn respectively represent the currents of windings A n and B n .

[0120] When calculating the current in the opposite winding, the above electromagnetic reasonable expression can be used for calculation.

[0121] As shown in Figure 6 , the embodiment further includes: open-circuit fault identification; the open-circuit fault identification includes:

[0122] detecting the currents i n and i n in the windings A an and B cn , and determining that a group of switch tubes S 2n-1 , S 2n+2 , S 2n+2N-1 and S 2n+2N+2 for controlling the windings A limiit and B n has an open-circuit fault if the sum of the two currents is less than a preset current threshold i n ″.

[0123] wherein i limiit ″<i limiit ′; it is easy to understand that i limiit ″ is less than twice the bias current, and i limiit ′ is greater than twice the bias current.

[0124] As shown in Figure 6 , after determining the group of switch devices that has an open-circuit fault, the embodiment can locate the specific fault switch tube according to the bridge arm voltage instruction. When the switch devices of the upper bridge arm are open-circuited, since the bridge arm voltage is always lower than the instruction value, the instruction value of the bridge arm voltage will increase and quickly reach positive saturation under the action of the current loop PI controller; similarly, when the switch devices of the lower bridge arm are open-circuited, the corresponding bridge arm voltage instruction value will decrease and quickly reach negative saturation. Based on this, the embodiment further includes open-circuit fault positioning on the basis of the short-circuit fault identification; the open-circuit fault positioning includes:

[0125] After identifying that the group of switch tubes S 2n-1 , S 2n+2 , S 2n+2N-1 and S 2n+2N+2 for controlling the windings A n and B n has an open-circuit fault, the voltage instruction values of the bridge arms L n , L n+1 , L n+N and L n+N+1 are monitored.

[0126] If the voltage instruction value of the bridge arm L n increases and eventually reaches positive saturation, it is determined that the switch tube S 2n-1 has an open-circuit fault.

[0127] If the voltage instruction value of the bridge arm Ln+1 If the voltage command value of the bridge arm L 2n+2 increases and eventually reaches positive saturation, it is determined that the switching tube S n+N has a short-circuit fault;

[0128] If the voltage command value of the bridge arm L 2n+2N-1 decreases and eventually reaches negative saturation, it is determined that the switching tube S n+N+1 has an open-circuit fault;

[0129] If the voltage command value of the bridge arm L 2n+2N+2 increases and eventually reaches positive saturation, it is determined that the switching tube S N has an open-circuit fault.

[0130] The recognition result of the open-circuit fault switching tube provides a reliable basis for subsequent replacement or maintenance of the fault switching device.

[0131] Overall, based on the working characteristics of the magnetic suspension bearing of the full-bridge series winding topology, the embodiment proposes a corresponding short-circuit fault recognition method and a short-circuit fault tolerance strategy, which can effectively recognize the short-circuit fault of the switching tube and timely perform fault tolerance, effectively improving the operation safety and stability of the magnetic suspension bearing and the entire magnetic suspension expansion motor. On this basis, the application further proposes a switching tube open-circuit fault recognition method and a corresponding fault switching tube positioning method, further improving the operation safety and stability of the magnetic suspension bearing and the entire magnetic suspension expansion motor.

[0132] Embodiment 2:

[0133] A magnetic suspension expansion generator controller fault tolerance control system.

[0134] In the embodiment, the magnetic suspension bearing in the magnetic suspension expansion generator has N degrees of freedom, and includes 2N windings A1-A N and B1-B N , the winding A n and the winding B n are used to control the nth degree of freedom, n e {1, 2, …, N}; the magnetic suspension bearing adopts a full-bridge series winding topology structure, including 2N+1 bridge arms L1-L 2N+1 ; the 2N windings are sequentially connected in order of A1-A N , B1-B N , the two ends of the winding A n are connected to the midpoints of the bridge arms L n and L n+1 , respectively, and the two ends of the winding B n are connected to the midpoints of the bridge arms L n+N and L n+N+1 , respectively.

[0135] The magnetic suspension expansion generator controller fault-tolerant control system provided by the embodiment comprises a short-circuit fault identification module, a short-circuit fault tolerance module, an open-circuit fault identification module and an open-circuit fault positioning module.

[0136] The short-circuit fault identification module is configured to detect currents i n and i n in the windings A an and B cn , and determine that a short-circuit fault exists in a group of switch tubes S limiit , S n , S n and S 2n-1 used for controlling the windings A 2n+2 and B 2n+2N-1 when a sum of the currents i 2n+2N+2 and i 2n-1 is greater than a preset current threshold i n '; wherein S 2n+2 is an upper switch tube of the bridge arm L n+1 , S 2n+2N-1 is a lower switch tube of the bridge arm L n+N , S 2n+2N+2 is an upper switch tube of the bridge arm L n+N+1 , and S n is a lower switch tube of the bridge arm L n .

[0137] The short-circuit fault tolerance module is configured to calculate current sizes and current directions of the windings with a target that a resultant force of electromagnetic forces generated by the windings in each degree of freedom is a preset value after the short-circuit fault is identified, and generate PWM signals used for controlling turn-on and turn-off of the switch tubes in each bridge arm according to the current sizes and the current directions of the windings, and apply the PWM signals to the corresponding switch tubes.

[0138] The open-circuit fault identification module is configured to detect currents i an and i cn in the windings A limiit and B n , and determine that an open-circuit fault exists in a group of switch tubes S n , S 2n-1 , S 2n+2 and S 2n+2N-1 used for controlling the windings A 2n+2N+2 and B limiit when a sum of the currents i limiit and i n is less than a preset current threshold i n "; i 2n-1 "<i 2n+2 ′.

[0139] The open-circuit fault positioning module is configured to calculate current sizes and current directions of the windings with a target that a resultant force of electromagnetic forces generated by the windings in each degree of freedom is a preset value after the open-circuit fault is identified, and generate PWM signals used for controlling turn-on and turn-off of the switch tubes in each bridge arm according to the current sizes and the current directions of the windings, and apply the PWM signals to the corresponding switch tubes.2n+2N-1 and S 2n+2N+2 When a circuit breaker fault occurs, perform the following actions:

[0140] Monitoring bridge arm L n 、L n+1 、L n+N and L n+N+1 Voltage command value;

[0141] If the bridge arm L n The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n-1 A circuit breaker fault occurs;

[0142] If the bridge arm L n+1 The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n+2 A short circuit fault occurs;

[0143] If the bridge arm L n+N The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n+2N-1 A circuit breaker fault occurs;

[0144] If the bridge arm L n+N+1 The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n+2N+2 A circuit breaker fault has occurred.

[0145] In this embodiment, the short-circuit fault tolerance module identifies the short-circuit fault used to control winding A. n and B n A set of switching tubes S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 After a short circuit fault occurs, the current magnitude and current direction of each winding are calculated with the goal of making the resultant electromagnetic force generated by the two windings in each degree of freedom equal to a preset value, including the following steps:

[0146] S1: Positioning switch tube S 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 There is a short circuit fault in the switch tube, if it is used to control winding A n If the switch tube is on, it switches to S2; otherwise, it switches to S3;

[0147] S2: Set winding A1~A n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding A is set n+1 ~A NThe current magnitude is equal to the original current magnitude, the current direction is the same as the original current direction, and the electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings B1~B N The magnitude and direction of the current;

[0148] S3: Set winding B1~B n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding B is set n+1 ~B N The current magnitude is equal to the original current magnitude and the current direction is the same as the original current direction. The electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings A1~A N The magnitude and direction of the current;

[0149] The original current magnitude and original current direction of the winding respectively represent the current magnitude and current direction of the winding under normal working conditions.

[0150] In this embodiment, in step S1 executed by the short-circuit fault tolerance module, the switch tube S is positioned. 2n-1 、S 2n+2 、S 2n+2N-1 and S 2n+2N+2 The switching tubes with short circuit faults include:

[0151] Monitoring bridge arm L n 、L n+1 、L n+N and L n+N+1 Voltage command value;

[0152] If the bridge arm L n The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n-1 A short circuit fault occurs;

[0153] If the bridge arm L n+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n+2 A short circuit fault occurs;

[0154] If the bridge arm L n+N The voltage command value decreases and eventually reaches negative saturation, then the switch tube S 2n+2N-1 A short circuit fault occurs;

[0155] If the bridge arm L n+N+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube S 2n+2N+2 A short circuit fault has occurred.

[0156] In this embodiment, the specific implementation of each module can refer to the description in the above embodiment 1 and will not be repeated here.

[0157] It is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the application should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. A fault-tolerant control method for a magnetic levitation expansion generator controller, wherein the magnetic bearing in the magnetic levitation expansion generator has N degrees of freedom, including 2 N Windings A1~A N and B1~B N , Winding A n and winding B n To control the n degrees of freedom, The magnetic bearing adopts a full-bridge series winding topology, including 2 N +1 bridge arm L1~L 2N+1 ; 2 N Each winding is divided into two groups according to A1~A N 、B1~B N The order of winding A is connected in series. n The two ends of the bridge arm L n and L n+1 The midpoint of winding B is connected n The two ends of the bridge arm L n+N and L n+N+1 The midpoints of are connected; it is characterized by, The fault tolerance control method includes: short circuit fault identification and short circuit fault tolerance; The short circuit fault identification includes: detecting winding A n and B n Current in i an and i cn , if the sum of the two is greater than the preset current threshold , then it is determined that the winding A used to control n and B n A set of switching tubes S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 There is a short circuit fault; S 2n-1 is the bridge arm L n The upper switch tube, S 2n+2 is the bridge arm L n+1 The lower switch tube, S 2n+2N-1 is the bridge arm L n+N The upper switch tube, S 2n+2N+2 is the bridge arm L n+N+1 The lower switch tube; The short-circuit fault tolerance method includes: after identifying a short-circuit fault, calculating the current magnitude and current direction of each winding with the goal of ensuring that the resultant electromagnetic force generated by the two windings in each degree of freedom is a preset value; generating a PWM signal for controlling the on and off of each switch in each bridge arm based on the current magnitude and current direction of each winding, and applying the PWM signal to the corresponding switch; After identifying the control winding A n and B n A set of switching tubes S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 After a short circuit fault occurs, the current magnitude and current direction of each winding are calculated with the goal of making the resultant electromagnetic force generated by the two windings in each degree of freedom equal to a preset value, including the following steps: S1: Positioning switch tube S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 There is a short circuit fault in the switch tube, if it is used to control winding A n If the switch tube is on, it switches to S2; otherwise, it switches to S3; S2: Set winding A1~A n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding A is set n+1 ~A N The current magnitude is equal to the original current magnitude and the current direction is the same as the original current direction. The electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings B1~B N The magnitude and direction of the current; S3: Set winding B1~B n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding B is set n+1 ~B N The current magnitude is equal to the original current magnitude and the current direction is the same as the original current direction. The electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings A1~A N The magnitude and direction of the current; No. n The calculation expression of the electromagnetic force generated by the two windings in one degree of freedom is: The original current magnitude and original current direction of the winding respectively represent the current magnitude and current direction of the winding under normal working conditions; F Before the short circuit fault occurs, n The resultant electromagnetic force generated by the two windings on each degree of freedom; represents the vacuum permeability, m Indicates the number of coil turns in the winding, represents the magnetic pole area, represents the angle between the magnetic pole and the net force; dis 0 means twice the air gap of the magnetic bearing, dis 1 represents the distance from the rotor center to coil A n The distance to the corresponding magnetic pole; I an and I cn Respectively represent winding A n and B n of current.

2. The fault-tolerant control method for a magnetic levitation expansion generator controller according to claim 1, characterized in that: In step S1, the switch tube is positioned S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 The switching tubes with short circuit faults include: Monitoring bridge arm L n 、L n+1 、L n+N and L n+N+1 Voltage command value; If the bridge arm L n The voltage command value decreases and eventually reaches negative saturation, then the switch is judged to be S 2n-1 A short circuit fault occurs; If the bridge arm L n+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube is judged to be S 2n+2 A short circuit fault occurs; If the bridge arm L n+N The voltage command value decreases and eventually reaches negative saturation, then the switch is judged to be S 2n+2N-1 A short circuit fault occurs; If the bridge arm L n+N+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube is judged to be S 2n+2N+2 A short circuit fault has occurred.

3. The fault-tolerant control method for a magnetic levitation expansion generator controller according to claim 1 or 2, characterized in that: Also includes: Circuit breaker fault identification; The circuit breaker fault identification includes: Detection winding A n and B n Current in i an and i cn , if the sum of the two is less than the preset current threshold , then it is determined that the winding A used to control n and B n A set of switching tubes S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 There is a circuit breaker fault; in, .

4. The fault-tolerant control method for a magnetic levitation expansion generator controller according to claim 3, characterized in that: Also includes: Circuit breaker fault location; The circuit breaker fault location includes: After identifying the control winding A n and B n A set of switching tubes S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 After a circuit breaker fault occurs, monitor the bridge arm L n 、L n+1 、L n+N and L n+N+1 Voltage command value; If the bridge arm L n The voltage command value increases and eventually reaches positive saturation, then the switch tube is judged to be S 2n-1 A circuit breaker fault occurs; If the bridge arm L n+1 The voltage command value decreases and eventually reaches negative saturation, then the switch is judged to be S 2n+2 A short circuit fault occurs; If the bridge arm L n+N The voltage command value increases and eventually reaches positive saturation, then the switch tube is judged to be S 2n+2N-1 A circuit breaker fault occurs; If the bridge arm L n+N+1 The voltage command value decreases and eventually reaches negative saturation, then the switch is judged to be S 2n+2N+2 A circuit breaker fault has occurred.

5. A fault-tolerant control system for a magnetic levitation expansion generator controller, wherein the magnetic bearing in the magnetic levitation expansion generator has N degrees of freedom, including 2 N Windings A1~A N and B1~B N , Winding A n and winding B n To control the n degrees of freedom, The magnetic bearing adopts a full-bridge series winding topology, including 2 N +1 bridge arm L1~L 2N+1 ; 2 N Each winding is divided into two groups according to A1~A N 、B1~B N The order of winding A is connected in series. n The two ends of the bridge arm L n and L n+1 The midpoint of winding B is connected n The two ends of the bridge arm L n+N and L n+N+1 The midpoints of are connected; It is characterized in that The fault-tolerant control system comprises: Short circuit fault identification module, used to detect winding A n and B n Current in i an and i cn , and the sum of the two is greater than the preset current threshold When the voltage is used to control winding A n and B n A set of switching tubes S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 There is a short circuit fault; S 2n-1 is the bridge arm L n The upper switch tube, S 2n+2 is the bridge arm L n+1 The lower switch tube, S 2n+2N-1 is the bridge arm L n+N The upper switch tube, S 2n+2N+2 is the bridge arm L n+N+1 The lower switch tube; and a short-circuit fault tolerance module, which is used to calculate the current magnitude and direction of each winding after identifying a short-circuit fault, with the goal of ensuring that the resultant electromagnetic force generated by the two windings in each degree of freedom is a preset value; based on the current magnitude and direction of each winding, generate a PWM signal for controlling the on and off of each switch in each bridge arm, and apply it to the corresponding switch; Among them, when identifying the control winding A n and B n A set of switching tubes S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 After a short circuit fault occurs, the current magnitude and current direction of each winding are calculated with the goal of making the resultant electromagnetic force generated by the two windings in each degree of freedom equal to a preset value, including the following steps: S1: Positioning switch tube S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 There is a short circuit fault in the switch tube, if it is used to control winding A n If the switch tube is on, it switches to S2; otherwise, it switches to S3; S2: Set winding A1~A n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding A is set n+1 ~A N The current magnitude is equal to the original current magnitude and the current direction is the same as the original current direction. The electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings B1~B N The magnitude and direction of the current; S3: Set winding B1~B n The current size is equal to the original current size and the current direction is opposite to the original current direction, and the winding B is set n+1 ~B N The current magnitude is equal to the original current magnitude and the current direction is the same as the original current direction. The electromagnetic force generated by the two windings on each degree of freedom is used as the preset value as the target. Calculate the windings A1~A N The magnitude and direction of the current; No. n The calculation expression of the electromagnetic force generated by the two windings in one degree of freedom is: The original current magnitude and original current direction of the winding respectively represent the current magnitude and current direction of the winding under normal working conditions; F Before the short circuit fault occurs, n The resultant electromagnetic force generated by the two windings on each degree of freedom; represents the vacuum permeability, m Indicates the number of coil turns in the winding, represents the magnetic pole area, represents the angle between the magnetic pole and the net force; dis 0 means twice the air gap of the magnetic bearing, dis 1 represents the distance from the rotor center to coil A n The distance to the corresponding magnetic pole; I an and I cn Respectively represent winding A n and B n of current.

6. The fault-tolerant control system of the magnetic levitation expansion generator controller according to claim 5, characterized in that: In step S1, the switch tube is positioned S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 The switching tubes with short circuit faults include: Monitoring bridge arm L n 、L n+1 、L n+N and L n+N+1 Voltage command value; If the bridge arm L n The voltage command value decreases and eventually reaches negative saturation, then the switch is judged to be S 2n-1 A short circuit fault occurs; If the bridge arm L n+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube is judged to be S 2n+2 A short circuit fault occurs; If the bridge arm L n+N The voltage command value decreases and eventually reaches negative saturation, then the switch is judged to be S 2n+2N-1 A short circuit fault occurs; If the bridge arm L n+N+1 The voltage command value increases and eventually reaches positive saturation, then the switch tube is judged to be S 2n+2N+2 A short circuit fault has occurred.

7. The fault-tolerant control system of the magnetic levitation expansion generator controller according to claim 5, characterized in that: Also includes: Open circuit fault identification module, used to detect winding A n and B n Current in i an and i cn , and the sum of the two is less than the preset current threshold When the voltage is used to control winding A n and B n A set of switching tubes S 2n-1 、 S 2n+2 、 S 2n+2N-1 and S 2n+2N+2 There is a circuit breaker fault; in, .

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