Three-phase asynchronous motor operation control management method and system

Abstract

The invention relates to the technical field of motor control, and discloses a three-phase asynchronous motor operation control management method and system, and the method comprises the following steps: 1, obtaining the pulse number per revolution of an encoder, the rated rotating speed of a motor nameplate, the acceleration time, the sliding stalling time, a thermal permission threshold, a load shedding threshold, a jump gate threshold, the upper limit of a start-stop token, and an expected rotation direction; determining the maximum allowable acceleration time and the minimum cooling locking time; 2, starting access judgment is carried out according to the three-phase existence state, the under-voltage state and the time condition; 3, pulse accumulation and rotation direction comparison are executed to generate a start judgment result, and the number of start-stop tokens is deducted; 4, calculating a thermal index based on temperature detection during operation, comparing the thermal index with each threshold, and outputting an operation continuing, load shedding or shutdown instruction; and 5, updating the thermal index, and outputting an unlocking result when an unlocking condition is met. According to the invention, safe management of the whole process of starting determination, operation regulation and control and shutdown unlocking of the three-phase asynchronous motor is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of motor control, and particularly relates to a three-phase asynchronous motor operation control management method and system. BACKGROUND

[0002] Three-phase asynchronous motors have been widely used in industrial automation production lines, mechanical transmission equipment and energy transmission systems and other fields due to their simple structure, reliable operation, convenient maintenance and relatively low manufacturing cost. With the increasing degree of automation of industrial production, the start-stop frequency and operation mode of the motor under complex load conditions increase, and higher requirements for the safety and fine management of the motor control system are needed.

[0003] The existing motor control system generally uses fixed threshold or single temperature monitoring to control start-stop, and cannot comprehensively reflect the thermal accumulation characteristics, acceleration process and cooling behavior of the motor in the dynamic operation process. This control method is prone to cause the motor to overheat too quickly under the conditions of frequent start-stop, high load or poor heat dissipation, and risks such as winding insulation aging, efficiency reduction and even burning, and it is difficult to meet the needs of long-term stable operation. In addition, the three-phase motor start control in the prior art mostly relies on phase sequence detection or voltage detection means, and the determination accuracy of power supply stability and cooling recovery time is low. When the motor is in an under-voltage, open-phase or insufficient cooling state, it may still be misjudged as a startable state, thereby causing overload operation or protection failure. SUMMARY

[0004] The application provides a three-phase asynchronous motor operation control management method and system, which solves the technical problems of motor start-stop control relying on a single parameter, being unable to consider the dynamic changes of thermal state, and causing overheating, misstart and system impact due to multi-machine operation scheduling in the related art.

[0005] The application provides a three-phase asynchronous motor operation control management method, which comprises the following steps:

[0006] Step 1, obtaining the number of encoder pulses per revolution of the motor, the rated speed of the motor nameplate, the acceleration time, the coasting stop time, the thermal permission threshold, the load reduction threshold, the trip threshold, the upper limit of the start-stop token and the expected rotation direction, and determining the maximum allowed acceleration time and the minimum cooling locking time;

[0007] Step 2, performing admission judgment according to the three-phase presence state, the under-voltage state, the maximum allowed acceleration time and the minimum cooling locking time, and outputting a start admission result, wherein the start admission result includes permission to start and prohibition to start;

[0008] Step 3, close the main contactor under the condition of allowing starting and start counting and accumulating pulses, determine the minimum accumulated pulse number for acceleration qualification according to the number of pulses per revolution of the encoder, the rated speed of the motor nameplate and the maximum allowed acceleration time, in the acceleration window, generate the starting judgment result according to the comparison of pulse accumulation and minimum accumulated pulse number for acceleration qualification and the comparison of actual rotation direction and expected rotation direction, and deduct the start-stop token number after closing;

[0009] Step 4, calculate the current thermal index based on temperature monitoring during operation, compare the current thermal index with the thermal permission threshold, the load reduction threshold and the trip threshold respectively, and output the control instruction of continuing operation, load reduction or shutdown;

[0010] Step 5, record the fault event of the motor and power off, count and update the current thermal index during shutdown, and output the unlocking result when the unlocking condition is met.

[0011] Further, the maximum allowed acceleration time is obtained by multiplying the measured acceleration time by a preset margin coefficient, and the minimum cooling lock time is obtained by adding the measured sliding stop time to a preset cooling compensation time constant.

[0012] Further, the three-phase existence state includes valid and invalid, and the under-voltage state includes normal and abnormal.

[0013] When the three-phase existence state is valid, the under-voltage state is normal, the actual cooling time is not less than the minimum cooling lock time, and the accumulated running time does not exceed the maximum allowed acceleration time, output the allowed starting signal, otherwise output the prohibited starting signal.

[0014] Further, determining the minimum accumulated pulse number for acceleration qualification comprises:

[0015] Step 11, set the accumulated pulse value to 0, and in the acceleration process, take the pulse signal output by the encoder as the input source, perform counting and accumulation once for every complete pulse period detected, and obtain the real-time accumulated pulse number;

[0016] Step 12, calculate the product of the rated speed of the motor nameplate, the number of pulses per revolution of the encoder and the maximum allowed acceleration time, and divide the product by sixty to obtain the minimum accumulated pulse number for acceleration qualification;

[0017] Step 13, monitor the accumulated pulse number in the time window of the maximum allowed acceleration time, when the real-time accumulated pulse number is greater than or equal to the minimum accumulated pulse number for acceleration qualification and the accumulated time does not exceed the maximum allowed acceleration time, determine that the acceleration qualification is met and output the acceleration success signal; when the accumulated time reaches the maximum allowed acceleration time and the real-time accumulated pulse number is less than the minimum accumulated pulse number for acceleration qualification, determine that the acceleration qualification is not met and output the power-off shutdown instruction.

[0018] Further, the generation of the starting judgment result comprises:

[0019] Step 21, read the real-time cumulative pulse number in the acceleration time window under the permission of starting, and compare it with the minimum cumulative pulse number of acceleration qualification, to generate a speed-up judgment signal; at the same time, determine the actual rotation direction according to the sequence of the two-way signals of the encoder, and compare it with the expected rotation direction, to generate a rotation direction judgment signal;

[0020] Step 22, take the logical AND result of the speed-up judgment signal and the rotation direction judgment signal as the starting voting criterion, output the starting success result when the speed-up judgment signal and the rotation direction judgment signal are both valid; output the power-off stop instruction when any of the judgment signals is invalid, and record the corresponding blocking reason according to the preset fault code rule;

[0021] Step 23, when the main contactor is closed, perform a deterministic deduction on the start-stop token number, update the start-stop token number to the current start-stop token number minus one, and limit the start-stop token number to zero when the updated start-stop token number is less than zero.

[0022] Further, the step 4 specifically comprises:

[0023] Step 31, periodically collect motor temperature data and perform sliding average processing to obtain average temperature, calculate the temperature rise change rate through the ratio of the change amount of average temperature in adjacent sampling periods to the sampling interval, obtain the temperature deviation according to the preset reference temperature, and obtain the current thermal index through the weighted combination of the temperature deviation and the temperature rise change rate;

[0024] Step 32, when the current thermal index is less than or equal to the thermal permission threshold, it is determined to be a continuous running state; when the current thermal index is greater than the thermal permission threshold and less than or equal to the load reduction threshold, it is determined to be a load reduction warning state; when the current thermal index is greater than the load reduction threshold and less than or equal to the tripping threshold, it is determined to be a load reduction running state; when the current thermal index is greater than the tripping threshold, it is determined to be a shutdown protection state;

[0025] Step 33, output the corresponding control instruction according to the determined state.

[0026] Further, the value range of the thermal permission threshold and the load reduction threshold is adjusted based on the Bayesian optimization method, including:

[0027] Step 41, at the end of each running control period, obtain the running temperature of the motor, the current thermal index, the threshold triggering time, the environmental temperature and the running load rate, calculate the square reciprocal of the difference between the running temperature of the motor at the load reduction triggering time and the thermal permission threshold to obtain the thermal safety margin, calculate the output power decline rate per unit time after the load reduction triggering as the energy efficiency loss, and weight the normalized value of the thermal safety margin and the normalized value of the energy efficiency loss to combine to obtain the threshold performance index function;

[0028] Step 42, taking the threshold combination of the thermal permission threshold and the load reduction threshold as an optimization parameter, taking the threshold performance index function as the objective function, establishing a Gaussian process model, calculating the prediction mean and prediction covariance of each threshold combination to form the prediction distribution of the objective function;

[0029] Step 43, constructing an expected improvement acquisition function based on the prediction distribution of the objective function, calculating the acquisition value with the prediction mean and the prediction covariance as input, and determining a new threshold combination by maximizing the acquisition value;

[0030] Step 44, setting a safety constraint interval for the new threshold combination, and when the increment of the objective function value after continuous optimization is less than a preset increment threshold, the threshold combination is rolled back to the threshold combination with the maximum objective function value in the last time.

[0031] Further, the step 5 specifically comprises:

[0032] Step 51, recording the current time as the shutdown starting point after the motor is shut down and calculating the cumulative shutdown cooling time, and when the cumulative cooling time reaches the minimum cooling locking time, outputting a cooling completion flag;

[0033] Step 52, in the shutdown cooling process, calculating the ratio of the cumulative cooling time to the cooling time constant, multiplying it by the decay coefficient and taking the opposite number, and then performing exponential operation to obtain the cooling decay index, and multiplying the cooling decay index by the thermal index of the previous operation control period to obtain the updated thermal index;

[0034] Step 53, when the updated thermal index is less than or equal to the thermal permission threshold, and the cumulative shutdown cooling time is greater than or equal to the minimum cooling locking time, outputting an unlock result signal to allow the motor to re-enter the start-up judgment process.

[0035] Further, when multiple motors coexist, the updated thermal index, the number of start-stop tokens, and the cumulative running time are sorted; in each operation control period, only the motor at the top of the sorting is output with a start permission instruction allowing start-up, and other motors are prohibited from starting.

[0036] The application provides a three-phase asynchronous motor operation control management system, comprising:

[0037] A parameter acquisition module is configured to acquire the number of encoder pulses per revolution of the motor, the motor nameplate rated speed, the acceleration time, the coasting shutdown time, the thermal permission threshold, the load reduction threshold, the trip threshold, the upper limit of the start-stop token, and the expected rotation direction, and determine the maximum allowed acceleration time and the minimum cooling locking time.

[0038] A start-up admission judgment module is configured to perform admission judgment according to the three-phase presence state, the under-voltage state, the maximum allowed acceleration time, and the minimum cooling locking time, and output a start-up admission result, wherein the start-up admission result includes permission to start and prohibition to start.

[0039] The start execution and voting module is used for closing the main contactor and starting the timing and pulse accumulation under the permission of starting, determining the minimum cumulative pulse number of acceleration qualification according to the number of pulses per revolution of the encoder, the rated rotating speed of the motor nameplate and the maximum allowed acceleration time, generating a start determination result in the acceleration window according to the comparison of the pulse accumulation and the minimum cumulative pulse number of acceleration qualification and the comparison of the actual rotating direction and the expected rotating direction, and deducting the start-stop token number after closing.

[0040] The running control module is used for calculating the current thermal index based on temperature monitoring during the running, comparing the current thermal index with the thermal permission threshold, the load reduction threshold and the trip threshold respectively, and outputting the control instructions of continuing running, load reduction or shutdown.

[0041] The shutdown cooling and unlocking module is used for recording the fault events of the motor and cutting off the power, timing and updating the current thermal index during the shutdown, and outputting the unlocking result when the unlocking condition is met.

[0042] The beneficial effects of the present application are that the present application realizes the dynamic determination and accurate control of the whole process of the start and stop of the three-phase asynchronous motor through the comprehensive management of the motor encoder signal, the power supply state, the temperature parameter and the start-stop token. The misstart under the conditions of under-voltage, phase loss or insufficient cooling is avoided by introducing the access judgment mechanism. The safety and consistency of the acceleration process and the rotating direction are ensured by the double verification of pulse accumulation and rotating direction comparison during the start process. The continuous assessment of the motor temperature rise state is realized by using the thermal index model in the running stage, and the intelligent switching of continuous running, load reduction and shutdown is realized by the multi-level threshold grading control. The cooling decay model is introduced during the shutdown period, the thermal state is dynamically updated, and the unlocking time is automatically determined to prevent the accumulation of heat caused by frequent start and stop. Overall, the present application can effectively improve the running safety and thermal management accuracy of the motor, reduce the equipment failure rate, prolong the service life of the motor, realize orderly scheduling and load balancing in the scene of multiple motors running in parallel, and improve the overall running efficiency and reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a flow chart of a three-phase asynchronous motor running control management method of the present application. DETAILED DESCRIPTION

[0044] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that the discussion of these implementations is merely meant to provide a better understanding of the subject matter described herein and can be changed in function and arrangement without departing from the scope of the present specification. Various processes or components can be omitted, substituted, or added according to various examples. Additionally, features described with respect to some examples can be combined in other examples.

[0045] As Figure 1 shown, a three-phase asynchronous motor operation control management method, comprising the following steps:

[0046] Step 1, obtain the number of encoder pulses per revolution of the motor, the rated speed of the motor nameplate, the acceleration time, the coasting stop time, the thermal permission threshold, the load reduction threshold, the tripping threshold, the upper limit of the start-stop token, and the expected rotation direction, and determine the maximum allowed acceleration time and the minimum cooling locking time;

[0047] Step 2, make an access judgment according to the three-phase state, the under-voltage state, the maximum allowed acceleration time and the minimum cooling locking time, and output a start access result, wherein the start access result includes permission to start and prohibition to start;

[0048] Step 3, close the main contactor and start timing and pulse accumulation under permission to start, determine the minimum cumulative pulse number for acceleration compliance according to the number of encoder pulses per revolution, the rated speed of the motor nameplate and the maximum allowed acceleration time, and generate a start determination result in the acceleration window according to the comparison of pulse accumulation and the minimum cumulative pulse number for acceleration compliance and the comparison of actual rotation direction and expected rotation direction. The number of start-stop tokens is deducted after closing;

[0049] Step 4, calculate the current thermal index based on temperature monitoring during operation, compare the current thermal index with the thermal permission threshold, the load reduction threshold and the tripping threshold respectively, and output control instructions for continuous operation, load reduction or shutdown;

[0050] Step 5, record the fault events of the motor and power off, time and update the current thermal index during shutdown, and output an unlock result when the unlock condition is met.

[0051] In an embodiment of the present application, the number of encoder pulses per revolution refers to the total number of pulses output by the encoder when the motor rotates one revolution, which is used to represent the resolution of the encoder, with the unit of pulse / revolution; the rated speed of the motor nameplate is the rated working speed marked on the motor nameplate by the manufacturer, with the unit of revolution / minute; the acceleration time refers to the time required for the motor to start from a stationary state to reach the rated speed, with the unit of seconds; the coasting stop time refers to the time for the motor to rely on inertia to coast until the speed drops to zero after power off, which is used to represent the mechanical inertia and heat release rate of the system.

[0052] The maximum allowed acceleration time is obtained by multiplying the measured acceleration time by a preset margin coefficient, and the minimum cooling locking time is obtained by adding the measured coasting stop time to a preset cooling compensation time constant. The maximum allowed acceleration time is the longest acceleration duration allowed during the motor from the stationary state to the stable operation, which is used to limit the acceleration phase of the motor to be completed within a reasonable time to prevent the winding from overheating or the power supply system from overloading due to long-time high-current operation. The preset margin coefficient is a correction factor determined according to the motor power level and load inertia experience, which is used to introduce a safety margin in the acceleration control, and the value range is 1.1 to 1.3. The correction can ensure that the motor acceleration process under different load conditions does not exceed the thermal safety limit. The minimum cooling locking time is used to limit the minimum interval time before the motor starts again after shutdown, so as to ensure that the motor winding and core temperature returns to a safe level, preventing thermal accumulation caused by repeated start-up too early. The preset cooling compensation time constant is a constant determined according to the motor structure form, heat dissipation mode and environmental temperature, which is used to compensate for the delay in the natural cooling stage, and the value range is 30 seconds to 120 seconds. Through the constant, the motor thermal decay characteristics can be more accurately reflected, and effective constraint on the thermal equilibrium process can be realized.

[0053] In an embodiment of the present application, in order to ensure that the motor starts under safe operating conditions, the power supply state and cooling state of the motor are comprehensively judged. The judgment process generates a start-up access result by detecting the existence state of three-phase power supply, the undervoltage state of bus voltage, the actual cooling time and the cumulative running time, so as to realize the safety management of the motor starting behavior.

[0054] The three-phase existence state is used to reflect whether the three-phase power supply of the motor power supply circuit is normally connected, including effective and ineffective; when the amplitude and phase sequence of the three-phase power supply meet the preset standard, it is determined that the three-phase existence state is effective; when any phase appears open phase, phase sequence error or voltage serious imbalance, it is determined that the three-phase existence state is ineffective. The undervoltage state is used to indicate whether the bus voltage of the motor is in the rated operating range, including normal and abnormal; when the detected voltage is within 90% to 110% of the rated voltage, it is determined that the undervoltage state is normal; when the detected voltage is lower than 90% of the rated voltage or higher than 110% of the rated voltage, it is determined that the undervoltage state is abnormal.

[0055] The actual cooling time is the cumulative cooling duration from the shutdown of the motor to the current time; the cumulative running time is the continuous power-on time of the motor in the current running control cycle; when the three-phase existence state is effective, the undervoltage state is normal, the actual cooling time is not less than the minimum cooling locking time, and the cumulative running time is not more than the maximum allowed acceleration time, the allowed start signal is output, and the motor enters the starting process, otherwise the prohibited start signal is output, and the motor remains in the power-off state.

[0056] Through the above process, the motor starting stage of the application not only restricts the power supply quality, but also combines the thermal recovery state and the running time of the motor itself for comprehensive checking, which can improve the safety and reliability of the motor starting, and ensure the motor to start and run in a safe electrical and thermal environment.

[0057] In an embodiment of the application, determining the minimum cumulative pulse number for acceleration compliance comprises:

[0058] Step 11, set the cumulative pulse value to 0, and take the pulse signal output by the encoder as the input source during the acceleration process, and perform counting and accumulation once for each complete pulse period, to obtain the real-time cumulative pulse number; the cumulative pulse number is the cumulative value of the pulse count in the acceleration stage, indicating the total rotation angle of the motor from the start to the current time. In this way, the real-time angular displacement information of the motor rotor can be obtained in the acceleration stage, and the speed-up trend can be calculated;

[0059] Step 12, calculate the product of the motor nameplate rated speed, the number of pulses per revolution of the encoder and the maximum allowed acceleration time, and divide the product by sixty to obtain the minimum cumulative pulse number for acceleration compliance; the calculation formula of the minimum cumulative pulse number for acceleration compliance is: , Nmin represents the minimum cumulative pulse number for acceleration compliance, N represents the motor nameplate rated speed, Np represents the number of pulses per revolution of the encoder, Tmax represents the maximum allowed acceleration time, in seconds, and 60 is the unit conversion constant, used to convert the unit of the motor nameplate rated speed from revolutions / minute to revolutions / second, to ensure that the time unit of the calculation result is consistent;

[0060] Step 13, monitor the cumulative pulse number within the time window of the maximum allowed acceleration time, when the real-time cumulative pulse number is greater than or equal to the minimum cumulative pulse number for acceleration compliance and the cumulative time does not exceed the maximum allowed acceleration time, determine that the acceleration is up to the standard and output an acceleration success signal; when the cumulative time reaches the maximum allowed acceleration time and the real-time cumulative pulse number is less than the minimum cumulative pulse number for acceleration compliance, determine that the acceleration is not up to the standard and output a power-off stop command.

[0061] Through the above process, the acceleration compliance determination method of the embodiment can improve the safety and reliability of the motor starting process, and provide accurate dynamic basic data for subsequent operation state control.

[0062] In an embodiment of the application, the generation of the starting determination result comprises:

[0063] Step 21, read the real-time cumulative pulse number in the acceleration time window allowed to start, and compare it with the minimum cumulative pulse number of acceleration standard, when the real-time cumulative pulse number is greater than or equal to the minimum cumulative pulse number of acceleration standard, generate the speed-up judgment signal, indicating that the motor reaches the expected speed-up requirement within a limited time; at the same time, determine the actual rotation direction according to the sequence of the two signals of the encoder, and compare it with the expected rotation direction to generate the rotation direction judgment signal; specifically, the two signals output by the encoder are usually A and B signals, which are 90° apart in electrical angle. When the A signal leads the B signal in phase, the motor rotates in the forward direction; when the A signal lags behind the B signal, the motor rotates in the reverse direction. The system determines the actual rotation direction according to the sequence of the two signals, and compares it with the expected rotation direction set by the system to generate the rotation direction judgment signal. If the actual rotation direction is consistent with the expected rotation direction, the rotation direction judgment signal is valid, otherwise it is invalid;

[0064] Step 22, take the logical AND result of the speed-up judgment signal and the rotation direction judgment signal as the start voting criterion, when both the speed-up judgment signal and the rotation direction judgment signal are valid, output the start success result, indicating that the motor successfully accelerates within the specified time and operates in the correct rotation direction; when any of the judgment signals is invalid, output the power-off stop instruction to prevent abnormal situations such as motor reverse rotation, locked rotor or insufficient acceleration, and record the corresponding blocking reason according to the pre-set fault code rule, which includes but is not limited to: acceleration failure, rotation direction error, overload stop, etc.

[0065] Step 23, when the main contactor is closed, to prevent thermal stress accumulation and system impact caused by frequent start-stop, perform a deterministic deduction on the start-stop token number, update the start-stop token number to the current start-stop token number minus one, and when the updated start-stop token number is less than zero, limit the start-stop token number to zero; the start-stop token number is an integer variable used to limit the number of motor starts within a certain time.

[0066] Through the above process, the embodiment realizes double safety verification of the motor start-up stage. The acceleration state and rotation direction are detected simultaneously within the acceleration time window, and only when both judgment signals are valid can the start success result be output; if any abnormality occurs, the motor will be immediately powered off and the fault reason will be recorded. By introducing the start-stop token number management, the number of motor starts is limited, effectively preventing thermal accumulation and mechanical impact caused by frequent start-stop, thereby improving the safety of the motor start-up process and the overall stability of the running system.

[0067] In one embodiment of the present application, when the cumulative pulse number in a plurality of consecutive operation control periods is lower than a preset steady-state threshold, it is determined that the motor has a low-speed fault, and a power-off shutdown instruction is output; the low-speed fault is usually caused by overload, under-voltage, mechanical jamming or winding partial fault, etc., which can cause the motor to be unable to maintain normal speed and increase the risk of overheating; the preset steady-state threshold represents the minimum cumulative pulse number that the motor should reach when operating stably under rated load conditions.

[0068] In one embodiment of the present application, a current thermal index is calculated based on temperature detection during operation, and the current thermal index is compared with a thermal permission threshold, a load reduction threshold and a trip threshold, respectively, to output control instructions for continuous operation, load reduction or shutdown, including:

[0069] Step 31, periodically collecting motor temperature data and performing sliding average processing to obtain average temperature, calculating temperature rise rate by the ratio of the change amount of average temperature in adjacent sampling periods to the sampling interval, obtaining temperature deviation according to the preset reference temperature, and obtaining the current thermal index by weighted combination of the temperature deviation and the temperature rise rate;

[0070] Step 32, when the current thermal index is less than or equal to the thermal permission threshold, it is determined to be a continuous operation state; when the current thermal index is greater than the thermal permission threshold and less than or equal to the load reduction threshold, it is determined to be a load reduction warning state; when the current thermal index is greater than the load reduction threshold and less than or equal to the trip threshold, it is determined to be a load reduction operation state, and the control system reduces the output power or speed to reduce the thermal load; when the current thermal index is greater than the trip threshold, it is determined to be a shutdown protection state, and the system immediately outputs a power-off shutdown instruction to execute forced protection; specifically, the thermal permission threshold is used to define the safe temperature rise range of the motor, the load reduction threshold is used to indicate that the motor is in an overheating trend state, and the trip threshold is used to indicate that the motor temperature has approached or reached the insulation safety limit;

[0071] Step 33, outputting the corresponding control instruction according to the determined state to realize closed-loop thermal management control of the motor operation state.

[0072] Through the above process, the present embodiment can reflect the motor temperature change trend in real time, realize dynamic early warning and graded response to thermal risk, and improve the thermal management precision and operation safety.

[0073] In one embodiment of the present application, the value range of the thermal permission threshold and the load reduction threshold is adjusted based on the Bayesian optimization method, including:

[0074] Step 41, at the end of each operation control cycle, the operating temperature, thermal index, threshold triggering time, ambient temperature and operation load rate of the motor are obtained, the thermal safety margin is obtained by calculating the reciprocal of the square of the difference between the operating temperature at the load reduction triggering time and the thermal permission threshold, the output power reduction rate per unit time after the load reduction triggering is calculated as the energy efficiency loss, the normalized value of the thermal safety margin and the normalized value of the energy efficiency loss are weighted, and the threshold performance index function is obtained by combination; wherein the calculation formula of the threshold performance index function is: ;

[0075] F represents the value of the threshold performance index function, which is used to measure the comprehensive performance of the current threshold combination between thermal safety and energy efficiency balance, the greater the value, the better the threshold setting; represents the operating temperature at the load reduction triggering time, represents the thermal permission threshold, and respectively represent the minimum and maximum values of the thermal safety margin in each operation control cycle, represents the thermal safety margin, represents the average output power before load reduction, represents the average output power after load reduction, represents the sampling time interval, and respectively represent the minimum and maximum values of the energy efficiency loss in each operation control cycle, represents the energy efficiency loss, and respectively represent the first weight coefficient and the second weight coefficient;

[0076] Step 42, taking the threshold combination of the thermal permission threshold and the load reduction threshold as the optimization parameter and the threshold performance index function as the objective function, a Gaussian process model is established to calculate the predicted mean and predicted covariance of each threshold combination to form the predicted distribution of the objective function; the Gaussian process model is a non-parametric probability model, which predicts the distribution characteristics of the objective function under new parameters through training samples, and through Gaussian process inference, the system can obtain the predicted mean and predicted covariance of each threshold combination, thereby forming the predicted distribution of the threshold performance index function;

[0077] Step 43, based on the predicted distribution of the objective function, an expected improvement acquisition function is constructed, the acquisition value is calculated by taking the predicted mean and predicted covariance as input, and a new threshold combination is determined by maximizing the acquisition value;

[0078] Step 44, set a safety constraint interval for the new threshold combination, when the increment of the objective function value after continuous optimization is less than the preset increment threshold, the threshold combination is rolled back to the threshold combination with the maximum objective function value in the last time; wherein the safety constraint interval is determined according to the insulation level of the motor, the maximum allowable temperature rise and the design margin coefficient, to ensure that the threshold value is always within the thermal safety operating range.

[0079] Through the above process, the embodiment realizes the adaptive dynamic update of the motor thermal protection parameter. The method combines Gaussian process modeling and expected improvement strategy, and can realize iterative optimization of the threshold without large sample training, and takes into account thermal safety and operating efficiency. By introducing the safety constraint interval and the rollback mechanism, the system realizes self-convergent control of the threshold under the premise of ensuring insulation safety, thereby significantly improving the intelligence and stability of the motor thermal management system.

[0080] In an embodiment of the present application, the step 5 specifically comprises:

[0081] Step 51, record the current time as the shutdown starting point after the motor is shut down and calculate the cumulative shutdown cooling time, when the cumulative cooling time reaches the minimum cooling locking time, output the cooling completion flag;

[0082] Step 52, during the shutdown cooling process, calculate the ratio of the cumulative cooling time to the cooling time constant, multiply it by the decay coefficient and take the opposite number, then perform exponential operation to obtain the cooling decay index, multiply the cooling decay index with the thermal index of the previous running control period to obtain the updated thermal index; wherein the update formula of the thermal index is: , represents the cooling decay coefficient, the value range is 0 to 1, which represents the decay proportion of thermal energy with time, represents the thermal index of the previous running control period, represents the decay coefficient, which is used to correct the cooling speed under different heat dissipation conditions, the value range is 0.8 to 1.2, represents the cumulative shutdown cooling time, represents the cooling time constant, the value range is 500 seconds to 700 seconds;

[0083] Step 53, when the updated thermal index is less than or equal to the thermal permission threshold, and the cumulative shutdown cooling time is greater than or equal to the minimum cooling locking time, output the unlocking result signal to allow the motor to re-enter the start-up judgment process; otherwise, continue to keep the locking state until the thermal index drops to the safety range.

[0084] Through the above process, the embodiment can adaptively calculate the thermal decay speed under different environmental temperatures and heat dissipation conditions, ensure the accuracy of the unlocking condition judgment, and improve the availability of the motor and the system operation efficiency.

[0085] In one embodiment of the present application, when multiple motors coexist, sorting is performed based on the updated thermal index, the number of start-stop tokens, and the cumulative running time; in each running control cycle, only the motor at the top of the sorting is output with a start permission instruction allowing starting, and other motors are prohibited from starting; specifically, the sorting priority of each motor is obtained by weighted summation of the reciprocal of the updated thermal index, the number of start-stop tokens, and the cumulative running time, and only the motor with the highest sorting priority is output with a start permission instruction, and the remaining motors receive a start prohibition signal and enter a standby state until the next running control cycle re-evaluates; this mechanism ensures that only one motor is in a start authorized state in each running control cycle, thereby effectively preventing current surges or power fluctuations caused by multiple simultaneous starts, and ensuring the stability and safety of the system under high load conditions.

[0086] The present application also provides a three-phase asynchronous motor running control management system, comprising:

[0087] A parameter acquisition module is configured to acquire the number of encoder pulses per revolution of the motor, the motor nameplate rated speed, the acceleration time, the coasting stop time, the thermal permission threshold, the load reduction threshold, the trip threshold, the start-stop token upper limit, and the desired rotation direction, and determine the maximum allowed acceleration time and the minimum cooling lock time.

[0088] A start admission determination module is configured to determine admission based on the three-phase presence state, the under-voltage state, the maximum allowed acceleration time, and the minimum cooling lock time, and output a start admission result, wherein the start admission result includes permission to start and prohibition to start.

[0089] A start execution and voting module is configured to close the main contactor and start timing and pulse accumulation when permission to start is given, determine the minimum acceleration compliance cumulative pulse number based on the number of encoder pulses per revolution, the motor nameplate rated speed, and the maximum allowed acceleration time, generate a start determination result based on a comparison of the pulse accumulation and the minimum acceleration compliance cumulative pulse number and a comparison of the actual rotation direction and the desired rotation direction within the acceleration window, and deduct the number of start-stop tokens after closing.

[0090] A running control module is configured to calculate the current thermal index based on temperature monitoring during running, compare the current thermal index with the thermal permission threshold, the load reduction threshold, and the trip threshold, and output a control instruction to continue running, reduce load, or shut down.

[0091] A shutdown cooling and unlocking module is configured to record motor fault events and disconnect power, time and update the current thermal index during shutdown, and output an unlock result when the unlock condition is met.

[0092] It should be noted that the interval and the threshold size are set for the convenience of comparison, wherein the size of the threshold depends on how much sample data and the base number set by the person skilled in the art for each group of sample data, as long as it does not affect the proportional relationship between the parameters and the quantized values. And the above formula is the calculation of the dimensionless value, the formula is obtained by collecting a large amount of data to simulate the formula of the nearest real situation, and the preset parameters in the formula are set by the person skilled in the art according to the actual situation.

[0093] The above describes the embodiments of the present application, but the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative but not restrictive, and the person skilled in the art can make many forms under the inspiration of the present embodiment, which all belong to the protection of the present embodiment.

Claims

1. A method for controlling and managing the operation of a three-phase asynchronous motor, characterized in that, Includes the following steps: Step 1: Obtain the number of encoder pulses per revolution of the motor, the rated speed on the motor nameplate, the acceleration time, the coasting stop time, the thermal allowance threshold, the load reduction threshold, the trip threshold, the start / stop token upper limit and the desired rotation direction, and determine the maximum allowable acceleration time and the minimum cooling lock-in time. Step 2: Based on the three-phase state, undervoltage state, maximum allowable acceleration time and minimum cooling lock-up time, make an admission judgment and output the start admission result, which includes allowing start and prohibiting start; Step 3: With the start-up permitted, close the main contactor and start timing and pulse accumulation. Determine the minimum cumulative pulse count for acceleration based on the number of pulses per encoder revolution, the rated speed on the motor nameplate, and the maximum allowable acceleration time. Within the acceleration window, generate the start-up judgment result by comparing the pulse accumulation with the minimum cumulative pulse count for acceleration and comparing the actual rotation direction with the expected rotation direction. After closing the circuit breaker, deduct the number of start / stop tokens. Step 4: During operation, calculate the current heat index based on temperature monitoring, compare the current heat index with the heat permit threshold, load reduction threshold and trip threshold respectively, and output control commands to continue operation, reduce load or stop the machine. Step 5: Record the motor fault event and disconnect the power. During the shutdown, keep track of the time and update the current thermal index. Output the unlocking result when the unlocking conditions are met.

2. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 1, characterized in that, The maximum allowable acceleration time is obtained by multiplying the measured acceleration time by a preset margin coefficient, and the minimum cooling lock-up time is obtained by adding the measured coasting stop time to a preset cooling compensation time constant.

3. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 1, characterized in that, The three-phase states include active and inactive, and the undervoltage states include normal and abnormal. When the three-phase state is valid, the undervoltage state is normal, the actual cooling time is not less than the minimum cooling lock-in time, and the cumulative running time does not exceed the maximum allowable acceleration time, an enable start signal is output; otherwise, an disable start signal is output.

4. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 1, characterized in that, Determine the minimum cumulative pulse count required to achieve the acceleration target, including: Step 11: Set the cumulative pulse value to 0, and during the acceleration process, use the pulse signal output by the encoder as the input source. Perform a counting accumulation once for each complete pulse cycle detected to obtain the real-time cumulative pulse count. Step 12: Calculate the product of the motor nameplate rated speed, the number of encoder pulses per revolution, and the maximum allowable acceleration time, and divide the product by sixty to obtain the minimum cumulative number of pulses required to achieve acceleration. Step 13: Monitor the cumulative pulse count within the time window of the maximum allowable acceleration time. When the real-time cumulative pulse count is greater than or equal to the minimum cumulative pulse count for acceleration and the cumulative time does not exceed the maximum allowable acceleration time, the acceleration is determined to be successful and an acceleration success signal is output. When the cumulative time reaches the maximum allowable acceleration time and the real-time cumulative pulse count is less than the minimum cumulative pulse count for acceleration, the acceleration is determined to be unsuccessful and a power-off shutdown command is output.

5. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 1, characterized in that, The generation of the start-up determination result includes: Step 21: Read the real-time cumulative pulse count within the acceleration time window under the allowed start-up condition, and compare it with the minimum cumulative pulse count for acceleration to reach the target, and generate an acceleration determination signal; at the same time, determine the actual rotation direction according to the order of the two encoder signals, and compare it with the expected rotation direction to generate a rotation direction determination signal. Step 22: The logic and result of the speed-up determination signal and the rotation direction determination signal are used as the start-up voting criteria. When both the speed-up determination signal and the rotation direction determination signal are valid, the start-up success result is output. When either determination signal is invalid, a power-off shutdown command is output, and the corresponding blocking reason is recorded according to the preset fault code rules. Step 23: When the main contactor is closed, perform a deterministic deduction on the number of start / stop tokens, update the number of start / stop tokens to the current number of start / stop tokens minus one, and limit the number of start / stop tokens to zero when the updated number of start / stop tokens is less than zero.

6. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 1, characterized in that, Step 4 specifically includes: Step 31: Periodically collect motor temperature data and perform moving average processing to obtain the average temperature. Calculate the temperature rise rate by the ratio of the change in average temperature within adjacent sampling periods to the sampling interval. Obtain the temperature deviation based on the preset reference temperature. Obtain the current thermal index by weighted combination of the temperature deviation and the temperature rise rate. Step 32: When the current heat index is less than or equal to the heat permit threshold, it is determined to be in the continuous operation state; when the current heat index is greater than the heat permit threshold and less than or equal to the load reduction threshold, it is determined to be in the load reduction warning state; when the current heat index is greater than the load reduction threshold and less than or equal to the trip threshold, it is determined to be in the load reduction operation state; when the current heat index is greater than the trip threshold, it is determined to be in the shutdown protection state. Step 33: Output the corresponding control command based on the determined state.

7. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 6, characterized in that, The value ranges of the heat permit threshold and the load reduction threshold are adjusted based on the Bayesian optimization method, including: Step 41: After each operation control cycle, obtain the motor's operating temperature, current thermal index, threshold trigger time, ambient temperature, and operating load rate. Calculate the reciprocal of the square of the difference between the motor's operating temperature at the load reduction trigger and the thermal allowable threshold to obtain the thermal safety margin. Calculate the output power reduction rate per unit time after the load reduction trigger as the energy efficiency loss. Weight the normalized value of the thermal safety margin and the normalized value of the energy efficiency loss to obtain the threshold performance index function. Step 42: Using the combination of the thermal permit threshold and the load reduction threshold as optimization parameters, and the threshold performance index function as the objective function, establish a Gaussian process model, calculate the predicted mean and predicted covariance of each threshold combination, and form the predicted distribution of the objective function. Step 43: Construct the desired improved acquisition function based on the distribution predicted by the objective function, calculate the acquisition value with the predicted mean and predicted covariance as input, and determine a new threshold combination by maximizing the acquisition value; Step 44: Set a safety constraint range for the new threshold combination. When the increment of the objective function value after multiple consecutive optimizations is less than the preset increment threshold, the threshold combination is rolled back to the threshold combination with the largest objective function value in the most recent time.

8. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 1, characterized in that, Step 5 specifically includes: Step 51: After the motor stops, record the current time as the start of the stop and calculate the cumulative stop cooling time. When the cumulative cooling time reaches the minimum cooling lock time, output a cooling completion flag. Step 52: During the shutdown cooling process, calculate the ratio of the cumulative cooling time to the cooling time constant, multiply it by the attenuation coefficient and take the opposite number, and then perform exponential calculation to obtain the cooling attenuation index. Multiply the cooling attenuation index by the thermal index of the previous operating control cycle to obtain the updated thermal index. Step 53: When the updated thermal index is less than or equal to the thermal allowance threshold and the cumulative downtime cooling time is greater than or equal to the minimum cooling lock time, output the unlock result signal to allow the motor to re-enter the start-up determination process.

9. The method for controlling and managing the operation of a three-phase asynchronous motor according to claim 1, characterized in that, When multiple motors are in operation, they are sorted based on the updated thermal index, number of start / stop tokens, and cumulative running time. In each operation control cycle, only the motor ranked first is given a start permission command to start, while other motors are prohibited from starting.

10. A three-phase asynchronous motor operation control and management system, characterized in that, The method for controlling and managing the operation of a three-phase asynchronous motor as described in any one of claims 1-9 includes: The parameter acquisition module is used to acquire the number of encoder pulses per revolution of the motor, the rated speed on the motor nameplate, the acceleration time, the coasting and stopping time, the thermal allowance threshold, the load reduction threshold, the tripping threshold, the start / stop token upper limit and the desired rotation direction, and to determine the maximum allowable acceleration time and the minimum cooling lock-in time. The startup admission judgment module is used to make admission judgments based on the three-phase status, undervoltage status, maximum allowable acceleration time and minimum cooling lock-up time, and output the startup admission result, which includes startup allowed and startup prohibited. The start execution and voting module is used to close the main contactor and start timing and pulse accumulation when start is allowed. It determines the minimum cumulative pulse count for acceleration based on the number of pulses per encoder revolution, the rated speed on the motor nameplate, and the maximum allowable acceleration time. Within the acceleration window, it generates a start judgment result based on the comparison between the pulse accumulation and the minimum cumulative pulse count for acceleration, as well as the comparison between the actual rotation direction and the expected rotation direction. After closing the circuit, the number of start / stop tokens is deducted. The operation control module is used to calculate the current heat index based on temperature monitoring during operation, compare the current heat index with the heat permit threshold, load reduction threshold and trip threshold respectively, and output control commands to continue operation, reduce load or stop the machine. The shutdown cooling and unlocking module is used to record motor fault events and cut off power. During shutdown, it keeps track of time and updates the current thermal index. When the unlocking conditions are met, it outputs the unlocking result.

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