Non-stop alternate output control method of multi-motor co-driving belt conveyor

Abstract

The application discloses a multiple-motor co-driving belt conveyor non-stop alternate output control method, and relates to the technical field of belt conveyor control, and sequentially comprises the following contents: collecting the stator temperature, vibration, rotating speed, current, bus voltage and environmental temperature and humidity of each driving motor, performing sub-health evaluation and forming an alternate scheduling instruction; generating a time stamp macro instruction package containing absolute starting time, handover window, target torque trajectory parameters and dynamic tolerance envelope parameters according to the alternate scheduling instruction; implementing complementary torque cross and online handover determination according to the time stamp macro instruction package; after the handover is completed, controlling the motor to be withdrawn into a zero torque follow-up mode, and implementing endogenous anti-condensation control. The application realizes multiple-motor non-stop smooth relay, controlled standby of the motor to be withdrawn and online identification of handover abnormity, reduces the execution misplacement caused by communication jitter, and inhibits the risks of bus backflow, mechanical counter-dragging and condensation of the motor to be withdrawn.

Description

Technical Field

[0001] This invention relates to the field of belt conveyor control technology, specifically to a non-stop alternating output control method for multi-motor driven belt conveyors. Background Technology

[0002] For bulk cargo loading and unloading at ports, transportation of raw coal and gangue in mines, long-distance transport of metallurgical raw materials, and large stockpiling and reclaiming yards, conveyors typically involve long conveying distances, large load variations, high start-stop frequency, and long continuous operating times. Currently, multi-drive belt conveyors generally install multiple motors in the head drive section or intermediate drive section, and control these motors through frequency converters or master-slave controllers. The main control approach is to perform frequency following correction and master-slave control based on the frequency converter's broadcast frequency and active current, or to group multiple motors within a drive section according to a master-slave relationship and control them based on torque balance, speed balance, or load balance.

[0003] Chinese patent CN105048885A discloses a master-slave control method for a multi-motor drive of a belt conveyor. The method treats the motors in a drive unit as several groups, collects the operating parameters of each motor within a group, and, according to a master-slave distribution scheme, controls one or more of the torque, speed, and load balances of each motor by controlling the rotational angular velocity of different motors. The structure and control relationship are as follows: first, the master motor and the slave motors in different relative positions within a drive unit are determined; then, torque, speed, and load balances are performed separately depending on whether the motors are coaxial or non-coaxial; the overall process is torque balance first, then speed balance, and finally load balance.

[0004] The basic idea behind this approach is to enable multiple motors in a single drive unit to drive a belt conveyor together and maintain the same output, thereby reducing the load distribution differences between different drive units.

[0005] The existing technologies mentioned above focus on the synchronization and balancing of multiple motors driving simultaneously, with the control objective being that all drive units are in a state of joint output. In continuous heavy-load conveying scenarios such as ports and mines, if a drive motor is temporarily deactivated due to temperature rise, vibration increase, or maintenance needs, and this drive motor is mechanically connected to other drive units via coaxial, coupling, or other rigid transmission links, then this drive motor will still be dragged by the conveying system after deactivating its output. The control logic for this type of situation does not address "online deactivation but mechanical disconnection," meaning it does not distinguish between transient imbalances and abnormal operating conditions during the handover process. Therefore, if a drive unit needs to reduce its load or stop electromagnetic output, it may cause the normal transition process to be confused with fault deviations, leading to loss of control in continuous conveying conditions. Furthermore, under conditions of high humidity, high salt spray, and large diurnal temperature differences, a drive unit may even detach from the network due to insulation moisture in low-load or standby states.

[0006] Therefore, existing technologies also have their limitations in the above scenarios. The technical problem is the safe and orderly output switching of a single drive unit in a multi-motor co-driven belt conveyor that is running continuously and where the drive units are mechanically connected. Summary of the Invention

[0007] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a non-stop alternating output control method for multi-motor co-driven belt conveyors. Based on alternating scheduling instructions, a timestamp macro instruction package is generated, containing absolute start time, handover window, target torque trajectory parameters, and dynamic tolerance envelope parameters. Complementary torque crossover and online handover determination are implemented based on the timestamp macro instruction package. After handover, the de-energized motor is controlled to enter a zero-torque following mode, and intrinsic anti-condensation control is implemented. This achieves smooth, non-stop relay of multiple motors, controlled standby of the de-energized motor, and online identification of handover anomalies, suppressing the risks of busbar backflow, mechanical backdraft, and de-energized condensation; thus solving the technical problems in the background technology.

[0008] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: The non-stop alternating output control method for multi-motor co-driven belt conveyors includes collecting stator temperature, vibration, speed, current, bus voltage and ambient temperature and humidity of each drive motor, conducting sub-health assessment, forming alternating scheduling instructions and determining candidate rotation motors and candidate relay motors. Based on the alternating scheduling instruction, a timestamp macro instruction package is generated. The timestamp macro instruction package includes the absolute start time, handover window, target torque trajectory parameters, and dynamic tolerance envelope parameters. Based on the timestamp macro instruction package, the candidate relay motor and the candidate rotation motor are controlled to perform complementary torque crossover, and continuous online handover determination is performed based on the dynamic tolerance envelope. After the handover is completed, the motor is controlled to enter the zero torque following mode and outputs direct shaft suppression current and quadrature shaft compensation current. The intrinsic anti-condensation control is implemented based on the coaxial speed, stator temperature and ambient dew point.

[0009] Furthermore, the sub-health assessment includes: continuously collecting stator temperature, temperature rise rate, vibration, speed, current, bus voltage, and ambient temperature and humidity of each drive motor; constructing sub-health indicators based on stator temperature, temperature rise rate, vibration, and cumulative operating time; ranking and determining each drive unit; and forming a candidate set of alternating scheduling instructions based on the ranking results.

[0010] Furthermore, the alternation scheduling instruction includes: triggering alternation when the stator temperature approaches the upper limit, the temperature rise derivative is abnormal, the vibration exceeds the limit, or the running time reaches the rotation condition; determining the candidate rotation motor, the candidate relay motor and the corresponding triggering reason; and using the candidate rotation motor, the candidate relay motor and the triggering reason as input for subsequent handover parameter calculation.

[0011] Furthermore, the generation of timestamp macro instruction packages includes: calculating the handover window by combining belt length or equivalent transmission path parameters, driver time base, current speed and load status, and writing the absolute start time, handover window, target torque trajectory parameters and dynamic tolerance envelope parameters into the timestamp macro instruction package for candidate off-duty motors and candidate relay motors.

[0012] Furthermore, the timestamp macro instruction package is pre-issued to the drive inverters of the candidate rotating motors and the candidate relay motors before the handover begins, and under a unified time base, the time synchronization and alternating scheduling module continuously provides the same set of handover parameters to the complementary torque cross-execution and dynamic tolerance monitoring.

[0013] Furthermore, the complementary torque crossing includes: after the absolute start time is reached, the candidate relay motor gradually increases the load according to the target torque trajectory parameters, and the candidate rest motor gradually decreases the load according to its complementary trajectory, while maintaining the total traction force continuously within the handover window until the candidate rest motor completes unloading.

[0014] Furthermore, the continuous online handover determination includes: continuously comparing the actual current difference, actual torque difference, speed deviation, and bus abnormality during the handover period; maintaining handover execution when the actual current difference, actual torque difference, speed deviation, and bus abnormality are within the dynamic tolerance envelope; and outputting an abnormality protection command when the dynamic tolerance envelope is penetrated.

[0015] Furthermore, controlling the de-grid motor to enter zero torque following mode includes: maintaining the controlled operation of its drive inverter after the torque of the old main working motor drops to a threshold, outputting direct-axis suppression current based on the coaxial speed, and outputting quadrature-axis compensation current based on the coaxial speed, stator temperature, and friction state estimates, so that the de-grid motor maintains zero net torque following under rigid connection conditions. Implementing intrinsic anti-condensation control includes: maintaining a lower limit current within the safe demagnetization boundary when the stator temperature of the de-grid motor approaches the dew point warning line due to ambient temperature difference and humidity, and releasing the lower limit current maintenance after the stator temperature recovers above the dew point warning line; exiting the zero torque following mode and outputting a protection signal when overvoltage, abnormal temperature rise, or demagnetization risk occurs.

[0016] Furthermore, when applied to multiple drive units in rotation, the upper controller cyclically executes alternating outputs according to the state transition mode of the main unit, relay unit, and follower unit, so that the motor that is in zero torque following mode and whose conditions have been restored re-enters the process of determining the candidate relay motor and participates in the next round of switching and subsequent rotation control.

[0017] (III) Beneficial Effects This invention provides a non-stop alternating output control method for a multi-motor co-driven belt conveyor, which has the following beneficial effects: By uniformly collecting data on stator temperature, vibration, speed, current, bus voltage, and ambient temperature and humidity of each drive motor, and combining this with sub-health assessments to generate alternating scheduling instructions, the determination of candidate rotation motors and candidate relay motors has a continuous basis, avoiding the problems of trigger lag and inaccurate object selection in experience-based rotation.

[0018] The absolute start-up time, handover window, target torque trajectory parameters, and dynamic tolerance envelope parameters are encapsulated into a timestamp macro instruction package and pre-issued, enabling the drive inverter to hand over according to a unified time base. This avoids interference from communication jitter and execution misalignment on the alternating output without stopping the machine, and makes the handover rules highly continuous.

[0019] By using complementary torque crossover within the handover window, and employing a dynamic tolerance envelope to continuously determine the actual current difference, actual torque difference, speed deviation, and bus abnormality during online handover, the transient state of normal handover deviates from the actual fault, thus avoiding misjudging normal handover as abnormal shutdown.

[0020] After the handover is completed, the de-grid motor achieves zero torque following and jointly outputs direct-axis suppression current and quadrature-axis compensation current, transforming the passive drive under rigid connection into controlled following, suppressing the backflow trend of the busbar, reducing mechanical drive resistance, and making the de-grid state controllable; by embedding the inherent anti-condensation control into the controlled standby process of the de-grid motor, the insulation safety maintenance is embedded into the main control chain according to the setting of coaxial speed, stator temperature and ambient dew point maintenance lower limit current, preventing the de-grid motor from cooling into an unstable state under high humidity conditions. Attached Figure Description

[0021] Figure 1 This is the overall architecture diagram of the non-stop alternating output control system for the multi-motor co-drive belt conveyor of the present invention;

[0022] Figure 2 This is a flowchart of the multi-source state compilation and alternation determination process in step one of the present invention;

[0023] Figure 3 This is a schematic diagram illustrating the generation and distribution of timestamp macro instruction packets in step two of this invention;

[0024] Figure 4 This is a diagram showing the synergistic relationship between the handover window, complementary torque trajectory, and dynamic tolerance envelope of the present invention.

[0025] Figure 5 This is a flowchart of the handover execution and anomaly classification handling process in step three of this invention;

[0026] Figure 6 This is a block diagram of the zero-torque following and endogenous anti-condensation control of the degrinding motor in step four of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see Figures 1-6 This invention provides a non-stop alternating output control method for a multi-motor co-driven belt conveyor, comprising: This step is the starting point of the non-stop alternating output control method for a multi-motor co-driven belt conveyor. Its task is not to form a general collection of equipment measurement points, but to, under the triple constraints of continuous conveying, heavy-load inertia, and rigid co-drive, first convert the timing of alternation, which motor exits, and which motor takes over into calculable, comparable, and transferable preliminary judgment results. Since the subsequent step two needs to directly call the alternating scheduling command, candidate rotating motor, candidate relay motor, and triggering reason output by this step, this step simultaneously completes multi-source state compilation, sub-health quantification, alternation urgency determination, and relay object screening, and ensures that the output results have a clear temporal sequence relationship and parameter interface relationship.

[0029] Step 1: Under the operating conditions of continuous operation and uninterrupted rigid transmission link, converge the dispersed operating state quantities into a single alternating trigger basis, and provide an alternating scheduling instruction that can be directly invoked in Step 2.

[0030] Multi-motor co-driven belt conveyors in port bulk cargo transportation scenarios operate under high loads, long distances, and continuous day and night operations. Although multiple drive motors share the traction task, they differ in terms of heat dissipation, base vibration, installation coaxiality, local dust accumulation, and the degree of humid heat intrusion from sea breezes. This leads to asynchronous thermal degradation and mechanical fatigue rates among the drive motors. If a fixed rotation cycle or manual experience-based switching method is still used, drive motors that have not yet entered the danger zone may be prematurely deactivated, while drive motors that are truly approaching the abnormal boundary continue to bear the main traction task. This can then drag the local sub-healthy state, which could have been addressed proactively, into a stage of sudden temperature rise, amplified vibration, or busbar disturbance.

[0031] Based on this engineering contradiction, instead of using a single threshold trigger, the stator temperature, temperature rise rate, vibration amplitude, current load, bus stability, and environmental humidity and heat coupling relationship are jointly integrated to form a sub-health evaluation chain for alternating control, providing stable input from the source for the construction of subsequent handover windows.

[0032] This step is executed by the host controller, with the status acquisition unit responsible for data acquisition and transmission. Specifically, the temperature acquisition branch continuously reads the stator temperature of each drive motor. The vibration acquisition branch continuously reads the vibration amplitude of the bearing housing or machine base. The driver feedback branch continuously reads the rotational speed. Phase current With bus voltage The environmental acquisition branch continuously reads the ambient temperature. With relative humidity The operation management branch continuously records the cumulative runtime. The upper-level controller first performs time alignment on data from different sampling periods, then replaces missing values ​​with the most recent reliable sample value, and eliminates abnormal spikes according to a three-point slope constraint to prevent single-impact noise from mistakenly raising subsequent alternation judgments. After the compilation is completed, the system does not directly compare whether a single measuring point exceeds the limit, but forms a single-chain processing path in the order of thermal load identification, mechanical instability verification, and relay margin screening. This ensures that the alternation action is not mistakenly triggered by a single sporadic signal, but is driven by the common deviation of multiple source states on the same time axis.

[0033] First, a baseline for thermo-mechanical coupling suboptimal conditions is established for each drive motor. Stator temperature is not included here. With vibration amplitude Instead of directly weighting and summing, we first couple the temperature rise rate with the humid and hot background, and then introduce mechanical disturbance as an amplification factor to highlight the two hidden risks of high humidity without high temperature and medium temperature with high vibration in the port environment.

[0034] For example, the upper-level controller generates the sub-health baseline according to the following formula. : ; In the formula, the sub-health baseline : The overall deviation of the current drive motor from the baseline state under this operating condition. The value is a continuous quantity greater than 0; the larger the value, the closer it is to the priority rest zone; stator temperature. Temperature at the corresponding measuring point on the motor windings or stator core is preferably obtained using an embedded thermal resistor; ambient temperature. Ambient temperature near the drive cabinet or motor mounting area; temperature reference. The thermal equilibrium reference temperature obtained by setting the machine at the current load level; temperature rise rate. Stator temperature The first derivative with respect to time is preferably calculated using a sliding five-point difference; rate reference Reference value for temperature rise rate under normal heat accumulation conditions; vibration amplitude. The vibration response value of the machine base or bearing housing is preferably the effective value of velocity or the displacement envelope value; Vibration reference Long-term healthy vibration reference value for the corresponding installation location; dew point approximation. The degree to which the motor surface temperature approaches the ambient dew point is used to demonstrate the amplifying effect of high humidity on insulation risks; amplification factor. The coupling strength between the dew point approximation amount and the sub-health baseline is preferably positive, which is used to adjust the impact of dew point risk on the sub-health baseline; it is preferable to adjust this by minimizing the number of false triggers during the debugging phase. Nonlinear exponent The sensitivity shaping factor for the temperature difference term is best selected as 1.2~2.0. It should be determined during the commissioning phase based on the historical operation data playback, when the ranking result of the sub-health baseline for the artificially known abnormal precursor conditions is consistent with the operation and maintenance records. Among them, dew point approximation amount Further, obtain the following formula: ; Among them: Dew point approximation amount The degree to which a depleted motor or a candidate for rotational shutdown approaches the dew point boundary is positively evaluated; a positive value is also applied when the temperature is below the dew point temperature plus a safety margin. Dew point temperature Due to ambient temperature With relative humidity The temperature margin was obtained by referring to tables or using the Magnus approximation formula. The optimal temperature difference for preventing condensation is 3 to 5°C.

[0035] Through this process, the system isomorphizes the pure thermal state, mechanical disturbance, and condensation risk onto a single evaluation plane. Subsequent alternating triggers no longer only involve overheating boundaries but can pre-determine the target drive motor whose insulation environment has deteriorated even before the temperature exceeds the limit. Thus, step one yields a directional sub-health baseline, rather than discrete alarm points; the sub-health baseline maintains its coupling relationship with environmental dew point, vibration, and temperature rise rate, facilitating its retrieval in step four.

[0036] In obtaining a sub-healthy baseline Subsequently, the upper controller does not immediately identify the drive motor corresponding to the maximum value as a candidate rotation motor. Instead, it further introduces the degree of traction occupation and the continuity of operation to form an alternation urgency, thereby avoiding the mistaken withdrawal of the drive motor that is in slightly worse condition but is currently undertaking the task of relay preparation.

[0037] For example, alternating urgency is formed according to the following formula: ; In the formula, alternating urgency : The urgency of the drive motor entering the priority rest sequence, a continuous value greater than 0; sub-health baseline. Inherit the aforementioned output; phase current : Current output current of the drive motor; current reference : Rated continuous operating reference current at the current belt speed setting; cumulative operating time The duration of continuous operation as the main traction task after this round of deployment; duration benchmark. : Reference runtime for rotation management settings; Speed ​​margin factor This is the correction amount for the relay flexibility of the drive motor under the current coaxial speed constraint. A larger value indicates greater suitability as a relay motor rather than a rotational motor. Therefore, it is placed in the denominator to suppress misjudgments. The correction amount is jointly determined by the current speed synchronization deviation, the current output torque margin, and the fault lockout state. Its generation rule is: if the drive inverter is in a fault lockout state, the corresponding motor is not included in the sorting; if the current speed deviation is greater than the synchronization tolerance, then... Take the larger value to lower its priority in the rest-time sequence; if the current output torque margin is low, then let Take a smaller value to make it more likely to be used as a rotation object.

[0038] Subsequently, the upper-level controller adjusts the urgency level accordingly. All drive motors are sorted in descending order, and a secondary filtering is performed based on fault lockout status, maintenance lockout status, and current online status. The first motor in the sorted list is marked as a candidate for rotation, provided its rotation urgency is considered. Multiple consecutive sampling windows maintain a leading position rather than a momentary spike; the remaining objects after sorting enter the candidate relay pool, but the candidate relay motor is not yet directly determined.

[0039] By distinguishing between which motors should retreat more and which are more capable of retreating at the moment, based on traction occupancy level and continuous running time, the generation of candidate rotational motors becomes condition-specific. Furthermore, the output is not an isolated ranking, but rather a list of candidate rotational motor identifiers with continuous constraints, laying the foundation for relay matching.

[0040] After the candidate motors for rotation are determined, the host controller needs to select the candidate relay motor that best matches the current operating conditions from the candidate relay pool. If only the drive motor with the lowest temperature or the longest idle time is selected here, it is easy to overlook the coaxial speed response, the steady-state load-bearing capacity of the bus, and the available capacity of the current drive. This will cause the handover impact to be amplified due to inaccurate object selection, even if the timestamp macro instruction is pre-issued in the subsequent step two.

[0041] Therefore, using the candidate off-duty motors as a reference, the relay adaptability of the remaining online drive motors is calculated one by one. The relay adaptability is achieved using a lookup table method, a piecewise interpolation method, or a bounded nonlinear scoring method; preferably, the upper-level controller simultaneously considers speed deviation, current margin, bus stability margin, and temperature difference recovery margin to screen out the candidate relay motors most suitable for undertaking the main traction task in the next time period. After matching is completed, the system generates an alternation scheduling instruction, which includes at least the candidate off-duty motor identifier, the candidate relay motor identifier, the trigger reason code, the current alternation urgency level, and the alternation activation preparation flag, and writes it into the data area called in step two.

[0042] A motor can only enter the candidate relay pool if all of the following conditions are met: no fault lockout and the drive inverter is in a controlled operating state; the current stator temperature is below its upper temperature limit and has thermal margin; the current output torque margin is greater than the minimum relay margin; the deviation between the current speed and the coaxial reference speed is less than the synchronization tolerance; the current bus condition is normal and not in the overvoltage warning zone; and it is not in the anti-condensation lockout period or the following instability period of step four. Methods for obtaining torque margin: ; Among them: output torque margin : No. Taiwan Electric can still output torque for relay; maximum capacity. : No. The maximum sustainable torque of the motor under the current linear speed setting, temperature conditions, and driver capacity is given by the calibration table; the current output torque... : No. The actual output torque of the motor is given by the torque estimator of the drive inverter or the torque sensor.

[0043] To prevent false triggering caused by abnormal state sampling, two boundary processing paths are set up: First, when the urgency of alternation of candidate rotating motors continues to rise, but the relay adaptability of all candidate relay motors is below the activation threshold, the system does not directly alternate, but outputs a delayed alternation flag and increases the sampling refresh rate; Second, when the bus voltage rises abnormally or any drive motor has entered the hard fault lockout zone, the system freezes the alternation scheduling instruction, only retains state tracking, and does not grant execution permission to step two. The purpose of this processing is to ensure that the output of step one is an executable alternation request, rather than a theoretical judgment that is out of execution condition.

[0044] Finally, step one outputs an alternating scheduling instruction with object, cause, level, and permission status. This alternating scheduling instruction corresponds one-to-one with the timestamp macro instruction encapsulation interface in step two, and can be directly read without further interpretation. This transforms multi-source measurement point inputs into executable alternating scheduling instructions, eliminating the lag that previously occurred when rotating based on single temperature limit exceedances or manual experience.

[0045] Step 2: Convert the status judgment result output in Step 1 into a timestamp macro instruction package containing absolute start time, handover window, torque trajectory parameters and dynamic tolerance envelope parameters, and write the timestamp macro instruction package into the local execution area of ​​each drive inverter.

[0046] If the instantaneous torque command is still issued point by point by the upper controller according to the communication cycle, the handover process will be directly exposed to the coupled disturbances of bus congestion, clock drift, driver refresh cycle difference and load change. Even if the candidate rotating motor and candidate relay motor have been correctly identified in step one, the timing misalignment may still occur due to the inconsistent arrival of commands, such as load reduction before load increase, load increase before protection, or simultaneous lifting of two motors.

[0047] Therefore, step two no longer interprets handover control as continuous remote control, but rather refactors it into a local script execution process involving one pre-calculation, one pre-deployment, and autonomous unfolding of the driver according to a unified time semantic. The significance of this approach is that step two directly determines the smoothness of the complementary torque crossover, the criterion for dynamic tolerance monitoring, and the trigger boundary for anomaly protection in step three. Therefore, its output must have a clear parameter interface, a unified time anchor point, and a repeatable generation path.

[0048] This step is executed by the host controller, with each drive inverter acting as the configured entity. The host controller first reads the alternation scheduling command, candidate off-duty motor identifiers, candidate relay motor identifiers, trigger reason codes, and alternation urgency from the output of step one. Then, the current belt length, coaxial speed feedback, bus voltage status, and driver local clock status are read synchronously. The processing then proceeds in the following order: first, determine the handover window; then, set the absolute start time; and finally, encapsulate the trajectory and envelope. This is because the handover window is the mother parameter of the entire handover script: setting it too short will cause the complementary torque crossover in step three to be too steep, amplifying the belt longitudinal tension wave; setting it too long will lengthen the opening time of the dynamic tolerance envelope, expanding the protection exposure area.

[0049] Therefore, the handover window is constructed first, and then the local time base is aligned to ensure that each drive inverter starts at the same absolute start time, thereby ensuring that the subsequent trajectory advance and dynamic tolerance envelope phase remain consistent.

[0050] The handover window cannot be a fixed empirical value, nor can it be determined solely by the belt length. Instead, it should simultaneously reflect the belt's elastic propagation, the release of inertia from rotating components, and the alternating tension given in step one. .

[0051] The upper-level controller takes belt length, equivalent longitudinal wave velocity, equivalent inertia, coaxial speed, and current traction margin as inputs to form a handover window. The first-order solution value is then constrained within a preset safe range by boundary clamping logic; preferably, the safe range is 3s to 8s. Wherein: ; In the formula: handover window : Total handover time, its function is to specify the duration of the complementary torque crossover in step three, with a clamping time of 3 to 8 seconds; handover base time The minimum time base under low load conditions is used to ensure that the total handover time is non-zero and is taken as a positive value; belt length. The effective transmission section length, which characterizes the propagation path of the tension wave, is determined by the structural dimensions. Equivalent longitudinal wave velocity The longitudinal disturbance propagation speed of a belt system, which converts length into propagation time, is calibrated by impact tests or tension wave tests, and identified by tension wave impact tests or loaded disturbance tests; inertia coefficient. : Propagation path weight, its function is to correct the delay effect under different belt structures, and it takes a positive value; Equivalent inertia The combined inertia of the coaxial drive chain and the rollers characterizes the mechanical hysteresis during unloading and loading, and is calculated from no-load coasting tests or from the inertia of the motor, coupling, and rollers; coaxial speed. The actual rotational speed at the current handover moment serves to couple the release of inertia with the operating gear. Traction margin The remaining adjustable traction torque margin is used to prevent the window from being incorrectly shortened under high load conditions. It is obtained by subtracting the required torque from the current output capacity and is a value greater than 0. ; Among them: traction margin The minimum remaining torque margin that both parties can use for safe handover under the current operating conditions; the upper limit of the capacity of the receiving side. The upper limit of the current sustainable torque output of the candidate relay motor; the upper limit of the rest-day capacity. The upper limit of torque that the candidate rotating motor can stably maintain before unloading; required torque. The equivalent traction torque required to maintain belt speed and material conveying under current conveying conditions; ; Among them: absolute startup time The unified starting time for this handover operation; the current time. : The current clock value when the host controller generates the timestamp macro instruction packet; pre-buffer time Minimum preparation time required for the drive inverter to receive, verify, and latch macro instruction packets; maximum communication delay. The maximum measured single-pass delay or synchronization compensation delay of the bus in the recent period; the maximum communication delay. The upper-level controller continuously collects statistics during the debugging and operation periods. The statistical object is the round-trip time between the issuance and receipt of the timestamp macro instruction packet, and the conservative value of the one-way trip is taken.

[0052] Urgency coefficient : Inertia term weight, which reflects the influence of mechanical inertia on smooth relay, takes a positive value; urgency reduction coefficient Alternating urgency compression weights are used to advance the handover completion time when candidate rotating motors approach the risk zone, and are assigned positive values; alternating urgency : Continuing from the output of step one, its function is to directly incorporate the feedforward decision into the solution of the intersection window, taking values ​​greater than 0; Furthermore, the handover window It is no longer an empirical constant detached from the working conditions, but instead incorporates the alternating urgency of step one. Based on the field transmission characteristics, a robust time mother parameter is thus provided for step three.

[0053] At the handover window Once determined, the host controller further determines the absolute start-up time. The trajectory parameters are then written into the timestamp macro instruction package. (Absolute start time) An absolute time stamp method under a unified time base is adopted; the unified time base is preferably formed by industrial Ethernet clock synchronization, but can also be formed by synchronization pulses or a shared clock. The fields of the timestamp macro instruction packet include at least: candidate rotation motor address, candidate relay motor address, and absolute start time. handover window Total traction reference torque The data includes the trajectory function number, dynamic tolerance envelope parameters, protection backoff flag, and verification field. After encapsulation, the upper-level controller sends a configuration receipt to both drive inverters and requests a return configuration receipt. If either receipt fails verification, the current timestamp macro instruction package is revoked, but the alternating scheduling instruction from step one is retained, and execution permission is not granted to step three.

[0054] Preferably, the trajectory function employs a cubic smoothing function to avoid abrupt changes in the torque slope at both ends of the window. Its normalized phase and complementary torque trajectories are generated by the following formula: ; Where: normalized phase The current execution time advances within the handover window as a percentage, its function is to map the actual time to... Range; Execution time : The current time under the local time base of the drive inverter, its function is to gradually advance the drive trajectory; absolute start-up time The unified start time of this handover script is used to eliminate differences in the order of communication arrival; handover window. Its function is to define the total duration of phase advancement; Trajectory function The normalized load trajectory of the candidate relay motor serves to maintain a zero slope at the beginning and end of the window. ; Where: Relay torque command The target torque of the candidate relay motor in the current phase, its function is to gradually assume the total traction task along a smooth trajectory; rotation torque command. The target torque of the candidate rotating motor in the current phase, its function is to gradually unload according to the complementary trajectory; total traction reference torque. The target torque benchmark corresponding to the total traction demand before handover is used to ensure the continuity of the total traction capacity of the system before and after the handover. Secondly, step two transforms the central continuous remote control into a central pre-configuration and edge local execution model, reducing the impact of communication jitter on handover smoothness and increasing the total traction reference torque. It will also maintain continuous conservation within the window.

[0055] But there is only a handover window. Complementary trajectories still cannot achieve non-stop handover because step three requires knowing within which deviation ranges imbalance constitutes a legitimate handover transient. Therefore, the upper-level controller needs to generate a dynamic tolerance envelope when encapsulating timestamp macro instruction packets and send it to the trajectory parameters. The dynamic tolerance envelope does not have a fixed threshold; instead, it is appropriately widened in the middle of the handover window and gradually tightened at the beginning and end, allowing the protection system to accommodate the transient deviations required for actual handover without losing its ability to detect axle breakage, jamming, and stall for an extended period. Specifically: ; Where: dynamic tolerance envelope Normalized phase The upper bound of the allowable comprehensive deviation serves as the boundary for distinguishing the deviation between the transient state and the actual fault during the legal handover in step three; the lower bound of the static deviation. The minimum tolerance level maintained at the beginning and end of the window is used to ensure that the protection system does not become excessively relaxed. A positive value is taken, representing the upper bound of the maximum normalized deviation of the system under non-transitional steady state; envelope broadening. : Relative to the static bottom boundary The additional opening margin serves to provide a transient buffer for complementary torque crossing; it is taken as a positive value, representing the peak value of the combined deviation from multiple normal handover tests. The upper bound of the increment; Shape Index The steepness of the envelope peak is determined by offline playback of multiple sets of normal junction data. Under the conditions that there is no penetration throughout the normal junction process and the beginning and end of the steady state are tightened as soon as possible, the minimum envelope area value is selected from the discrete candidate set. Its function is to control the width of the middle section and the speed of the beginning and end of the junction. The preferred value is 1.2 to 2.5. Normalized phase Its function is to ensure that the dynamic tolerance envelope and the complementary torque trajectory use the same temporal semantics; sine kernel function : Used to ensure that the dynamic tolerance envelope naturally converges at the beginning and end of the window and forms a single peak expansion in the middle; circumferential constant The trigonometric phase constant is used to normalize the phase. Mapped to half-wave interval; ; Where: Overall deviation The maximum normalized deviation among current deviation, torque deviation, and speed deviation serves as the single execution criterion; the maximum operator. Selecting the most unfavorable term from multiple normalized biases serves to prevent a single indicator from masking the true anomaly; current bias. The actual current difference between the candidate relay motor and the candidate rotation motor during the handover window serves to characterize the degree of imbalance on the electromagnetic side; current reference. The current normalization scale is used to unify the judgment criteria for different load levels, and takes a value greater than 0. Torque deviation The sum of actual complementary torques relative to the total traction reference torque The deviation amount serves to characterize whether the handover deviates from the target traction conservation relationship; torque reference. Torque normalization metric: Its function is to standardize the judgment criteria for different traction gears, taking a value greater than 0; Speed ​​deviation. The deviation of the actual coaxial speed from the reference speed before handover is used to characterize the impact of handover on the continuity of belt speed; speed reference. The speed normalization scale is used to place speed determination, current determination, and torque determination at the same evaluation level, and takes a value greater than 0. When the comprehensive deviation Not greater than the dynamic tolerance envelope At that time, the upper-level controller issues an execution permission to the relevant drive inverter; when the comprehensive deviation... If an over-limit is predicted during the encapsulation stage, or if the bus voltage is in an abnormally rising state, then step two will only retain the draft timestamp macro instruction package and will not issue an execution license. As a supplement: the timestamp macro instruction package field structure should at least include: candidate off-duty motor address; candidate relay motor address; and absolute start time. ; handover window Total traction reference torque ; Trajectory function number or trajectory lookup table address; Dynamic tolerance envelope parameter , , ; Handover failure rollback strategy number; Package sequence number; Cyclic redundancy check field.

[0056] Both drive inverters must return a configuration receipt after receiving the timestamp macro instruction packet; if either receipt times out, field verification fails, or packet sequence number is inconsistent, execution permission will not be granted during this handover, and the system will maintain the original traction allocation.

[0057] Furthermore, in step two, the discrimination boundary is written into each drive inverter before the handover is executed, so that step three has both a unified torque trajectory and a unified deviation interpretation rule, thereby reducing the probability of legal transients being falsely stopped, and retaining a clear interface for rapid protection after abnormal penetration of the envelope.

[0058] Step 3: Based on the timestamp macro instruction packet issued in Step 2, complete the complementary torque crossover between the candidate relay motor and the candidate rotation motor, and based on the dynamic tolerance envelope... The system performs real-time analysis of deviation evolution during the handover period, thereby outputting the stable relay result or abnormal protection result of the new main working motor.

[0059] For long-distance, heavy-duty belt conveyors, once the handover process enters the execution phase, the core challenge is no longer whether to rotate the drive motors, but rather how to disengage one drive motor and smoothly engage another without disrupting the overall traction continuity. If a step-based load factor is used, the candidate relay motor will rapidly increase its load in a short period, while the candidate idler motor will simultaneously unload. This will cause longitudinal disturbances as the belt tension propagates along the conveying direction, potentially leading to material spillage, belt speed fluctuations, and idler roller impact. If the deviation within the handover window continues to be handled using static protection thresholds, normal complementary torque crossings will be misidentified as shaft breakage or jamming. Therefore, the execution logic is constructed as a single-chain process: local synchronous deployment, comprehensive deviation aggregation, and tiered handling output.

[0060] This step is executed collaboratively by the drive inverters of the candidate relay motor, the drive inverters of the candidate rotation motor, and the host controller. The two drive inverters are responsible for unfolding the torque trajectory according to the local time base, while the host controller is responsible for receiving feedback and reconstructing the overall deviation. After receiving the timestamp macro instruction packet from step two, the two drive inverters first latch the absolute start time. Then, the execution time is read within each current loop refresh cycle. Calculate the normalized phase And accordingly, they will advance their respective target torque commands.

[0061] With normalized phase As the window progresses from its starting point to its ending point, the target torque borne by the candidate relay motor continuously increases, while the target torque borne by the candidate off-duty motor continuously decreases. Simultaneously, the upper-level controller synchronously compares whether the actual current difference, actual torque difference, coaxial speed deviation, and bus voltage deviation remain within the dynamic tolerance envelope. Within this range. The handover action is considered valid only when trajectory advancement and deviation monitoring occur in parallel under the same phase reference.

[0062] The first challenge is to ensure that two drive inverters can operate synchronously without relying on real-time point-to-point scheduling. The drive inverters of the candidate relay motors are configured based on their absolute start-up time within each refresh cycle. and handover window Calculate normalized phase Then normalize the phase Substitute the trajectory function configured in step two This generates a relay torque command. The drive inverters of the candidate rotational motors are in the same normalized phase. Generate rest torque command .

[0063] Both together use the total traction reference torque Since this is the parent quantity, the torque conservation relationship is maintained within the transition window. Where: ; Where: normalized phase The execution time within the handover window represents the advancement ratio. Its function is to map candidate relay motors and candidate rotation motors to the same temporal semantics. The value range is... Execution time : Real-time counting time under the local time base of the drive inverter, its function is to drive the normalized phase. Continuous advancement, with a value greater than or equal to the absolute start-up time. Absolute startup time The unified start time for this handover action serves to constrain the two drive inverters to synchronously enter the trajectory deployment state. ; Where: current time : Local clock value when the host controller encapsulates the timestamp macro instruction packet; pre-buffer time Minimum preparation time required for the drive inverter to receive, verify, and latch timestamp macro instruction packets; maximum communication delay. Maximum single-pass bus latency and maximum communication latency, as measured during runtime. The data is obtained by statistically analyzing the round-trip time of the recent timestamp macro instruction packets and taking a conservative one-way value. handover window The total allowed duration of this handover operation is used to control the normalized phase. The propulsion speed is preferably between 3 and 8 seconds; relay torque command Candidate relay motors in normalized phase The target torque is used to drive the candidate relay motor to smoothly increase the load, and its value range is [value range missing]. ; Rotation torque command Candidate rotational motors in normalized phase The target torque is used to drive the candidate rotating motor to smoothly reduce its load, and its value range is [value range missing]. Total traction reference torque The total traction capacity benchmark that the system needs to maintain before handover serves as a common metric for the two complementary torque trajectories, and its value is greater than 0; trajectory function. Step 2: The pre-issued smoothing trajectory function defines the change process of the load increase slope and the load decrease slope; preferably, a cubic smoothing function, a quintic smoothing function, or a lookup table interpolation function is used. In use, the candidate relay motor and the candidate rotation motor share the same normalized phase. and the same total traction reference torque Therefore, synchronous load increase and synchronous load decrease can be completed without relying on the upper controller to resend instructions point by point, and the torque conservation relationship is embedded into the trajectory execution itself.

[0064] Complementary torque crossing does not automatically equate to safe handover, as actual operation is also affected by driver current loop hysteresis, changes in roller attachment status, and localized material accumulation disturbances.

[0065] To avoid missed detections due to a single current difference or a single speed difference, the current deviation, torque deviation, speed deviation, and bus voltage deviation are aggregated into a comprehensive deviation. Then take the overall deviation amount With the dynamic tolerance envelope issued in step two In the same normalized phase The following comparison will be performed. Specifically: ; Where: Overall deviation The normalized result of the most unfavorable deviation term within the handover window serves to unify different physical quantities onto the same judgment scale, with a value greater than or equal to 0; the maximum operator. The purpose of selecting the maximum value from multiple normalized biases is to prevent critical biases from being masked by other stationary quantities. Current deviation The difference between the actual current of the candidate relay motor and the actual current of the candidate rotational motor reflects the degree of balance in load transfer on the electromagnetic side; current reference. The normalized current scale defined in step two serves to standardize the current deviation range, and its value is greater than 0; torque deviation... The actual torque of the candidate relay motor and the actual torque of the candidate rotation motor relative to the total traction reference torque. The deviation reflects whether the traction conservation relationship is maintained during the handover process; Torque Reference The normalized torque scale defined in step two serves to provide a unified denominator for torque deviation, and its value is greater than 0; speed deviation The deviation of the actual coaxial speed from the reference speed before handover reflects whether the continuity of belt speed has been disrupted by handover disturbances; speed reference. The normalized speed scale defined in step two is used to limit the drift of the discrimination caliber under different linear speed gears, and its value is greater than 0. Bus voltage deviation The deviation of the current DC bus voltage from the stable bus voltage before commissioning serves to identify potential risks of reverse energy surge or driver overvoltage in advance; bus voltage reference. The normalized scale of bus voltage is used to ensure that bus disturbances can be included in the same judgment system, and its value is greater than 0. In obtaining the comprehensive deviation Subsequently, the upper-level controller further generates a handover discrimination ratio. ; ; Where: handover discrimination ratio Current overall deviation Compared to dynamic tolerance envelope The degree of occupancy serves as a direct criterion for whether to continue executing the handover trajectory in step three, and its value is greater than or equal to 0; the overall deviation... : Following the previous output, its function is to characterize the normalized amplitude of the most unfavorable deviation; dynamic tolerance envelope Following the output of step two, its function is to provide the current normalized phase. The upper bound of the allowable comprehensive deviation, which takes a value greater than 0; normalized phase : Maintain the same time reference for both the deviation criterion and trajectory advancement; when the handover criterion is higher than the standard deviation criterion... When the value is less than or equal to 1, the upper-level controller maintains the handover execution permission; when the handover discrimination ratio is less than or equal to 1, the upper-level controller maintains the handover execution permission. A value greater than 1 indicates a comprehensive deviation. Exceeded dynamic tolerance envelope The system then proceeds to the next steps.

[0066] Furthermore, the validity of the handover transient is no longer determined by human experience, but rather by a comprehensive assessment of the deviation. With dynamic tolerance envelope The phase synchronization comparison yielded a unified interpretation.

[0067] When the handover judgment ratio is determined When within the safe range, the drive inverter of the candidate relay motor continues to advance the relay torque command. The drive inverter of the candidate rotational motor continues to advance the rotational torque command. until the normalized phase Proceed to the end of the window. At this point, if the actual torque of the candidate relay motor has stably tracked the relay torque command... If the actual torque of the candidate rotating motor has decreased to the preset unloading threshold, the upper-level controller outputs a new main working motor stable takeover flag and an old main working motor unloading completion flag. Accordingly, the identifier of the old main working motor is rewritten as the decommissioned motor identifier. This decommissioned motor identifier, along with the coaxial speed, bus voltage status, and current stator temperature at the end of step three, is transmitted to step four as a direct input for zero torque follow-up control.

[0068] When the handover judgment ratio is determined When the deviation exceeds the safe range, a single emergency stop is not used; instead, a tiered approach is taken based on the source of the deviation. If the dynamic tolerance envelope is penetrated first... The bus voltage deviation The upper-level controller will first send a holding torque command to the drive inverter of the candidate rotating motor to prevent it from continuing to reduce the load too quickly, and simultaneously send a freeze relay torque command to the drive inverter of the candidate relay motor. If the dynamic tolerance envelope is penetrated first... The speed deviation Then the system executes a slope-limited backoff strategy, in the current normalized phase. A short-term buffer trajectory is generated in reverse nearby, gradually pulling the two drive inverters back to the most recent safe phase; if the dynamic tolerance envelope is penetrated first... The torque deviation or current deviation If the system fails to complete the abnormal unloading abort flag, it will directly output the abnormal unloading abort flag and enter the protection shutdown preparation state.

[0069] Furthermore, supplementary criteria for successful handover: When the following conditions are met simultaneously and continuously... During each control cycle, a successful handover is determined when the actual output torque corresponding to the rest torque command is not greater than the unloading threshold. ; handover discrimination ratio The absolute value of the coaxial speed deviation is not greater than the speed threshold. .

[0070] ; Wherein: actual rest torque Actual output torque of candidate rotational motors; unloading threshold : The minimum residual torque threshold used to determine if the conditions for network decommissioning are met; handover discrimination ratio The extent to which the overall deviation occupies the dynamic tolerance envelope; speed deviation. The deviation of the actual coaxial speed from the reference speed during the handover period; speed threshold. : The maximum permissible deviation used to determine if belt speed continuity has not been disrupted; number of consecutive cycles. The number of hold periods to prevent misjudgment due to jitter in a single sampling period; Furthermore, supplementary anomaly classification rules: If If the slope is limited, the execution will be reversed; or If the current deviation exceeds the limit but the speed is not unstable, the phase advance is frozen first, and then the two cycles are checked.

[0071] Furthermore, step three not only outputs the result of whether the relay was completed at the end of the execution, but also outputs the protection information of what kind of deviation dominated the anomaly. Therefore, step four can directly enter zero torque following control for the successfully unloaded motor. In addition, the graded handling makes the protection action correspond one-to-one with the source of the deviation, and improves the input determinism of subsequent degrifting control.

[0072] Step 4: Under the condition that the degrinding motor does not disconnect from the rigid transmission link, a zero torque following state is established through the coordinated control of the direct shaft suppression current and the quadrature shaft compensation current. When the dew point approaches, the controlled current is used to form an endogenous anti-condensation heat source, so that the degrinding motor is kept in the system in a controlled standby mode.

[0073] After step three is completed, although the old main working motor has been unloaded, its rotor has not been separated from the coaxial system and continues to be driven to rotate by the rollers and belt. If the trigger pulse of the power device is simply blocked at this time, the de-energized motor will be dragged in reverse without control, and the induced electromotive force inside will flow back along the DC link, causing the bus voltage to rise. At the same time, since the de-energized motor no longer undertakes the main traction task, the stator copper loss drops sharply and the machine body temperature drops. The high humidity and cold wind at night in the port will cause its internal surface temperature to approach the ambient dew point, thereby inducing condensation.

[0074] Therefore, step four does not treat the de-energized motor as a device that has been removed from the grid, but rather as a controlled object that has been unloaded but is still rotating and needs to maintain insulation safety. The process is carried out in the following order: first, reconstructing the drag disturbance; then, applying electrical virtual decoupling; and finally, introducing dew point linkage thermal maintenance.

[0075] This step is executed collaboratively by the drive inverter, host controller, and environmental acquisition unit of the decommissioned motor. The drive inverter of the decommissioned motor continuously reads the coaxial speed. Bus voltage The upper controller continuously receives stator temperature data along with the current loop feedback value. Vibration amplitude and the dew point temperature already established in step one. Temperature reference Vibration reference In each refresh cycle, the passive drive disturbance experienced by the degrinding motor is first estimated, and then the disturbance is decomposed into an induced electromotive force term that needs to be suppressed and a mechanical resistance term that needs to be canceled. Subsequently, the upper controller issues direct-axis suppression current commands and quadrature-axis compensation current commands respectively, so that the drive frequency converter keeps the degrinding motor in a zero torque following state under the field-oriented control framework. If the dew point approach continues to rise, an anti-condensation lower limit current is superimposed on the quadrature-axis compensation current to form a closed loop of disturbance identification - current solution - safety judgment - thermal maintenance - re-online preparation.

[0076] First, we need to address why the bus pump rises when the de-energized motor is passively driven. The reason is the coaxial speed... The motor does not return to zero, and the de-energized motor still maintains magnetic flux. When it is driven to rotate, it will generate an induced electromotive force on the stator side. If the induced electromotive force is not suppressed, it will manifest as DC link backflow on the inverter bridge.

[0077] The host controller does not use a fixed direct-axis current preset value, but instead uses the coaxial speed... Together with the bus voltage offset, it is mapped into a direct-axis suppression current command. And in the bounded integer function, the instruction is always kept within the demagnetization safety boundary.

[0078] ; In the formula; direct-axis suppression current The target current of the direct-axis component of the de-grid motor is used to weaken the induced electromotive force and suppress DC link backflow; its value is within a negative bounded range. The upper limit of the direct-axis current... : The amplitude boundary of the direct-axis suppression current, used to ensure that flux weakening does not exceed the overmagnetic safety boundary; coaxial speed The actual rotational speed of the de-energized motor as it rotates with the coaxial system is used to characterize the growth trend of the induced electromotive force; speed reference. Coaxial speed The normalized reference value is used to maintain the consistency of the diameter at different line speed levels; bus voltage Real-time voltage of the DC link of the drive inverter to which the decommissioned motor belongs, used to reflect the reinjection strength; bus reference. The reference bus voltage during the steady-state following period, used to provide a normalized denominator for the bus voltage offset; shaping function. Bounded odd functions are used to compress any real number into an open interval. Internally, to avoid a sudden increase in direct-axis suppression current at high speeds or instantaneous overvoltage; variable Integer functions The input variables are used to receive the speed ratio or bus voltage ratio; Furthermore, direct-axis suppression current Simultaneously affected by coaxial rotation speed and bus voltage The constraints allow for the suppression of induced electromotive force at the driving speed and the timely shortening of the backflow channel as soon as the busbar is raised. After completing the direct-axis suppression, it is also necessary to address the mechanical resistance generated during the dragging process of the driven motor. If the direct-axis suppression current consists only of direct-axis resistance, although the de-energized motor will not backflow to the busbar, the equivalent dragging torque generated by bearing resistance, low-temperature viscous resistance, and rotor magnetic reluctance changes will still exist, and the coaxial motor will still need to be driven.

[0079] Therefore, the host controller utilizes stator temperature Vibration amplitude and coaxial speed Estimate the passive driving resistance torque, and then convert that resistance torque into quadrature axis compensation current. This allows the decoupling motor to transparently follow the coaxial system with minimal net torque.

[0080] in: ; Where: Driving resistance torque The estimated value of the combined passive drag torque under operating conditions, used to characterize the mechanical load that needs to be offset; drag base torque. The basic drag torque under the reference operating condition is used to reflect the initial drag caused by bearings, seals and no-load magnetic resistance; coefficient : Rotational speed coupling coefficient, used to characterize the contribution of coaxial rotational speed to the drag torque; coaxial rotational speed : Following the previous definition, it is used to reflect the increasing trend of viscous and wind resistance components; speed reference : Continuing from the previous definition, used for coaxial speed Provides a normalization scale; coefficients Temperature coupling coefficient: used to characterize the intensity of the mapping effect of deteriorating lubrication conditions and increased resistance after stator temperature decreases; temperature reference. The reference temperature at normal thermal equilibrium, used to correlate with the current stator temperature. This constitutes the cooling offset; Stator temperature : Current winding or stator core measuring point temperature, used to reflect the internal thermal state; temperature difference scale : Safe temperature difference window for normalized temperature offset; coefficient : Vibration coupling coefficient, used to characterize the amplification of drag resistance by installation deviation or bearing micro-damage; vibration amplitude Vibration response value of the machine base or bearing housing, used to reflect the additional resistance on the mechanical side; vibration reference. Reference vibration amplitude under healthy conditions; Quadrature axis compensation current The target current applied to the quadrature axis component is used to counteract the driving resistance torque through electromagnetic torque. Torque-current coefficient : The conversion factor between the electromagnetic torque of the motor and the quadrature axis current, used to convert the estimated resistance torque into the quadrature axis compensation current; Quadrature axis compensation current After the issuance, the drive inverters of the decommissioned motors synchronously read the actual current and bus status in each refresh cycle, and construct a following safety indicator. This is used to determine whether the zero torque following state can be maintained continuously. ; Where: Follow safety indicators The comprehensive risk index of the de-energized motor in zero-torque following state is used as a direct criterion for maintaining or disengaging from following; bus voltage. Following the previous definition, this is used to reflect whether the risk of reinjection is still suppressed; bus reference. : Continuing from the previous definition, it is used to normalize the bus voltage offset; residual torque The net torque that is not offset after cross-axis compensation is used to characterize whether the de-coupling motor still exerts a drag or reverse thrust on the coaxial system. Torque Reference Residual torque Normalized scale; speed deviation The offset between the motor's following speed and the coaxial reference speed is used to characterize whether the following transparency has been compromised; speed reference. : Continuing from the previous definition, it is used to measure speed deviation. Perform normalization; When following safety indicators When the value is not greater than 1, the system maintains a zero torque following state; when the following safety index is not greater than 1, the system maintains a zero torque following state. When the value is greater than 1, the system freezes the re-online preparation flag and switches the de-energized motor into protective standby mode. Subsequently, the quadrature shaft compensation current... Dynamic corrections are made based on changes in temperature, vibration, and speed, enabling the degrinding motor to maintain a near-transparent following state at different cooling stages and different linear speed levels.

[0081] After the zero-torque following state is established, the de-grid motor enters a low-load cooling phase, and its internal temperature continues to decrease. If only the quadrature-axis compensation current is maintained... Then, under high humidity conditions at night, the stator temperature Possibly below the dew point temperature Increasing the safety margin leads to condensation forming at the winding ends, lead transition area, and inside the end cap.

[0082] Therefore, using the dew point temperature established in step one... Based on this, construct the lower limit current for preventing condensation. and compare it with the quadrature axis compensation current. Amplitude comparison is performed to ensure that the degrinding motor achieves zero torque following while minimizing Joule heat input. Specifically: ; Where: Lower limit current for anti-condensation : Minimum current command used to maintain the internal temperature rise margin of the degrinding motor, providing controllable Joule heating as the dew point approaches; stator temperature Following the previous definition, dew point temperature is the direct temperature measure used to assess the risk of condensation. The dew point temperature, calculated from ambient temperature and relative humidity, is used to characterize the thermal boundary at which condensation begins; temperature margin. Anti-condensation safety temperature difference, used to ensure stator temperature Temperature above dew point Within a certain range, preferably 3 to 5°C; basic thermal maintenance current The initial thermal sustaining current when the dew point is approaching but not yet severe is used to prevent the current command from jumping from zero to an excessively high value; thermal gain coefficient. The mapping coefficient for thermoelectric conversion is used to gradually increase the Joule heat input as the dew point approaches. The drive inverter of the de-energized motor obtains the lower limit current for anti-condensation. Then, the actual holding current is set to the quadrature axis compensation current. With the lower limit current of anti-condensation The larger one, while continuously checking the direct-axis suppression current. Is it still within the demagnetization safety boundary? If the stator temperature... Continuously above the dew point temperature Add temperature margin And follow safety indicators If the value remains no greater than 1, the upper-level controller outputs a readiness status and sends this status back to step one; if the dew point continues to approach and worsens or follows safety indicators... If instability occurs, the system will only remain in a controlled standby state and will not be allowed to go online again.

[0083] Furthermore, the de-energized motor can achieve stable insulation maintenance without the need for additional independent heating hardware, and its readiness to go back online is determined by both temperature and follow-up conditions.

[0084] Furthermore, step four involves feedforward suppression of the induced electromotive force while the de-energized motor is still driven by the coaxial system, thus mitigating the risk of busbar backflow at the current level. (Quadrature axis compensation current) With drag resistance torque Dynamic correction ensures that the de-energized motor no longer becomes a hidden resistance source in the coaxial system. Anti-condensation lower limit current. Zero torque follower control and insulation maintenance control are coupled into the same execution channel, and the readjustment status is sent back to step one, forming a closed loop of the multi-motor non-stop alternating output control method.

[0085] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0086] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0087] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0088] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0089] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A non-stop alternating output control method for a multi-motor co-driven belt conveyor, characterized in that: include, Collect stator temperature, vibration, speed, current, bus voltage, and ambient temperature and humidity of each drive motor to conduct sub-health assessment, generate alternating scheduling instructions, and determine candidate off-duty motors and candidate relay motors; A timestamp macro instruction package is generated based on the alternating scheduling instruction. The timestamp macro instruction package includes the absolute start time, handover window, target torque trajectory parameters, and dynamic tolerance envelope parameters. Based on the timestamp macro instruction packet, the candidate relay motor and the candidate rotation motor are controlled to perform complementary torque crossover, and continuous online handover determination is performed based on the dynamic tolerance envelope; After the handover is completed, the motor is controlled to enter the zero torque following mode and outputs direct shaft suppression current and quadrature shaft compensation current. The intrinsic anti-condensation control is implemented based on the coaxial speed, stator temperature and ambient dew point.

2. The non-stop alternating output control method according to claim 1, characterized in that: Sub-health assessment includes: continuously collecting stator temperature, temperature rise rate, vibration, speed, current, bus voltage, and ambient temperature and humidity of each drive motor; constructing sub-health indicators based on stator temperature, temperature rise rate, vibration, and cumulative operating time; ranking and judging each drive unit; and forming a candidate set of alternating scheduling instructions based on the ranking results.

3. The non-stop alternating output control method according to claim 2, characterized in that: The alternation scheduling instruction includes: triggering alternation when the stator temperature approaches the upper limit, the temperature rise derivative is abnormal, the vibration exceeds the limit, or the running time reaches the rotation condition; determining the candidate rotation motor, the candidate relay motor and the corresponding triggering reason; and using the candidate rotation motor, the candidate relay motor and the triggering reason as input for subsequent handover parameter calculation.

4. The non-stop alternating output control method according to claim 3, characterized in that: The generation timestamp macro instruction package includes: calculating the handover window by combining the belt length or equivalent transmission path parameters, driver time base, current speed and load status, and writing the absolute start time, handover window, target torque trajectory parameters and dynamic tolerance envelope parameters into the timestamp macro instruction package for candidate off-duty motors and candidate relay motors.

5. The non-stop alternating output control method according to claim 4, characterized in that: The timestamp macro instruction package is pre-issued to the drive inverters of the candidate rotating motors and the candidate relay motors before the handover begins. Under a unified time base, the time synchronization and alternating scheduling module continuously provides the same set of handover parameters to the complementary torque cross-execution and dynamic tolerance monitoring.

6. The non-stop alternating output control method according to claim 5, characterized in that: The complementary torque crossover process includes: after the absolute start-up time is reached, the candidate relay motor gradually increases the load according to the target torque trajectory parameters, and the candidate rest motor gradually decreases the load according to its complementary trajectory, while maintaining the total traction force continuously within the handover window until the candidate rest motor completes unloading.

7. The non-stop alternating output control method according to claim 6, characterized in that: The continuous online handover determination includes: continuously comparing the actual current difference, actual torque difference, speed deviation, and bus abnormality during the handover period; maintaining handover execution when the actual current difference, actual torque difference, speed deviation, and bus abnormality are within the dynamic tolerance envelope; and outputting an abnormality protection command when the dynamic tolerance envelope is penetrated.

8. The non-stop alternating output control method according to claim 7, characterized in that: Controlling the de-grid motor to enter zero torque following mode includes: maintaining the controlled operation of its drive frequency converter after the torque of the old main working motor drops to a threshold, outputting direct shaft suppression current according to the coaxial speed, and outputting quadrature shaft compensation current according to the coaxial speed, stator temperature and friction state estimates, so that the de-grid motor maintains zero net torque following under rigid connection conditions.

9. The non-stop alternating output control method according to claim 8, characterized in that: The implementation of endogenous anti-condensation control includes: maintaining a lower limit current within the safe demagnetization boundary when the stator temperature of the demagnetized motor approaches the dew point warning line due to ambient temperature difference and humidity, and releasing the lower limit current maintenance after the stator temperature recovers to above the dew point warning line; exiting the zero torque follow mode and outputting a protection signal when overvoltage, abnormal temperature rise or demagnetization risk occurs.

10. The non-stop alternating output control method according to claim 9, characterized in that: Applied to multiple drive units in rotation operation, the upper controller cyclically executes alternating outputs according to the state transition mode of the main unit, relay unit and follower unit, so that the motor that is in zero torque following mode and whose conditions have been restored re-enters the process of determining the candidate relay motor and participates in the next round of switching and subsequent rotation control.

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