A switching control method for a permanent magnet mechanism vacuum circuit breaker

Abstract

The present application relates to the technical field of vacuum circuit breaker control, and particularly relates to a kind of permanent magnet mechanism vacuum circuit breaker's switching control method, comprising: based on the pre-check parameter of target circuit breaker determines whether in switching control operation interval;Based on the preset drive parameter starts soft start brake stage;Based on coil current duty ratio starts full acceleration brake stage;Based on coil real-time current determines whether coil current duty ratio is dynamically compensated;Based on moving iron core real-time position and real-time speed determines the brake trigger position of moving iron core, to end full acceleration brake stage;Contact detection parameters are acquired to verify whether the current brake cycle meets the standard;Based on cumulative operation characteristic factor determines whether the drive parameter is adjusted and the drive parameter of subsequent brake cycle is output.The present application improves the switching control precision of circuit breaker and reduces the damage risk of circuit breaker in switching control process.

Description

Technical Field

[0001] This invention relates to the field of vacuum circuit breaker control technology, and in particular to a method for controlling the opening and closing of a permanent magnet mechanism vacuum circuit breaker. Background Technology

[0002] With the increasing demands for power supply reliability and automation in medium-voltage power distribution, permanent magnet vacuum circuit breakers, due to their simple structure, long mechanical life, and maintenance-free operation, are gradually replacing traditional spring mechanisms as the mainstream choice for frequent operation scenarios such as capacitor bank switching and transformer switching. The permanent magnet mechanism utilizes the magnetic holding force of a permanent magnet and the driving force of an electromagnetic coil to achieve opening and closing operations. Its fast action speed and good controllability meet the power system's requirements for rapid response from switching equipment. In practical applications, users expect the circuit breaker to maintain stable opening and closing performance throughout its entire lifespan, while avoiding operational failures or equipment damage due to mechanism wear.

[0003] However, existing control methods for opening and closing permanent magnet vacuum circuit breakers generally employ open-loop or semi-open-loop strategies, with drive parameters fixed at the factory and unable to adaptively adjust according to the actual operating conditions of the equipment. As the number of operations accumulates, the magnetic energy product of the permanent magnet gradually decreases, mechanical friction increases, and contact wear intensifies. Fixed parameter control leads to deviations in closing speed from the target value, prolonged contact bounce time, and increased contact resistance, potentially causing excessive inrush current or opening failure in severe cases. Furthermore, existing methods lack real-time monitoring and dynamic compensation mechanisms for the operation process, making it impossible to promptly identify and address faults such as abnormal coil current or mechanism jamming. They also lack wear assessment and parameter self-learning functions based on historical qualified operating data, hindering predictive maintenance and lifecycle performance retention. Therefore, a closed-loop control method capable of real-time monitoring, dynamic compensation, and self-learning optimization is urgently needed.

[0004] Chinese Patent Publication No. CN121416369A discloses a vacuum circuit breaker and a phase-selective closing control method. The vacuum circuit breaker includes a hybrid electromagnetic mechanism and a vacuum interrupter. The hybrid electromagnetic mechanism includes a permanent magnet closing assembly and an electromagnetic repulsion opening assembly. The permanent magnet closing assembly includes a parallel-connected double coil and a T-shaped moving iron core, forming a discharge circuit to drive the moving contact of the vacuum interrupter to complete the closing action and maintain the closed state. The electromagnetic repulsion opening assembly includes a coaxially opposite stationary coil disk and a moving coil disk, forming a reverse current repulsion circuit to drive the moving contact of the vacuum interrupter to complete the opening action and maintain the open state. The moving coil disk is connected to the T-shaped moving iron core of the permanent magnet closing assembly via an insulating guide rod. The vacuum interrupter includes a drive connecting rod, a moving contact, and a stationary contact. One end of the drive connecting rod is connected to the moving contact, and the other end is connected to the insulating guide rod. Therefore, the prior art has the following problems: In the existing technology, there are potential problems such as external power grid anomalies and internal overheating risks before the opening and closing operation is performed, current fluctuations during the braking process, and cumulative characteristics of permanent magnet mechanism and contacts that cause equipment parameter deviations that affect the opening and closing control accuracy. This leads to low opening and closing control accuracy of the circuit breaker and a high risk of damage to the circuit breaker during the opening and closing control process. Summary of the Invention

[0005] Therefore, the present invention provides a method for controlling the opening and closing of a vacuum circuit breaker with a permanent magnet mechanism, in order to overcome the problems in the prior art where the current fluctuates during the braking process and the permanent magnet mechanism and contacts have cumulative characteristics, resulting in low accuracy of the circuit breaker's opening and closing control and a high risk of damage to the circuit breaker during the opening and closing control process.

[0006] To achieve the above objectives, the present invention provides a method for controlling the opening and closing of a permanent magnet mechanism vacuum circuit breaker, comprising: The pre-detection parameters of the target circuit breaker are compared and analyzed with the pre-detection parameter thresholds to determine whether it is in the opening and closing control operation range. The pre-detection parameters include grid voltage, load current and coil temperature. In response to the determination result that the circuit breaker is in the opening and closing control operation range, the soft start braking stage is initiated for the coil current of the target circuit breaker based on the preset driving parameters. The coil current duty cycle obtained during the soft start braking phase is compared and analyzed with a preset coil current duty cycle threshold to initiate a full acceleration braking phase for the target circuit breaker's coil current based on preset driving parameters. Based on the real-time coil current obtained during the full acceleration braking phase, determine whether to dynamically compensate the coil current duty cycle. The braking trigger position of the moving iron core is determined based on the real-time position and real-time speed of the moving iron core obtained during the full acceleration braking phase, and the full acceleration braking phase ends based on the real-time position of the moving iron core and the braking trigger position. After the full acceleration braking phase ends, the contact detection parameters of the target circuit breaker are obtained to verify whether the current braking cycle meets the standard; In response to the current braking cycle meeting the standard, the cumulative operating characteristic factor of the target circuit breaker is analyzed based on the cumulative characteristic parameters of the historical braking cycles that meet the standard. The cumulative characteristic parameters include cumulative coil energy consumption and cumulative braking number. The cumulative operating characteristic factor is compared and analyzed with a preset cumulative operating characteristic factor threshold to determine whether to adjust the driving parameters of the subsequent braking cycle and output the driving parameters of the subsequent braking cycle. The driving parameters include the duty cycle rise rate of the soft start braking phase and the driving voltage amplitude of the full acceleration braking phase.

[0007] Furthermore, the process of determining whether the circuit is within the opening and closing control operation range includes: If all the pre-inspection parameters meet the first preset condition, it is determined that the circuit is in the opening and closing control operation range. The first preset condition is that the grid voltage is within a preset grid voltage range, the load current is less than a preset load current threshold, and the coil temperature is less than a preset coil temperature threshold.

[0008] Furthermore, the process of initiating the soft-start braking phase includes: The coil current duty cycle of the target circuit breaker is linearly increased based on the preset coil current duty cycle rise rate. Calculate the variance of the deviation between the actual duty cycle sequence of the coil current and the theoretical linear rise sequence to determine the stability index during the soft start braking phase. Based on the comparison results of the stability index being greater than the preset stability index threshold, the preset coil current duty cycle rise rate is dynamically adjusted.

[0009] Furthermore, the process of initiating the full acceleration braking phase of the target circuit breaker's coil current includes: Based on the first time the coil current duty cycle reaches the preset coil current duty cycle threshold, it is determined that the coil current of the target circuit breaker is in the full acceleration braking stage based on the preset driving voltage amplitude.

[0010] Furthermore, the process of determining whether to dynamically compensate for the coil current duty cycle includes: The current deviation value is calculated by comparing the real-time current sequence of the coil with the preset current time sequence. Based on the comparison results of the duration of the current deviation value being greater than the preset current deviation value threshold being greater than the preset duration threshold, it is determined that dynamic compensation of the coil current duty cycle is required.

[0011] Furthermore, the process of dynamically compensating for the coil current duty cycle includes: The first duty cycle adjustment amount is determined based on the difference between the current deviation value and the current deviation value threshold. The second duty cycle adjustment amount is determined based on the integral of the current deviation value over time; The duty cycle compensation amount is determined based on the first duty cycle adjustment amount and the second duty cycle adjustment amount.

[0012] Furthermore, the process of determining the braking trigger position of the moving iron core includes: Based on the first time the real-time position of the moving iron core reaches the preset position of the moving iron core, the current real-time speed of the moving iron core is obtained; Calculate the ratio of the current real-time speed of the moving iron core to a preset moving iron core speed threshold, and determine the braking trigger position based on the product of the ratio and a preset braking offset threshold.

[0013] Furthermore, the process of verifying whether the current braking cycle meets the standard includes: Based on the comparison results showing that all the contact detection parameters are less than the preset contact detection parameter threshold, it is determined that the current braking cycle meets the standard.

[0014] Furthermore, the process of analyzing the cumulative operating characteristic factors of the target circuit breaker includes: The first cumulative operation characteristic factor is determined based on the ratio of the cumulative coil energy consumption to the preset cumulative coil energy consumption threshold. The second cumulative operation characteristic factor is determined based on the ratio of the cumulative number of braking actions to a preset cumulative braking action threshold.

[0015] Furthermore, the process of determining whether to adjust the drive parameters for subsequent braking cycles includes: Based on the fact that the cumulative operating characteristic factor meets the second preset condition, the driving parameters for subsequent braking cycles are adjusted. The second preset condition is that the first cumulative operation feature factor is greater than a preset first cumulative operation feature factor threshold and the second cumulative operation feature factor is greater than a preset second cumulative operation feature factor threshold.

[0016] Compared with existing technologies, the advantages of this invention lie in constructing a full-lifecycle opening and closing control system through a complete process from pre-inspection condition determination to soft start, full acceleration, dynamic compensation, adaptive braking, control qualification verification, cumulative operation characteristic factor analysis, and even drive parameter self-learning. This system uses data feedback from each operation to optimize the next operation, allowing control parameters to automatically evolve with the increase in accumulated energy consumption and cumulative braking frequency, thus maintaining stable opening and closing dynamic characteristics throughout the entire lifecycle. Specifically, the pre-inspection stage eliminates external power grid anomalies and internal overheating hazards; the soft start braking stage eliminates the impact of current surges on the mechanism; the full acceleration stage ensures rapid response; dynamic compensation makes the electromagnetic force output precise and controllable; the adaptive braking process achieves precise braking by determining the braking trigger position; control qualification verification provides an objective basis for evaluation; the cumulative operation characteristic factor analysis stage quantifies energy consumption and the number of actions into first and second cumulative operation characteristic factors, respectively; and the updating of drive parameters ensures that the control process fully conforms to the equipment state, automatically adjusting the drive force as the service time increases, avoiding performance degradation in the later stages. This invention improves the accuracy of circuit breaker opening and closing control and reduces the risk of damage to the circuit breaker during the opening and closing control process.

[0017] Furthermore, this invention, by comparing thresholds of three key pre-detection parameters—grid voltage, load current, and coil temperature—can eliminate the risks of external power anomalies, on-load tripping, and coil overheating before operation, effectively preventing equipment damage or power accidents caused by forced operation under dangerous conditions. Specifically, grid voltage detection avoids insufficient electromagnetic force due to excessively low voltage and damage to the mechanism due to excessively high voltage; load current detection confirms that the current is close to zero before closing, preventing the large current generated by closing under load from burning the contacts, and confirms that the current is within the safe breaking capacity before opening, preventing breaking failure; coil temperature detection prevents serious faults such as coil overheating, insulation aging, and even coil burnout caused by continuous operation. By verifying the pre-detection parameters, operational safety and equipment reliability are improved, enabling the circuit breaker to proactively refuse operation under adverse conditions rather than passively suffering damage.

[0018] Furthermore, this invention, by calculating the variance of the actual rising sequence during the linear duty cycle increase process and comparing it with a stability index threshold, can quantitatively assess the smoothness of soft start and dynamically adjust the rising rate, making the soft start process adaptable to different mechanical friction states and power supply fluctuations. The difference in variance directly characterizes the smoothness of the drive waveform; the smaller the variance, the closer the actual duty cycle is to the ideal linear rising curve, the more continuous the current change, and the smoother the core start-up; excessive variance indicates the presence of step jumps or jitter, which will generate additional mechanical shocks. By dynamically adjusting the rising rate, this method can automatically adapt to the inductance differences of different batches of coils, the resistance changes under different ambient temperatures, and the changes in mechanical characteristics after long-term wear, thereby minimizing the initial impact force, extending the life of transmission components, and maintaining a consistently smooth soft start process.

[0019] Furthermore, this invention uses the initial attainment of a threshold duty cycle as the criterion for initiating full acceleration, achieving a seamless switch from soft start to full acceleration. This avoids insufficient driving force or excessive impact caused by switching too early or too late. Switching too early, before the duty cycle reaches a sufficient value, can lead to a sudden application of maximum driving force before the core has acquired sufficient initial velocity, resulting in secondary impact. Switching too late, with an excessively high duty cycle, can prolong the soft start phase, extending the total operation time and reducing response speed. This method matches the switching timing with the actual motion state of the core, ensuring that the core immediately receives maximum driving force after acquiring a suitable initial velocity, shortening the total operation time, and avoiding additional mechanical vibration caused by improper switching timing.

[0020] Furthermore, by monitoring the coil current in real time and comparing it with an ideal curve, combined with a dual judgment of deviation threshold and duration, this invention can accurately identify normal fluctuations requiring compensation and serious faults requiring emergency shutdown. This achieves a tiered safety protection mechanism while ensuring control accuracy.

[0021] Furthermore, this invention calculates the duty cycle compensation using both proportional and integral channels, balancing rapid response to current errors with steady-state accuracy, enabling the coil current to precisely track the ideal curve. The proportional channel directly responds to the current instantaneous error, with stronger compensation for larger errors, quickly pulling the current back to the ideal trajectory. The integral channel accumulates historical errors, eliminating static residual errors caused by system friction, inductance changes, etc., ensuring the current precisely matches the ideal value in the later stages of operation. This ensures the coil current fluctuates around the ideal curve throughout the entire operation, thereby guaranteeing the stability and controllability of the electromagnetic force output.

[0022] Furthermore, this invention achieves speed-adaptive braking start control by dynamically calculating the braking trigger position based on real-time speed. This allows for earlier braking at high speeds and delayed braking at low speeds, ensuring that the contact reaches the target position with a consistent final velocity regardless of changes in the mechanism's frictional resistance or the decay of the permanent magnet's energy product. In the braking trigger position calculation formula, the offset is proportional to the current speed: the faster the speed, the larger the offset, meaning earlier braking begins; the slower the speed, the smaller the offset, and the closer the braking point is to the target position. This overcomes the shortcomings of traditional fixed-position braking methods, avoiding the problems of delayed braking leading to violent impacts and severe bouncing at high contact speeds, and premature braking preventing the contact from reaching the target position at low contact speeds. This method reduces speed fluctuations and contact bouncing, extending electrical and mechanical lifespan.

[0023] Furthermore, this invention, through dual verification of contact resistance and bounce count after operation, can quantitatively assess the actual quality of the operation and promptly identify problems such as contact wear and mismatched braking parameters. Contact resistance is the most direct indicator of the reliability of electrical contact; an abnormally high resistance indicates severe oxidation, wear, or pitting on the contact surface, which may lead to excessive heating or even welding under closed conditions. Bounce count is an important indicator of mechanical buffering and braking effectiveness; excessive bounce can cause repeated arc reignition between contacts, accelerating contact erosion. Through automatic quality verification after each operation, performance degradation trends can be detected in a timely manner, providing accurate input data for cumulative operation characteristic factor analysis, while also providing traceable operation records to support predictive maintenance decisions.

[0024] Furthermore, this invention quantifies the work done and frequency of operation of the equipment by calculating a first cumulative operating characteristic factor and a second cumulative operating characteristic factor based on cumulative coil energy consumption and cumulative braking frequency, respectively. The drive parameters are adjusted only when both characteristic factors exceed their respective thresholds, avoiding misjudgments caused by the bias of a single indicator. Cumulative coil energy consumption characterizes the total output energy of the electromagnetic mechanism; the greater the energy consumption, the more severe the decay of the permanent magnet's magnetic energy product. Cumulative braking frequency directly reflects the fatigue wear of vulnerable components such as springs and bearings due to the number of mechanical cycles. Compensation is triggered only when both factors exceed their thresholds, providing a more reliable characterization of the actual degree of equipment degradation and offering an objective basis for adaptive adjustment of drive parameters, thereby enabling predictive maintenance based on equipment condition.

[0025] Furthermore, this invention achieves adaptive compensation for equipment aging and wear by comparing the first and second cumulative operating characteristic factors with their respective thresholds, and dynamically adjusting the drive voltage amplitude and duty cycle rise rate when both are greater than the thresholds. When both cumulative operating characteristic factors exceed the set thresholds, the full-acceleration drive voltage amplitude is increased and the soft-start duty cycle rise rate is improved, ensuring that the circuit breaker maintains a consistent closing speed and bounce level throughout its entire lifespan, avoiding the problem of severely low speed and deteriorated bounce that occurs in the later stages of its lifespan under fixed parameter control. Attached Figure Description

[0026] Figure 1 This is a flowchart of the opening and closing control method of the permanent magnet mechanism vacuum circuit breaker according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating how to determine whether a circuit breaker is in the opening / closing control operation range, as described in this embodiment of the invention. Figure 3 This is a flowchart illustrating the soft-start braking phase in an embodiment of the present invention. Figure 4 This is a flowchart illustrating the initiation of the full acceleration braking phase in an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0028] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0029] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] As an explanation, the opening and closing control method of the permanent magnet mechanism vacuum circuit breaker in this invention is mainly applied to frequent switching scenarios in medium-voltage power distribution systems where precise control of the operation timing is required. In this invention, the permanent magnet mechanism vacuum circuit breaker refers to a circuit breaker comprising a vacuum interrupter and a permanent magnet operating mechanism. The vacuum interrupter is equipped with moving and stationary conductive contacts; the permanent magnet operating mechanism consists of a permanent magnet, a moving iron core, a closing coil, a opening coil, and an opening spring.

[0031] Please see Figure 1 The diagram shows a flowchart of the opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to an embodiment of the present invention. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to an embodiment of the present invention includes: Step S1: Compare and analyze the pre-detection parameters of the target circuit breaker with the pre-detection parameter thresholds to determine whether it is in the opening and closing control operation range. The pre-detection parameters include grid voltage, load current and coil temperature. Step S2: In response to the determination result that the circuit breaker is in the opening and closing control operation range, the soft start braking stage is initiated for the coil current of the target circuit breaker based on the preset driving parameters. Step S3: Compare and analyze the coil current duty cycle obtained in the soft start braking stage with the preset coil current duty cycle threshold, and start the full acceleration braking stage of the target circuit breaker coil current based on the preset driving parameters. Step S4: Determine whether to dynamically compensate the coil current duty cycle based on the real-time coil current obtained during the full acceleration braking phase. Step S5: Determine the braking trigger position of the moving iron core based on the real-time position and real-time speed of the moving iron core obtained during the full acceleration braking phase, and end the full acceleration braking phase based on the real-time position of the moving iron core and the braking trigger position. Step S6: After the full acceleration braking phase ends, obtain the contact detection parameters of the target circuit breaker to verify whether the current braking cycle meets the standard. Step S7: In response to the current braking cycle meeting the standard, analyze the cumulative operating characteristic factor of the target circuit breaker based on the cumulative characteristic parameters of the historical braking cycles that meet the standard. The cumulative characteristic parameters include cumulative coil energy consumption and cumulative braking number. Step S8: Based on the comparison analysis between the accumulated operation feature factor and the preset accumulated operation feature factor threshold, determine whether to adjust the driving parameters of the subsequent braking cycle and output the driving parameters of the subsequent braking cycle. The driving parameters include the duty cycle rise rate of the soft start braking phase and the driving voltage amplitude of the full acceleration braking phase.

[0032] Please see Figure 2 As shown, it is a flowchart of determining whether the circuit is in the opening and closing control operation range according to an embodiment of the present invention.

[0033] Specifically, in step S1, the process of determining whether the circuit is in the opening and closing control operation range includes: If all the pre-inspection parameters meet the first preset condition, it is determined that the circuit is in the opening and closing control operation range. The first preset condition is that the grid voltage is within a preset grid voltage range, the load current is less than a preset load current threshold, and the coil temperature is less than a preset coil temperature threshold.

[0034] This embodiment also includes a pre-detection parameter acquisition unit, which is used to acquire pre-detection parameters, including grid voltage, load current and coil temperature, to provide real-time monitoring data for determining the opening and closing control operation range.

[0035] Among them, the grid voltage is the effective value of the three-phase line voltage obtained by connecting the secondary winding of the voltage transformer on the incoming side of the circuit breaker to a resistor divider circuit; the load current is the maximum effective value of the three-phase current obtained by connecting the sampling resistor on the secondary side of the current transformer on the outgoing side; the coil temperature is measured by a platinum resistance sensor mounted on the surface of the closing coil and the opening coil, and the resistance value is converted to degrees Celsius by constant current source excitation in the existing technology, which will not be elaborated here.

[0036] This embodiment also includes a circuit breaker control operation range determination unit, which is used to determine whether the first preset conditions are met, including the grid voltage being within the grid voltage preset range, the load current being less than the preset load current threshold, and the coil temperature being less than the preset coil temperature threshold. This is used to eliminate safety hazards such as external grid anomalies, excessive load current, and overheating of the mechanism before the circuit breaker operation is executed, and to ensure that the operating conditions meet safety and performance requirements.

[0037] Specifically, the closing control operation range determination unit compares the grid voltage with a preset grid voltage range to determine whether the grid voltage is within the allowable opening and closing voltage range. In this embodiment, the grid voltage is compared with the preset grid voltage range; if the grid voltage is within the preset range, the condition is met. It is understood that the lower limit of the preset grid voltage range should ensure that the electromagnetic driving force generated by the coil is sufficient to reliably complete the opening and closing action, avoiding failure to operate or insufficient closing speed; the upper limit should prevent excessive electromagnetic impact force from exacerbating contact bounce and mechanical component wear. Both can be set through a limited number of tests or empirical values, and will not be elaborated further.

[0038] Specifically, the closing control operation range determination unit is used to compare the load current with a preset threshold to determine whether the load current is within the current range that allows for opening and closing operations.

[0039] In this embodiment, the load current is compared with a preset threshold. If the load current is less than the load current threshold, the requirement is met. It is understood that for closing operations, the load current threshold should be set so that the arc energy generated at the moment of closing does not exceed the maximum value within the rated current range corresponding to the allowable range of the contacts, in order to avoid severe ablation or welding; for opening operations, the load current threshold should be set to ensure that the vacuum interrupter can reliably extinguish the arc, avoiding the minimum value within the rated current range corresponding to the failure of interruption, so as to leave sufficient interruption margin.

[0040] Specifically, the closing control operation range determination unit is used to compare the coil temperature with a preset coil temperature threshold to determine whether the coil temperature is within the temperature range that allows for opening and closing operations.

[0041] In this embodiment, the coil temperature is compared with a preset coil temperature threshold. If the coil temperature is lower than the threshold, the condition is met. It is understood that when the long-term operating temperature of the permanent magnet mechanism coil exceeds the critical value, the aging rate of the insulating material accelerates significantly, the coil resistance increases with temperature, leading to a decrease in driving force at the same voltage; simultaneously, excessive temperature rise accelerates fatigue of the internal solder joints and cracking of the epoxy encapsulation. Using this critical value as the operational allowable threshold achieves a balance between coil thermal aging and driving force attenuation, and provides a safety margin for instantaneous overload.

[0042] In this embodiment, when the grid voltage, load current, and coil temperature simultaneously meet the corresponding conditions, the closing control operation range determination unit determines that the first preset condition is met, determines that the circuit is in the opening and closing control operation range, and outputs a signal that allows opening and closing operations; otherwise, it outputs a prohibition operation signal and blocks the drive circuit.

[0043] Please see Figure 3As shown, it is a flowchart of the soft-start braking phase in an embodiment of the present invention.

[0044] Specifically, in step S2, the process of initiating the soft-start braking phase includes: Step S21: Based on the preset coil current duty cycle rise rate, the coil current duty cycle of the target circuit breaker is linearly increased; Step S22: Calculate the variance of the deviation between the actual duty cycle sequence of the coil current and the theoretical linear rise sequence to determine the stability index of the soft start braking stage. Step S23: Based on the comparison results of the stability index being greater than the preset stability index threshold, the preset coil current duty cycle rise rate is dynamically adjusted.

[0045] This embodiment also includes a soft-start duty cycle linear modulation unit, which linearly increases the coil current duty cycle of the target circuit breaker based on a preset coil current duty cycle rise rate, thereby smoothly increasing the coil current to achieve soft-start braking. The preset coil current duty cycle rise rate ensures a smooth increase in the coil current. It can be understood that the duty cycle is defined as the ratio of the time the power switch is in the conducting state to the total time of that switching cycle, ranging from 0% to 100%. The higher the duty cycle, the higher the average voltage obtained by the coil in one cycle, the faster the current rises, and the greater the electromagnetic force generated. By adjusting the duty cycle, the average current of the coil can be continuously controlled, thereby precisely controlling the driving force and movement speed of the moving iron core. The preset coil current duty cycle rise rate is obtained from the driving parameters determined in the previous opening and closing braking cycle. The rise rate must suppress the electromagnetic shock caused by sudden current changes while ensuring sufficient starting acceleration to avoid excessively long soft-start time affecting the operation response speed. Specifically, the preset rate of increase of the coil current duty cycle should match the total duration of the soft start phase with the coil electrical time constant and the starting inertia of the moving iron core.

[0046] This embodiment also includes a stability index determination unit for the soft-start braking phase. This unit determines the stability index for the soft-start braking phase based on the variance of the deviation between the actual duty cycle sequence and the theoretical linear rise value sequence of the coil current. This index characterizes the smoothness of the actual duty cycle tracking the theoretical curve. In a preferred embodiment, during the soft-start braking phase, the actual duty cycle value is recorded every millisecond to determine several values ​​of the actual duty cycle sequence, while simultaneously calculating the theoretical linear rise value sequence. The theoretical value at any point is determined as the product of the rise rate and the rise time. The variance of the difference between the actual and theoretical values ​​is calculated. This variance characterizes the smoothness of the actual duty cycle tracking the theoretical curve; a smaller variance indicates a smoother drive waveform and less mechanical shock. It is understood that factors such as coil inductance and drive voltage fluctuations may prevent the actual current response from achieving perfectly ideal linear tracking. Therefore, by calculating the variance of the deviation between the actual duty cycle and the theoretical value, the smoothness of the soft-start process can be quantitatively evaluated, providing a basis for dynamically adjusting the rise rate.

[0047] This embodiment also includes a stability determination unit, which dynamically adjusts the preset coil current duty cycle rise rate based on the comparison result of the stability index being greater than the preset stability index threshold, in order to eliminate the step or jitter during the duty cycle rise process.

[0048] The stability determination unit also determines a stability index threshold based on the variance of the duty cycle deviation sequence corresponding to the maximum permissible deviation between the actual duty cycle allowed in engineering and the theoretical linear rise value. This threshold quantifies the maximum volatility achievable during a soft-start process within the permissible deviation range. Furthermore, by comparing the stability index with the stability index threshold, it distinguishes between stable and unstable states in the soft-start process. The maximum permissible deviation limits the upper limit of the absolute value of the deviation allowed at each sampling point in engineering, and is set according to specific engineering standards, which will not be elaborated further here.

[0049] Specifically, the stability determination unit is also used to determine that at least one sampling point has a deviation that exceeds the maximum allowable range of the project when the current stability index is greater than the stability index threshold. It also determines that an unacceptable step or jitter has occurred during the soft start process, determines to dynamically adjust the rise rate to make the change smoother, and re-executes the soft start until the variance meets the requirements.

[0050] The stability determination unit is also used to determine that the deviation of all sampling points is within the allowable range and the duty cycle rises smoothly, based on the current stability index being less than or equal to the stability index threshold, thus determining that the soft start is smooth and maintaining the existing rise rate.

[0051] Understandably, after adjusting the ascent rate, a soft start is re-executed until the soft start is determined to be stable, thus completing the ascent rate adjustment.

[0052] Understandably, the purpose of the soft-start stage is to prevent the huge electromagnetic shock force generated by the sudden increase in coil current from acting directly on the stationary iron core, causing the iron core to violently collide with the end face of the stationary iron core, resulting in severe bouncing and mechanical noise, while protecting the power switching transistor from overcurrent stress.

[0053] Please see Figure 4 As shown, it is a flowchart of the full acceleration braking phase in an embodiment of the present invention.

[0054] Specifically, in step S3, the process of initiating the full acceleration braking phase for the coil current of the target circuit breaker includes: Based on the first time the coil current duty cycle reaches the preset coil current duty cycle threshold, it is determined that the coil current of the target circuit breaker is in the full acceleration braking stage based on the preset driving voltage amplitude.

[0055] This embodiment also includes a full acceleration phase triggering switching unit. Based on the first time the coil current duty cycle reaches a preset coil current duty cycle threshold, it determines that a full acceleration braking phase is initiated for the target circuit breaker's coil current based on a preset driving voltage amplitude. This is used to trigger maximum electromagnetic force acceleration after the soft-start phase is completed. During the soft-start braking phase, the duty cycle value of the current pulse width modulation signal is read at a sufficiently high sampling frequency and compared with the preset coil current duty cycle threshold. This threshold is set as the target value that the duty cycle should reach after the soft-start phase ends. Its value should ensure that the moving iron core has obtained sufficient initial kinetic energy while reserving sufficient acceleration stroke for the full acceleration phase. When the duty cycle is detected to first reach or exceed this threshold, the soft-start phase is immediately determined to end, and the full acceleration braking phase is initiated.

[0056] Specifically, the full acceleration braking phase includes: stopping the linear increase control of the duty cycle, forcibly setting the duty cycle to a fully conducting state, and simultaneously switching the drive voltage to a preset full acceleration drive voltage amplitude, thereby driving the moving iron core to move rapidly with maximum electromagnetic force.

[0057] Understandably, during the soft-start phase, when the duty cycle linearly increases from its initial value to the preset coil current duty cycle threshold, the moving core has already achieved a peak speed ratio corresponding to the duty cycle threshold. This ratio should ensure that the core accumulates sufficient initial kinetic energy to overcome static friction, while avoiding mechanical shock caused by prematurely applying full voltage. If the threshold is set too low, the core will not start sufficiently, and the sudden acceleration after switching will still cause significant vibration; if the threshold is set too high, the soft-start time will be too long, extending the total operation time. Once the duty cycle reaches this threshold, it immediately switches to the fully conducting state and applies a full acceleration drive voltage. This aims to drive the core quickly across the intermediate stroke with maximum electromagnetic force, shortening the total operation time and reserving sufficient kinetic energy adjustment margin for subsequent adaptive braking, ensuring that the contacts close or open at an ideal speed.

[0058] This embodiment also includes a full-acceleration drive voltage amplitude acquisition unit, which is used to acquire the full-acceleration drive voltage amplitude as the basis for providing the maximum electromagnetic driving force during the full-acceleration braking phase. The full-acceleration drive voltage amplitude is obtained from the drive parameters determined in the previous opening and closing braking cycle. The initial amplitude is determined based on the coil's electrical parameters, insulation heat resistance level, and rated voltage of the energy storage capacitor. It should ensure that the temperature rise and insulation stress of the coil under continuous operation are within a safe range, while ensuring that the generated electromagnetic force is sufficient to reliably drive the moving iron core, taking into account both operational reliability and equipment lifespan.

[0059] Understandably, the purpose of setting up the full acceleration braking stage is to apply the maximum electromagnetic force after the moving iron core gains initial momentum, so that it can quickly cross the intermediate stroke, shorten the total operation time, and at the same time reserve sufficient kinetic energy adjustment margin for subsequent braking to ensure that the contacts close or break at an ideal speed.

[0060] Specifically, in step S4, the process of determining whether to dynamically compensate the coil current duty cycle includes: Step S41: Compare the real-time current sequence of the coil with a preset current time sequence to calculate the current deviation value. Step S42: Based on the comparison result that the duration of the current deviation value being greater than the preset current deviation value threshold is greater than the preset duration threshold, it is determined that dynamic compensation of the coil current duty cycle is required.

[0061] Step S43: Dynamically compensate the coil current duty cycle based on the current deviation value.

[0062] This embodiment also includes a current deviation value determination unit, which determines the current deviation value by comparing the real-time current timing sequence of the coil with a preset current timing sequence. This value is used to quantify the degree of deviation between the actual current and the expected current under standard operating conditions. In a preferred embodiment, during the full acceleration braking phase, the instantaneous current value in the coil circuit is continuously read at a sampling frequency of 10 kHz to form the actual current timing sequence. The preset current timing sequence is determined by the cluster centers of the actual current timing sequences during the full acceleration braking phase, which conform to the standard opening and closing braking cycle. This characterizes the trajectory that the coil current should follow under standard operating conditions. Using the standard operating cycle cluster centers as the preset sequence allows for dynamic updates to the standard operating condition template, eliminating the influence of batch differences. At each sampling moment, the corresponding current deviation value is determined by the difference between the actual current and the corresponding current in the preset current timing sequence. This difference quantifies the degree to which the driving force deviates from the expected value, providing a quantitative input for dynamic compensation.

[0063] This embodiment also includes a current deviation threshold and corresponding duration threshold determination unit, which is used to determine the current deviation threshold and corresponding duration threshold to distinguish between mild deviation requiring compensation and severe deviation requiring shutdown. The current deviation threshold and corresponding duration threshold include a mild deviation threshold and its corresponding mild duration threshold, and a severe deviation threshold and its corresponding severe duration threshold. These are determined based on the allowable fluctuation range and corresponding duration upper limit of the coil current under normal operating conditions and the allowable fluctuation range and corresponding duration upper limit under fault conditions, respectively. This is used to quantify the tolerance level of current deviation within the allowable range, and then distinguish between mild deviation requiring compensation and severe deviation requiring shutdown by comparing the current deviation value with the threshold. The allowable fluctuation range under normal operating conditions limits the upper limit of the instantaneous deviation of the coil current, and is set according to the coil electrical time constant and the statistical characteristics of the current ripple during the switching cycle; the allowable fluctuation range under fault conditions limits the lower limit of the deviation of severe faults, and is set according to the critical point when the electromagnetic force decreases or the overshoot exceeds the acceptable range; the corresponding duration threshold is set based on the coil electrical time constant and the mechanical motion characteristic time of the moving iron core, respectively, to eliminate instantaneous noise interference and confirm the persistence of the fault.

[0064] Specifically, if the current deviation value exceeds the minor deviation threshold and continues to exceed the minor duration threshold, it is determined to be a minor deviation that requires dynamic compensation, and duty cycle compensation is initiated; if the current deviation value exceeds the severe deviation threshold and continues to exceed the severe duration threshold, it is determined to be a severe fault, and an emergency shutdown is immediately executed.

[0065] If the current deviation value does not exceed the slight deviation threshold or the duration is less than the slight duration threshold, it is determined to be a normal fluctuation or instantaneous noise interference, and the current state is maintained without triggering compensation or shutdown.

[0066] Specifically, in step S43, the process of dynamically compensating the duty cycle of the coil current includes: Step S431: Determine the first duty cycle adjustment amount based on the difference between the current deviation value and the current deviation value threshold; Step S432: Determine the second duty cycle adjustment amount based on the integral of the current deviation value over time; Step S433: Determine the duty cycle compensation amount based on the first duty cycle adjustment amount and the second duty cycle adjustment amount.

[0067] This embodiment also includes a duty cycle compensation determination unit, which determines the duty cycle compensation amount based on the first duty cycle adjustment amount and the second duty cycle adjustment amount. This unit integrates proportional and integral regulation to achieve precise current tracking control. In a preferred embodiment, the sum of the first and second duty cycle adjustment amounts is determined as the duty cycle compensation amount. The adjustment direction is determined based on the sign of the current deviation value. If the actual current is higher than the ideal current (i.e., the deviation value is positive), the new duty cycle equals the current duty cycle minus the compensation amount. If the actual current is lower than the ideal current (i.e., the deviation value is negative), the new duty cycle equals the current duty cycle plus the compensation amount. Finally, the new duty cycle is subjected to amplitude limiting adjustment to ensure it is between 0% and 100%, and is immediately output to the pulse width modulation signal generator to drive subsequent switching cycles.

[0068] The duty cycle compensation determination unit is also used to determine a first duty cycle adjustment amount, which is used to calibrate the macroscopic adjustment scale of the duty cycle based on the current instantaneous error. The larger the current instantaneous error, the larger the first duty cycle adjustment amount; the smaller the current instantaneous error, the smaller the first duty cycle adjustment amount. The first duty cycle adjustment amount is determined by multiplying the difference between the current deviation value and the threshold value for a slight current deviation value at the current moment by the instantaneous deviation adjustment gain. The instantaneous deviation adjustment gain is determined based on the duty cycle adjustment amount corresponding to each ampere deviation, used to determine the adjustment range of the current and duty cycle. A higher duty cycle adjustment amount corresponding to each ampere deviation results in a higher adjustment amount of the average voltage obtained by the coil in one cycle, which can easily lead to overshoot oscillation. Conversely, a lower duty cycle adjustment amount corresponding to each ampere deviation results in a lower adjustment amount of the average voltage obtained by the coil in one cycle, which can easily lead to insufficient compensation. Preferably, it is set to the maximum instantaneous deviation adjustment gain that does not cause overshoot oscillation in the corresponding scenario.

[0069] The duty cycle compensation determination unit is also used to determine a second duty cycle adjustment amount, which is used to calibrate the micro-adjustment scale of the duty cycle based on the cumulative effect of the current deviation. The larger the accumulated current deviation, the larger the second duty cycle adjustment amount; the smaller the accumulated current deviation, the smaller the second duty cycle adjustment amount. The second duty cycle adjustment amount is determined by multiplying the time integral of the current deviation value from the start of the full acceleration phase by the accumulated charge adjustment gain. The accumulated charge adjustment gain is determined based on the duty cycle adjustment amount corresponding to each coulomb of charge, used to determine the micro-adjustment amplitude of the cumulative effect of the current deviation over time in duty cycle compensation. A higher duty cycle adjustment amount corresponding to each coulomb of charge is prone to overshoot oscillation due to integral saturation; a lower duty cycle adjustment amount corresponding to each coulomb of charge is prone to insufficient compensation. Preferably, it is the maximum instantaneous deviation adjustment gain that does not cause overshoot oscillation in the corresponding scenario.

[0070] Specifically, in step S5, the process of determining the braking trigger position of the moving iron core includes: Step S51: Based on the first time the real-time position of the moving iron core reaches the preset position of the moving iron core, obtain the current real-time speed of the moving iron core; Step S52: Calculate the ratio of the current real-time speed of the moving iron core to the preset moving iron core speed threshold, and determine the braking trigger position based on the product of the ratio and the preset braking offset threshold.

[0071] This embodiment also includes a real-time speed determination unit for the moving core. This unit determines the real-time speed of the moving core based on the real-time speed obtained when the moving core first reaches a preset position, providing a speed basis for the dynamic calculation of the braking trigger position. During the full acceleration braking phase, the moving core position value output by the linear Hall position sensor is read in real-time at a sufficiently high sampling frequency. A preset position for the moving core is set at a reference point before the end of the travel. This preset position should satisfy the following conditions: when the core reaches this position, it has acquired sufficient speed to represent the current kinetic energy level, while reserving sufficient remaining travel for subsequent braking. This ensures that at the highest speed and maximum braking offset, the braking trigger position is still located after the preset position, thereby ensuring that speed capture precedes braking trigger.

[0072] The moving core real-time speed determination unit is used to immediately record the real-time speed of the moving core at the current moment based on the detection that the current real-time position first reaches or exceeds the preset position of the moving core, and calculate the real-time speed through position difference. The real-time speed determination process is as follows: calculate the difference between the current position and the position at the previous sampling moment, and determine the real-time speed by the ratio of the difference to the sampling interval.

[0073] This embodiment also includes a moving core speed ratio determination unit, which determines the moving core speed ratio based on the ratio of the current real-time speed of the moving core to a preset moving core speed threshold. This ratio is used to quantify the proportional relationship between the current speed and the maximum permissible speed. The moving core speed threshold is the maximum permissible speed. When the speed exceeds this value, the collision energy during contact closure increases significantly, and the bounce time and number of bounces rise sharply, easily causing contact welding or premature burnout. Simultaneously, excessively high speeds can impact transmission components, shortening mechanical life.

[0074] This embodiment also includes a braking trigger position determination unit, which determines the braking trigger position based on the difference between the target position and the braking offset. This unit dynamically adjusts the braking start point according to the current speed to achieve precise braking. The braking offset is determined by the product of the moving core speed ratio and a braking offset threshold, representing the braking distance that needs to be reserved before the target position. It can be understood that the faster the current speed, the larger the offset, meaning earlier braking begins; when the current speed is slow, the offset is small, and the braking point is closer to the target position. The preset braking offset threshold is determined based on the maximum advance braking distance to ensure that at maximum speed, when decelerating from the braking trigger position to the target position, the speed drops to a safe final speed, avoiding impact or incomplete braking. At slower speeds, the offset decreases proportionally, and the braking point is closer to the target position, ensuring proper braking.

[0075] This embodiment also includes a braking trigger and mode switching unit, which continuously compares the calculated braking trigger position with the real-time position. When the real-time position first reaches or exceeds the braking trigger position, it immediately executes the operation to end the full acceleration braking phase: switching the duty cycle of the pulse width adjustment signal from the full acceleration state to the reverse pulse mode, i.e., the braking duty cycle. At this point, the full acceleration phase officially ends, and the electromagnetic braking phase begins. The value of the braking duty cycle is determined based on the reverse electromagnetic force required to smoothly decelerate the moving iron core from the current speed to the target speed within the remaining braking stroke. This reverse electromagnetic force should maintain an appropriate proportional relationship with the maximum forward driving force to ensure sufficient braking deceleration while avoiding excessive braking force leading to overshoot or insufficient braking force leading to impact.

[0076] Specifically, the braking duty cycle must meet the following conditions: at the highest speed and maximum stroke, when decelerating from the braking trigger position to the target position, the speed of the moving iron core drops to within the allowable final speed range.

[0077] Specifically, in step S6, the process of verifying whether the current braking cycle meets the standard includes: Based on the comparison results showing that all the contact detection parameters are less than the preset contact detection parameter threshold, it is determined that the current braking cycle meets the standard.

[0078] This embodiment also includes a contact detection parameter determination unit, which is used to determine contact detection parameters to provide measured data for verifying whether the current braking cycle meets the standard, and is suitable for verifying the contact closure quality during closing operations. In a preferred embodiment, after the full acceleration braking phase ends, the electromagnetic braking phase is completed, and the moving iron core stabilizes, two types of contact detection parameters are obtained: contact resistance and contact bounce count. It can be understood that a contact refers to the dynamic and static conductive contact pair within the vacuum interrupter chamber, whose function is to carry rated current and short-circuit current in the closed state, and to isolate high voltage and interrupt fault current in the open state. The contact resistance directly characterizes the electrical contact quality after contact closure, and the contact bounce count directly measures the degree of mechanical impact during the braking process.

[0079] The contact parameter determination unit is used to determine the contact resistance, which quantifies the conductivity of the contact in the closed state. In a preferred embodiment, the contact resistance measurement employs a four-wire method: after the contact is closed, a constant DC test current is applied through an independent current lead, and the voltage drop across the contact is measured using an independent voltage detection lead. The resistance is then calculated using Ohm's law. It is understood that the four-wire method eliminates measurement errors in lead resistance and contact resistance, and the constant DC test current is sufficient to penetrate the oxide film on the contact surface to obtain the true contact resistance value.

[0080] The contact detection parameter determination unit is used to determine the number of contact bounces, that is, to count the number of tiny separations and re-closures caused by mechanical collisions during the contact closure process. Bounces can lead to arc reignition and contact erosion, therefore, accurate counting of bounces is necessary. Specifically, it monitors minute fluctuations in the auxiliary contact signal or coil current at a sufficiently high sampling rate. Each time the signal amplitude decreases beyond a preset amplitude decrease threshold and the duration exceeds a preset duration threshold, it is counted as one bounce, and the total number of bounces is counted within a preset detection window. The amplitude decrease threshold is determined based on the upper limit of the normal signal fluctuation range to filter out normal signal fluctuations; the duration threshold is determined based on the maximum possible duration of instantaneous noise interference to avoid misjudging instantaneous noise as bounce while not missing genuine bounce events; the detection window width is determined based on the maximum possible duration of the bounce process after contact closure to fully capture the entire bounce process.

[0081] The closing operation braking determination unit compares the measured contact resistance with a preset contact detection parameter threshold during the closing operation to determine whether the closing operation braking cycle is qualified. Based on the comparison result that all contact detection parameters are less than the preset contact detection parameter threshold, the current braking cycle is determined to meet the standard.

[0082] Specifically, if the contact resistance is less than a preset safe contact resistance threshold and the number of contact bounces is less than a preset upper limit for the number of bounces, then the current braking cycle is deemed to meet the standard. The safe contact resistance threshold is determined based on the maximum allowable contact resistance value of the contact material during long-term operation. Exceeding this threshold may lead to localized overheating at the contact point, potentially causing contact welding or burn-out. The upper limit for the number of bounces is determined based on the impact of arc erosion on contact life during contact closure. Excessive bounces will exacerbate arc reignition and accelerate the wear of the contact surface material.

[0083] This embodiment also includes a tripping position verification unit, which verifies the tripping position signal during tripping operations. Specifically, by confirming through a position sensor that the deviation of the final position of the moving iron core relative to the target tripping position is less than the allowable position deviation threshold, and that the tripping rebound amplitude is less than the allowable rebound amplitude threshold, the tripping operation is determined to meet the standard. The position deviation threshold is determined based on the minimum insulation distance required between the moving and stationary contacts after tripping and the measurement accuracy of the position sensor, to ensure sufficient insulation gap after tripping and prevent breakdown. The rebound amplitude threshold is determined based on the critical gap distance for arc reignition after contact separation and the typical characteristics of mechanical rebound, to prevent contact rebound from causing arc reignition and ensure reliable disconnection.

[0084] The closing operation braking determination unit determines that the current braking cycle is unqualified based on the determination result that any parameter is not less than the corresponding threshold, and issues a performance degradation warning.

[0085] Specifically, in step S7, the process of analyzing the cumulative operating characteristic factors of the target circuit breaker includes: Step S71: Determine the first cumulative operation characteristic factor based on the ratio of the cumulative coil energy consumption to the preset cumulative coil energy consumption threshold; Step S72: Determine the second cumulative operation characteristic factor based on the ratio of the cumulative braking number to the preset cumulative braking number threshold.

[0086] This embodiment also includes a single-cycle energy consumption determination unit, which determines the single-cycle energy consumption based on the capacitor discharge voltage and capacitor capacity during the current operation, providing basic data for the accumulation of coil energy consumption. Each time a closing or opening operation is completed, the single-cycle energy consumption is calculated based on the capacitor discharge voltage and capacitor capacity during the current operation.

[0087] This embodiment also includes an accumulated coil energy consumption determination unit, which determines the accumulated coil energy consumption based on the sum of single energy consumption, and is used to record the total work done by the equipment under normal conditions. It should be noted that only standard-compliant operating data is collected to directly characterize the cumulative characteristics of the equipment under normal conditions, avoiding distortion of analysis results by faulty operating data, which could lead to premature or late adjustment of drive parameters.

[0088] This embodiment also includes a cumulative operation characteristic factor determination unit, which determines a first cumulative operation characteristic factor based on the ratio of cumulative coil energy consumption to a preset cumulative coil energy consumption threshold. This factor characterizes the positive correlation between the overall work done by the equipment and the degradation of electromagnetic performance. The cumulative coil energy consumption threshold is determined through accelerated aging tests on the same model of equipment throughout its entire life cycle. Specifically, the cumulative coil energy consumption value corresponding to the first time performance indicators such as a decrease in permanent magnet remanence, a decrease in closing speed, and an increase in contact bounce time exceed the allowable range is taken as the critical threshold. When the cumulative coil energy consumption reaches this threshold, it indicates that the electromagnetic system has experienced significant performance degradation, requiring compensation and adjustment of the driving voltage to restore initial performance.

[0089] The cumulative operation characteristic factor determination unit determines a second cumulative operation characteristic factor based on the ratio of the cumulative braking count to a preset cumulative braking count threshold. This factor characterizes the degree of wear on moving parts caused by the number of mechanical friction cycles. The cumulative operation characteristic factor determination unit also determines the cumulative braking count based on the total number of successfully completed opening and closing operations, with each single closing and opening operation counted as one. The cumulative braking count threshold preferably corresponds to the rated mechanical life of the permanent magnet vacuum circuit breaker. Exceeding the rated mechanical life will cause a decrease in the magnetic energy product of the permanent magnet and mechanical wear, leading to a significant deviation of the opening and closing speed from the initial value.

[0090] In this embodiment, the first cumulative operating characteristic factor and the second cumulative operating characteristic factor are stored in the historical record, respectively, to provide a data basis for subsequent adaptive adjustment of driving parameters.

[0091] Specifically, in step S8, the process of determining whether to adjust the drive parameters for subsequent braking cycles includes: Based on the fact that the cumulative operation characteristic factor meets the second preset condition, it is determined that the driving parameters for subsequent braking cycles will be adjusted. The second preset condition is that the first cumulative operation feature factor is greater than a preset first cumulative operation feature factor threshold and the second cumulative operation feature factor is greater than a preset second cumulative operation feature factor threshold.

[0092] This embodiment also includes a drive parameter adjustment unit, which determines to adjust the drive parameters for subsequent braking cycles based on the cumulative operation characteristic factor meeting a second preset condition, for identifying a state where the equipment's cumulative consumption has reached the point requiring compensation and adjustment. If the first cumulative operation characteristic factor is greater than a preset first cumulative operation characteristic factor threshold and the second cumulative operation characteristic factor is greater than a preset second cumulative operation characteristic factor threshold, it is determined that the equipment has accumulated sufficient operation consumption, and the drive parameters for subsequent braking cycles are adjusted accordingly. The first and second cumulative operation characteristic factor thresholds are determined based on statistical characteristics of the equipment when its overall performance deteriorates to an inflection point in the middle of its lifespan. Specifically, this is achieved by conducting full life-cycle tests on the same model of equipment, collecting the correlation between cumulative coil energy consumption, cumulative braking counts, and closing speed decay and bounce deterioration, and taking the threshold value as the critical value at which both simultaneously cause the speed decay to exceed the allowable range but has not yet entered the accelerated deterioration stage.

[0093] Specifically, when the cumulative operating characteristic factors all exceed the cumulative operating characteristic factor threshold, it is determined that both electromagnetic and mechanical performance have shown significant but recoverable degradation. At this time, adjusting the drive parameters can not only proactively compensate before the performance declines significantly, but also avoid premature adjustment that leads to frequent parameter changes.

[0094] Specifically, if the first cumulative operating characteristic factor or the second cumulative operating characteristic factor does not exceed the corresponding threshold, the current driving parameter remains unchanged.

[0095] In this embodiment, the drive parameter adjustment unit is used to adjust the drive parameters, including increasing the amplitude of the full-acceleration drive voltage by a preset first adjustment step size and increasing the soft-start duty cycle rise rate by a preset second adjustment step size, to shorten the soft-start duration and thus compensate for the start-up delay caused by the decrease in the permanent magnet's magnetic energy product and the increase in friction. The electromagnetic force is proportional to the square of the drive voltage; increasing the drive voltage increases the electromagnetic force synchronously. Increasing the soft-start duty cycle rise rate shortens the start-up delay, and the combined compensation of these two factors allows the closing speed to be restored to a safe deviation range from the initial value. The first and second adjustment step sizes are determined based on the typical performance degradation amplitude of the equipment when the accumulated operating characteristic factors reach the adjustment threshold. Specifically, by statistically analyzing the speed degradation data of the same model of equipment during the middle of its lifespan, the minimum adjustment amplitude required to restore the speed to within the allowable positive and negative deviations of the initial value is selected, while ensuring that a single adjustment does not cause bounce deterioration or overshoot. If the speed still does not recover after adjustment, the adjustment continues to gradually increase by the same step size until the speed returns to the safe range.

[0096] The alternative drive parameter adjustment unit is also used to determine the performance degradation trend and trigger adjustment when the cumulative factor does not reach the threshold, based on the average speed deviation of the most recent operations. Even if the cumulative operation characteristic factor does not reach the aforementioned threshold, it is determined that the equipment has shown a performance degradation trend, and drive parameter adjustment is triggered in the same way as when the cumulative characteristic factor meets the standard. The average speed deviation safety value is determined based on the normal fluctuation range of the speed deviation within the qualified operation cycle of the equipment. Specifically, it is taken as a high quantile value of the statistical distribution of speed deviation in historical qualified operations to distinguish between normal speed fluctuations and abnormal speed deviations caused by performance degradation.

[0097] The drive parameter adjustment unit is also used to use the adjusted drive parameters as preset parameters for the next closing or opening operation and output them to the drive module to realize adaptive updating and closed-loop control of the drive parameters.

[0098] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for controlling the opening and closing of a permanent magnet mechanism vacuum circuit breaker, characterized in that, include: The pre-detection parameters of the target circuit breaker are compared and analyzed with the pre-detection parameter thresholds to determine whether it is in the opening and closing control operation range. The pre-detection parameters include grid voltage, load current and coil temperature. In response to the determination result that the circuit breaker is in the opening and closing control operation range, the soft start braking stage is initiated for the coil current of the target circuit breaker based on the preset driving parameters. The coil current duty cycle obtained during the soft start braking phase is compared and analyzed with a preset coil current duty cycle threshold to initiate a full acceleration braking phase for the target circuit breaker's coil current based on preset driving parameters. Based on the real-time coil current obtained during the full acceleration braking phase, determine whether to dynamically compensate the coil current duty cycle. The braking trigger position of the moving iron core is determined based on the real-time position and real-time speed of the moving iron core obtained during the full acceleration braking phase, and the full acceleration braking phase ends based on the real-time position of the moving iron core and the braking trigger position. After the full acceleration braking phase ends, acquire the contact detection parameters of the target circuit breaker to verify whether the current braking cycle meets the standard; In response to the current braking cycle meeting the standard, the cumulative operating characteristic factor of the target circuit breaker is analyzed based on the cumulative characteristic parameters of the historical braking cycles that meet the standard. The cumulative characteristic parameters include cumulative coil energy consumption and cumulative braking number. The cumulative operating characteristic factor is compared and analyzed with a preset cumulative operating characteristic factor threshold to determine whether to adjust the driving parameters of the subsequent braking cycle and output the driving parameters of the subsequent braking cycle. The driving parameters include the duty cycle rise rate of the soft start braking phase and the driving voltage amplitude of the full acceleration braking phase.

2. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 1, characterized in that, The process of determining whether the circuit is within the opening and closing control operation range includes: If all the pre-detection parameters meet the first preset condition, it is determined that the circuit breaker is in the opening and closing control operation range. The first preset condition is that the grid voltage is within a preset grid voltage range, the load current is less than a preset load current threshold, and the coil temperature is less than a preset coil temperature threshold.

3. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 2, characterized in that, The process of initiating the soft start braking phase includes: The coil current duty cycle of the target circuit breaker is linearly increased based on the preset coil current duty cycle rise rate. Calculate the variance of the deviation between the actual duty cycle sequence of the coil current and the theoretical linear rise sequence to determine the stability index during the soft start braking phase. Based on the comparison results of the stability index being greater than the preset stability index threshold, the preset coil current duty cycle rise rate is dynamically adjusted.

4. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 3, characterized in that, The process of fully accelerating the braking phase of opening the coil current of the target circuit breaker includes: Based on the first time the coil current duty cycle reaches the preset coil current duty cycle threshold, it is determined that the coil current of the target circuit breaker is in the full acceleration braking stage based on the preset driving voltage amplitude.

5. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 4, characterized in that, The process of determining whether to dynamically compensate for the coil current duty cycle includes: The current deviation value is calculated by comparing the real-time current sequence of the coil with the preset current time sequence. Based on the comparison results of the duration of the current deviation value being greater than the preset current deviation value threshold being greater than the preset duration threshold, it is determined that dynamic compensation of the coil current duty cycle is required.

6. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 5, characterized in that, The process of dynamically compensating for the duty cycle of the coil current includes: The first duty cycle adjustment amount is determined based on the difference between the current deviation value and the current deviation value threshold. The second duty cycle adjustment amount is determined based on the integral of the current deviation value over time; The duty cycle compensation amount is determined based on the first duty cycle adjustment amount and the second duty cycle adjustment amount.

7. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 6, characterized in that, The process of determining the braking trigger position of the moving iron core includes: Based on the first time the real-time position of the moving iron core reaches the preset position of the moving iron core, the current real-time speed of the moving iron core is obtained; Calculate the ratio of the current real-time speed of the moving iron core to a preset moving iron core speed threshold, and determine the braking trigger position based on the product of the ratio and a preset braking offset threshold.

8. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 7, characterized in that, The process of verifying whether the current braking cycle meets the standard includes: Based on the comparison results showing that all the contact detection parameters are less than the preset contact detection parameter threshold, it is determined that the current braking cycle meets the standard.

9. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 8, characterized in that, The process of analyzing the cumulative operating characteristic factors of the target circuit breaker includes: The first cumulative operation characteristic factor is determined based on the ratio of the cumulative coil energy consumption to the preset cumulative coil energy consumption threshold. The second cumulative operation characteristic factor is determined based on the ratio of the cumulative number of braking actions to a preset cumulative braking action threshold.

10. The opening and closing control method for a permanent magnet mechanism vacuum circuit breaker according to claim 9, characterized in that, The process of determining whether to adjust the drive parameters for subsequent braking cycles includes: Based on the fact that the cumulative operating characteristic factor meets the second preset condition, the driving parameters for subsequent braking cycles are adjusted. The second preset condition is that the first cumulative operation feature factor is greater than a preset first cumulative operation feature factor threshold and the second cumulative operation feature factor is greater than a preset second cumulative operation feature factor threshold.

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