Serial communication system for frequency converter of explosion-proof elevator

Abstract

The invention relates to the technical field of elevator control, provides an explosion-proof elevator frequency converter serial communication system, realizes current real-time detection, dynamic threshold adjustment and graded early warning through cooperation of multiple modules, and solves the problems of response lag, high malfunction rate and high maintenance cost of a traditional protection device. The method has the advantage of improving the safety and the operation efficiency of an elevator system.

Description

TECHNICAL FIELD

[0001] The present application relates to the elevator control technical field, and in particular to an elevator serial control system circuit device with overload protection function. BACKGROUND

[0002] The existing elevator circuit protection device generally has the following technical defects: first, the traditional fuse protection mode needs manual replacement of the fuse body when the circuit is overloaded, which not only has high maintenance cost, but also causes long-time shutdown of the elevator system. Second, the response time of the mechanical protection device is usually in milliseconds, which cannot meet the requirement of modern elevator control system for rapid circuit cut-off, and easily causes cumulative damage to the motor winding and electronic components in the initial stage of overload. In addition, the existing protection device lacks intelligent judgment function and cannot distinguish between transient impulse current and continuous overload current, which is prone to misoperation. More importantly, the traditional protection scheme cannot dynamically adjust the protection threshold according to the actual operating conditions of the elevator, and may cause premature or late protection in special conditions such as elevator acceleration and full load uplink. At the same time, the existing system generally lacks a hierarchical warning mechanism and cannot issue a warning in advance when the circuit reaches the critical state, which is not conducive to preventive maintenance.

[0003] In view of the above problems, the existing technology needs to be improved. SUMMARY

[0004] The purpose of the present application is to provide an elevator serial control system circuit device with overload protection function, which has the functions of automatic cut-off of overload circuit, dynamic adjustment of protection threshold, hierarchical warning and intelligent recovery, effectively reduces the maintenance cost and improves the system reliability.

[0005] The present application provides a kind of explosion-proof elevator frequency converter serial communication system, technical scheme is as follows: a kind of explosion-proof elevator frequency converter serial communication system, for a elevator serial control system, including power module, detection module, control module, execution module and early warning module;Wherein: power module, respectively with detection module, control module, execution module and early warning module electric connection, provides operating power for each module;Detection module is connected in series in main circuit, for detecting the current value of main circuit, and the current signal detected is transmitted to control module;Control module is respectively electrically connected with detection module, execution module and early warning module, and the overload current threshold is preset in control module, when the current value detected by detection module exceeds the overload current threshold, control module sends control signal to execution module and early warning module;Execution module is connected in series in main circuit, for receiving the control signal of control module and cutting off main circuit;Early warning module receives the control signal of control module and sends early warning signal;Early warning signal is the sound and light combination early warning signal containing overload level information.

[0006] Furthermore, this application also proposes to dynamically adjust the overload current threshold based on the elevator's operating status and ambient temperature; receive and process the current signal sampled by the detection module; when the current value detected in multiple consecutive sampling cycles exceeds the dynamically adjusted overload current threshold and continues to exceed the preset first time threshold, it is determined to be a valid overload fault; when a valid overload fault is determined, a cut-off command is sent to the execution module and a warning command is sent to the warning module.

[0007] Furthermore, this application proposes that after the main circuit is cut off, the signal of the detection module is continuously monitored; when the current value is detected to be continuously lower than the preset safety recovery threshold and exceeds the preset second time threshold, and an external reset signal is received or the fault is confirmed to be eliminated, a closing command is sent to the execution module and a warning cancellation command is sent to the warning module at the same time.

[0008] Furthermore, this application also proposes that the elevator operating status includes the elevator operating direction and speed; and that the overload current threshold is dynamically adjusted based on the elevator operating status and ambient temperature, including: calculating and updating the maximum allowable operating current threshold in real time according to the elevator operating direction, speed signal and ambient temperature signal through a built-in algorithm.

[0009] Furthermore, this application proposes to calculate and update the maximum allowable operating current threshold in real time based on the elevator's running direction, speed signal, and ambient temperature signal using a built-in algorithm. This includes: determining the base current threshold Ibase based on the speed command signal through a pre-stored speed-current mapping relationship; multiplying Ibase by a direction correction coefficient of 115% to 125% when the running direction is upward, and multiplying it by a direction correction coefficient of 85% to 95% when the running direction is downward; and calculating the maximum operating current threshold using the formula Itthreshold=Ibase×[1+α(T−25)], where α is a compensation coefficient.

[0010] Furthermore, this application also proposes to determine the base current threshold Ibase based on the speed command signal through a pre-stored speed-current mapping relationship, including: calculating the base current threshold using the linear function Ibase = Imin + β⋅Vspeed; where Imin is the low-speed reference threshold, i.e., the minimum protection current when the elevator approaches zero speed (≤0.3m / s); β is the speed-current slope coefficient, i.e., the current threshold that increases for every 1m / s increase in speed; and Vspeed is the real-time speed of the elevator.

[0011] Furthermore, this application also proposes that the elevator serial control system includes: a control cabinet with a built-in main control board, connected to the hoistway module via a first RS485 bus and connected to the car module via a second RS485 bus; the hoistway module is composed of a cascaded 1-floor HIH module and 2 to n-floor HTH modules, each HTH module communicating with adjacent modules via an RS485 bus, with a maximum number of floors n≤30; the car module includes a blue light parallel integrated machine, at least one internal selection module and at least one display module, the internal selection module and the display module being connected in parallel to the car RS485 network via an RS485 bus.

[0012] Furthermore, this application also proposes that the car RS485 bus is connected to the control cabinet through the J2 interface; the J2 interface defines signals including: TRA2 - differential A line, TRB2 - differential B line, GD2 - ground line, and spare signal IRA2 / IRB2.

[0013] Furthermore, this application also proposes that each HTH module transmits RS485 signals through the CNIO / CNO / CNS / CNC / NG interface, supporting hot-swappable expansion to 30 layers.

[0014] As can be seen from the above, the elevator serial control system circuit device with overload protection function provided in this application realizes real-time current detection, dynamic threshold adjustment and graded early warning through multi-module collaboration, which solves the problems of slow response, high false alarm rate and high maintenance cost of traditional protection devices, and has the advantages of improving the safety and operating efficiency of elevator system. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the serial communication system structure of the explosion-proof elevator frequency converter disclosed in an embodiment of the present invention;

[0017] Figure 2 This is a wiring diagram of a serial control system disclosed in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0019] In existing technologies, circuit protection devices generally use fuses as the core component. When an overload or short circuit occurs, the fuse breaks the current path by melting. This protection method has two inherent drawbacks: after the fuse blows, it must be manually replaced to restore power, resulting in prolonged system downtime; and the fuse's action response has a mechanical delay, failing to achieve millisecond-level rapid disconnection, which may cause secondary damage to the equipment. Furthermore, traditional solutions lack a fault warning mechanism, making it difficult for operators to detect potential overload risks in a timely manner.

[0020] To address these issues, designers noted the high requirements for power supply continuity in elevator control systems and the correlation between overload current and operating conditions. System analysis revealed that the physical characteristics of traditional fuses limited the improvement of protection performance, necessitating the introduction of electronic control technology to achieve intelligent protection. By modularizing current detection, logic judgment, and rapid tripping functions, and adding a warning signal output interface, a closed-loop control system was formed. The system focused on solving three core problems: how to achieve lossless continuous current monitoring, how to establish a dynamic judgment mechanism to replace fixed fuse values, and how to organically combine protection actions with status feedback.

[0021] Therefore, this application proposes a serial communication system for an explosion-proof elevator frequency converter, used in an elevator serial control system, such as... Figure 1 As shown, the system includes a power module 101, a detection module 102, a control module 103, an execution module 104, and an early warning module 105.

[0022] The power module 101 is electrically connected to the detection module 102, the control module 103, the execution module 104 and the early warning module 105 respectively, and provides working power to each module.

[0023] The detection module 102 is connected in series in the main circuit and is used to detect the current value of the main circuit and transmit the detected current signal to the control module 103.

[0024] The control module 103 is electrically connected to the detection module 102, the execution module 104 and the early warning module 105 respectively. It is used to preset an overload current threshold in the control module. When the current value detected by the detection module exceeds the overload current threshold, the control module sends a control signal to the execution module and the early warning module.

[0025] The execution module 104 is connected in series in the main circuit and is used to cut off the main circuit after receiving the control signal from the control module.

[0026] The early warning module 105 is used to send an early warning signal after receiving the control signal from the control module; the early warning signal is a combination of sound and light warning signal containing overload level information.

[0027] The power supply module refers to an independent power supply unit, which can be implemented using an isolated DC-DC converter to ensure the power supply stability of each functional module. The detection module refers to a current sensing device, which can be implemented using a Hall effect sensor to achieve non-contact current measurement, avoiding additional impedance to the main circuit. The control module refers to a logic processing unit, which can be implemented using a microcontroller with analog-to-digital conversion capabilities and a built-in comparator circuit for threshold judgment. The execution module refers to a circuit cutting-off device, which can be implemented using a solid-state relay or IGBT power switch to achieve millisecond-level response. The warning module refers to a signal output device, which can be implemented using a multi-color LED array combined with a piezoelectric buzzer to distinguish overload levels through different colors and sound frequencies.

[0028] Specifically, the main circuit current is converted into a voltage signal by the detection module and then input to the control module. The control module compares the real-time sampled value with the stored overload threshold. When the detected value continuously exceeds the threshold, the control module simultaneously sends a high-level signal to the execution module to trigger the power switch to disconnect and sends a digital signal containing fault level data to the warning module. Upon receiving the disconnection command, the power switch device in the execution module can cut off the main circuit current path within milliseconds. After parsing the control signal, the warning module drives an LED to display a specific color and controls a buzzer to emit an alarm sound of the corresponding frequency. For example, a solid red light combined with a high-frequency buzzer indicates a severe overload, while a flashing yellow light combined with an intermittent buzzer indicates a warning state.

[0029] Compared to existing technologies, this solution uses electronic control instead of mechanical fuses, reducing the protection response time from seconds to milliseconds, effectively preventing insulation damage caused by overheating from overload. Through multi-level signal outputs from the early warning module, maintenance personnel can distinguish between temporary overloads and persistent faults, avoiding unnecessary shutdowns due to misjudgments. The execution module uses repeatedly triggerable electronic switching devices, automatically restoring power supply via control signals after fault clearance, eliminating the need for manual fuse replacement.

[0030] Through the above technical solutions, this application achieves an intelligent upgrade of the overload protection of the elevator control system. The electronic current detection and control mechanism significantly improves protection accuracy and response speed, effectively reducing the risk of equipment damage. The combined audible and visual warning signals provide intuitive evidence for fault diagnosis, shortening maintenance response time. Reusable actuator modules reduce the frequency of spare parts replacement, improving system operational continuity. The modular design facilitates integration into existing elevator control cabinets, enabling functional upgrades without modifying the main circuit structure.

[0031] This application further proposes that the control module dynamically adjusts the overload current threshold based on the elevator's operating status and ambient temperature; receives and processes the current signal sampled by the detection module; when the current value detected in multiple consecutive sampling cycles exceeds the dynamically adjusted overload current threshold and continues to exceed the first time threshold, it is determined to be a valid overload fault; when a valid overload fault is determined, a cut-off command is sent to the execution module and a warning command is sent to the warning module.

[0032] Dynamic adjustment of the overload current threshold refers to adaptively correcting the protection threshold based on real-time elevator operating parameters and changes in ambient temperature. This can be achieved through a built-in algorithm combined with speed, direction, and temperature sensor signals, addressing the misjudgment problem caused by fixed thresholds failing to match different elevator operating conditions. Multiple consecutive sampling cycles refer to periodically acquiring and judging the current signal. This can be achieved using digital filtering algorithms to process the sampled data, eliminating the influence of transient interference signals on overload judgment. The first time threshold refers to the shortest duration of the overload state before triggering protection action. This can be set based on the overload duration characteristics under typical elevator operating conditions, distinguishing between transient current fluctuations and actual overload faults.

[0033] Specifically, during elevator operation, the control module acquires speed, direction signals, and ambient temperature data in real time, and dynamically calculates the maximum allowable operating current threshold using a preset algorithm. For example, when the elevator is moving upwards and the ambient temperature rises, the threshold can be adjusted to 115%-125% of the baseline value. The detection module continuously collects the main circuit current, and the control module periodically analyzes the sampled data. If the current value exceeds the dynamic threshold for multiple consecutive cycles (e.g., 3 cycles) and the duration exceeds a preset value (e.g., 5 seconds), it is determined to be a valid overload fault. At this time, the execution module immediately cuts off the main circuit, and the warning module issues an audible and visual signal indicating the overload level.

[0034] Compared to existing technologies, traditional fuse protection uses a fixed threshold, which cannot adjust protection parameters according to changes in elevator load direction, speed, and temperature. This makes it prone to false tripping under heavy loads (upward movement) or high temperatures due to excessively low thresholds, or delayed protection under light loads (downward movement) due to excessively high thresholds. This solution, through a dynamic threshold and multi-condition joint judgment mechanism, avoids false triggering caused by instantaneous current surges during elevator start-up and shutdown, and accurately identifies the true overload state under different operating conditions.

[0035] Through the above technical solution, this application solves the problems of high false judgment rate and false triggering due to instantaneous overload caused by the fixed threshold of traditional protection devices. By adjusting the dynamic threshold to adapt to changes in elevator operating status, and using multi-cycle sampling and time threshold dual conditions to filter interference signals, it can simultaneously achieve rapid power-off protection and graded early warning, thereby improving the accuracy of overload protection and system reliability.

[0036] This application further proposes to continuously monitor the signal of the detection module after the main circuit is cut off. When the detected current value is continuously lower than the preset safety recovery threshold and exceeds the preset second time threshold, and an external reset signal is received or the fault is confirmed to be eliminated, a closing command is sent to the execution module and a warning cancellation command is sent to the warning module at the same time.

[0037] The continuous monitoring module's signal refers to the real-time acquisition of current data from the main circuit via a current sensor. This can be implemented using a Hall effect sensor or a shunt resistor in conjunction with an analog-to-digital converter to determine if the circuit is in a stable and safe state. The preset safety recovery threshold is the upper limit of the current allowed for circuit re-closure, specifically set to 50%-70% of the rated operating current, to prevent accidental triggering of closure due to instantaneous current fluctuations. The preset second time threshold is the duration for which the current value is below the safety recovery threshold, specifically set to 5-30 seconds, to ensure that the circuit fault has been completely eliminated. The external reset signal is a reset command sent via a physical button or remote control terminal, specifically received via a digital input interface, to support manual intervention to confirm fault resolution. Confirming fault resolution involves verifying the circuit is free of abnormalities through a self-test program or external diagnostic equipment, specifically through insulation testing or load impedance testing, to ensure the safety of power restoration.

[0038] Specifically, after the main circuit is disconnected, the current sensor continuously transmits sampling signals to the control module. When the current value continuously falls below the safety recovery threshold and reaches the second time threshold, it indicates that the circuit has reached a stable state. At this time, if an external reset signal is received or the self-test program confirms that the fault has been eliminated, the control module sends a closing command to the execution module to restore power supply, and simultaneously sends a release command to the warning module to disable the audible and visual alarms. This process, through a combination of dual condition constraints and manual or automatic confirmation mechanisms, ensures that the recovery operation is only performed when the circuit is in a safe state, avoiding repeated overloads due to instantaneous current drops or misjudgments.

[0039] Compared to existing technologies, traditional fuses require manual replacement after blowing and cannot automatically restore circuits. This solution, however, achieves intelligent restoration through continuous monitoring and multiple condition checks, closing the circuit without human intervention. Existing technologies lack a safety verification mechanism for restoration conditions; this solution uses a combination of time and safe current thresholds, along with external reset or troubleshooting confirmation, effectively preventing secondary faults caused by misoperation.

[0040] Through the above technical solution, this application achieves automatic recovery after circuit protection, reducing the manual steps of replacing fuses. By using a dual judgment of preset safety recovery thresholds and time thresholds, the stability of the circuit during recovery is ensured, avoiding malfunctions caused by instantaneous current fluctuations. Combined with an external reset signal and a fault-clearing confirmation mechanism, the safety and reliability of the recovery operation are further improved, solving the problems of traditional protection devices' inability to automatically recover and lack of safety confirmation.

[0041] This application further proposes a scheme for dynamically adjusting the overload current threshold based on the elevator's operating status and ambient temperature. Specifically, it includes calculating and updating the maximum allowable operating current threshold in real time using a built-in algorithm based on the elevator's operating direction, speed signal, and ambient temperature signal.

[0042] The elevator's operating direction refers to the direction of movement of the elevator car, which can be detected by encoders or position sensors to indicate upward or downward movement. The operating direction directly affects the traction machine's load characteristics. The speed signal refers to the elevator's real-time operating speed, which can be acquired through a tachogenerator or rotary encoder. Speed ​​is positively correlated with motor power requirements. The ambient temperature signal refers to the temperature data of the elevator machine room or shaft, which can be acquired using digital temperature sensors. Temperature changes affect conductor resistance and equipment heat dissipation efficiency. The built-in algorithm refers to the calculation program stored in the control module, which can be implemented using linear interpolation or polynomial fitting methods to generate dynamic thresholds by integrating multiple parameters.

[0043] Specifically, when the elevator is traveling upwards, the traction machine needs to overcome gravity to lift the car, resulting in increased motor current demand. When traveling downwards, there is a potential energy recovery effect, reducing the current demand accordingly. The speed signal reflects the elevator's current operating power level; higher speeds correspond to a higher base current threshold. When the ambient temperature rises, the conductor resistance increases, causing the current value to rise under the same load, requiring adjustment of the threshold using a temperature compensation coefficient. After receiving the direction, speed, and temperature signals, the built-in algorithm first matches the pre-stored base current threshold based on the speed value, then adds the direction correction coefficient and temperature compensation coefficient, ultimately generating a dynamically adjusted maximum operating current threshold. This threshold serves as an overload judgment benchmark, adapting in real-time to the current fluctuation characteristics under different elevator operating conditions.

[0044] Compared to existing technologies, traditional overload protection devices use a fixed current threshold, which cannot distinguish the load differences between the elevator's upward and downward movements, ignores the impact of speed changes on current demand, and does not consider the physical effect of temperature on conductor resistance. This solution, through a dynamic parameter adjustment mechanism, enables the overload protection threshold to accurately match the actual operating state of the elevator, avoiding the problems of premature protection triggering in low-temperature environments or delayed protection response during high-speed operation.

[0045] Through the above technical solution, this application solves the problem of inaccurate threshold setting of elevator overload protection devices due to changes in operating status and ambient temperature. By introducing a multi-dimensional parameter dynamic adjustment mechanism, the overload current threshold can be adapted to changes in elevator running direction, speed and ambient temperature in real time, improving the accuracy of overload protection action, while enhancing environmental adaptability under different working conditions, and effectively reducing the probability of false triggering and missed triggering.

[0046] This application further proposes a method to calculate and update the maximum allowable operating current threshold in real time based on the elevator's running direction, speed signal, and ambient temperature signal using a built-in algorithm. This includes: determining the base current threshold Ibase based on the speed command signal through a pre-stored speed-current mapping relationship; multiplying Ibase by a direction correction coefficient of 115%~125% when the running direction is upward, and multiplying it by a direction correction coefficient of 85%~95% when the running direction is downward; and calculating the maximum operating current threshold using the formula Itthreshold=Ibase×[1+α(T−25)], where α is a compensation coefficient.

[0047] The speed-current mapping relationship refers to the preset correspondence between elevator operating speed and the corresponding allowable current threshold. Specifically, it can be implemented using the linear function Ibase = Imin + β⋅Vspeed, where Imin is the low-speed baseline threshold, such as the minimum protection current when the elevator approaches zero speed, and β is the speed-current slope coefficient, such as the current threshold increase for every 1 m / s increase in speed. This mapping relationship is used to establish a dynamic correlation between speed changes and current carrying capacity. The direction correction coefficient is a parameter that proportionally adjusts the base current threshold according to the elevator's upward or downward movement. Specifically, it can be implemented using a coefficient range of 115%~125% for upward movement and 85%~95% for downward movement. This coefficient is used to compensate for the asymmetrical effect of gravity on the motor load. The temperature compensation coefficient α is a parameter used to correct the influence of ambient temperature on conductor resistance and heat dissipation conditions. Specifically, it can be implemented using a coefficient value of 0.1%~0.5% per degree Celsius. This coefficient incorporates the temperature variable into the threshold calculation using the formula Itthreshold = Ibase × [1 + α(T−25)].

[0048] Specifically, the base current threshold is determined through a pre-stored linear relationship between speed and current. For example, as the elevator speed increases, the allowable current threshold increases by a fixed slope. A direction correction coefficient is applied to the base threshold. For instance, when moving upwards, gravity increases the motor load, so the threshold is increased by 15% to 25% to avoid false tripping; when moving downwards, gravity helps reduce the load, so the threshold is decreased by 5% to 15% to prevent missed detections. In the temperature compensation formula, when the ambient temperature is above 25℃, the increased conductor resistance leads to a decrease in the allowable current, which is compensated for using an α coefficient; when the temperature is below 25℃, the allowable current is increased. The three-layer adjustment mechanism uses a built-in algorithm to fuse speed, direction, and temperature parameters in real time to generate a dynamically changing maximum operating current threshold.

[0049] Compared to existing technologies, traditional overload protection uses a fixed current threshold, which cannot distinguish the difference in motor load when the elevator is moving upwards and downwards. For example, when moving upwards under no-load conditions, the current may increase due to gravity, causing false triggering of the protection, or when moving downwards under full load, the overload may be missed due to an excessively high threshold. This solution eliminates the interference of the running direction on load judgment through a direction correction coefficient, offsets current fluctuations caused by environmental factors through a temperature compensation coefficient, and matches the load characteristics of different operating stages through a speed-current mapping relationship, forming a multi-dimensional dynamic adjustment mechanism.

[0050] Through the above technical solution, this application solves the problem of insufficient adaptability of fixed threshold under complex working conditions, avoids overload misjudgment or missed judgment due to different elevator running directions, eliminates the interference of temperature changes on current carrying capacity judgment, realizes the adaptive adjustment of overload protection threshold with speed, direction and environmental parameters, and improves the protection accuracy and reliability of elevator system under different operating conditions.

[0051] This application further proposes to determine the base current threshold Ibase based on the speed command signal through a pre-stored speed-current mapping relationship, including calculating the base current threshold using the linear function Ibase = Imin + β⋅Vspeed; where Imin is the low-speed reference threshold, i.e., the minimum protection current when the elevator approaches zero speed; β is the speed-current slope coefficient, i.e., the current threshold that increases for every 1m / s increase in speed; and Vspeed is the real-time speed of the elevator.

[0052] The low-speed reference threshold Imin refers to the minimum protective current value set when the elevator speed is below or equal to 0.3 m / s. This can be implemented using fixed parameters stored in the control module to prevent false triggering of protection actions due to minute current fluctuations when the elevator is at low speed or stationary. The speed-current slope coefficient β refers to the proportion of current threshold increase corresponding to a 1 m / s increase in elevator speed. This can be obtained by linearly fitting a speed-current relationship curve obtained from experimental testing to establish a positive correlation between speed and current threshold. The real-time elevator speed Vspeed refers to the elevator's operating speed signal acquired in real time through an encoder or speed sensor. This can be implemented using pulse counting or frequency conversion circuits and serves as the core input parameter for dynamically adjusting the protection threshold.

[0053] Specifically, during elevator operation, the control module continuously acquires real-time speed signals through speed sensors and inputs these signals into a preset linear function model. When the elevator is near zero speed, the system automatically calls the low-speed baseline threshold Imin as the basic protection value, avoiding false tripping caused by current fluctuations in the traditional fixed threshold at low speeds. As the elevator accelerates, the product of the speed-current slope coefficient β and the real-time speed Vspeed linearly compensates for the baseline threshold, causing the protection threshold to increase synchronously with the speed increase. For example, when the elevator is running at a speed of 2 m / s, the calculated baseline current threshold will have a current margin of 2β compared to the stationary state, thus matching the normal operating current range of the drive motor at that speed. This speed-based linear compensation mechanism allows the overload protection threshold to dynamically adapt to changes in load characteristics at different operating stages.

[0054] Compared to existing technologies, traditional elevator overload protection devices use a fixed current threshold, which cannot distinguish between normal load fluctuations and actual overload faults at different elevator speeds. This solution establishes a linear mapping relationship between speed and current threshold, solving the problem of frequent malfunctions caused by insufficient current margin at low speeds when using a fixed threshold. Simultaneously, it avoids protection delay risks at high speeds by increasing the threshold. Existing technologies lack a dynamic response mechanism for speed parameters, while this solution achieves adaptive adjustment of the protection threshold through a combination of real-time speed signals and linear functions.

[0055] Through the above technical solution, this application effectively solves the problem of false triggering caused by excessively low protection threshold settings during elevator low-speed operation. Simultaneously, by increasing the threshold during high-speed operation, it prevents normal load current from being mistakenly identified as an overload fault. Through dynamic matching of speed parameters and current thresholds, it ensures protection sensitivity at low speeds while avoiding protection delays during high-speed operation, achieving accurate overload protection across the entire speed range.

[0056] This application further proposes an elevator serial control system, such as Figure 2 This is the wiring diagram for the serial control system in this embodiment. The system includes a control cabinet, a hoistway module, and a car module. The control cabinet has a built-in main control board, which is connected to the hoistway module via a first RS485 bus and to the car module via a second RS485 bus. The hoistway module consists of one cascaded HIH module and two to n cascaded HTH modules. Each HTH module communicates with adjacent modules via an RS485 bus, with a maximum number of floors n ≤ 30. The car module includes a Blu-ray parallel integrated machine, at least one internal selection module, and at least one display module. The internal selection module and the display module are connected in parallel to the car's RS485 network via an RS485 bus.

[0057] The control cabinet is the core equipment for centralized management of elevator communication. It has a built-in main control board and connects different modules via an independent bus, specifically using a dual RS485 bus architecture to isolate the communication path between the hoistway and the car, avoiding signal interference. The hoistway module is a hierarchical structure formed by cascading the first-floor HIH module and subsequent HTH modules. It can be implemented layer by layer via RS485 bus, supporting hot-swappable expansion up to 30 floors, allowing for flexible addition or removal of modules according to actual floor requirements. The car module is a functional unit containing a parallel blue light unit, an internal selection module, and a display module. It uses a parallel RS485 bus connection to the network, allowing each module to be configured independently without affecting the wiring structure. The parallel blue light unit integrates multiple signal processing functions, such as using a multi-channel communication chip to achieve data interaction between the inside and outside of the car. The internal selection module is an input unit for receiving user commands, such as using a touch panel or button array for floor selection. The display module is an output unit for providing feedback on elevator status, such as using an LED display or LCD panel for real-time information display.

[0058] Specifically, the control cabinet connects to the hoistway module via a first RS485 bus and to the car module via a second RS485 bus, forming a split-bus architecture. The first floor of the hoistway module uses a HIH module as the communication starting point, with subsequent floors cascading through HTH modules. Each HTH module establishes a point-to-point connection with adjacent modules via an RS485 bus, enabling layer-by-layer signal transmission within the hoistway. In the car module, the Blu-ray parallel integrated unit serves as the core processing unit, interacting with the internal selection module and display module via a parallel RS485 bus. After the user inputs commands through the internal selection module, the commands are transmitted via the bus to the Blu-ray parallel integrated unit for processing. Simultaneously, the display module receives status information in real time and updates the interface. When elevator floors need to be expanded, the hoistway module can add HTH modules and hot-swap them to the bus, while the car module can expand its functionality by connecting new internal selection or display modules in parallel, without rewiring or adjusting the existing communication structure.

[0059] Compared to existing technologies, traditional elevator control systems typically use a single bus to connect all modules, leading to signal path crosstalk and requiring overall wiring adjustments during expansion. This solution, however, isolates communication between the hoistway and car via a split bus, achieves linear expansion of hoistway modules through a cascaded structure, and simplifies the addition and removal of car modules through a parallel design. This significantly improves system scalability and module collaboration capabilities while ensuring communication efficiency.

[0060] Through the above technical solutions, this application achieves the optimization of the communication structure of the elevator control system, reduces the wiring complexity of multi-module collaboration, supports hot-swappable expansion at the shaft level and flexible configuration of car functions, ensures the real-time performance of command transmission and status feedback, and avoids communication errors caused by signal interference.

[0061] This application further proposes that the car RS485 bus is connected to the control cabinet via the J2 interface; the J2 interface defines signals including TRA2 - differential A line, TRB2 - differential B line, GD2 - ground line, and spare signal IRA2 / IRB2.

[0062] Among them, TRA2 - Differential A line refers to the positive signal line used to transmit RS485 bus differential signals, which can be implemented using twisted-pair shielded cable, suppressing common-mode interference through differential transmission. TRB2 - Differential B line refers to the negative signal line used to transmit RS485 bus differential signals, which can be implemented using twisted-pair cables of the same specification as TRA2 line, forming a symmetrical transmission path to enhance electromagnetic interference resistance. GD2 - Ground line refers to the grounding wire that provides a reference potential for differential signals, which can be implemented using independent grounding copper foil, used to eliminate the potential difference between the signal line and the device. IRA2 / IRB2 spare signal line refers to a reserved communication interface with undefined functions, which can be implemented using cables of the same physical specification as TRA2 / TRB2, providing a physical connection basis for future functional expansion.

[0063] Specifically, an RS485 bus communication link is established between the car module and the control cabinet via the J2 interface. The TRA2 and TRB2 differential signal lines form a balanced transmission line, where common-mode noise generated during signal transmission is automatically canceled by the differential receiver, effectively reducing the impact of electromagnetic interference on communication quality. The GD2 ground wire is directly connected to the equipment's metal casing, forming a unified reference potential plane and avoiding signal distortion caused by ground potential differences. IRA2 and IRB2 are reserved interfaces that can be used as auxiliary communication lines when the existing communication channels are fully loaded, or for connecting new functional modules during system upgrades. The standardized design of the interface definitions enables physical layer compatibility between devices from different manufacturers, while also supporting signal integrity maintenance during hot-swapping operations.

[0064] Compared to existing technologies, traditional elevator communication interfaces mostly use single-ended signal transmission and lack a unified grounding standard, making them susceptible to electromagnetic interference and data errors. Some systems, while employing differential transmission, lack reserved expansion interfaces, requiring rewiring when additional functional modules are needed. This solution, by clearly defining differential signal lines, independent grounding lines, and spare interfaces, ensures both the anti-interference performance of the current communication link and provides plug-and-play capability for system expansion.

[0065] Through the above technical solution, this application achieves physical layer standardization of the elevator control system communication link, ensuring the stability of data transmission between the car module and the control cabinet. The differential signal transmission mechanism effectively suppresses the interference of the strong electromagnetic environment in the elevator shaft on communication quality, and the reserved spare interface allows for system expansion without modifying the existing wiring structure, reducing the risk of communication failures due to interface incompatibility.

[0066] This application further proposes that each HTH module transmits RS485 signals through CNIO / CNO / CNS / CNC / NG interfaces, supporting hot-swappable expansion to 30 layers.

[0067] The CNIO interface is the communication network input interface, which can be implemented using the receiver pins of a DB9 connector. It receives RS485 signals from the upper-level module, and its built-in impedance matching circuit suppresses signal reflection. The CNO interface is the communication network output interface, which can be implemented using the transmitter pins of a DB9 connector. It forwards RS485 signals to the lower-level module, and its driver circuit enhances signal transmission distance. The CNS and CNC interfaces form a differential signal transmission channel, which can be implemented using a twisted-pair connection. A balanced transmission mechanism reduces common-mode interference. The NG interface is the network grounding terminal, which can be implemented using an independent grounding copper busbar to establish a unified signal reference ground potential. Hot-swappable expansion capability is achieved through short-circuit protection design of the physical interface and handshake response mechanism of the communication protocol, automatically reconfiguring the bus topology when a module is inserted or removed. The 30-layer expansion limit is achieved through bus termination resistor configuration and signal relay optimization, ensuring signal transmission integrity conforms to the RS485 protocol standard.

[0068] Specifically, after receiving signals from the upper-level module, the CNIO interface processes them through a differential amplifier circuit and forwards them to the CNO interface, forming a cascaded transmission path. The CNS and CNC interfaces connect adjacent modules via twisted-pair cables, and their differential transmission characteristics effectively suppress electromagnetic interference within the elevator shaft. The NG interface connects to the metal casing of each module, forming a continuous grounding loop to eliminate potential differences. When a new module is added, the hot-plug detection circuit identifies the physical connection status and triggers the address allocation process. The system automatically updates the bus node information without interrupting communication. When the number of expansion layers reaches 30, the terminating resistor of the end module is automatically activated to match the bus impedance and prevent waveform distortion caused by signal reflection.

[0069] Compared to existing technologies, traditional elevator control systems use a single RS485 interface serial module, which suffers from signal attenuation leading to communication failures at higher floors, and expansion requires system shutdown and bus reconfiguration. This solution uses discrete interfaces to achieve physical isolation between signal reception, transmission, differential transmission, and grounding, ensuring the signal maintains a complete waveform within a 30-story expansion range. The hot-swappable function, through a dynamic bus reconfiguration mechanism, avoids the power-off requirement of traditional expansion methods.

[0070] Through the above technical solutions, this application solves the problem of insufficient signal transmission stability in elevator serial control systems, suppresses signal attenuation and interference through discrete interface design, breaks through the traditional system expansion layer limit, and achieves flexible expansion to 30 layers while ensuring communication speed, and supports online hot-swappable operation, which significantly improves system maintenance efficiency and operational continuity.

[0071] This application further proposes that each HTH module transmits RS485 signals through CNIO / CNO / CNS / CNC / NG interfaces, supporting hot-swappable expansion to 30 layers.

[0072] The CNIO interface is a control signal input / output interface, which can be implemented using an RJ45 connector and is used to transmit elevator operation status commands and control feedback signals. The CNO interface is the main communication channel interface, which can be implemented using shielded twisted-pair cable and RS485 differential signal lines, handling high-speed data transmission between floors. The CNS interface is the status monitoring interface, which can be implemented using optocoupler-isolated I / O ports, used for real-time acquisition of module operating voltage and ambient temperature parameters. The CNC interface is the cascaded control interface, which can be implemented using a daisy-chain topology, achieving automatic module identification and data relay through an address encoding protocol. The NG interface is the grounding shield interface, which can be implemented using a metal casing and an independent grounding terminal, used to eliminate the impact of electromagnetic interference on signal integrity. The hot-swappable expansion mechanism refers to the module's hot-swappable capability, which can be implemented using redundant power supply design and communication protocol verification mechanisms to ensure continuous system operation when a new module is added.

[0073] Specifically, during the deployment of elevator shaft modules, the CNIO interface connects to the main control board of the control cabinet to receive operating commands, the CNO interface establishes a data link with adjacent floor modules, the CNS interface collects door lock and leveling signals on the current floor through sensors, the CNC interface forwards communication data packets to lower-level modules, and the NG interface eliminates common-mode interference through an independent grounding wire. When adding a floor, the new HTH module is directly inserted into the existing link through the standard interface group. The system automatically identifies the new address and updates the routing table, without needing to cut off power or restart the control cabinet. The physical isolation design of each interface ensures that control signals, communication data, and status monitoring information are transmitted independently, avoiding the problem of increased bit error rate caused by signal coupling. The effective communication distance is extended to 30 floors through the combination of differential signal lines and shielding layers.

[0074] Compared to existing technologies, traditional shaft modules use a single RS485 interface to transmit control commands and status data, which carries the risk of communication failure due to signal conflicts. Furthermore, expansion operations require power-off replacement of bus node devices. This solution employs a multi-interface, separate design, physically isolating the control command transmission path from the status monitoring channel. Communication data is transmitted via dedicated differential lines, effectively reducing the probability of signal crosstalk. A hot-swappable mechanism combined with an automatic address allocation protocol reduces system expansion operation time to 20% of the traditional method, and increases the maximum supported layer station count from 16 nodes on a conventional RS485 bus to 30 nodes.

[0075] Through the above technical solutions, this application achieves online expansion and stable communication of elevator shaft modules, solves the signal distortion problem caused by the mixed functions of interfaces in traditional systems, and overcomes the technical bottleneck that limits the number of bus nodes due to signal attenuation. The standardized interface group design enables direct compatibility between module devices from different manufacturers, the hot-swappable function avoids operational interruptions caused by system downtime for maintenance, and the grounding shield and physical isolation structure ensure communication reliability in high-rise station scenarios.

[0076] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A serial communication system for an explosion-proof elevator frequency converter, used in an elevator serial control system, characterized in that, The device includes a power supply module, a detection module, a control module, an execution module, and an early warning module; wherein: The power supply module is electrically connected to the detection module, control module, execution module and early warning module respectively, and provides working power to each module; The detection module, connected in series in the main circuit, is used to detect the current value of the main circuit and transmit the detected current signal to the control module; The control module is electrically connected to the detection module, execution module and early warning module respectively. It is used to preset an overload current threshold in the control module. When the current value detected by the detection module exceeds the overload current threshold, the control module sends a control signal to the execution module and the early warning module. The execution module, connected in series in the main circuit, is used to receive control signals from the control module and then disconnect the main circuit. The early warning module is used to receive control signals from the control module and then issue an early warning signal; the early warning signal is a combination of sound and light warning signals containing overload level information.

2. The serial communication system for an explosion-proof elevator frequency converter according to claim 1, characterized in that, The control module is also used for: The overload current threshold is dynamically adjusted based on the elevator's operating status and ambient temperature. The system receives and processes the current signal sampled by the detection module; when the current value detected in multiple consecutive sampling periods exceeds the dynamically adjusted overload current threshold and continues to exceed the preset first time threshold, it is determined to be a valid overload fault. When a valid overload fault is determined, a cut-off command is sent to the execution module and a warning command is sent to the warning module.

3. The serial communication system for an explosion-proof elevator frequency converter according to claim 2, characterized in that, The control module is also used to continuously monitor the signal of the detection module after the main circuit is cut off; when the current value is detected to be continuously lower than the preset safety recovery threshold and exceeds the preset second time threshold, and an external reset signal is received or the fault is confirmed to be eliminated, the control module sends a closing command to the execution module and simultaneously sends a warning cancellation command to the warning module.

4. The serial communication system for an explosion-proof elevator frequency converter according to claim 3, characterized in that, The elevator operating status includes the elevator's direction of travel and speed; The method of dynamically adjusting the overload current threshold based on the elevator's operating status and ambient temperature includes: Based on the elevator's direction of travel, speed signal, and ambient temperature signal, the maximum allowable operating current threshold is calculated and updated in real time using a built-in algorithm.

5. The serial communication system for an explosion-proof elevator frequency converter according to claim 4, characterized in that, The process of calculating and updating the maximum allowable operating current threshold in real time based on elevator running direction, speed signals, and ambient temperature signals using a built-in algorithm includes: The base current threshold I is determined based on the speed command signal and the pre-stored speed-current mapping relationship. base； When the direction of movement is upward, I will... base Multiply by a directional correction factor of 115% to 125%, and when the direction of operation is downward, multiply by a directional correction factor of 85% to 95%. According to formula I threshold =I base The maximum operating current threshold is calculated as ×[1+α(T−25)], where α is the compensation coefficient.

6. The serial communication system for an explosion-proof elevator frequency converter according to claim 5, characterized in that, The base current threshold Ibase is determined based on the speed command signal using a pre-stored speed-current mapping relationship, including: through a linear function I... base = I min +β⋅V speed Calculate the base current threshold; wherein, the I min The signal is the low-speed reference threshold, which is the minimum protection current when the elevator approaches zero speed (≤0.3m / s); β is the speed-current slope coefficient, which is the current threshold increase for every 1m / s of lifting speed; V speed This represents the elevator's real-time speed.

7. The serial communication system for an explosion-proof elevator frequency converter according to claim 1, characterized in that, The elevator serial control system includes: The control cabinet has a built-in main control board, which is connected to the hoistway module via a first RS485 bus and to the car module via a second RS485 bus. The shaft module consists of a cascaded 1-layer HIH module and 2 to n-layer HTH modules. Each layer of HTH module communicates with adjacent modules via an RS485 bus. The maximum number of layers n≤30. The car module includes a Blu-ray parallel integrated machine, at least one internal selection module and at least one display module. The internal selection module and the display module are connected in parallel to the car RS485 network via an RS485 bus.

8. The serial communication system for an explosion-proof elevator frequency converter according to claim 7, characterized in that, The car's RS485 bus is connected to the control cabinet via the J2 interface; the J2 interface defines signals including: TRA2 - differential A line, TRB2 - differential B line, GD2 - ground line, and the spare signal IRA2 / IRB2. A serial communication system for an explosion-proof elevator frequency converter according to claim 8, characterized in that, Each HTH module transmits RS485 signals through the CNIO / CNO / CNS / CNC / NG interface, supporting hot-swappable expansion to 30 layers.

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