Fault-tolerant control method for driving motor of deep-sea robot

Abstract

The invention discloses a fault-tolerant control method for a driving motor of a deep-sea robot. The fault-tolerant control method comprises the following steps: acquiring the position, the rotating speed, the bus voltage and different stator module phase currents of the driving motor; acquiring a rotating speed instruction, comparing the rotating speed instruction with a feedback rotating speed, and acquiring a total current instruction value by using a PI controller; s2, carrying out feature analysis on the phase current sampled in the step S1, and judging whether a fault state exists or not; determining an optimal control electrical parameter loaded to each stator module according to the fault state; comparing the current instruction value and the feedback value of each stator module, and obtaining the voltage instruction value of each stator module by using a PI controller; pWM pulse signals are generated through coordinate transformation and space vector modulation, and each stator module inverter is driven to control the operation of the motor. When a fault occurs, the fault module is not cut off, the overall electromagnetic torque is improved by coordinately controlling the fault module and the health module and utilizing the residual value of the fault module, and the loss is reduced after the current is reasonably distributed.

Description

Technical Field

[0001] The present invention relates to the technical field of deep-sea motor control, and more specifically, to a fault-tolerant control method for a deep-sea robot driving motor. Background Art

[0002] Deep-sea robot drive motors are widely used in underwater equipment such as deep-sea pipeline inspection robots, submarine cable inspection robots, deep-sea cable-laying robots, and deep-sea cleaning robots. In order to ensure long-term stable operation in the deep sea, high reliability requirements are placed on them. Even with good insulation and heat dissipation, faults such as turn-to-turn short circuits and winding open circuits are inevitable. When encountering a fault, traditional control methods can only choose to stop running or run at low power after removing the faulty unit. Stopping the operation is unacceptable for the long-term high-reliability working requirements of deep-sea motors, and removing the faulty module at low power also cannot give full play to the advantages of multi-module deep-sea motors (i.e., deep-sea robot drive motors with multiple modular stators).

[0003] Therefore, it is necessary to design a drive control method for a deep-sea robot drive motor with multiple modular stators so that it can operate with high efficiency and high torque even when a fault occurs. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a fault-tolerant control method for a deep-sea robot drive motor.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A fault-tolerant control method for a deep-sea robot driving motor comprises the following steps:

[0007] Step S1, obtaining the drive motor position, speed, bus voltage and phase currents of different stator modules;

[0008] Step S2, obtaining a speed command and comparing it with the feedback speed and using a PI controller to obtain a total current command value;

[0009] Step S3, performing characteristic analysis on the phase current sampled in step S1 to determine whether there is a fault state;

[0010] Step S4, determining the optimal control electrical parameters loaded into each stator module according to the fault state;

[0011] Step S5, comparing the current command value of each stator module with the feedback value and using a PI controller to obtain the voltage command value of each stator module;

[0012] Step S6, generating a PWM pulse signal through coordinate transformation and space vector modulation, driving the inverters of each stator module to control the operation of the motor.

[0013] Furthermore, in step S3, characteristic analysis of the sampled phase current is performed to determine the fault state, so as to facilitate the subsequent determination of control electrical parameters of each stator module, including the following steps:

[0014] Step S301, performing amplitude detection on the sampled phase current and recording the current amplitude of each stator module. The amplitude detection method is: sampling data at a fixed period time, recording the maximum and minimum values ​​of the data in the period by comparison method, calculating the phase current amplitude by the maximum and minimum values, and the period of amplitude detection is twice the motor operation period;

[0015] Step S302, comparing the peak-to-peak values ​​of all stator module phase currents in sequence, when a phase current is much greater than the other two phase currents of the same stator module, it is considered that a turn-to-turn short circuit occurs, and the corresponding switch tube is directly turned off, which is equivalent to an open circuit fault for processing;

[0016] Step S303, check the peak-to-peak values ​​of all stator module phase currents in turn. If there is a current zero value and the remaining two phase currents of the same module have the same amplitude and opposite directions, it can be determined that the stator module has an open circuit fault.

[0017] Furthermore, in step S4, current distribution is performed using the principle of minimum copper loss, including the following steps:

[0018] Step S401: If a single-phase short circuit or open circuit fault occurs, after the switch tube of the corresponding inverter bridge arm is blocked, the remaining phase current is expressed as:

[0019] (1)

[0020] (2)

[0021] (3)

[0022] Formula (1) is the residual phase current when phase A fails, formula (2) is the residual phase current when phase B fails, and formula (3) is the residual phase current when phase C fails. In formulas (1), (2) and (3), represents the A phase current, represents the B phase current, represents the C phase current, represents the amplitude, Represents the electrical angle, represents the initial phase angle, j=(1,2,3,4) represents the jth stator module;

[0023] Step S402, based on equations (1), (2) and (3), at this time axis, The shaft current can be expressed as:

[0024] (4)

[0025] In formula (4), represent Shaft current, represent Shaft current;

[0026] Step S403, the currents of the four stator modules are distributed as follows:

[0027] (5)

[0028] In formula (5), Represents the total current amplitude, ; For the first stator module Shaft current, For the first stator module Shaft current, assuming the first stator module is the faulty stator module, For the second stator module Shaft current, For the second stator module Shaft current, For the third stator module Shaft current, For the third stator module Shaft current, For the fourth stator module Shaft current, For the fourth stator module Shaft current, assuming that the second, third and fourth stator modules are healthy stator modules;

[0029] Step S404, the total copper consumption is expressed as:

[0030] (6)

[0031] In formula (6), Represents the total copper loss, is the resistance of each stator module;

[0032] Step S405: During the operation of the driving motor, It changes periodically from 0 to 2pi, and its integral is zero. The average value of copper loss in formula (6) can be expressed as:

[0033] (7)

[0034] Solving equation (7) yields the minimum copper loss: .

[0035] Furthermore, the deep-sea robot drive motor includes a casing, a rotating shaft, a modular stator and a rotor module. The rotating shaft is axially arranged in the casing, and a plurality of modular stators are axially spaced on the inner wall of the casing and arranged one-to-one with the rotor modules. Each modular stator can cooperate with the corresponding rotor module to make the rotating shaft output torque. The modular stator includes four separately arranged stator modules, and four sets of voltage source two-level inverters are used to control the four stator modules.

[0036] The beneficial effect of the present invention is that when a fault occurs, the present invention does not cut off the faulty module, but coordinates and controls the faulty module and the healthy module, utilizes the residual value of the faulty module to improve the overall electromagnetic torque, and reduces the loss after reasonably distributing the current, thereby ensuring high-efficiency and high-torque operation during a fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of the structure of a deep-sea robot driving motor in this embodiment;

[0038] Figure 2 is a structural schematic diagram of a modular stator in this embodiment;

[0039] Figure 3 A block diagram of the fault-tolerant control method of the deep-sea robot driving motor in this embodiment;

[0040] Figure 4 A flow chart of the fault-tolerant control method of the deep-sea robot driving motor in this embodiment;

[0041] Figure 5 This is a simulation result diagram of the deep-sea robot drive motor fault tolerance method in this embodiment.

[0042] Reference numerals: housing 100 , rotating shaft 200 , modular stator 300 , stator module 330 , rotor module 400 . DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example: Figure 1 As shown, it is a deep-sea robot driving motor, including a housing 100, in which a rotating shaft 200 is axially arranged, and a plurality of modular stators 300 are axially spaced and arranged on the inner wall of the housing, and are arranged one by one with the rotor modules 400. Each modular stator 300 can cooperate with the corresponding rotor module 400 to make the rotating shaft 200 output torque, so as to reduce the radial size of the modular stator 300 on the basis of outputting substantially the same torque, and at the same time, the modular stators 300 are independent of each other, and when one of the modular stators 300 is damaged, the remaining modular stators 300 can still operate normally; as shown in FIG. Figure 2 As shown, the modular stator 300 includes a plurality of separately arranged stator modules 330. By splitting the modular stator 300 into a plurality of mutually independent stator modules 330, when one of the stator modules 330 is damaged, the remaining stator modules 330 can still operate normally.

[0045] In this embodiment, three modular stators 300 are provided, and each modular stator 300 includes four separately provided stator modules 330; when in use, for a single modular stator 300, a mode in which four stator modules 330 are independently wound into a three-phase motor is adopted, that is, a single modular stator 300 is composed of four three-phase motors to correspond to four stator modules 330, and four sets of voltage source type two-level inverters are used to control the four stator modules 330 respectively. By adopting the above design, the four stator modules 330 are independently formed into three-phase motors, which can evenly distribute the output power, effectively reduce the level of power devices, and reduce the dependence on high-power devices; on the other hand, the degree of freedom of motor control can be improved, and the ability of the motor to operate with high quality in the event of a fault can be improved by flexibly using each stator module 330.

[0046] The traditional method generally shuts down when a fault occurs, or removes the faulty module (i.e., a single stator module 330 when a fault occurs), and uses the remaining healthy modules for operation, which has the problems of low efficiency and low torque. To solve the above problems, this embodiment proposes a fault-tolerant control method for a deep-sea robot drive motor, which does not remove the faulty module when a fault occurs, coordinates the control of the faulty module and the healthy module, fully utilizes the residual value of the faulty module, improves the overall electromagnetic torque, and reduces the loss after reasonably distributing the current.

[0047] A fault-tolerant control method for a deep-sea robot driving motor, such as Figure 3-Figure 4 As shown, the following steps are included:

[0048] Step S1, obtaining the drive motor position, speed, bus voltage and phase currents of different stator modules;

[0049] Step S2, obtaining a speed command and comparing it with the feedback speed and using a PI controller to obtain a total current command value;

[0050] Step S3, performing characteristic analysis on the phase current sampled in step S1 to determine whether there is a fault state;

[0051] Step S4, determining the optimal control electrical parameters loaded to each stator module according to the fault state, that is, the dq axis current command value of each stator module;

[0052] Step S5, comparing the current command value of each stator module with the feedback value and using a PI controller to obtain the voltage command value of each stator module;

[0053] Step S6, generating a PWM pulse signal through coordinate transformation and space vector modulation, driving the inverters of each stator module to control the operation of the motor.

[0054] Furthermore, in step S3, characteristic analysis is performed on the sampled phase current to determine the fault state, so as to facilitate the subsequent determination of the control electrical parameters of each stator module, including the following steps:

[0055] Step S301, performing amplitude detection on the sampled phase current and recording the current amplitude of each stator module. The amplitude detection method is: sampling data at a fixed period time, recording the maximum and minimum values ​​of the data in the period by comparison method, and calculating the phase current amplitude by the maximum and minimum values. To ensure the correctness of the detection, the period of amplitude detection is twice the motor operation period.

[0056] Step S302, comparing the peak-to-peak values ​​of all stator module phase currents in sequence, when a phase current is much greater than the other two phase currents of the same stator module, it is considered that a turn-to-turn short circuit occurs, and the corresponding switch tube is directly turned off, which is equivalent to an open circuit fault for processing;

[0057] Step S303, checking the peak-to-peak values ​​of all stator module phase currents in sequence, if there is a current zero value, and there is a state where the remaining two phase currents of the same module have the same amplitude and opposite directions, it can be determined that the stator module has an open circuit fault.

[0058] Furthermore, in step S4, current distribution is performed using the principle of minimum copper loss, including the following steps:

[0059] Step S301: If a single-phase short circuit or open circuit fault occurs, after the switch tube of the corresponding inverter bridge arm is blocked, the remaining phase current is expressed as:

[0060] (1)

[0061] (2)

[0062] (3)

[0063] Formula (1) is the residual phase current when phase A fails, formula (2) is the residual phase current when phase B fails, and formula (3) is the residual phase current when phase C fails. In formulas (1), (2) and (3), represents the A phase current, represents the B phase current, represents the C phase current, represents the amplitude, Represents the electrical angle, represents the initial phase angle, j=(1,2,3,4) represents the jth stator module;

[0064] Step S402, based on equations (1), (2) and (3), at this time axis, The shaft current can be expressed as:

[0065] (4)

[0066] In formula (4), represent Shaft current, represent Shaft current;

[0067] For example, the first stator module is faulty and the second to fourth stator modules are healthy. axis, The shaft current can be expressed as:

[0068] (4)

[0069] Step S403: according to the current characteristics of the faulty stator module, the currents of the four stator modules are distributed as follows:

[0070] (5)

[0071] In formula (5), Represents the total current amplitude, ; For the first stator module Shaft current, For the first stator module Shaft current, assuming the first stator module is the faulty stator module, For the second stator module Shaft current, For the second stator module Shaft current, For the third stator module Shaft current, For the third stator module Shaft current, For the fourth stator module Shaft current, For the fourth stator module Shaft current, assuming that the second, third and fourth stator modules are healthy stator modules;

[0072] The advantage of this allocation method is that, on the one hand, Set to 0 to increase torque output; on the other hand, the healthy second, third and fourth stator modules Shaft current , , To offset the faulty stator module The secondary pulsation generated can reduce the overall torque output pulsation;

[0073] Step S404, the total copper consumption is expressed as:

[0074] (6)

[0075] In formula (6), Represents the total copper loss, is the resistance of each stator module;

[0076] Step S405: During the operation of the driving motor, It changes periodically from 0 to 2pi, and its integral is zero. The average value of copper loss in formula (6) can be expressed as:

[0077] (7)

[0078] Solving equation (7) yields the minimum copper loss: .

[0079] At this time, by Set it to 0.231 to ensure high efficiency and high torque operation during faults.

[0080] In this embodiment, specific parameters of the simulation model used to verify this embodiment are: d-axis inductance 24 mH, q-axis inductance 24 mH, pole pair number 11, rotor permanent magnet flux 0.1 Wb, and stator module resistance 0.4Ω.

[0081] The simulation conditions used to verify the present embodiment are as follows: a speed of 200 r / min, a load of 20 N•m, a single-phase fault occurs at 0.1s, the faulty module is removed at 0.2s, and the method of the present invention is run at 0.3s. Figure 5The simulation result diagram is shown, from top to bottom, respectively, the q-axis current setting of the fault module / healthy module (since the three healthy modules are given in the same way, only one module's waveform is given in the diagram), the speed waveform, and the copper loss waveform. It can be seen from the diagram that when the motor is operating normally, the speed does not fluctuate, and the q-axis current setting values ​​of the four stator modules are consistent; when a fault occurs, the q-axis current and the speed fluctuate; after the fault module is removed, the q-axis stator current setting value of the fault module is 0, and the q-axis stator current setting value of the healthy module rises to 4 / 3 times of the original, and the speed can also run smoothly; finally, when running according to the method of this embodiment, the q-axis current of the fault module is also distributed, which is inconsistent with the q-axis current distribution of the healthy module, but the speed does not pulsate at this time, and the copper loss decreases, which can prove the beneficial effect of this embodiment.

[0082] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A fault-tolerant control method for a deep-sea robot driving motor, characterized in that: The steps include: Step S1, obtaining the drive motor position, speed, bus voltage and phase currents of different stator modules; Step S2, obtaining a speed command and comparing it with the feedback speed and using a PI controller to obtain a total current command value; Step S3, performing characteristic analysis on the phase current sampled in step S1 to determine whether there is a fault state; Step S4, determining the optimal control electrical parameters loaded into each stator module according to the fault state; Step S5, comparing the current command value of each stator module with the feedback value and using a PI controller to obtain the voltage command value of each stator module; Step S6, generating a PWM pulse signal through coordinate transformation and space vector modulation, driving the inverters of each stator module to control the operation of the motor.

2. According to claim 1, a fault-tolerant control method for a deep-sea robot driving motor is characterized in that: In step S3, characteristic analysis of the sampled phase current is performed to determine the fault state, so as to facilitate the subsequent determination of the control electrical parameters of each stator module, including the following steps: Step S301, performing amplitude detection on the sampled phase current and recording the current amplitude of each stator module. The amplitude detection method is: sampling data at a fixed period time, recording the maximum and minimum values ​​of the data in the period by comparison method, calculating the phase current amplitude by the maximum and minimum values, and the period of amplitude detection is twice the motor operation period; Step S302, comparing the peak-to-peak values ​​of all stator module phase currents in sequence, when a phase current is much greater than the other two phase currents of the same stator module, it is considered that a turn-to-turn short circuit occurs, and the corresponding switch tube is directly turned off, which is equivalent to an open circuit fault for processing; Step S303, checking the peak-to-peak values ​​of all stator module phase currents in sequence, if there is a current zero value, and there is a state where the remaining two phase currents of the same module have the same amplitude and opposite directions, it can be determined that the stator module has an open circuit fault.

3. A fault-tolerant control method for a deep-sea robot driving motor according to claim 1, characterized in that: In step S3, current distribution is performed using the principle of minimum copper loss, including the following steps: Step S401: If a single-phase short circuit or open circuit fault occurs, after the switch tube of the corresponding inverter bridge arm is blocked, the remaining phase current is expressed as: (1) (2) (3) Formula (1) is the residual phase current when phase A fails, formula (2) is the residual phase current when phase B fails, and formula (3) is the residual phase current when phase C fails. In formulas (1), (2) and (3), represents the A phase current, represents the B phase current, represents the C phase current, represents the amplitude, Represents the electrical angle, represents the initial phase angle, j=(1,2,3,4) represents the jth stator module; Step S402, based on equations (1), (2) and (3), at this time axis, The shaft current can be expressed as: (4) In formula (4), represent Shaft current, represent Shaft current; Step S403, the currents of the four stator modules are distributed as follows: (5) In formula (5), Represents the total current amplitude, ; For the first stator module Shaft current, For the first stator module Shaft current, assuming the first stator module is the faulty stator module, For the second stator module Shaft current, For the second stator module Shaft current, For the third stator module Shaft current, For the third stator module Shaft current, For the fourth stator module Shaft current, For the fourth stator module Shaft current, assuming that the second, third and fourth stator modules are healthy stator modules; Step S404, the total copper consumption is expressed as: (6) In formula (6), Represents the total copper loss, is the resistance of each stator module; Step S405: During the operation of the driving motor, It changes periodically from 0 to 2pi, and its integral is zero. The average value of copper loss in formula (6) can be expressed as: (7) Solving equation (7) yields the minimum copper loss: .

4. A fault-tolerant control method for a deep-sea robot driving motor according to claim 1, characterized in that: A deep-sea robot driving motor comprises a housing (100), a rotating shaft (200), a modular stator (300) and a rotor module (400); a rotating shaft (200) is axially arranged inside the housing (100); a plurality of modular stators (300) are axially spaced and arranged on the inner wall of the housing (100), and are arranged one-to-one with the rotor modules (400); each modular stator (300) can cooperate with the corresponding rotor module (400) to make the rotating shaft (200) output torque; the modular stator (300) comprises four separately arranged stator modules (330), and four sets of voltage source type two-level inverters are used to control the four stator modules (330).

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