Control circuit system for medium voltage switchgear

Abstract

The application relates to the technical field of medium-voltage switch cabinets, and discloses a control loop system for a medium-voltage switch cabinet, which replaces a traditional simple control loop with a control platform integrating a PLC controller, a microcomputer protection device and an edge computing module; meanwhile, a combination of an electronic spring simulation mechanism and a closing / opening coil with simplified structure is used to replace complex mechanical energy storage and tripping components. Before operation, the control platform performs rigorous condition self-checking through a state sensor, and only after safety is confirmed, accurate electromagnetic drive signals are output, so that a fundamental change from open loop and passive execution to closed loop and active management is realized, and the reliability, safety and intelligent level of the system are comprehensively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medium voltage switchgear, and more particularly, to a control circuit system for medium voltage switchgear. BACKGROUND

[0002] As a crucial component in power systems, medium voltage switchgear bears the core responsibility of controlling and protecting the safe and stable operation of power grids. Its core functions, i.e., the closing (closing) and opening (opening) of the circuit, rely on the accurate and reliable execution of its internal operating mechanism and control circuit. When the power grid fails or needs to be operated normally, whether the control circuit can respond quickly and drive the operating mechanism to complete the predetermined action is directly related to the continuity of power supply, the safety of equipment assets, and even the personal safety of maintenance personnel. Therefore, developing a more efficient, reliable, and intelligent control circuit system for medium voltage switchgear is of great significance to improving the performance and safety level of the entire power distribution network.

[0003] However, most existing medium voltage switchgears use traditional mechanical spring energy storage operating mechanisms and their supporting control circuits. This type of solution usually pre-stores mechanical energy in a mechanical spring through a motor, and after receiving an operation instruction, the control circuit outputs a simple on / off type electrical signal to the trip coil to release the mechanical energy stored in the spring to drive the main contact of the circuit breaker to complete the opening and closing operation. Although this method has been widely used in the past, its inherent defects have become increasingly apparent: First, the mechanical structure of the system is complex, containing a large number of connecting rods, shaft pins, buckles, and other components, which are prone to performance degradation or even mechanical failures such as malfunction and misoperation due to wear, rust, or poor lubrication after long-term operation, making it difficult to ensure reliability. Second, its operation process is an open-loop control, and once the spring energy storage, transmission mechanism, etc. changes (such as spring fatigue, environmental temperature influence, power voltage fluctuation, etc.), the key characteristic parameters such as the opening and closing speed and operation time will deviate from the optimal value, affecting the closing and opening performance, and possibly accelerating the electrical wear of the main contact, shortening the overall life of the switchgear. In addition, this traditional control circuit lacks intelligent monitoring and diagnostic capabilities, and cannot fine-tune the operation process or self-correct, making it difficult to meet the higher requirements of modern power grids for device state perception, fault prediction, and intelligent operation and maintenance. SUMMARY

[0004] To solve the above technical problems, the present application is proposed. The embodiments of the present application propose a control circuit system for medium voltage switchgear to overcome the defects of low reliability, poor operation consistency, and lack of intelligent management means of traditional medium voltage switchgear control circuits in the prior art due to reliance on complex mechanical spring mechanisms.

[0005] According to an aspect of the present application, a control loop system for a medium voltage switch cabinet is provided, comprising: a power supply system, a control platform and an actuator; the power supply system comprises a multi-source input module, an energy storage unit and a low-power management module; the control platform comprises a PLC controller, a microcomputer protection device and an edge computing module; the actuator comprises a closing / opening coil, an energy storage motor, an electronic spring simulation mechanism and a state sensor; wherein, after receiving a closing instruction, the control platform queries the state sensor of the actuator to determine whether the circuit breaker is in an open position and whether the state of the energy storage motor is energy stored; when it is determined that the circuit breaker is in the open position and the state of the energy storage motor is energy stored, the control platform outputs a control signal to the closing / opening coil, which is used to drive the electronic spring simulation mechanism by electromagnetic force so that the main contact of the circuit breaker is closed.

[0006] In a possible implementation, the control platform comprises: a signal acquisition module configured to acquire a coil current flow and an auxiliary contact state flow; an operation time sequence analysis module configured to perform operation time stamp analysis and actual time calculation on the coil current flow and the auxiliary contact state flow to obtain an actual operation time; a PWM parameter self-correction module configured to perform PWM driving parameter correction based on a comparison between the actual operation time and a target operation time to obtain a PWM configuration file for next operation; and a PWM signal generation module configured to generate a digital PWM signal as the control signal based on the PWM configuration file for next operation in response to receiving a new closing instruction.

[0007] In a possible implementation, the operation time sequence analysis module comprises: a current starting time detection unit configured to perform current starting point analysis on the coil current flow based on a preset threshold to obtain a current starting time; a contact action time detection unit configured to perform contact action point analysis on the auxiliary contact state flow to obtain a contact closing time; and an actual operation time calculation unit configured to calculate a difference between the contact closing time and the current starting time to obtain the actual operation time.

[0008] In a possible implementation, the current starting time detection unit is configured to: find a data point at which a current value exceeds a preset threshold for the first time from the coil current flow; and record a time offset of the data point relative to a starting time stamp to obtain the current starting time.

[0009] In a possible implementation, the contact action time detection unit is configured to: find a data point at which a state changes from 0 to 1 for the first time from the auxiliary contact state flow; and record a time offset of the data point relative to a starting time stamp to obtain the contact closing time.

[0010] In a possible implementation, the PWM parameter self-correction module comprises: a time deviation calculation unit configured to calculate a difference between the actual operation time and the target operation time as a time deviation; a PI adjustment amount generation unit configured to input the time deviation into a PI controller to obtain a proportional correction amount and an integral correction amount; and a PWM parameter correction unit configured to correct PWM parameters of a current PWM configuration file based on the proportional correction amount and the integral correction amount to obtain the PWM configuration file for the next operation.

[0011] In a possible implementation, the PWM parameter correction unit is configured to: calculate a sum of the proportional correction amount and the integral correction amount as a total correction amount; extract a current duty cycle from the current PWM configuration file; and add the total correction amount to the current duty cycle to obtain a new duty cycle in the PWM configuration file for the next operation.

[0012] Compared with the prior art, the control loop system for the medium-voltage switch cabinet provided in the application first replaces the traditional mechanical spring mechanism with an electronic spring simulation mechanism and electromagnetic driving, greatly simplifies the mechanical structure, fundamentally eliminates the failure points caused by mechanical wear, fatigue, corrosion, and the like, significantly improves the reliability of operation and the long-term stability of the mechanism, and reduces the maintenance cost. Second, the control platform integrated with the edge computing module is introduced, so that the driving of the closing / coiling coil is no longer the on-off control in a rough way, but the electromagnetic force control in a fine way, which makes it possible to realize accurate adjustment of the operation speed and suppress the current impact and mechanical vibration in the operation process, thereby effectively protecting the main contact of the circuit breaker and prolonging the electrical and mechanical life of the switch cabinet. Third, the state self-checking logic before operation ensures that each operation is performed within the preset safety boundary, avoids misoperation or equipment damage caused by abnormal state (such as no energy storage or position error), and greatly enhances the operation safety of the system. BRIEF DESCRIPTION OF DRAWINGS

[0013] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description of embodiments of the present application taken in conjunction with the accompanying drawings. The accompanying drawings are intended to provide a further understanding of embodiments of the present application and are incorporated in and constitute a part of this specification, illustrate embodiments of the present application and serve to explain the present application, but do not limit the present application. In the drawings, the same reference numerals generally refer to the same components or steps throughout the drawings.

[0014] Figure 1 FIG. 1 illustrates a schematic block diagram of a control loop system for a medium-voltage switch cabinet according to an embodiment of the present application.

[0015] Figure 2 FIG. 1 illustrates a schematic block diagram of a control loop system for a medium-voltage switch cabinet according to an embodiment of the present application.

[0016] Figure 3 The figure shows a schematic block diagram of an operation timing analysis module in a control circuit system for a medium-voltage switchgear according to an embodiment of this application.

[0017] Figure 4 The figure shows a schematic block diagram of a PWM parameter self-calibration module in a control loop system for a medium-voltage switchgear according to an embodiment of this application. Detailed Implementation

[0018] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0019] Figure 1 The illustration shows a schematic block diagram of a control circuit system for a medium-voltage switchgear according to an embodiment of this application. Figure 1 As shown, this application provides a control loop system 1 for a medium-voltage switchgear, including: a power supply system 10, a control platform 20, and an actuator 30; the power supply system 10 includes a multi-source input module 11, an energy storage unit 12, and a low-power management module 13; the control platform 20 includes a PLC controller 21, a microcomputer protection device 22, and an edge computing module 23; the actuator 30 includes a closing / opening coil 31, an energy storage motor 32, an electronic spring simulation mechanism 33, and a status sensor 34.

[0020] Specifically, the power supply system is the energy foundation of the entire control loop system. Its core design objective is to provide continuous, stable electrical energy with high instantaneous power output capability to meet the stringent requirements of the switchgear under various power grid conditions. The power supply system internally includes a multi-source input module, an energy storage unit, and a low-power management module. The multi-source input module, as the system's energy entry point, is designed with full consideration of power supply redundancy and reliability. It can connect to and manage electrical energy from different sources. For example, one source can connect to the AC operating power supply from the substation where the switchgear is located, which is converted into stable DC power through internal rectification and filtering circuits; another source can connect to the station's DC power supply system or a backup battery bank. This module incorporates intelligent power selection and switching logic, which can monitor the voltage stability and availability of each input source in real time, prioritizing the use of the highest quality power supply. When the main power supply fails or deteriorates, seamless switching can be achieved within milliseconds, ensuring uninterrupted power supply to downstream circuits. This design significantly improves the system's survivability under power grid fluctuations or power outages.

[0021] The output end of the multi-source input module is connected with the energy storage unit. The energy storage unit is the key of the power supply system which is different from the traditional switch cabinet power supply. Its main function is to serve as a temporary large power energy buffer pool. Considering that the closing / opening coil needs to consume huge peak power in a very short time (usually tens of milliseconds) when driving the actuator, which is far beyond the instantaneous supply capacity of the conventional power supply, the energy storage unit is set. The energy storage unit preferably adopts an electronic energy storage scheme composed of a super capacitor array or a high-rate discharge lithium battery pack. Compared with the traditional scheme, electronic energy storage has the advantages of fast charging speed, long cycle life, high power density, and wide working temperature range. In the standby state of the system, the multi-source input module will trickle charge or constant voltage charge the energy storage unit with a relatively stable power until it reaches the preset energy reserve level. When the control platform issues an operation instruction to drive the coil, the energy storage unit can release the huge energy stored in it instantly to provide a stable and strong current pulse for the coil, ensuring the success rate and consistency of the operation. The output of the energy storage unit is directly connected with the closing / opening coil in the actuator and the energy storage motor through power switching devices.

[0022] The low-power management module monitors the working state of the entire control loop system in real time through close communication with the control platform. When the system is in a static standby state (i.e., no operation instruction) for a long time, the low-power management module will actively execute a series of energy-saving strategies. For example, it can send instructions to the edge computing module in the control platform to enter a low-power sleep or hibernate mode, leaving only the core interrupt wake-up function; it can also appropriately reduce the scanning frequency of the PLC controller or turn off the power supply of some non-critical peripherals. Through these fine power management, the static power consumption of the system in standby state can be significantly reduced, which is of great significance to prolong the endurance time of the energy storage unit in backup power supply mode and reduce the operating energy consumption of the entire switch cabinet. When there is an operation instruction or external event to be processed, the module can quickly wake up the relevant units to restore their full-function running state.

[0023] The control platform is responsible for receiving instructions, analyzing states, executing complex algorithms, making decisions, and generating accurate control signals. The platform innovatively integrates PLC controllers, microcomputer protection devices, and edge computing modules, realizing the deep integration of traditional industrial control logic, power system protection logic, and modern information processing technology.

[0024] The PLC controller, i.e., programmable logic controller, undertakes the basic and high-reliability sequential logic control and input / output processing tasks in the platform. It guarantees the stability and timeliness of the control logic execution through its industrial-grade hardware design and deterministic real-time operating system. The input end of the PLC controller is connected with the upper computer monitoring system (such as SCADA), local operation buttons, and microcomputer protection devices, etc., for receiving external operation instructions such as closing and opening, and key interlocking signals. The output end is connected with the edge computing module and part of auxiliary devices (such as status indicator lights) in the actuator. In the whole control process, the PLC is responsible for executing the most core and error-tolerant logic judgment, for example, after receiving the closing instruction, it will first start the whole judgment and execution sequence to ensure the orderly progress of the whole operation process.

[0025] The microcomputer protection device is the key equipment to ensure the safety of the switch cabinet and the connected line, and it plays the role of safety supervisor and final vetoer in the platform. The device monitors the electrical parameters of the main circuit in real time through high-precision current and voltage transformers, and independently runs a series of complex protection algorithms such as over-current protection, instantaneous trip protection, and grounding protection. It has a high-speed and high-priority communication link with the PLC controller and the edge computing module, usually connected by hardwiring or dedicated industrial field bus. In normal operation, the microcomputer protection device sends its normal state signal to the PLC as one of the prerequisites for allowing operation. Once any power failure is detected, it will take immediate action, on the one hand, it will directly drive the opening coil through its independent outlet contact to trip, achieving rapid removal of the fault; on the other hand, it will immediately send a blocking signal to the PLC controller and the edge computing module to forcibly prohibit any closing operation that may exacerbate the fault. This design ensures the absolute priority of power system protection and is the fundamental guarantee of the safety of the whole control loop system.

[0026] The edge computing module is the core carrier for implementing advanced functions and intelligence in the control platform. It is a powerful embedded computing unit, usually equipped with a high-performance processor (such as ARM or FPGA), a large-capacity memory, and a rich set of high-speed communication interfaces. The module is tightly connected with all other major components in the system. It is directly connected to the state sensors in the actuator through a high-speed data acquisition interface, and can acquire high-frequency dynamic data such as coil current, contact displacement, vibration at a sampling rate of kilohertz or even higher. It exchanges data with the PLC controller, obtains operation instructions and feeds back detailed execution status and analysis results. It also communicates with the microcomputer protection device to obtain detailed fault recording data for fault analysis. The core task of the edge computing module is to process these massive, multi-dimensional data. For example, after receiving the closing instruction from the PLC, it will accurately generate the complex waveform control signal required to drive the closing coil, such as the pulse width modulation (PWM) signal, instead of the traditional simple on-off signal. By precisely controlling the duty cycle, frequency, and duration of the PWM signal, the energy applied to the coil can be flexibly adjusted, thereby achieving fine control of operation speed, impact, and noise.

[0027] The actuator is the final destination of the control instructions, responsible for converting electrical energy into powerful mechanical force to drive the main contacts of the circuit breaker to complete the opening and closing actions. The actuator of the present application completely abandons the traditional mechanical spring energy storage device and adopts a more direct and reliable electromagnetic drive scheme. It includes closing / opening coils, energy storage motors, electronic spring simulation mechanisms, and state sensors.

[0028] The closing / opening coil is the core of energy conversion, usually two independent and high-performance electromagnetic coils. They receive large current pulses from the control platform control and the energy storage unit of the power supply system. When the closing coil is excited, it generates a transient and powerful electromagnetic field, which directly acts on the movable parts (such as armature or moving core) of the electronic spring simulation mechanism, driving it to move at high speed. The function of the opening coil is similar, used to perform the opposite action. The electrical input terminals of the two coils are tightly connected to the power output stage of the power supply system, and their control signals come from the precise drive signals generated by the edge computing module in the control platform.

[0029] The electronic spring simulation mechanism is a major innovation in mechanical structure of the application. It is not a real spring, but an optimized and simplified mechanical transmission and locking system. It efficiently transmits the linear or rotary motion generated by the closing / opening coil to the main contact link of the circuit breaker, and reliably locks the main contact in the closed or open position after the operation is completed. Compared with the traditional complex spring energy storage operation mechanism, the electronic spring simulation mechanism eliminates a large number of mechanical parts such as energy storage spring, hook, release half shaft, which are prone to wear and failure, and has a more compact structure and shorter transmission chain, thereby greatly improving the mechanical reliability and response speed of the action.

[0030] The role of the energy storage motor in this system has also undergone a fundamental change. It is no longer used to slowly store energy for a huge mechanical spring, but mainly used to drive some components of the electronic spring simulation mechanism to reset after a operation (such as closing) is completed, so that it can respond to the next opposite operation (such as opening). For example, it can be used to restore a magnetic or mechanical lock to a trigger-ready state. It should be particularly noted that in the context of the application, when the energy storage motor completes the above-mentioned reset operation, the entire execution mechanism returns to a ready-to-respond state at any time to the next operation instruction. This ready-to-respond state is functionally equivalent to the state in which the mechanical energy has been stored in the traditional spring mechanism, as it indicates that the system has all the prerequisites and potential capabilities to perform the next action. Therefore, in order to maintain continuity with the terminology of the prior art and clearly define this key state, the application defines the state in which the energy storage motor completes the reset and the execution mechanism is on standby as the energy storage state. Accordingly, the energy storage state detected by the state sensor means that it has detected that the reset operation has been completed. Because its load is much smaller than that of the traditional energy storage motor, its volume, power consumption and reset time can be significantly reduced. The start and stop of the energy storage motor are precisely controlled by the control platform according to the feedback signal of the state sensor.

[0031] The state sensor is used to realize closed-loop control and intelligent sensing of the system. It is not a single sensor, but a sensor group, which may include a Hall sensor or microswitch for detecting the final position (closed or open) of the main contact of the circuit breaker; an optical encoder or linear displacement sensor for accurately measuring the dynamic displacement of the electronic spring simulation mechanism; and a current sensor for monitoring the coil drive current, etc. The signal output ends of these sensors are directly connected to the control platform. Among them, the low-frequency on-off signal reflecting the final position is mainly provided to the PLC controller for basic logic judgment and state display. While the high-frequency, high-precision analog or digital signals reflecting the dynamic process are sent to the edge computing module as the data basis for its fine control, state evaluation and fault diagnosis.

[0032] Specifically, the entire operation process of the control loop system for the medium-voltage switchgear is as follows: after receiving a closing instruction, the control platform queries the state sensor of the actuator to determine whether the circuit breaker is in an open position and whether the state of the energy storage motor is energy stored; when it is determined that the circuit breaker is in the open position and the state of the energy storage motor is energy stored, the control platform outputs a control signal to the closing / opening coil, which is used to drive the electronic spring simulation mechanism by electromagnetic force to make the circuit breaker main contact closed.

[0033] In one embodiment, as shown in FIG. 1, the control platform 20 comprises: a signal acquisition module 210 for acquiring coil current flow and auxiliary contact state flow; an operation time sequence analysis module 220 for performing operation time stamp analysis and actual time calculation on the coil current flow and auxiliary contact state flow to obtain actual operation time; a PWM parameter self-correction module 230 for performing PWM driving parameter correction based on a comparison between the actual operation time and a target operation time to obtain a PWM configuration file for the next operation; and a PWM signal generation module 240 for generating a digital PWM signal as the control signal based on the PWM configuration file for the next operation in response to receiving a new closing instruction. Figure 2

[0034] For example, in the signal acquisition module 210, the coil current flow and the auxiliary contact state flow are acquired. It should be understood that in a traditional switchgear control loop, the control system completes its control task after outputting an operation instruction to the execution coil. The system lacks the ability to perceive whether the operation is successful, the dynamic characteristics of the action process (such as operation time, response smoothness, etc.), and is unable to optimize subsequent operations based on actual execution results. This open-loop control mode has inherent defects: it is difficult to cope with system characteristic drift caused by factors such as equipment aging, mechanical wear, environmental temperature changes, or power supply voltage fluctuations, resulting in a gradual decline in operation reliability and consistency over time.

[0035] ​To overcome this limitation, this application proposes to collect coil current flow and auxiliary contact state flow, aiming to provide a precise and quantitative dynamic profile of the complete physical process of each opening and closing operation, thereby achieving observability and analyzability of the operation process. Specifically, coil current flow refers to the continuous data sequence of the current flowing through the closing or opening coil over time, from the output of the control signal and the start of the drive coil excitation to the completion of the operation and the current decay to zero. This data flow has significant engineering implications: the starting moment of its current rise marks the starting point of electromagnetic driving force generation, providing the most direct and reliable electrical characteristic for determining the start of the operation and offering a precise starting reference for subsequent operation timing analysis. Auxiliary contact state flow refers to the discrete record of the state (usually 0 for open and 1 for closed) of auxiliary contacts mechanically linked to the main contacts of the circuit breaker, changing over time. Since the action of the auxiliary contacts is strictly synchronized with the final closing or opening of the main contacts, the moment when their state undergoes a stable transition can be considered the end point of the mechanical operation. Therefore, this data flow provides highly reliable mechanical position feedback for identifying the end time of the operation.

[0036] In one embodiment, the process of acquiring the aforementioned data stream is as follows: When the control platform decides to perform a closing operation, simultaneously with outputting a control signal to the closing coil, the edge computing module immediately initiates its built-in high-speed data acquisition program. This program synchronously samples the input channel connecting the current sensor and auxiliary contacts at a frequency (e.g., 10 kHz or higher) far exceeding the time resolution required for the dynamic operation process. Each sample is accompanied by a precise timestamp from the module's internal high-precision real-time clock (RTC). Thus, over time, two time-stamped discrete data sequences are formed: a series of timestamped current values ​​constitute the coil current flow; and a series of state values ​​(0 or 1) with corresponding timestamps constitute the auxiliary contact state flow.

[0037] For example, in the operation timing analysis module 220, the coil current flow and auxiliary contact state flow are analyzed using operation timestamps and calculated using actual time to obtain the actual operation time. It should be noted that the circuit breaker's opening and closing operation time is not a secondary parameter, but a key performance indicator directly affecting power system safety and equipment lifespan. When a short-circuit fault occurs in the power grid, the opening time determines the rate at which the fault current is cleared: an excessively long operation time will cause the equipment to withstand the fault current impact for a longer period, potentially leading to an expansion of the fault area or equipment damage. During closing operations, especially when closing a faulty line, an excessively long operation time will prolong the arcing process, exacerbate the electrical wear of the main contacts, and accelerate their aging.

[0038] However, in the traditional control loop, due to the lack of effective monitoring means for the execution process, the system can only issue execution instructions, but cannot know the actual response of the instruction execution, that is, whether the execution is fast or slow, whether it is completed within the ideal time window, and is in a blind control state. This open-loop control mode is difficult to cope with the operation time drift caused by factors such as mechanical wear, lubrication deterioration, environmental temperature change, power voltage fluctuation, etc. Under long-term operation, the performance of the switch cabinet gradually deviates from the design benchmark, and the reliability decreases accordingly.

[0039] To solve the above problems, the application realizes the observability of the whole operation process by analyzing the two time-stamped original data sequences of the coil current flow and the auxiliary contact state flow. The original data itself only records process information and has not formed a quantifiable evaluation conclusion. Only by accurately identifying the starting time and ending time of the operation in the data through time sequence analysis can the actual operation time be extracted.

[0040] Specifically, the time when the coil current first significantly rises marks the beginning of the electromagnetic driving energy, which is the most direct and explicit electrical characteristic of operation start, and is defined as the operation start timestamp. The time when the auxiliary contact state stably jumps reflects the completion of the main contact mechanical stroke, which is a reliable mechanical indication of operation end, and is defined as the operation end timestamp. By calculating the difference between the two timestamps, an actual operation time independent of the timing of the control instruction and truly reflecting the electromagnetic-mechanical conversion efficiency can be obtained. This value accurately represents the dynamic response capability of the actuator and provides key feedback basis for subsequent closed-loop control.

[0041] In one embodiment, as shown in Figure 3 The operation time sequence analysis module 220 includes a current start time detection unit 221 for analyzing the current start point of the coil current flow based on a preset threshold to obtain the current start time; a contact action time detection unit 222 for analyzing the contact action point of the auxiliary contact state flow to obtain the contact closing time; and an actual operation time calculation unit 223 for calculating the difference between the contact closing time and the current start time to obtain the actual operation time.

[0042] Specifically, the parsing algorithm running inside the edge computing module will first process the coil current flow data sequence. In one embodiment, the current start time detection unit is configured to find the data point where the current value first exceeds a preset threshold from the coil current flow, and record the time offset of the data point relative to the start timestamp to obtain the current start time. Specifically, the preset threshold is set according to the coil electrical characteristics and sensor accuracy, which is significantly higher than the background noise level (for example, 0.48 A, which is only an example, and can be adjusted according to actual conditions), to avoid misjudging weak leakage current or noise as a driving start signal. The algorithm starts scanning from the beginning of the sequence, and once the first out-of-limit point is found, the timestamp of the point is locked as the start time of the operation.

[0043] Next, the parsing algorithm of the edge computing module will process the auxiliary contact state flow data sequence. The values of this data sequence are usually binary (for example, 0 represents the open position and 1 represents the closed position). In one embodiment, the contact action time detection unit is configured to find the data point where the state first changes from 0 to 1 from the auxiliary contact state flow, and record the time offset of the data point relative to the start timestamp to obtain the contact closing time. It should be understood that, in order to avoid the interference of contact jitter caused by mechanical vibration, the algorithm only identifies the first stable jump to ensure that the initial time of the action completion is captured, rather than the subsequent bounce signal. Once the jump point is located, its timestamp is recorded as the end time of the operation.

[0044] After successfully obtaining the current start time and the contact closing time, the time difference between the two is calculated. The difference is the actual operation time of the operation, which can reach millisecond level or even higher. This result is used as a historical record of the operation performance for state evaluation and fault tracing, and more importantly, as a core feedback parameter, it is transmitted to the PWM parameter self-correction module in real time, compared with the target operation time, and a correction amount is generated to dynamically optimize the driving strategy of the next operation, thereby realizing performance closed-loop control.

[0045] After successfully obtaining the start timestamp and the end timestamp, the edge computing module calculates the difference between the contact closing time and the current start time. This difference, which is the actual operation time, is a value accurate to milliseconds or higher. It is stored, on the one hand, as a performance record of the operation, which can be used for historical tracing and state evaluation, and on the other hand, more importantly, it will be used as a core input parameter and immediately transmitted to the parameter self-correction function module in the control platform for comparison with the target operation time, and a correction amount is generated to adjust the control strategy of the next operation.

[0046] Exemplarily, in the PWM parameter self-correction module 230, based on the comparison between the actual operation time and the target operation time, the PWM driving parameter is corrected to obtain the PWM configuration file for the next operation. It should be noted that the performance of any physical system, especially an electromechanical system containing mechanical moving parts, will drift due to internal and external factors. In the life cycle of the medium-voltage switch cabinet, the mechanical characteristics of the actuator may gradually deteriorate due to factors such as component wear, aging or drying of lubricating grease, loosening of fasteners, etc., resulting in an increase in the mechanical resistance that needs to be overcome during operation. At the same time, changes in the external environment (such as temperature fluctuations) will cause thermal expansion and contraction of metal parts and changes in the viscosity of lubricants, further affecting the operation response. In addition, the power supply voltage may also fluctuate with the load of the power grid. The above factors will ultimately be reflected in the actual operation time.

[0047] Without a dynamic correction mechanism, even if the switch cabinet is debugged to the optimal state when it leaves the factory, the operation time may increase as the running time increases. Too long operation time not only reduces the protection response speed of fault removal, but also may cause the arc time during closing or breaking to be prolonged, aggravate the electrical wear of the main contact, and thus shorten the service life of the equipment.

[0048] Therefore, the present application introduces a target operation time as a design reference, which represents the optimal performance point of the switch cabinet of this model under ideal working conditions, and is a preset constant reference value; and the actual operation time reflects the current health status and dynamic performance of the system. The difference between the two constitutes an accurate and quantitative performance deviation signal, which directly represents the gap between the current system performance and the expected target.

[0049] Based on the deviation signal, the PWM driving parameters are corrected, which is the key path to realize performance recovery. If not corrected, the system will not be able to resist various disturbances, and the performance will continue to degrade. On the contrary, by establishing a closed-loop feedback mechanism, the system obtains adaptive ability: it can perceive the operation delay caused by aging, wear or temperature change, and automatically and incrementally adjust the driving energy output to compensate for performance degradation, and strive to make the actual time of the next operation approach the target value. This continuous self-correction mechanism ensures that the switch cabinet maintains dynamic performance close to the factory level throughout the service cycle, significantly improving its operation reliability, consistency and safety.

[0050] In one embodiment, as Figure 4As shown, the PWM parameter self-correction module 230 includes: a time deviation calculation unit 231 for calculating the difference between the actual operation time and the target operation time as the time deviation; a PI adjustment amount generation unit 232 for inputting the time deviation into a PI controller to obtain a proportional correction amount and an integral correction amount; and a PWM parameter correction unit 233 for correcting the current PWM configuration file based on the proportional correction amount and the integral correction amount to obtain the PWM configuration file for the next operation.

[0051] Specifically, the implementation process is as follows: the edge computing module first reads the preset target operation time from its internal non-volatile memory. This value is set by the device manufacturer according to the product design and type test results as the benchmark for performance optimization. Subsequently, the system calculates the difference between the actual operation time and the target operation time to obtain the time deviation. The deviation is a signed numerical value: if it is positive, it indicates that the operation is slow and the driving energy needs to be increased; if it is negative, it indicates that the operation is fast and there may be an overdrive risk (such as excessive mechanical impact), and the driving energy should be appropriately reduced; if it is close to zero or within the allowed error range, it indicates that the current parameters are well matched and do not need to be adjusted.

[0052] Only obtaining the deviation is not enough to complete effective control, and the correction amplitude also needs to be determined. For this purpose, the edge computing module runs a PI controller algorithm, taking the time deviation as input and outputting the corresponding proportional correction amount and integral correction amount. Among them: the proportional (P) element provides an immediate response proportional to the current deviation, the larger the deviation, the stronger the correction strength, and the faster the adjustment; the integral (I) element is used to eliminate static error, and through the cumulative effect of historical deviation, it gradually corrects the small deviation that exists continuously (such as long-term slight delay), and ensures that the system finally converges accurately to the target value. Subsequently, the PWM parameter correction unit adds the proportional correction amount and the integral correction amount to obtain the total correction amount. Then, the current duty cycle is extracted from the current PWM configuration file, and the total correction amount is added to generate a new duty cycle value. It should be understood that in an electromagnetic drive system, the duty cycle of the PWM signal is the most direct and effective parameter for regulating output energy: the higher the duty cycle, the longer the coil is powered on, the greater the average power, and the stronger the electromagnetic driving force. Therefore, by adjusting the duty cycle, fine control of the driving energy can be achieved.

[0053] When the proportional term and the integral term of the PI controller based on the time deviation correction and the current duty cycle based on the total correction amount correction are performed, the dimension does not match, therefore, the design of the PI controller needs to be decoupled from the physical characteristics of the controlled object, specifically, an explicit parameter with physical meaning is introduced to describe the dynamic characteristics of the controlled object, for example, the process gain. In this way, the PI controller is only responsible for calculating the standardized correction amount based on the time deviation, and then accurately converting the correction amount into the adjustment value of the PWM duty cycle through the process gain.

[0054] That is, in another embodiment, based on the comparison between the actual operation time and the target operation time, the PWM driving parameter correction is made to obtain the PWM profile for the next operation, further comprising: estimating a process gain online according to the actual operation time and the corresponding PWM duty ratio of at least two historical operations, the process gain being used to represent the response sensitivity of the actual operation time to the change of the PWM duty ratio; inputting the time deviation into a PI controller to generate a normalized correction instruction decoupled from the physical dimension; converting the normalized correction instruction into an adjustment amount for the PWM duty ratio by using the process gain; and correcting the current PWM duty ratio by the adjustment amount for the PWM duty ratio to generate the PWM profile for the next operation.

[0055] Specifically, first, the process gain is estimated according to the actual operation time and the corresponding PWM duty ratio of the last two operations. The process gain represents the sensitivity of the system to the control energy input at the current working point (current temperature, wear, voltage): where the partial derivative represents the local linear approximation of the operation time to the duty ratio near the duty ratio of the th operation. In the actual system, the difference is used for approximation, and the last two operation data are used for online estimation: ; and are the actual operation times measured in the th operation and the th operation, respectively, and and are the corresponding PWM duty ratios. At the same time, to avoid a zero denominator, when , maintains the last valid value . And at the first start of the system, can be assigned an initial value based on experience.

[0056] Thus, assuming that the time deviation of the th operation is , the comprehensive correction instruction output by the PI controller can be obtained, which is used to represent the expected operation time compensation: ; in this way, the proportional gain and the integral gain are both dimensionless pure control parameters, which are used to determine the speed and stability of the controller response.

[0057] Then, the normalized control command needs to be converted to the actual PWM duty cycle adjustment, and it has been set above that a 1% change in duty cycle results in a time change under the current operating condition, so to achieve time compensation, the duty cycle adjustment needs to be , and the duty cycle adjustment is: .

[0058] After the above improvement, the PWM duty cycle adjustment based on the PI controller will have high adaptability and robustness. For example, when the ambient temperature decreases and the mechanical resistance increases, the closing time will become longer. Then, the same change in duty cycle will result in a smaller time change , that is, the absolute value of the process gain becomes smaller. In this way, in the duty cycle adjustment step, since becomes smaller, even if remains unchanged, the calculated duty cycle adjustment will automatically increase. This means that the controller realizes that the system has become sluggish and needs to use more force (a larger duty cycle increment) to push it, thereby quickly and accurately pulling the operating time back to the target value. Moreover, this adaptive ability has strong robustness to changes in operating conditions such as temperature changes and mechanical wear.

[0059] In addition, because the gain of the controller is real-time matched to the current state of the system, it avoids the overshoot or response delay problems that may occur when the gain of a fixed gain controller changes, and achieves faster convergence speed and higher control accuracy.

[0060] Finally, the edge computing module creates or updates the PWM configuration file, writes the newly calculated duty cycle into it, and saves the file to the non-volatile memory. When the same operation command (such as closing) arrives next time, the control system will automatically call this updated configuration file to generate the PWM signal. By using the self-corrected and optimized duty cycle parameters, the system output driving energy is more in line with the current actual state of the device, so that the actual time of the next operation is closer to the target operation time, forming a complete closed-loop adaptive control.

[0061] Exemplarily, in the PWM signal generation module 240, in response to receiving a new closing command, a digital PWM signal is generated as the control signal based on the PWM configuration file of the next operation. It should be noted that the traditional control method usually outputs a simple constant DC on / off signal to the execution coil, which is essentially a fixed mode of driving. Regardless of changes in system state, its output energy remains constant, making it difficult to cope with performance drift caused by mechanical wear, aging or environmental changes.

[0062] In contrast, the present application uses digital PWM signals to achieve fine and quantifiable adjustment of driving energy. Pulse width modulation (PWM) technology controls the average power delivered to the load by adjusting the duty cycle of a high-frequency square wave signal. By adjusting the duty cycle, the control platform can accurately regulate the total amount of energy applied to the closing coil per unit time: the higher the duty cycle, the greater the average power, and the stronger the electromagnetic driving force generated. Therefore, the PWM signal can be regarded as a digital energy regulating valve.

[0063] More importantly, the PWM profile for the next operation adopted by the present application is not static and unchanging, but is the latest version dynamically corrected based on the actual effect of the last operation via a self-correcting algorithm, reflecting the system's understanding of the current state. When a new closing instruction arrives, using this updated profile to generate a PWM signal means that the system applies the experience of the last operation directly to the current control process. For example, if the last closing action was slow, the duty cycle for this time will be moderately increased to enhance the driving force; otherwise, it will be reduced. This mechanism makes the control behavior continuous and adaptive, forming a closed-loop feedback, effectively combating performance degradation, and ensuring that the operating characteristics are long-term stable in the target interval.

[0064] In one embodiment, when a new closing instruction is received, the control platform will generate a digital PWM signal based on the PWM profile for the next operation as the specific implementation process of the control signal as follows: After receiving the closing instruction and completing the necessary logical interlocking judgment (such as confirming that there is no protection interlocking signal), the PLC controller sends the execution instruction to the edge computing module. After receiving the trigger signal, the edge computing module immediately starts the relevant program.

[0065] First, the program reads the PWM profile for the next operation updated and saved by the previous self-correcting process from the internal non-volatile memory. This file contains the key parameters needed to generate the PWM signal this time, of which the most core is the corrected duty cycle value.

[0066] Subsequently, the processor (usually a microcontroller MCU or a SoC with programmable logic) of the edge computing module uses its built-in special hardware modules (such as PWM generators or advanced timers) to write the parameters in the configuration file to the corresponding registers. For example, write the frequency value to the period register, and write the converted duty cycle to the comparison register, to accurately set the waveform characteristics of the PWM signal.

[0067] After the configuration is completed, the software issues an enable instruction to start the PWM hardware module. Once enabled, the module autonomously outputs a continuous, stable digital PWM square wave signal on the specified GPIO pin with high-precision clock, and its logic level (such as 0V / 3.3V) strictly follows the set frequency and duty cycle. This hardware-level generation method not only ensures the accuracy of the signal timing, but also significantly reduces the CPU burden, allowing it to handle other tasks in parallel.

[0068] Finally, the digital PWM signal is sent as a control signal to the power drive stage circuit. The drive circuit, as the interface between the control platform and the actuator, receives low-power logic signals and controls the high-speed on-off of power semiconductor devices (such as MOSFET or IGBT), thereby regulating the large current delivered by the power storage unit to the closing coil. The closing coil ultimately obtains a current pulse consistent with the PWM signal waveform but with a significantly amplified power, achieving an energy-accurately controllable closing operation.

[0069] In summary, the control loop system for a medium-voltage switchgear provided by the present application has been illustrated. First, by replacing the traditional mechanical spring mechanism with an electronic spring simulation mechanism and electromagnetic drive, the mechanical structure is greatly simplified, fundamentally eliminating failure points caused by mechanical wear, fatigue, corrosion, etc., significantly improving the reliability of operation and the long-term stability of the mechanism, and reducing maintenance costs. Second, the introduction of the control platform with integrated edge computing module enables the drive of the closing / opening coil to be not only a rough on-off control, but also a fine electromagnetic force control, making it possible to achieve precise regulation of operation speed and suppress current surges and mechanical vibrations during operation, thereby effectively protecting the main contact of the circuit breaker and prolonging the electrical and mechanical life of the switchgear. Third, the pre-operation state self-checking logic ensures that each operation is performed within the preset safety boundary, avoiding misoperation or equipment damage due to abnormal states (such as no energy storage, incorrect position), and greatly enhancing the operational safety of the system.

[0070] As mentioned above, the control loop system for a medium-voltage switchgear according to the embodiments of the present application can be implemented in various wireless terminals, such as servers with innovative energy storage loop algorithms for medium-voltage switchgear operating mechanisms. In one possible implementation, the control loop system for a medium-voltage switchgear according to the embodiments of the present application can be integrated into a wireless terminal as a software module and / or a hardware module. For example, the control loop system for a medium-voltage switchgear can be a software module in the operating system of the wireless terminal, or an application program developed for the wireless terminal; of course, the control loop system for a medium-voltage switchgear can also be one of the many hardware modules of the wireless terminal.

[0071] Alternatively, in another example, the control circuit system for the medium voltage switchgear and the wireless terminal can also be separate devices, and the control circuit system for the medium voltage switchgear can be connected to the wireless terminal through a wired and / or wireless network and transmit interactive information in an agreed data format.

[0072] The implementations of the disclosure have been described above with the understanding that these implementations are exemplary, and are not exhaustive of all possible implementations. And, the implementations disclosed are not limited to that which has been described insofar as many modifications and changes can occur to ones skilled in the art to which the implementations pertain without departing from the spirit and scope of the implementations described.

Claims

1. A control circuit system for medium-voltage switchgear, characterized in that, include: Power supply system, control platform, and actuators; The power system includes a multi-source input module, an energy storage unit, and a low-power management module; The control platform includes a PLC controller, a microcomputer protection device, and an edge computing module; The actuators include closing / opening coils, energy storage motors, electronic spring simulation mechanisms, and status sensors; Upon receiving a closing command, the control platform queries the status sensor of the actuator to determine whether the circuit breaker is in the open position and whether the energy storage motor is in the stored state. When it is determined that the circuit breaker is in the open position and the energy storage motor is in the stored state, the control platform outputs a control signal to the closing / opening coil, which is used to drive the electronic spring simulation mechanism through electromagnetic force to close the main contacts of the circuit breaker. The control platform includes: The signal acquisition module is used to acquire the coil current flow and the auxiliary contact status flow; The operation timing analysis module is used to analyze the operation timestamp and calculate the actual time of the coil current flow and auxiliary contact state flow to obtain the actual operation time. The PWM parameter self-calibration module is used to correct the PWM drive parameters based on the comparison between the actual operation time and the target operation time in order to obtain the PWM configuration file for the next operation. The PWM signal generation module is used to generate a digital PWM signal as the control signal based on the PWM configuration file of the next operation in response to receiving a new closing command.

2. The control circuit system for medium-voltage switchgear according to claim 1, characterized in that, The operation timing analysis module includes: The current start time detection unit is used to analyze the coil current flow based on a preset threshold to obtain the current start time. The contact action timing detection unit is used to analyze the auxiliary contact state flow to obtain the contact closing time; The actual operation time calculation unit is used to calculate the difference between the contact closing time and the current initiation time to obtain the actual operation time.

3. The control circuit system for medium-voltage switchgear according to claim 2, characterized in that, The current start time detection unit is used for: Find the data point where the current value first exceeds a preset threshold from the coil current flow; Record the time offset of this data point relative to the start timestamp to obtain the start time of the current.

4. The control circuit system for medium-voltage switchgear according to claim 2, characterized in that, The contact action timing detection unit is used for: Find the data point in the auxiliary contact state stream where the state first changes from 0 to 1; Record the time offset of the data point relative to the start timestamp to obtain the closing time of the contact.

5. The control circuit system for medium-voltage switchgear according to claim 1, characterized in that, The PWM parameter self-calibration module includes: The time deviation calculation unit is used to calculate the difference between the actual operation time and the target operation time as the time deviation; A PI adjustment generation unit is used to input the time deviation into a PI controller to obtain a proportional correction and an integral correction. The PWM parameter correction unit is used to correct the PWM parameters of the current PWM configuration file based on the proportional correction amount and the integral correction amount to obtain the PWM configuration file for the next operation.

6. The control circuit system for medium-voltage switchgear according to claim 5, characterized in that, The PWM parameter correction unit is used for: The sum of the proportional correction and the integral correction is used as the total correction. Extract the current duty cycle from the current PWM configuration file; The current duty cycle is added to the total correction amount to obtain the new duty cycle in the PWM profile for the next operation.

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