Fault-tolerant control method for open-circuit fault of single coil of multi-rotor loop motor

Abstract

The invention discloses a fault-tolerant control method for an open-circuit fault of a single coil of a multi-rotor loop motor, and the method comprises the following steps: 1, judging a coil which is coupled with a rotor, and setting the coil to be in a working state when the coil is coupled with the rotor; step 2, calculating a current instruction of a coil having a coupling relation with the rotor during normal operation; step 3, when the coil coupled with the rotor has an open-circuit fault, reconstructing the residual current of the non-fault coil coupled with the rotor; 4, implementing a fault-tolerant control algorithm, and updating a coil current instruction into a reconstructed current instruction; and 5, when the rotor runs to be separated from the fault coil, namely, the fault coil and the rotor do not have a coupling relationship, updating the coil current instruction to the current instruction in the step 2. According to the multi-rotor annular motor driving strategy based on coil current independent control, the thrust is constant after fault-tolerant control by reconstructing the current of the healthy coil after the open-circuit fault, so that the stable operation of the rotor after the coil open-circuit fault is realized.

Description

Technical Field

[0001] The invention belongs to the field of motors, and relates to an electromagnetic conversion and control method, and in particular to a single coil open circuit fault tolerance control method for a multi-motor ring line motor. Background Art

[0002] With the industrial upgrading of processing and manufacturing, intelligent flexible ring lines have received extensive attention and application. Figure 1 As shown in the figure, the intelligent flexible ring line adopts a modular design, which is composed of multiple straight and arc-shaped stators. Multiple movable mover units composed of permanent magnets are arranged on it. The magnetic field of the permanent magnet on the mover interacts with the magnetic field excited by the stator coil to drive the mover to run. There is no feeder cable on the mover, and the track can be freely spliced ​​to meet industrial applications in different occasions.

[0003] The existing intelligent flexible ring-line mover drive technology usually uses a single straight or arc stator module as the basic control unit, and controls the corresponding stator module according to the position of the mover. The coil that is not coupled to the mover also flows with current, which increases the copper loss of the motor. At the same time, it is impossible to realize the operation of multiple movers on a single stator module, which greatly limits some application scenarios.

[0004] CN116961516A discloses a method for independent control of a single coil, which uses a single coil as a basic control unit to independently control the coil current, and can realize the simultaneous operation of multiple movers on a single stator. However, under the implementation of this method, each coil needs to be connected to a full-bridge or half-bridge power conversion circuit. Excessive use of power conversion circuits and coils will increase the system failure rate, and failures will cause unstable operation of the mover or even shutdown of the ring motor system.

[0005] Since power conversion circuit faults and coil faults can be converted into open-circuit faults through hardware isolation, fault-tolerant control under open-circuit faults is very important for multi-motor ring-line motor systems based on coil current independent control strategies. Summary of the invention

[0006] The present invention provides a fault-tolerant control method for an open-circuit fault of a single coil of a multi-motor ring-wire motor. The method is based on a multi-motor ring-wire motor driving strategy with independent control of coil current. By reconstructing the current of a healthy coil after an open-circuit fault, constant thrust is achieved after fault-tolerant control, thereby achieving smooth operation of the mover after an open-circuit fault of the coil.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A method for controlling a single coil open circuit fault of a multi-motor ring line motor comprises the following steps:

[0009] Step 1: Determine whether there is a coil coupled with the mover. If there is coupling, set it to the working state. The determination method uses the following formula:

[0010]

[0011]

[0012]

[0013] In the formula, x is the position of the actuator; i is the coil number; x c is the adjacent slot distance; when the coil belongs to coil A, state A (x,i) judgment; when the coil belongs to coil B, use state B (x,i) judgment; when the coil belongs to C coil, use state C (x,i) judgment;

[0014] Step 2: Calculate the current command of the coil that is coupled with the mover during normal operation:

[0015]

[0016] In the formula, I m is the coil current amplitude; θ0 is the initial electrical angle; i An 、i Bn 、i Cn is the coil current coupled with the mover, n is the unit where the coupling coil is located;

[0017] Step 3: When an open circuit fault occurs in the coil coupled with the mover, the current of the remaining non-faulty coil coupled with the mover is reconstructed. The specific steps are as follows:

[0018] Step 3-1: Assuming that the units where the coils coupled to the mover are located are k, k+1, and k+2, calculate the electromagnetic thrust during normal operation:

[0019]

[0020] Among them, B m is the air gap magnetic flux amplitude, δ=N c L, N c is the number of coil turns, L is the effective conductor length of the coil;

[0021] Step 3-2: When an open circuit fault occurs in the coil coupled with the mover, the reconstruction current of the remaining coil coupled with the mover without fault is and The reconstructed current satisfies the following formula:

[0022]

[0023] Step 3-3: Calculate the electromagnetic thrust F after the reconstruction current acts e ′:

[0024]

[0025] Step 3-4: Make F e ′=F e , combine the formula in step 3-2 to calculate the reconstruction current:

[0026]

[0027] Step 4: Implement the fault-tolerant control algorithm to update the coil current command to the reconstructed current command:

[0028]

[0029] Step 5: When the mover is running away from the faulty coil, that is, when there is no coupling relationship between the faulty coil and the mover, the coil current command is updated to the current command in step 2.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The present invention is applicable to a multi-motor ring motor control system and can provide a fault-tolerant control solution for a coil open circuit fault.

[0032] 2. The method of the present invention is simple and easy to operate, and has practical application value in industry.

[0033] 3. The method of the present invention is executed in an intelligent flexible ring line control system and can be completed by MCU, DSP, FPGA, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is an intelligent flexible ring line motor. In the figure, 1-straight segment stator, 2-arc segment stator, 3-guide rail, 4-position sensor, 5-motor;

[0035] Figure 2 The spatial structure of the rotor and coil of the ring motor. In the figure, x is the position of the rotor, n- is the unit number, and x c is the distance between adjacent slots, k is the kth unit;

[0036] Figure 3 This is the experimental waveform during normal operation in the current loop mode;

[0037] Figure 4 This is the experimental waveform during fault operation in current loop mode;

[0038] Figure 5 This is the experimental waveform when the fault-tolerant control is running in the current loop mode;

[0039] Figure 6 This is the experimental waveform during normal operation under load conditions;

[0040] Figure 7 This is the experimental waveform during fault operation under load conditions;

[0041] Figure 8 It is the experimental waveform when fault-tolerant control is running under load conditions. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0043] The present invention provides a single coil open circuit fault tolerance control method for a multi-motor ring line motor, and the method performs coil open circuit fault tolerance control based on the coil current independent control strategy disclosed in CN116961516A. According to CN116961516A, the ring motor can be designed with a variety of pole numbers and slot numbers, but in practical applications, a 4-pole 6-slot motor structure is generally selected, such as Figure 2 As shown in the figure, x is the position of the actuator, n is the unit number, and x c is the adjacent slot distance, k is the kth unit, and the coils of each unit are defined as coil A, coil B, and coil C in sequence. The specific steps are as follows:

[0044] Step 1: Determine whether there is a coil coupled with the mover. If there is coupling, set it to the working state. The determination method uses the following formula:

[0045]

[0046]

[0047]

[0048] Where i is the coil number. When the coil belongs to coil A, use state A (x,i) judgment; when the coil belongs to coil B, use state B (x,i) judgment; when the coil belongs to C coil, use state C (x,i) judgment.

[0049] Step 2: Calculate the current command of the coil that is coupled with the mover during normal operation:

[0050]

[0051] In the formula, I m is the coil current amplitude; θ0 is the initial electrical angle, Figure 2 In the motor structure shown, θ0 = π / 6; i An 、i Bn 、i Cn is the coil current coupled to the mover, where n is the unit where the coupling coil is located.

[0052] Step 3: When an open circuit fault occurs in the coil coupled with the mover, the current of the remaining non-faulty coil coupled with the mover is reconstructed. The specific steps are as follows:

[0053] Step 3-1: Calculate the electromagnetic thrust during normal operation. Figure 2 Taking the figure as an example, the units where the coils coupled with the mover are located are k, k+1, and k+2 respectively, and the calculation formula is as follows:

[0054]

[0055] Among them, B m is the air gap magnetic flux amplitude, δ=N c L, N c is the number of coil turns, and L is the effective conductor length of the coil.

[0056] Step 3-2: Select C4 as the open-circuit fault coil, and the reconstructed current of the remaining non-fault coil coupled with the mover is and The reconstructed current satisfies the following formula:

[0057]

[0058] Step 3-3: Calculate the electromagnetic thrust F after the reconstruction current acts e ′:

[0059]

[0060] Step 3-4: Make F e ′=F e , combine the formula in step 3-2 to calculate the reconstruction current:

[0061]

[0062] It should be noted that in step 3, C4 is selected as the open circuit fault coil. When other coils have open circuit faults, the calculation method is the same as that in step 3 and is also within the scope of the present invention.

[0063] Step 4: Implement the fault-tolerant control algorithm to update the coil current command to the reconstructed current command:

[0064]

[0065] Step 5: When the mover is running away from the faulty coil, that is, when there is no coupling relationship between the faulty coil and the mover, the coil current command is updated to the current command in step 2.

[0066] The method of the invention is executed in an intelligent flexible ring line control system and is completed through DSP. Figure 3 , Figure 4 , Figure 5 This is the experimental result in current mode, setting I m =0.4A. Among them, Figure 3 The experimental effect of the present invention is demonstrated. Figure 4 and Figure 5 For comparative experiments, Figure 4 and Figure 5 The experimental results are shown respectively when an open circuit fault occurs and when the fault-tolerant control method is not used and when the fault-tolerant control method is used. Figure 3 , Figure 4 and Figure 5 It can be seen that when an open-circuit fault occurs in the coil, the acceleration of the mover without the fault-tolerant control method is reduced and the original thrust cannot be maintained. However, the mover speed with the fault-tolerant control method is the same as that in normal operation, and the effect of normal operation can be achieved. Figure 6 , Figure 7 , Figure 8 The experimental results under load conditions are shown in Figure 2. The loading is carried out by dragging the weight with a steel wire rope, and the weight mass is 1 kg. Figure 6 The experimental effect of the present invention is demonstrated. Figure 7 and Figure 8 For comparative experiments, Figure 7 and Figure 8 The experimental results of the open circuit fault without and with fault-tolerant control are shown. Figure 7 In the case of steady-speed operation, the speed of the mover without the method of the present invention fluctuates, and the acceleration changes significantly. Figure 8 In the implementation of the method of the present invention, the mover speed and normal operation ( Figure 6 ) are consistent and no fluctuation occurs. The present invention has superior performance under various working conditions.

Claims

1. A single coil open circuit fault tolerance control method for a multi-motor ring line motor, characterized in that The method comprises the following steps: Step 1, determine whether there is a coil coupled with the mover, and if there is coupling, set it to a working state; Step 2, calculating the current command of the coil that is coupled with the mover during normal operation; Step 3: When an open circuit fault occurs in the coil coupled with the mover, the current of the remaining non-faulty coil coupled with the mover is reconstructed. The specific steps are as follows: Step 3-1: Assuming that the units where the coils coupled to the mover are located are k, k+1, and k+2, calculate the electromagnetic thrust during normal operation: Among them, B m is the air gap magnetic flux amplitude, δ=N c L, N c is the number of coil turns, L is the effective conductor length of the coil; Step 3-2: When an open circuit fault occurs in the coil coupled with the mover, the reconstruction current of the remaining coil coupled with the mover without fault is and The reconstructed current satisfies the following formula: Step 3-3: Calculate the electromagnetic thrust F after the reconstruction current acts e ′: Step 3-4: Make F e ′=F e , combine the formula in step 3-2 to calculate the reconstruction current: Step 4: Implement a fault-tolerant control algorithm to update the coil current command to the reconstructed current command; Step 5: When the mover is running away from the faulty coil, that is, when there is no coupling relationship between the faulty coil and the mover, the coil current command is updated to the current command in step 2.

2. The method for fault-tolerant control of single coil open circuit fault of multi-motor ring line motor according to claim 1 is characterized in that In step 1, when determining whether there is a coil coupled with the mover, the following formula is used for determination: In the formula, x is the position of the actuator; i is the coil number; x c is the adjacent slot distance; when the coil belongs to coil A, state A (x,i) judgment; when the coil belongs to coil B, use state B (x,i) judgment; when the coil belongs to C coil, use state C (x,i) judgment.

3. The method for controlling a single coil open circuit fault of a multi-motor ring line motor according to claim 2 is characterized in that In step 2, the current instruction is: In the formula, I m is the coil current amplitude; θ0 is the initial electrical angle; i An 、i Bn 、i Cn is the coil current coupled with the mover, and n is the unit where the coupling coil is located.

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