A variable frequency speed regulation system for large construction hoists

Abstract

The application relates to the technical field of elevator driving control, and discloses a variable-frequency speed regulation system for a large construction elevator, which comprises the following steps: in a static stage before a brake of the elevator is released, a first tentative torque pulse is applied, a micro-rotation response is obtained, a load level is preliminarily identified, and then in a creeping stage after starting, a second same torque pulse is applied and a dynamic response is obtained; the difference between the two responses is compared, the influence of static friction at the starting moment is discriminated and compensated, and finally corresponding starting control parameters are matched according to the identified load level; the application acquires load information in advance at the source of control timing, changes the control mode which depends on lag information, matches the output of driving torque with the pre-acquired load information, and avoids the inherent starting impact and shaking due to the mismatch between driving force and load in the traditional mode.

Description

TECHNICAL FIELD

[0001] The present application relates to a variable frequency speed regulation system for a large construction hoist, belonging to the technical field of hoist driving control. BACKGROUND

[0002] Currently, in the driving control of large construction hoists, the use of variable frequency speed regulation systems has become the mainstream technical method, which realizes the control of motor speed and torque by adjusting the frequency and voltage of the output power. A common control strategy is to adjust the initial driving torque based on pre-set start parameters or real-time monitoring of motor current after starting. This method achieves stable operation of the hoist in a macroscopic sense, and its design logic has been widely applied and recognized in the industry.

[0003] However, when this control method is placed in the real application scenario of high frequency and random load changes in the construction site, the limitations in the control theory due to the lag in information acquisition begin to appear. Since the system cannot obtain the real load in the car before the brake is released, in order to ensure that the hoist can start smoothly under the maximum load that may be encountered in engineering practice, technicians often have to adopt a compromise and conservative parameter setting, that is, to pre-set a relatively large starting torque and a long acceleration time. As a result, in the light load or no load working conditions that occupy the majority of running times, this single driving method is no longer appropriate, and each start is inevitably accompanied by a mismatch between the driving torque and the actual load of the hoist car, which in turn causes a series of problems affecting the riding experience and equipment safety.

[0004] Specifically, the reactive control method in the prior art has the following deficiencies: 1. In light load start, the excess driving torque will cause a significant forward thrust of the car; while in heavy load start, if the initial torque is insufficient, it may cause instantaneous shaking and subsequent current shock, both of which directly reduce the running quality and cause poor experience for the passengers; 2. Long-term repeated start impact will continuously generate fatigue stress on key mechanical components such as gear box, transmission shaft and steel wire rope, accelerating their wear process; at the same time, the redundant start current generated to overcome the mismatch also constitutes a continuous waste of electric energy, and these two kinds of losses together increase the life cycle cost of the equipment. Therefore, how to pre-identify the real load state of the hoist before the hoist brake is released in a low-cost and high-reliability way, and realize the adaptive and accurate matching of the driving torque accordingly, so as to suppress the start impact, improve the running efficiency and reduce the damage to the mechanical system, has become a technical problem to be solved by the present application. SUMMARY

[0005] The application provides a variable frequency speed regulation system for a large construction elevator, which mainly aims to solve the problem that the real load in the elevator cabin cannot be predicted before the elevator starts, resulting in the mismatch between the driving torque and the actual load, and further causing the elevator starting impact, reducing the operation efficiency and aggravating the mechanical wear.

[0006] To achieve the above-mentioned purpose, the application provides a variable frequency speed regulation system for a large construction elevator, which comprises:

[0007] A pre-detection module is configured to, after receiving a starting instruction and when the brake of the construction elevator is in a braking engagement state, control the frequency converter to apply a first stored tentative torque pulse to the motor, and acquire a first micro-rotation response value representing the response of the motor rotor to the first stored tentative torque pulse via a rotor position sensor connected to the motor;

[0008] A load identification module is configured to preliminarily determine the load level of the current construction elevator from a plurality of stored load levels based on the first micro-rotation response value, and select a corresponding initial starting parameter curve accordingly;

[0009] A starting control module is configured to control the brake to release and drive the motor to start at a stored creep speed using the initial starting parameter curve, wherein the pre-detection module is further configured to, during the initial running stage of the motor at the creep speed, control the frequency converter to apply a second stored tentative torque pulse identical to the first stored tentative torque pulse to the motor, and acquire a second micro-rotation response value;

[0010] The load identification module is further configured to correct the load level by the following method: if the ratio of the second micro-rotation response value to the first micro-rotation response value is greater than a stored friction force determination threshold value for representing the influence of static friction, it is determined that the initial static friction is the main starting resistance, and the load level is corrected to a stored level corresponding to a lower load;

[0011] The starting control module is further configured to seamlessly switch the initial starting parameter curve to a target starting parameter curve corresponding to the corrected load level based on the corrected load level, so as to continue driving the motor.

[0012] Preferably, the first micro-rotation response value and the second micro-rotation response value are both the rotation angle of the motor rotor generated under the action of the stored tentative torque pulse; the initial starting parameter curve and the target starting parameter curve both define the torque rising rate or the frequency rising rate during the motor starting process.

[0013] Preferably, the load identification module is configured to follow a stored mapping relationship that the smaller the first micro-rotation response value is, the higher the preliminarily determined load level is.

[0014] Preferably, the rotor position sensor is a Hall effect sensor, and the pre-probing module is configured to calculate the rotation angle by high-frequency sampling and time integration of the on-off time sequence signal output by the Hall effect sensor.

[0015] Preferably, the system further comprises a temperature compensation unit configured to, before the load identification module preliminarily determines the load level, first acquire a current temperature value from the frequency converter or the motor , and according to the current temperature value , look up a compensation coefficient through a storage table representing a non-linear mapping relationship of the viscosity-temperature characteristic of the lubricating oil, to compensate and correct the first micro-rotation response value, wherein the corrected response value , wherein is the corrected response value, is the original acquisition value of the first micro-rotation response value; the load identification module is configured to preliminarily determine the load level based on the corrected response value.

[0016] Preferably, the system further comprises a safety self-check unit configured to, when the construction elevator is in an idle state of non-operation and the brake is in a braking engagement state, activate the pre-probing module to apply the first stored tentative torque pulse and acquire a self-check micro-rotation response value; compare the self-check micro-rotation response value with a zero value to determine whether the self-check micro-rotation response value is a non-zero value; and if it is determined that the self-check micro-rotation response value is a non-zero value, generate a pre-warning signal indicating that the health state of the brake is abnormal.

[0017] Preferably, the system further comprises a height adaptability unit configured to, before the load identification module performs the ratio comparison, first acquire a current vertical height of the car from a position control unit of the construction elevator; according to the current vertical height, determine a reference correction factor from a storage mapping table representing the influence of the self-weight of the steel wire rope; and based on the reference correction factor, dynamically adjust the storage friction force determination threshold to ensure consistency in the judgment of the initial static friction at different vertical heights.

[0018] Preferably, the system further comprises a health trend analysis module configured to: record the difference between the second micro-rotation response value and the first micro-rotation response value obtained by the load identification module after each comparison as a friction characteristic value representing the initial static friction; and store the friction characteristic value together with the corresponding floor position and time information in a health log; and perform trend analysis on a series of friction characteristic values arranged in time sequence at a specific floor position in the health log, and generate a predictive maintenance instruction indicating that the construction hoist guide rail system has potential abnormalities at the specific floor position when the analysis result indicates that the friction is continuously increasing.

[0019] Preferably, the system further comprises an operation data recording module configured to: store the load level finally determined by the load identification module each time, whether it is the initially determined load level or the corrected load level, as a data entry together with the current time information; and perform background statistical analysis on a plurality of data entries stored within a predetermined time period to generate statistical information representing the load pattern of the construction hoist during the time period, the statistical information including a distribution histogram of each load level and a time period operation heat map.

[0020] Preferably, the total duration of the first stored trial torque pulse or the second stored trial torque pulse applied by the pre-detection module is limited to within two hundred milliseconds; and the stroke distance of the motor driven by the start control module at the inching speed is limited to no more than two hundred millimeters.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] 1. The present application establishes a system resistance characteristic identification method based on homologous excitation and heterogeneous response by applying a first torque pulse during the stationary phase when the brake is engaged and applying a second identical torque pulse during the inching phase after starting; the method utilizes the physical state switching window of the system from static to dynamic micro-speed operation, and by comparing the difference between the two micro-rotation response values, the driving system obtains the ability to distinguish the starting resistance properties, i.e. from the macro-mixed starting total resistance, the persistent resistance determined by the load inertia is separated from the instantaneous static friction resistance determined by the contact surface state, and then the initial output of the driving torque is no longer based on the general total resistance, but on the persistent resistance component that is closer to the real load condition, avoiding the driving force redundancy caused by the resistance to instantaneous excessive static friction.

[0023] 2、The system of the present application acquires the initial load information of the whole transmission system in advance by using a micro-torque detection action in the stationary phase before the brake is released, so that the initial driving torque of each start is no longer based on a conservative and uniform setting, but becomes an output matched with the actual load of this operation, avoiding the start impact or jitter problem caused by the mismatch between the driving force and the load in the control mode, helping to improve the smoothness of the elevator during the start process under different loads, and reducing the power consumption caused by excessive starting current.

[0024] 3、The present application further constructs the extremely short creeping phase after starting as a window for dynamic verification of the initial static detection results, and by comparing the system response differences in static and dynamic states, the system obtains the ability to distinguish the nature of the starting resistance, and can distinguish the persistent resistance caused by load inertia from the instantaneous resistance caused by local friction of the guide rail; when the initial judgment is identified to be disturbed by the instantaneous resistance, the system can immediately and smoothly correct its driving strategy to adapt to the real load condition; this prediction-verification-correction closed-loop working mode helps to maintain the accuracy and reliability of the starting control when facing complex working conditions such as friction force mutation caused by rust or dirt in construction sites.

[0025] 4、The present application also uses its core micro-torque detection mechanism to realize the expansion of functions in different working modes, for example, in the idle state of the system, the detection mechanism is used to actively inquire the gripping state of the brake, and by judging whether there is an abnormal micro-response, the automatic monitoring of the health state of this core safety component is realized; at the same time, the load level information generated by load identification in each operation is systematically recorded, and through the trend analysis of these long-term data, the speed regulation system itself becomes an operation data source that can reflect the use intensity and operation mode of the equipment, providing a new objective basis for equipment maintenance and management decision. BRIEF DESCRIPTION OF DRAWINGS

[0026] Fig. 1 It is a flowchart of the variable frequency speed regulation system for large construction elevators of the present application;

[0027] Fig. 2 It is a micro-rotational response value comparison diagram for characterizing the judgment of the nature of the starting resistance of the present application;

[0028] Fig. 3 It is a functional module and data flow diagram of the variable frequency speed regulation system for large construction elevators of the present application.

[0029] The purpose realization, functional characteristics and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0030] In order to make the objects, technical solutions and advantages of the present application clearer, the following will further describe the present application in a clearer and complete manner. It is to be understood that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art without creative effort based on the embodiments in the present application shall fall within the scope of protection of the present application.

[0031] The disclosed variable frequency speed regulation system for a large construction hoist has an overall technical solution in the control timing, which sequentially includes a pre-detection stage, a load identification and parameter selection stage, and a start control and dynamic correction stage. The accurate matching of the driving torque output and the actual load is realized by the collaborative configuration of a pre-detection module, a load identification module, and a start control module. After the system receives a start instruction, and the construction hoist brake is still in the braking engagement state, the pre-detection module is first activated, and the control frequency converter applies a preset first storage tentative torque pulse to the motor. The amplitude and action time, for example, the total time, of the pulse are limited within two hundred milliseconds, and are calibrated to be only enough to avoid the micro-gap and elastic deformation in the system, and insufficient to drive the hoist to produce macro displacement. At the same time, a rotor position sensor, for example, a Hall effect sensor, connected to the motor rotor, acquires a first micro-rotational response value representing the response of the motor rotor to the pulse by high-frequency sampling the timing signal output by the sensor and performing time integration procedures. The response value corresponds to the rotational angle of the rotor in physics. Subsequently, the load identification module receives the first micro-rotational response value, and preliminarily judges the load level according to a preset storage mapping relationship. The mapping relationship follows the physical principle that under the same torque pulse excitation, the smaller the response value, the greater the rotational inertia of the entire hoist transmission system, and the higher the load level in the car. Specifically, the module compares the acquired first micro-rotational response value with an internally stored response value-load level database established through offline calibration experiments, determines an initial load level therefrom, and selects a corresponding initial start parameter curve according to the initial load level. The curve presets the torque rising rate or frequency rising rate for the subsequent start process.

[0032] In the start-up control phase, the start-up control module first instructs the brake to release, and then drives the motor to start up at a preset crawling speed using the selected initial start-up parameter curve, the running distance corresponding to the crawling speed being limited within a small stroke, for example, no more than two hundred millimeters, which aims to make the system escape from the static friction state and enter the dynamic friction running interval. At the initial moment of the crawling stage, the pre-detection module is triggered again to apply a second stored trial torque pulse to the motor with the same parameters, and a second micro-rotational response value is obtained. The load identification module calculates the ratio of the second micro-rotational response value to the first micro-rotational response value, and compares it with a stored friction force judgment threshold value for representing the influence of static friction force. If the ratio is greater than the judgment threshold value, it indicates that the initial static response is significantly disturbed by the static friction force, and the system determines that the initial static friction force is the main start-up resistance, and corrects the load level to a preset level corresponding to a lower load. Correspondingly, the start-up control module switches the driving parameters to a target start-up parameter curve matching the corrected load level based on the corrected load level, to complete the subsequent acceleration and running process, thereby avoiding the start-up jitter or impact that may be caused by the misjudgment of the friction force. In order to make the system have unified and reproducible running criteria, the key running parameters, including the crawling speed and the friction force judgment threshold value, are determined through a standardized pre-delivery calibration procedure. The procedure first determines the crawling speed , which is defined as the average driving current required for the driving motor to maintain uniform speed running under the standard test load , the change rate of the running speed , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval , the speed value at which the current standard deviation first approaches zero and the speed value in the minimum stable interval .

[0033] After the load identification module completes the load level correction, the switching from the initial startup parameter curve to the target startup parameter curve executed by the startup control module is completed by a built-in parameter smoothing transition algorithm to ensure the continuity of driving force. This algorithm receives the switching command at the moment... Immediately lock the current driving parameter vector This vector contains control quantities such as the motor's current torque and frequency, and simultaneously obtains the corresponding target parameter vector from the target starting parameter curve. The algorithm then operates within a pre-defined transition time period, stored as an inherent attribute of the system. Inside (e.g.) (milliseconds), a continuous intermediate driving parameter vector is generated through a linear interpolation function. Its function expression is The time variable The range of values ​​is ;exist After a certain point, the drive parameters and target start-up parameters curves completely overlap, thus transforming a discrete logical judgment into a continuous and smooth control process at the physical execution level. To cope with changes in physical characteristics under different operating conditions, this system further integrates an adaptive compensation unit. Among them, a temperature compensation unit is configured to first obtain the current temperature value from the frequency converter or motor before performing load identification. A compensation coefficient is obtained by storing a nonlinear mapping relationship characterizing the viscosity-temperature properties of lubricating oil. And then through The operation yields the original value of the first microscopic rotational response. The correction is made to eliminate the influence of temperature change on the mechanical damping of the system; in addition, a highly adaptive unit is configured to obtain the current vertical height of the car from the position control unit of the elevator before performing the friction ratio comparison, and according to the height, determine a reference correction factor from a stored mapping table representing the influence of the weight of the wire rope, to dynamically adjust the stored friction determination threshold, ensuring the consistency of the initial static friction determination at different operating heights, the micro-probing mechanism of the present application is also applied to the health state monitoring and operation data management of the equipment, a safety self-checking unit uses the pre-probing module to probe the brake in the engaged state in the idle state of the elevator not in operation, if a non-zero self-checking micro-rotation response value is obtained, a warning signal indicating the abnormal health state of the brake is generated, a health trend analysis module stores the friction characteristic value representing the initial static friction obtained after each comparison, that is, the difference between the second micro-rotation response value and the first micro-rotation response value, together with the corresponding floor position and time information in the health log, and through trend analysis of a series of characteristic values at a specific floor position, when the analysis result indicates that the friction is continuously increasing, a predictive maintenance instruction indicating that the guide rail system at that position has potential abnormalities is generated; at the same time, an operation data recording module stores each final determined load level and time stamp as a data entry, through background statistical analysis of the data within a predetermined period, statistical information representing the load pattern of the elevator is generated, such as the distribution histogram of each load level and the time period operation heat map.

[0034] Example 1: In a super high-rise building construction project in a coastal city during the rainy season, a large construction elevator equipped with the variable frequency speed regulation system of the present application, its operating environment is intertwined with high humidity and random loading tasks, the previous night's rainfall caused a layer of floating rust on the surface of part of the vertical guide rail, increasing the initial static friction force at start-up, and the first task of the day was to transport a group of workers and a batch of waterproof materials temporarily moved due to the construction period, the weight of which is close to the rated load; After the operator issued the upstart command on the ground floor, the system applied a first stored trial torque pulse to the motor through the pre-detection module while the brake was engaged. Due to the combined resistance of the nearly full load of materials in the car and the floating rust on the guide rail, the drive system exhibits high inertia and high friction characteristics, so the first micro-rotational response value obtained by the rotor position sensor is very small. Based on this response value, the load identification module initially judges the current working condition as the highest load level and selects the initial start-up parameter curve corresponding to the maximum starting torque. Subsequently, the brake is released by the start-up control module, and the motor starts to move upward at a preset crawling speed strictly according to the initial start-up parameter curve. In the initial stage when the static friction between the car and the guide shoe is broken and converted to dynamic friction, the pre-detection module applies a second stored trial torque pulse with the same parameters. At this moment, although the load inertia of the car has not changed, the instantaneous excessive static friction resistance caused by the floating rust no longer exists, so the system's response to the second torque pulse is dynamic, and the second micro-rotational response value obtained is significantly higher than the first.

[0035] The load recognition module calculates the ratio of the second micro-rotation response value to the first micro-rotation response value, and confirms that the ratio exceeds a preset stored friction force determination threshold. The system determines that the high impedance sensed by the initial detection is mainly contributed by the instantaneous static friction, rather than all from the actual load in the car. Therefore, the load recognition module corrects the highest load level determined previously to a level corresponding to only heavy load, and the starting control module switches the driving curve to a target starting parameter curve matching the heavy load level, and the output torque is correspondingly lower than the planned maximum value. The closed-loop correction process based on static detection and dynamic verification essentially decomposes the difficult-to-determine starting total resistance into a persistent resistance component determined by the load inertia and an instantaneous friction component determined by the contact surface state. The system isolates and eliminates the influence of the latter, so that the driving force regulation is changed from a fuzzy mixed signal to a signal that better reflects the actual load, which resolves the inherent technical contradiction of traditional control, which presets high driving force to ensure heavy load starting, but causes starting impact in friction force sudden change conditions. Finally, the construction elevator completes the starting acceleration smoothly with a torque matching the corrected load condition, without impact due to excessive torque or shaking due to insufficient torque. In subsequent operation, whether transporting empty personnel or other materials of different weights, the system effectively distinguishes the system response difference caused by load changes from the friction difference caused by environmental or floor position changes, and adaptively outputs a driving torque matching the load at each start.

[0036] Example 2: To objectively quantify the effectiveness of the technical solution of the present application in distinguishing between load inertia and instantaneous static friction, a ground test platform based on a SC200 / 200 construction elevator is built, which includes a test tower with a height of thirty meters, and is equipped with a three-axis acceleration sensor and a Hall effect current sensor to record the vertical impact and instantaneous current of the motor during the starting process, respectively. The test has a control group and a test group. The control group uses the conventional variable frequency speed regulation system based on the preset torque curve of the elevator, and the test group uses the same device equipped with the variable frequency speed regulation system of the present application. The test aims to compare the starting performance of the two systems under three preset working conditions. Working condition one is zero load, working condition two is fifty percent rated load, and working condition three is based on fifty percent rated load, and an additional static friction equivalent to another fifty percent load is applied between the guide rail and the guide shoe through a device that can apply a predetermined brake force, to test the system's ability to distinguish the source of starting resistance.

[0037] In the system of the test group, the setting of the key parameter of the friction force determination threshold value needs to balance the detection sensitivity to the friction force change and the stability of avoiding noise misjudgment of the system. The threshold value is determined by the following procedure. First, under the condition of no additional static friction, a plurality of load levels are tested for starting multiple times, the ratio of the second micro-rotation response value to the first micro-rotation response value is recorded and a statistical distribution of the reference ratio is formed. The threshold value is finally set to the average value of the distribution plus three times the standard deviation. In this test, the exemplary value calculated is one point five. In the test process, the control systems of the control group and the test group perform starting operations for the above three working conditions, and the acceleration peak value and the motor peak current within two seconds after starting are recorded. For the test group, the first and second micro-rotation response values are recorded at the same time. Each group of tests is repeated five times and the average value is taken. Under working condition one and working condition two, the ratio of the first and second micro-rotation response values of the test group is less than one point five, and the system does not correct the load level. Under working condition three, the operating parameters of the systems of the two groups show significant differences. For specific data, see Table 1.

[0038] Table 1: Performance comparison table of the control group and the test group under working condition three.

[0039]

[0040] The data listed in Table 1 records that under working condition three, the control group system unifies the high static friction and the load as the total starting resistance, and directly starts with the torque corresponding to one hundred percent load, resulting in an impact acceleration of one point eight five meters per square second after the static friction is broken. The first micro-rotation response value obtained by the test group system is three point two milliradians, which is preliminarily determined as high load, but the second micro-rotation response value obtained during the crawling stage is eight point one milliradians, and the ratio of the two is about two point five three, which is greater than the one point five determination threshold value. The system determines that the initial resistance is mainly caused by static friction, and corrects the load level to the level corresponding to fifty percent load. The final starting torque is only about fifty-five percent of the rated value, and the peak acceleration is thus suppressed to zero point sixty-two meters per square second. The test results show that the variable frequency speed regulation system of the present application can effectively distinguish between the persistent resistance caused by the load inertia and the instantaneous resistance caused by the contact surface state through the static pre-detection and dynamic verification mechanism implanted in the starting time sequence, and correct the driving strategy according to the judgment of the resistance nature, so that when facing changing starting working conditions, the starting impact caused by the mismatch between the driving force and the actual load can be suppressed.

[0041] Embodiment 3: This embodiment combines Figs. 1 to 3 to describe a variable frequency speed regulation system for a large construction elevator, such as Fig. 1As shown, after receiving the start instruction, the system first enters the pre-probing stage in the static phase, at which time the brake remains engaged, the pre-probing module applies a first stored tentative torque pulse and acquires a first micro-rotation response value, while a parallel temperature compensation unit can acquire the current temperature , and through a stored nonlinear mapping relationship of viscosity-temperature characteristics, the compensation coefficient is found , and the first micro-rotation response value is corrected, then the load identification module performs preliminary load identification based on the response value, determines the initial load level and the starting parameter curve from the stored mapping relationship, enters the starting control and dynamic verification stage, the starting control module releases the brake to start at the crawling speed, while the pre-probing module applies a second identical torque pulse to acquire a second micro-rotation response value, followed by response comparison and correction determination, the ratio of the two response values is compared with a friction force determination threshold, which can be dynamically adjusted by a height adaptive unit that acquires the current vertical height of the car and determines the reference correction factor from a stored mapping table of the influence of the wire rope self weight, if the ratio is greater than the threshold, it is determined that the initial static friction is the main starting resistance, the load level is corrected to a lower level, if the ratio is not greater than the threshold, the preliminary judgment is maintained, finally, the starting control module seamlessly switches to the matching target starting parameter curve based on the finally determined load level, and drives the motor to run smoothly with the optimal torque.

[0042] As Fig. 2 shown, the graph takes the tentative opportunity as the horizontal axis and the micro-rotation response value mrad as the vertical axis, and shows that under a specific test condition, the micro-rotation response value obtained by the first tentative static is 3.2 mrad, and the response value obtained by the second tentative dynamic is 8.1 mrad, a dashed line in the graph represents the determination threshold line, which is set to 1.5 times the first response value, i.e. 4.8 mrad in this example, since the second response value 8.1 mrad is obviously higher than the determination threshold line, the system can determine that the initial static response is significantly disturbed by the static friction, thereby triggering the downward correction of the load level.

[0043] As Fig. 3As shown, module 1.0 temperature compensation utilizes the input current temperature value to query D1 viscous temperature characteristic mapping to correct the response value; module 2.0 pre-detection and response acquisition extracts the first and second microscopic rotational response values from the sensor signal; module 3.0 highly adaptive adjustment queries D2 wire rope self-weight mapping according to the current height to adjust the friction force determination threshold; these information is collectively fed into the core 4.0 load level identification and correction module, which determines the final load level in combination with D3 load-response mapping library, and transmits the level to 5.0 start parameter generation module, which generates the final target start parameter curve according to D4 start parameter curve library, and outputs to the frequency converter / motor for execution, at the same time, 4.0 module also writes the determined load level and friction force characteristic value and other data into 6.0 health and operation data recording module, and finally stores into D5 health and operation log to realize long-term monitoring and data analysis.

[0044] In a factory calibration process for a mass-produced construction elevator, in order to avoid the influence of temperature changes in different regions and seasons on the system load identification result, the nonlinear mapping relationship of the temperature compensation unit in the system needs to be determined; the process is carried out in a large environmental simulation cabin, and the elevator system to be calibrated is installed in the cabin, and the temperature sensor integrated on the motor or frequency converter is connected to the frequency conversion speed regulation system of the application; the initial step of the calibration procedure is to set and stabilize the temperature of the environmental simulation cabin at a reference temperature of 20 degrees Celsius, at this temperature, when the elevator car is in a completely unloaded state, a standardized first stored exploratory torque pulse is applied to the motor by the control system, and an original reference rotational response value is obtained from the rotor position sensor, denoted as At this time, the compensation coefficient of the system at the reference temperature is defined as one; next, the temperature of the environmental simulation cabin is gradually reduced by ten degrees Celsius, until the preset minimum working temperature of the system is minus ten degrees Celsius; at each temperature setting point, the temperature in the cabin is kept stable, so that the temperature of the lubricating oil in the elevator drive system, especially the reduction gearbox, reaches thermal equilibrium with the environmental temperature, and at each stable low temperature point, the same exploratory torque pulse as at the reference temperature is applied under the unloaded state, and the original microscopic rotational response value corresponding to each temperature point is recorded .

[0045] Since the decrease in temperature leads to an increase in the viscosity of the lubricating oil, the inherent mechanical resistance of the system increases accordingly, and the measured original microscopic rotational response value decreases with the decrease of temperature ; in order to offset this effect, the calculation logic of the temperature compensation coefficient is set to normalize the unloaded response at any temperature to the unloaded response at the reference temperature, and the calculation relationship is ; according to the relationship, the system can calculate the compensation coefficient value corresponding to each low temperature test point; after completing the calibration of the low temperature section, the temperature of the environmental simulation cabin is gradually increased from the reference temperature to the preset highest working temperature of forty degrees Celsius at the same step, and the above no-load test and coefficient calculation process is repeated at each stable high temperature point; in the high temperature zone, the viscosity of the lubricating oil decreases, the mechanical resistance decreases, and the measured will be greater than , and the corresponding calculated compensation coefficient will be less than one; finally, all the test temperature points and the corresponding compensation coefficients are taken as a data pair sequence, and a non-linear mapping curve covering the entire working temperature range is generated by a data fitting method, which is stored in the temperature compensation unit; after completing the calibration, the effectiveness of the temperature compensation mechanism can be verified, a counterweight equivalent to fifty percent of the rated load is placed in the car, and static detection before starting is carried out at three temperature points of minus ten degrees Celsius, twenty degrees Celsius and forty degrees Celsius; in each detection, the system first obtains the current temperature and the original response value , then calls the stored mapping relationship to find the corresponding compensation coefficient , and calculates the corrected response value ; the observation results show that although the original response values at different temperatures are different, the compensated response values remain consistent and can all point to the load level corresponding to fifty percent of the load, indicating that the calibration process provides the system with the ability to reliably identify loads in a wide temperature range.

[0046] Embodiment 5: After a set of construction elevator system is installed and debugged on site, before it is put into formal operation, in order to ensure the consistency and reliability of its load identification function in the entire operating height range, the height adaptability unit needs to be calibrated on site, this procedure starts under the condition that the car is empty and the guide rail system is in a clean reference state, the control system drives the car to stop at multiple reference floors that can represent its complete operating range, at each reference floor, the system automatically executes a detection sequence containing the first and second stored tentative torque pulses, and records the first microscopic rotation response value at that specific height, the system takes each reference floor and its corresponding first microscopic rotation response value as a data pair, and stores it in the mapping table of the height adaptability unit, thereby constructing a reference height response curve reflecting the change of the inertia of the empty system with the change of the weight of the steel wire rope under the specific installation condition.

[0047] In the subsequent daily operation, when the load recognition module judges the initial static friction, the high adaptability unit first obtains the current vertical height of the car, and obtains a theoretical no-load response reference value at the current height by consulting and interpolating the reference height response curve. The system then compares the first micro-rotation response value obtained in real time with the dynamic reference value, rather than a fixed global value, to separate the response change caused by the actual load; At the same time, in order to calibrate the warning logic of the safety self-check unit, the system is placed in a self-learning mode when it confirms that the brake is in a brand new and normal working healthy state. In this mode, the system continuously performs multiple standard test torque pulses sufficient to establish a stable statistical distribution on the engaged brake, and records the distribution of the self-check micro-rotation response value caused by sensor noise and mechanical micro-vibration each time. Finally, the system adds six standard deviations to the average value of the response value distribution to calculate and solidify a specific warning threshold. In subsequent self-check monitoring, any response value exceeding this statistical threshold is determined to be an effective signal indicating abnormal brake health status.

[0048] Example 6: After the variable frequency speed regulation system of a large construction elevator is mass-produced and integrated with the motor and reduction box of a specific model, a standardized parameter matrix calibration and self-check logic verification procedure needs to be performed. This procedure is carried out on a factory test bench, which is equipped with a drive motor, reduction box and brake assembly consistent with the target elevator model, and connected to the variable frequency speed regulation system to be calibrated. The primary task of this procedure is to determine the amplitude and duration of the first and second stored test torque pulses, with the goal of seeking the minimum driving energy that can produce a clear and repeatable micro-rotation response, while not challenging the rated holding force of the brake. The calibration program automatically performs an iterative search process, starting from an initial torque amplitude lower than the estimated response threshold, with a fixed step increment. At each step, a torque pulse of a preset duration is applied, and the signal-to-noise ratio of the rotor position sensor response signal is detected. When the signal-to-noise ratio first exceeds a judgment threshold sufficient to distinguish between effective signals and background noise, the program records the current torque amplitude. Subsequently, the program fixes this torque amplitude and tests with increasing duration steps to determine the pulse duration that produces the most stable response. These two determined torque amplitudes and pulse durations are solidified as the standard stored test torque pulse parameters for the hardware combination of this model.

[0049] The iterative search process also verifies the signal integrity of the sensor. A boundary condition judgment logic is built into the pre-probing module. If the data returned by the rotor position sensor indicates a rotation angle beyond the physically possible range or the signal is interrupted during the application of each trial pulse, the system will immediately abort the calibration process and generate a fault code indicating an abnormality in the sensor or its link. After the pulse parameters and the sensor are verified, the procedure enters the final construction phase of the load identification model. A series of precisely calibrated simulated load torques from no load to overload are applied to the output end of the test bench, and the standard trial torque pulse determined above is applied. The system records the first micro-rotation response value corresponding to each load level and writes these data pairs of load levels and response values into the storage mapping table of the load identification module. After this procedure is completed, each set of frequency conversion and speed regulation system shipped contains a set of verified detection pulse parameters and load identification model corresponding to the driving hardware it matches, thereby ensuring the initial identification accuracy in subsequent field deployment.

[0050] It is apparent for those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and the present application can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A variable frequency drive system for a large construction hoist, characterized by, The system comprises: a pre-detection module configured to, after receiving a start instruction and while a brake of the construction elevator is in a braking engagement state, control a frequency converter to apply a first stored tentative torque pulse to a motor, and acquire, via a rotor position sensor connected to the motor, a first micro-rotation response value representing a response of a rotor of the motor to the first stored tentative torque pulse; a load identification module configured to preliminarily determine a load level of the construction elevator from a plurality of stored load levels based on the first micro-rotation response value, and select a corresponding initial start parameter curve according to the load level; a start control module configured to control the brake to release and drive the motor to start at a stored creep speed using the initial start parameter curve, wherein the pre-detection module is further configured to, during an initial running stage of the motor at the creep speed, control the frequency converter to apply a second stored tentative torque pulse identical to the first stored tentative torque pulse to the motor, and acquire a second micro-rotation response value; the load identification module is further configured to correct the load level by determining that an initial static friction is a main starting resistance if a ratio of the second micro-rotation response value to the first micro-rotation response value is greater than a stored friction judgment threshold value representing an influence of the static friction, and correcting the load level to a stored level corresponding to a lower load; the start control module is further configured to seamlessly switch the initial start parameter curve to a target start parameter curve corresponding to the corrected load level based on the corrected load level, to continue driving the motor.

2. A variable frequency speed control system for a large construction hoist according to claim 1, wherein The first micro-rotation response value and the second micro-rotation response value are both rotation angles of the rotor of the motor under the action of the stored tentative torque pulse; the initial start parameter curve and the target start parameter curve both define a torque rising rate or a frequency rising rate during the start of the motor.

3. A variable frequency speed control system for a large construction elevator as defined in claim 1 wherein, The load identification module is configured to follow a stored mapping relationship that the smaller the first micro-rotation response value is, the higher the preliminarily determined load level is.

4. A variable frequency speed control system for a large construction elevator as defined in claim 1 wherein, The rotor position sensor is a Hall effect sensor, and the pre-detection module is configured to calculate the rotation angle by high-frequency sampling and time integration of a switching value time sequence signal output by the Hall effect sensor.

5. A variable frequency drive system for a large construction elevator as defined in claim 1, wherein, The system further comprises a temperature compensation unit, which is configured to: before the load identification module preliminarily determines the load level, first acquire a current temperature value from the frequency converter or the motor ; and according to the current temperature value , through a storage table representing a nonlinear mapping relationship of viscosity-temperature characteristics of lubricating oil, find a compensation coefficient , to compensate and correct the first micro-rotational response value, wherein the corrected response value , wherein is the corrected response value, is an original acquisition value of the first micro-rotational response value; and the load identification module is configured to preliminarily determine the load level based on the corrected response value.

6. A variable frequency speed control system for a large construction elevator as defined in claim 1 wherein, The system further comprises a safety self-check unit configured to, when the construction elevator is in an idle state of non-operation and the brake is in the braking engagement state, activate the pre-detection module to apply the first stored tentative torque pulse and acquire a self-check micro-rotation response value; compare the self-check micro-rotation response value with a zero value to determine whether the self-check micro-rotation response value is a non-zero value; and if it is determined that the self-check micro-rotation response value is a non-zero value, generate a pre-warning signal indicating that the brake is in an abnormal health state.

7. A variable frequency drive system for a large construction elevator as defined in claim 1, wherein The system further comprises a height adaptability unit configured to: obtain the current vertical height of the cage from the position control unit of the construction hoist before the load identification module performs the ratio comparison; determine a reference correction factor from a mapping table representing the influence of the self-weight of the steel wire rope according to the current vertical height; and dynamically adjust the stored friction force determination threshold based on the reference correction factor to ensure consistency in the determination of the initial static friction at different vertical heights.

8. A variable frequency drive system for a large construction elevator as defined in claim 1, wherein, The system further comprises a health trend analysis module configured to: record the difference between the second micro-rotation response value and the first micro-rotation response value obtained after each comparison by the load identification module as a friction force feature value representing the initial static friction; store the friction force feature value together with the corresponding floor position and time information in a health log; and perform trend analysis on a series of friction force feature values arranged in time sequence at a specific floor position in the health log, and generate a predictive maintenance instruction indicating that the construction hoist guide rail system has potential abnormalities at the specific floor position when the analysis result indicates that the friction force is continuously increasing.

9. A variable frequency speed control system for a large construction elevator as defined in claim 1 wherein, The system further comprises an operation data recording module configured to: store the load level finally determined by the load identification module each time, whether it is the initially determined load level or the corrected load level, together with the current time information as a data entry; and perform background statistical analysis on a plurality of data entries stored within a predetermined time period to generate statistical information representing the load pattern of the construction hoist during the time period, the statistical information including a distribution histogram of each load level and a time period operation heat map.

10. The variable frequency drive system for a large construction elevator according to claim 1, wherein The total duration of the first stored tentative torque pulse or the second stored tentative torque pulse applied by the pre-detection module is limited to within two hundred milliseconds; and the stroke distance of the motor driven by the start control module at the inching speed is limited to no more than two hundred millimeters.

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