Control method of rapid repulsion vacuum switch

Abstract

The invention relates to the technical field of vacuum switch control, and discloses a control method of a rapid repulsion vacuum switch, which comprises the following steps: forming a first discharge pulse in response to a closing instruction, so that a moving contact tends to move towards a target middle section; when it is detected that the displacement reaches a preset first displacement threshold value, a second discharge pulse is formed, so that the moving contact tends to the target middle speed; the voltage of the vacuum arc-extinguishing chamber and the current of the repulsion coil are collected in real time, when any one of the voltage and the current exceeds a limit, it is judged that pre-breakdown occurs, and a corresponding occurrence phase is recorded synchronously; in response to the pre-breakdown, executing a third discharge pulse according to the occurrence phase; if the pre-breakdown is not responded, when it is detected that the displacement reaches a preset second displacement threshold value, a third discharge pulse is formed according to a preset soft landing speed threshold value; and forming a fourth discharge pulse until it is monitored that the moving contact is switched on for the first time.

Description

Technical Field

[0001] This invention relates to the field of vacuum switch control technology, and more specifically, to a control method for a fast repulsive vacuum switch. Background Technology

[0002] With the continuous increase in power grid short-circuit capacity, traditional vacuum circuit breakers are gradually failing to meet the operational requirements of new systems in terms of opening and closing speed, synchronization accuracy, and vacuum switch reliability. Fast-repulsion vacuum switches have emerged to address this need. They employ a Thomson coil (also known as an eddy current repulsion coil) driven by capacitor discharge as the moving vacuum switch. A rapid pulse current generates a transient strong repulsive force to accelerate the moving contact, achieving high-speed closing (typical closing time less than 15ms) and high synchronization (three-phase dispersion less than 0.5ms). This technology is gradually being adopted in applications such as rail transit, wind power grid connection, and substation automation. Fast-repulsion vacuum switches have a relatively simple structure, typically consisting of an energy storage capacitor, pulse discharge, moving contact, and spring to form the actuation system. Their advantages include fast opening and closing speed, compact structure, and low maintenance. However, their motion control characteristics differ significantly from traditional spring-operated vacuum switches, especially presenting unique challenges at the final closing stage.

[0003] In the final stage of closing, the moving contact approaches the arc-extinguishing chamber contact. At this point, the main pulse driven by repulsion is nearing its end, and the movement of the moving contact mainly relies on inertia to complete the final displacement. During this process, because the closing speed is usually high (typically above 1 m / s), mechanical bouncing can easily occur when the moving contact strikes the main contact. The rebound behavior of the contact may cause short-term separation and re-contact, resulting in multiple arcing or micro-welding risks, leading to unstable contact, increased heat loss, shortened lifespan, and even unnecessary electrical breakdown under high voltage conditions.

[0004] Furthermore, in fast repulsion vacuum switches, the state of the terminal approaching the contact is affected by several nonlinear factors, such as: 1. Inertial residual vibration formed after the moving contact moves at high speed; 2. Elastic modulus, damping characteristics, and reaction force characteristics of the contact structure; 3. The electromagnetic force of the energy storage capacitor decays rapidly after discharge, resulting in a lack of effective driving force regulation at the end of the process. 4. Local electrical breakdown may occur during the closing process, causing current to flow through the contacts before mechanical contact is made, which further affects the contact quality and system response.

[0005] The combined effect of these problems makes it difficult for traditional single fixed pulse control methods to achieve a stable soft landing process at the end. A soft landing refers to a situation where the moving contact operates at a low speed upon contact and remains stable after contact, without significant bouncing or re-contact. Traditional control methods cannot effectively distinguish and handle minute disturbances caused by differences in speed, position, or electrical state. Therefore, in mass-produced products, problems such as poor closing consistency, wide bouncing distribution, and short mechanical life often occur.

[0006] To address this phenomenon, existing technologies mitigate it by increasing mechanical damping and raising holding current. However, these methods have many limitations in terms of space, power supply configuration, and response time, making it difficult to adapt to dynamic changes under different system states.

[0007] Therefore, existing technologies have the technical problem of making it difficult to accurately control the contact speed and holding force at the end of the closing stage. Summary of the Invention

[0008] This invention provides a control method for a fast repulsion vacuum switch, solving the technical problems mentioned in the background art.

[0009] This invention provides a control method for a fast repulsion vacuum switch, comprising: S1, in response to the closing command, generates the first discharge pulse, causing the moving contact to move towards the target middle section. S2, when the detected displacement reaches the preset first displacement threshold, a second discharge pulse is generated, causing the moving contact to move towards the target mid-section velocity; S3: Real-time acquisition of the voltage of the vacuum interrupter and the current of the repulsion coil. If either the voltage or the current exceeds the limit, it is determined that a pre-breakdown has occurred, and the corresponding phase of occurrence is recorded simultaneously. S4, in response to pre-breakdown, executes the third discharge pulse according to the occurrence phase; S5, if there is no response to pre-breakdown, then when the displacement is detected to reach the preset second displacement threshold, a third discharge pulse is generated according to the preset soft landing speed threshold; S6 continues until the first closing of the moving contact is detected, at which point the fourth discharge pulse is generated.

[0010] Furthermore, in response to the closing command, a first discharge pulse is generated, causing the moving contact to move towards the target middle section, including: Determine the timing of sending the closing command; The target duration of the first discharge pulse is calculated based on the target mid-section displacement, the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent mass of the moving contact, the equivalent resistance of the circuit, and the initial voltage of the first discharge, and the safe duration threshold of the first discharge pulse is determined. The first discharge pulse is applied at the moment the command is sent, and the current of the repulsion coil and the displacement of the moving contact are collected in real time. The first discharge pulse is terminated when the displacement of the moving contact reaches the target mid-section displacement. If the displacement of the moving contact does not reach the target mid-section displacement when the target duration of the first discharge pulse is reached, the pulse is terminated after a delay, provided that the safe duration threshold of the first discharge pulse is not exceeded.

[0011] Furthermore, when the detected displacement reaches a preset first displacement threshold, a second discharge pulse is generated, causing the moving contact to tend towards the target mid-section velocity, including: When the displacement of the moving contact reaches the preset first displacement threshold, the corresponding first arrival speed and first arrival time are determined. The speed increment is obtained by subtracting the target's mid-section speed from its initial arrival speed. The equivalent electromagnetic impulse of the second discharge pulse and the safe duration threshold of the second discharge pulse are determined based on the velocity increment. Based on the second discharge initial voltage, the equivalent inductance of the repulsion coil, the equivalent resistance of the loop, and the inductance gradient at the end of the repulsion coil, the target duration of the second discharge pulse is calculated. A second discharge pulse is applied at the first arrival time, and terminated when the target duration of the second discharge pulse is reached.

[0012] Furthermore, if either voltage or current exceeds its limit, a pre-breakdown is determined to have occurred, and the corresponding timestamp, occurrence gap, occurrence speed, and occurrence phase are recorded simultaneously, including: The voltage of the vacuum interrupter and the current of the repulsion coil are collected at fixed time intervals; The rate of change of current is determined based on the current in the repulsive coil; If the voltage of the vacuum interrupter is less than the preset voltage threshold and the current of the repulsion coil is greater than the preset current change rate threshold, then a pre-breakdown is determined to have occurred, and the pre-breakdown time is recorded. The occurrence time, occurrence gap, occurrence speed, and occurrence phase are determined at the pre-breakdown time.

[0013] Furthermore, in response to pre-breakdown, a third discharge pulse is executed according to the occurrence phase, including: The phase alignment delay is calculated based on the occurrence phase and the natural angular frequency of the moving contact, and the triggering time of the third discharge pulse is determined by the sum of the occurrence time and the phase alignment delay. The initial velocity of the third discharge pulse is calculated based on the displacement and velocity of the moving contact at the time of occurrence. The equivalent electromagnetic impulse required for the third discharge pulse is determined based on the initial velocity. The target duration of the third discharge pulse is calculated by combining the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent resistance of the circuit, and the initial voltage of the third discharge. The third discharge pulse is applied at the triggering time of the third discharge pulse and terminated when the target duration of the third discharge pulse is reached.

[0014] Furthermore, if there is no response to pre-breakdown, then when the detected displacement reaches a preset second displacement threshold, a third discharge pulse is generated based on a preset soft landing velocity threshold, including: When the displacement of the moving contact reaches the preset second displacement threshold, the corresponding second arrival speed and second arrival time are determined. The equivalent electromagnetic impulse of the third discharge pulse is calculated based on a preset soft landing speed threshold. The target duration of the third discharge pulse is calculated based on the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent resistance of the loop, and the initial voltage of the third discharge. A third discharge pulse is applied at the second arrival time, and terminated when the target duration of the third discharge pulse is reached.

[0015] Furthermore, until the first closing of the moving contact is detected, a fourth discharge pulse is generated, including: The voltage and displacement of the moving contact in the vacuum interrupter are collected at fixed time intervals. If the voltage of the vacuum interrupter is less than or equal to the preset contact voltage threshold, and the displacement of the moving contact is greater than or equal to the preset contact displacement threshold, then the first closing of the moving contact is determined, and the first closing time is recorded simultaneously. The rise time and total duration of the fourth discharge pulse are calculated based on the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, and the initial voltage of the fourth discharge. A fourth discharge pulse is applied during the initial closing time and terminated when the total duration of the fourth discharge pulse is reached.

[0016] The beneficial effects of this invention are as follows: By using a multi-segment discharge pulse control method, the system state is dynamically judged based on the displacement, speed and electrical state of the moving contact at different closing stages. Pulse electromagnetic drive with timing and quantitative characteristics is precisely applied, which effectively realizes the soft landing control of the fast repulsive vacuum switch during the end movement process, significantly suppresses contact bounce, improves closing stability and reliability, and ensures that the entire action process is fast, efficient and responsive. This solves the problems of insufficient output and mechanical impact caused by the difficulty in controlling the end movement characteristics in the prior art. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0018] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0019] like Figure 1 As shown, a control method for a fast repulsion vacuum switch includes: S1, in response to the closing command, generates the first discharge pulse, causing the moving contact to move towards the target middle section. S2, when the detected displacement reaches the preset first displacement threshold, a second discharge pulse is generated, causing the moving contact to move towards the target mid-section velocity; S3: Real-time acquisition of the voltage of the vacuum interrupter and the current of the repulsion coil. If either the voltage or the current exceeds the limit, it is determined that a pre-breakdown has occurred, and the corresponding phase of occurrence is recorded simultaneously. S4, in response to pre-breakdown, executes the third discharge pulse according to the occurrence phase; S5, if there is no response to pre-breakdown, then when the displacement is detected to reach the preset second displacement threshold, a third discharge pulse is generated according to the preset soft landing speed threshold; S6 continues until the first closing of the moving contact is detected, at which point the fourth discharge pulse is generated.

[0020] In detail, existing technologies mostly use a single fixed parameter discharge pulse to drive the moving contact movement, which cannot cope with the dynamic changes in each stage of closing: it is difficult to accurately control the mid-section displacement to lay a stable foundation during the start-up stage, the mid-section cannot correct the speed dispersion, and the end cannot take into account the differences between pre-breakdown and normal operating conditions, resulting in difficulty in soft landing, severe bouncing, and poor consistency.

[0021] The present invention constructs a complete dynamic control logic through the above steps: First, the closing process is divided into four core stages: start-up, mid-stage speed adjustment, end-stage deceleration, and landing hold. Each stage is triggered by pulses based on real-time monitored physical quantities (displacement, speed, voltage, and current), forming a closed-loop control of "state perception → pulse generation → dynamic correction", which breaks through the inherent defects of traditional open-loop fixed pulses. Second, a dedicated response mechanism from S3 to S4 was designed to address pre-breakdown, which affects the quality of end contact. This mechanism detects voltage / current over-limits in real time to determine pre-breakdown and generates a third pulse based on the recorded occurrence phase. This achieves precise dynamic compensation for random electrical disturbances and solves the problem that existing technologies cannot cope with contact instability caused by pre-breakdown. Third, by distinguishing between pre-breakdown and non-pre-breakdown scenarios, a third pulse is generated by combining phase alignment and the second displacement threshold with the soft landing velocity threshold, respectively, thus realizing adaptive deceleration control under different operating conditions and avoiding the inadequacy of a single control strategy to adapt to complex end environments. Fourth, by generating a fourth pulse during the first closing of the circuit via S6, a continuous holding force is provided, thereby suppressing bouncing and working in synergy with the preceding deceleration control to ultimately achieve a stable soft landing.

[0022] In one embodiment of the present invention, in response to a closing command, a first discharge pulse is generated, causing the moving contact to move towards the target middle section, including: Determine the timing of sending the closing command; The target duration of the first discharge pulse is calculated based on the target mid-section displacement, the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent mass of the moving contact, the equivalent resistance of the circuit, and the initial voltage of the first discharge, and the safe duration threshold of the first discharge pulse is determined. The first discharge pulse is applied at the moment the command is sent, and the current of the repulsion coil and the displacement of the moving contact are collected in real time. The first discharge pulse is terminated when the displacement of the moving contact reaches the target mid-section displacement. If the displacement of the moving contact does not reach the target mid-section displacement when the target duration of the first discharge pulse is reached, the pulse is terminated after a delay, provided that the safe duration threshold of the first discharge pulse is not exceeded.

[0023] In detail, the target duration is the pulse duration that theoretically allows the moving contact to reach the mid-section displacement of the target. Its calculation requires considering the relationship between electromagnetic drive and mechanical motion, as detailed below: The relationship between the electromagnetic force F generated by the repulsion coil, the coil current iL, and the inductance gradient Lx at the end of the repulsion coil is as follows: According to Newton's second law, the electromagnetic force F, the equivalent mass m of the moving contact, and the acceleration a of the moving contact have the following relationship: The relationship between the displacement x of the moving contact, the acceleration a of the moving contact, and time t is as follows: The relationship between the coil current iL and the initial voltage U1 of the first discharge, the equivalent inductance L of the repulsive coil, and time t is as follows: .

[0024] Combining the above relationships, substituting iL into the expression for F, then into the expression for a, and finally into the expression for x, we can obtain the relationship between the target mid-segment displacement Xmid and the target duration τ1 as follows: ; sorted out ; The setting of the safe duration threshold τ1max needs to take into account the maximum permissible Joule heat Qmax of the repulsion coil. The information was compiled and obtained. Where R represents the resistance of the repulsion coil, Imax represents the maximum allowable current of the repulsion coil, Imax is determined by the heat resistance characteristics of the repulsion coil material, and Qmax is determined by the heat capacity of the repulsion coil material.

[0025] In detail, the first discharge pulse includes: the first energy storage capacitor in the energy storage capacitor group discharges to the repulsion coil through the first switching device in the switching device group, forming the first discharge pulse.

[0026] In detail, the target mid-section displacement refers to the preset displacement target that the moving contact is expected to achieve in the mid-section stage during the closing process, as it moves from the initial position towards the closing direction. It serves as the control guide reference for the first discharge pulse, ensuring that the moving contact stably establishes a basic displacement in the initial stage of closing. The target mid-section displacement is designed to be between 40% and 60% of the total closing stroke.

[0027] In detail, the equivalent inductance of a repulsive coil represents a scalar approximation of the inductive impedance presented by the coil to current, reflecting the coil's ability to store magnetic energy and impede sudden changes in current. The equivalent inductance of a repulsive coil is calculated by measuring the impedance through a low-frequency AC excitation experiment.

[0028] In detail, the inductance gradient at the end of the repulsion coil represents the rate of change of inductance per unit displacement near the end position of the repulsion coil, directly affecting the electromagnetic force. The inductance gradient at the end of the repulsion coil is obtained by obtaining the inductance curve of the moving contact throughout its entire stroke through electromagnetic simulation, and then numerically differentiating the end region.

[0029] In detail, the equivalent mass of the moving contact represents the overall inertial characteristics of the moving contact and its following components as a concentrated mass, used to calculate the inertial force and kinetic energy of the moving contact's motion. The equivalent mass of the moving contact is obtained by directly weighing the mass of the moving contact and related moving components.

[0030] In detail, the equivalent resistance of the discharge circuit represents the equivalent series resistance of the discharge circuit (including the energy storage capacitor, triggering device, wires, repulsion coil, etc.), which affects the rise rate and peak value of the discharge current. The equivalent resistance of the discharge circuit is obtained by measuring the circuit impedance using an LCR meter and an impedance analyzer.

[0031] In detail, the initial voltage of the first discharge refers to the initial voltage across the first energy storage capacitor at the moment the first discharge pulse is triggered.

[0032] In detail, applying the first discharge pulse at the moment the command is sent directly links the closing command with the pulse drive, ensuring that the moving contact immediately receives driving force from a stationary state. Real-time acquisition of the current in the repulsion coil and the displacement of the moving contact is the core of closed-loop control. The current in the repulsion coil reflects the magnitude of the electromagnetic driving force, and the displacement of the moving contact reflects the actual motion state. Combining these two allows for real-time assessment of the matching degree between the pulse drive effect and the moving contact response. The first discharge pulse terminates when the displacement of the moving contact reaches the target mid-range displacement. This uses the target mid-range displacement as the core criterion, directly achieving precise control based on the target termination. This ensures that the moving contact can stably reach the preset target mid-range displacement in the initial stage of closing, avoiding excessive or insufficient movement. If the displacement of the moving contact has not reached the target mid-range displacement when the target duration of the first discharge pulse is reached, the circuit terminates after a delay, provided it does not exceed the safe duration threshold of the first discharge pulse. This design balances motion uncertainty and device safety. The target duration is the expected driving time based on theoretical calculations, while the safe duration threshold is the maximum allowable driving time set according to the coil's heat resistance and current resistance characteristics. The delayed termination can compensate for motion lag caused by factors such as frictional resistance and voltage fluctuations. At the same time, the pulse duration is strictly limited by the safe threshold to prevent the coil from being damaged due to prolonged energization.

[0033] In one embodiment of the present invention, when a displacement is detected to reach a preset first displacement threshold, a second discharge pulse is generated, causing the moving contact to tend toward the target mid-section velocity, including: When the displacement of the moving contact reaches the preset first displacement threshold, the corresponding first arrival speed and first arrival time are determined. The speed increment is obtained by subtracting the target's mid-section speed from its initial arrival speed. The equivalent electromagnetic impulse of the second discharge pulse and the safe duration threshold of the second discharge pulse are determined based on the velocity increment. Based on the second discharge initial voltage, the equivalent inductance of the repulsion coil, the equivalent resistance of the loop, and the inductance gradient at the end of the repulsion coil, the target duration of the second discharge pulse is calculated. A second discharge pulse is applied at the first arrival time, and terminated when the target duration of the second discharge pulse is reached.

[0034] In detail, when the displacement of the moving contact reaches a preset first displacement threshold, the corresponding first arrival speed and first arrival time are determined. The preset first displacement threshold is a displacement amount pre-set based on the mid-section position of the closing stroke, used to divide the mid-section control interval of the closing process.

[0035] In detail, the calculation of the first arrival velocity is based on the real-time rate of change of displacement. According to the sampling period Δt of the displacement sensor, the two consecutive sampling times before and after the first arrival time are t1 and t2, where t2 > t1, corresponding to displacements x1 and x2, respectively. When x2 equals a preset first displacement threshold, the first arrival velocity v1 can be calculated using the difference formula: v1 = (x2 - x1) / (t2 - t1). By utilizing the ratio of the displacement difference to the time difference between adjacent sampling points, the instantaneous velocity of the moving contact when it reaches the preset first displacement threshold is directly reflected.

[0036] In detail, the target mid-section speed is a pre-set ideal mid-section speed based on the dynamic characteristics of the closing process. The target mid-section speed is read as v0, and the speed increment Δv is calculated using the formula Δv = v0 - v1. If Δv is positive, it means the current speed is lower than the target and kinetic energy needs to be replenished through a second discharge pulse; if Δv is zero, it means the current speed exactly matches the target and no additional discharge is needed; if Δv is negative, it means the current speed has exceeded the target and no discharge is needed. The speed increment directly determines the equivalent electromagnetic impulse of the second discharge pulse.

[0037] In detail, the equivalent electromagnetic impulse and safe duration threshold of the second discharge pulse are determined based on the velocity increment. The velocity increment reflects the deviation between the actual velocity of the moving contact when it reaches the preset first displacement threshold and the velocity of the target mid-section. The velocity increment directly determines the required additional momentum. The equivalent electromagnetic impulse is a physical quantity that converts the velocity increment into the time-cumulative effect of the electromagnetic driving force, used to reflect the integral of the electromagnetic force over time. Since the electromagnetic force is related to the square of the repulsive coil current and the inductance gradient, and the current is determined by the discharge pulse parameters, it is necessary to establish the relationship between the velocity increment and the equivalent electromagnetic impulse through momentum conservation. Specifically, the momentum change required by the moving contact is equal to the product of its equivalent mass and the velocity increment. This momentum change needs to be provided by the equivalent electromagnetic impulse of the second discharge pulse. Therefore, the formula for calculating the equivalent electromagnetic impulse J2 is: J2 = m × Δv.

[0038] The safe duration threshold for the second discharge pulse is an upper limit set to prevent damage to the device due to over-discharge. Determining the second discharge pulse requires comprehensive consideration of the thermal tolerance of the repulsion coil, the discharge characteristics of the energy storage capacitor, and the electrical limits of the switching device. Typically, this is achieved by experimentally testing the temperature changes and insulation status of the device at different durations, and taking the maximum duration that does not lead to performance degradation as the safe threshold, denoted as τ2max.

[0039] The target duration of the second discharge pulse, calculated based on the equivalent inductance of the repulsion coil at the initial voltage of the second discharge, the equivalent resistance of the loop, and the inductance gradient at the end of the repulsion coil, needs to consider the dynamic characteristics of the electromagnetic drive. During the second discharge pulse, the current change in the repulsion coil is affected by circuit parameters. When the duration τ2 of the second discharge pulse is much smaller than the coil time constant (τ2≪L / R, where L is the equivalent inductance of the repulsion coil and R is the equivalent resistance of the loop), the current rise phase can be approximated as a linear change, i.e., iL(t)≈(U2 / L)×t, where U2 is the initial voltage of the second discharge, t is the duration of the second discharge pulse, and iL(t) represents the current of the repulsion coil as the pulse duration changes.

[0040] The impulse generated by the electromagnetic force is obtained by integrating (1 / 2)×i1²(t)×Lx over time, with the integration interval from 0 to τ2. Substituting the current expression into the integral, we get... The integral result must be equal to the aforementioned equivalent electromagnetic impulse J2, from which the formula for calculating the target duration τ2 can be derived: The equivalent electromagnetic impulse can be converted into a specific pulse duration by using the calculation formula of the target duration τ2, thus realizing the mapping from the velocity target to the discharge parameters.

[0041] In detail, the first arrival time, determined when the displacement of the moving contact reaches the preset first displacement threshold, is the precise starting point for applying the second discharge pulse. The selection of the first arrival time is directly related to the timeliness of the mid-range speed control. Only by starting the second discharge pulse at this moment can targeted speed correction be made based on the measured first arrival speed, avoiding control deviations caused by time delays.

[0042] The application of the second discharge pulse must strictly adhere to the calculated target duration. The target duration is the optimal discharge time derived from the equivalent electromagnetic impulse required for the speed increment and circuit parameters. The target duration ensures that the time-cumulative effect of the electromagnetic force precisely compensates for the momentum required for the moving contact to reach the target mid-range speed. Let the first arrival time be t2 and the target duration be τ3, then the formula for calculating the termination time t2 of the second discharge pulse is t2 = t1 + τ2. At time t2, the control system must immediately disconnect the second discharge circuit and terminate the pulse output to prevent over-discharge from causing speed overshoot or device overload.

[0043] The termination displacement of the second discharge pulse recorded at the termination time is the actual position of the moving contact at time t2. This displacement is obtained based on real-time sampling by a displacement sensor, and its value can be derived through kinematic relationships. According to the acceleration a of the moving contact during the second discharge pulse, the acceleration is determined by the electromagnetic force, i.e., a = F / m, where the electromagnetic force F = 0.5 × iL² × Lx, and iL changes approximately linearly during the pulse, iL(t) = (U² / L) × (t - t1). Then, the formula for calculating the termination displacement x2 is x2 = x1 + v1 × τ2 + 0.5 × a × τ2², where x1 is the preset first displacement threshold and v1 is the first arrival velocity.

[0044] The termination velocity is the instantaneous velocity of the moving contact at time t2, and it is a direct indicator of the control effect of the second discharge pulse. Its calculation formula is v2 = v1 + a × τ2, where a is the average acceleration during the pulse. The termination velocity should be close to the target mid-range velocity; its deviation reflects the control accuracy and provides crucial initial velocity values ​​for the parameter calculation of the subsequent third discharge pulse.

[0045] In one embodiment of the present invention, when either voltage or current exceeds its limit, a pre-breakdown is determined to have occurred, and the corresponding timestamp, occurrence gap, occurrence speed, and occurrence phase are recorded simultaneously, including: The voltage of the vacuum interrupter and the current of the repulsion coil are collected at fixed time intervals; The rate of change of current is determined based on the current in the repulsive coil; If the voltage of the vacuum interrupter is less than the preset voltage threshold and the current of the repulsion coil is greater than the preset current change rate threshold, then a pre-breakdown is determined to have occurred, and the pre-breakdown time is recorded. The occurrence time, occurrence gap, occurrence speed, and occurrence phase are determined at the pre-breakdown time.

[0046] In detail, acquiring the voltage of the vacuum interrupter and the current of the repulsion coil at fixed time intervals is the basis for pre-breakdown determination. A fixed sampling period of Ts is set, and the voltage signal of the vacuum interrupter and the current signal of the repulsion coil are acquired sequentially at each sampling moment. The voltage of the vacuum interrupter at the k-th sampling moment is denoted as uVI[k], and the current of the repulsion coil at the k-th sampling moment is denoted as iL[k]. The corresponding sampling moment is t[k] = t0 + k × Ts, where t0 is the initial sampling moment, and k is the sampling sequence number and is a non-negative integer.

[0047] In detail, determining the rate of change of current based on the current in the repulsion coil requires discrete-time difference analysis. The rate of change of current reflects the trend of current change over time and is a key characteristic quantity when pre-breakdown occurs. At the k-th sampling time, the formula for calculating the rate of change of current aiL[k] is aiL[k] = (iL[k] - iL[k-1]) / Ts. The formula for calculating the rate of change of current aiL[k] directly reflects the average rate of change of current by dividing the current difference between two adjacent sampling times by the sampling period, where iL[k] is the repulsion coil current at the k-th sampling time, and iL[k-1] is the repulsion coil current at the (k-1)-th sampling time.

[0048] In detail, the determination of pre-breakdown needs to be based on a dual threshold comparison of voltage and current change rate. The preset voltage threshold is Ups,th, and the preset current change rate threshold is Ips,th. When the voltage uVI[k] of the vacuum interrupter is less than Ups,th or the current change rate of the repulsion coil |aiL[k]| is greater than Ips,th, the single-time over-limit condition is met. To avoid misjudgment caused by transient noise interference, a continuous determination mechanism needs to be introduced: when any of the above over-limit conditions is met for three consecutive sampling times, pre-breakdown can be determined to have occurred.

[0049] It should be noted that pre-breakdown is a localized, transient electrical discharge phenomenon that occurs during the closing process of a vacuum switch, in the small gap stage (usually less than 1 mm) just before the contacts make mechanical contact. Essentially, as the gap between the moving and stationary contacts gradually decreases, the electric field strength generated by the voltage between the contacts (electric field strength E = voltage between contacts U / gap g) exceeds the critical breakdown field strength in a vacuum environment (the critical vacuum field strength is approximately 10). 6 -10 7When the vacuum interrupter is at a voltage (V / m), a weak discharge occurs in the gap due to electron emission and residual gas ionization. However, the discharge energy is low and the duration is short (usually on the order of microseconds), a stable arc has not yet formed, and the contacts have not yet made mechanical contact. Therefore, this is called pre-breakdown. Pre-breakdown is accompanied by two significant characteristics: first, the voltage across the vacuum interrupter suddenly drops (due to the voltage reduction caused by localized conduction in the gap); second, the current through the gap exhibits high-frequency pulses (due to the formation of a brief current due to instantaneous charge transfer). These characteristics can be monitored by voltage and current sensors and are the basis for determining pre-breakdown in the technical solution. The occurrence of pre-breakdown is random. The timing of its occurrence and the corresponding gap size (the gap in question) are affected by various factors, such as the microscopic morphology of the contact surface (e.g., burrs and erosion marks can change the local electric field), voltage fluctuations between contacts, and slight changes in vacuum. This results in the discreteness of the pre-breakdown state in different closing operations of the same batch of equipment or the same equipment. In summary, pre-breakdown is a phenomenon where electrical conduction precedes mechanical contact. It can react with electromagnetic force on the moving contact (affecting its speed) and may also cause micro-erosion of the contact surface due to energy generated by partial discharge, thus affecting the stability of subsequent mechanical contact (increasing the risk of bounce). Therefore, in the control of fast repulsion vacuum switches, accurately identifying pre-breakdown and recording its occurrence (time, gap, speed, phase) is a crucial prerequisite for achieving precise control and ensuring closing quality.

[0050] In detail, the recorded pre-breakdown time must be strictly synchronized with the judgment result. When pre-breakdown is confirmed to have occurred, the corresponding sampling sequence number is kps, and the calculation formula for the occurrence time tps is tps = t0 + kps × Ts. This timestamp precisely corresponds to the occurrence time of pre-breakdown.

[0051] In detail, the occurrence velocity is the speed at which the moving contact moves when pre-breakdown occurs. The moving contact velocity is obtained through differential processing of the displacement signal. To suppress measurement noise, a first-order low-pass filter is first applied to the displacement sequence. Based on the filtered displacement corresponding to the occurrence time tps as xf[kps], and the previous sampling time as xf[kps-1], the calculation formula for the occurrence velocity vps is vps = (xf[kps] - xf[kps-1]) / Ts. This formula obtains the instantaneous velocity at the pre-breakdown moment by the ratio of the difference in the filtered displacement to the sampling period, ensuring the smoothness and accuracy of the velocity signal.

[0052] In detail, the occurrence phase is a comprehensive characterization of the vibration state of the moving contact when pre-breakdown occurs. Based on the dynamic characteristics of vacuum switches, the approximate natural angular frequency ωn is used as a calibration parameter, and its value is... Where kc is the equivalent stiffness at the end and m is the equivalent mass of the moving contact. Combining the displacement xps and velocity vps at the occurrence time tps, the formula for calculating the occurrence phase ϕps is ϕps=atan2(ωn×xps,vps). This formula normalizes the displacement and velocity to the same dimension through the arctangent function, forming an angular quantity that can be directly used for phase registration, accurately describing the position of the moving contact during the vibration period.

[0053] In one embodiment of the present invention, in response to pre-breakdown, a third discharge pulse is executed according to the occurrence phase, including: The phase alignment delay is calculated based on the occurrence phase and the natural angular frequency of the moving contact, and the triggering time of the third discharge pulse is determined by the sum of the occurrence time and the phase alignment delay. The initial velocity of the third discharge pulse is calculated based on the displacement and velocity of the moving contact at the time of occurrence. The equivalent electromagnetic impulse required for the third discharge pulse is determined based on the initial velocity. The target duration of the third discharge pulse is calculated by combining the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent resistance of the circuit, and the initial voltage of the third discharge. The third discharge pulse is applied at the triggering time of the third discharge pulse and terminated when the target duration of the third discharge pulse is reached.

[0054] In detail, the purpose of calculating the phase alignment delay Δt* is to precisely apply the third discharge pulse to the reverse phase of the moving contact's velocity peak, thereby offsetting the velocity increment caused by residual vibration. Specifically: In the simple harmonic motion at the end of the moving contact, the extreme point of velocity v(t) corresponds to phase π (at this time, the velocity direction is opposite to the closing direction, which is the optimal moment to suppress the forward velocity). The pre-breakdown occurs at phase ϕps. To ensure the third discharge pulse acts at phase π, the time interval corresponding to the phase difference from the occurrence phase ϕps to π needs to be calculated, i.e., the phase alignment delay. Since the rate of change of phase with time in simple harmonic motion is equal to the natural angular frequency ωn, the relationship between the phase difference Δφ and the time difference Δt is Δφ = ωn × Δt. The phase difference to be compensated here is π - ϕps, therefore the formula for calculating the phase alignment delay is Δt* = (π - ϕps) / ωn. The triggering time tp3 is the time when the third discharge pulse begins to be applied, and it must be strictly determined based on the occurrence time of the pre-breakdown event and the calculated phase alignment delay. The logic is as follows: starting from the pre-breakdown occurrence time tps, after a time difference Δt delay, the moving contact moves to the velocity reversal stage corresponding to phase π. Applying the third discharge pulse at this time can maximize the cancellation of the forward velocity. Therefore, the formula for calculating the trigger time is tp3 = tps + Δt.

[0055] In detail, the initial velocity of the third discharge pulse refers to the velocity of the moving contact before the triggering time of the third discharge pulse, that is, the velocity of the moving contact before being affected by the discharge at the triggering time tp3, denoted as v(tp3-). This velocity needs to be calculated based on the displacement and velocity of the moving contact when the pre-breakdown occurs, and the core basis is the simple harmonic motion characteristics of the near-end motion of the moving contact. When the pre-breakdown occurs, the displacement of the moving contact is xps, and the velocity is vps. At the end of the closing phase, the moving contact is subjected to the elastic force and damping force of the vacuum switch, and its motion can be approximated as simple harmonic motion, and the relationship between its displacement and velocity and time satisfies the simple harmonic motion equation. Let the time interval from the pre-breakdown occurrence time tps to the triggering time of the third discharge pulse tp3 be the phase alignment delay Δt*, then the motion of the moving contact within the phase alignment delay Δt* can be described by the simple harmonic motion formula: The displacement changes with time as follows: x(tps+Δt*)=xps×cos(ωn×Δt*)+(vps / ωn)sin(ωn×Δt*) The change of speed over time is as follows: v(tp3-)=-ωn×xps×sin(ωn×Δt*)+vps×cos(ωn×Δt*) The velocity of the moving contact before the third discharge can be obtained by analyzing the measured state (xps, vps) and calibration parameter ωn when the pre-breakdown occurs.

[0056] In detail, the equivalent electromagnetic impulse is the integral of the electromagnetic force required by the third discharge pulse over time. Its function is to reduce the moving contact velocity to within the allowable range for soft landing. This equivalent electromagnetic impulse is determined based on the initial velocity before the third discharge, and the specific logic is as follows: Based on the preset momentum decay coefficient β3, whose value is between 0 and 1, it is used to specify the percentage of velocity reduction required for this discharge (for example, β3 = 0.8 means that 80% of the initial velocity needs to be reduced). According to the momentum theorem, the change in momentum of the moving contact is equal to the impulse of the net external force. Here, the momentum that the electromagnetic impulse needs to cancel is the product of the moving contact mass and the velocity to be reduced. Therefore, the formula for calculating the required equivalent electromagnetic impulse J3,req is: J3,req=m×β3×|v(tp3-)| Where |v(tp3-)| is the absolute value of the initial velocity before the third discharge. This formula transforms the velocity control target into a quantifiable electromagnetic impulse requirement, ensuring a precise match between the discharge energy and the velocity reduction target.

[0057] In detail, the target duration of the third discharge pulse refers to the time from the triggering of the pulse to its termination, denoted as τ3*. It needs to be calculated in conjunction with circuit parameters and equivalent electromagnetic impulse requirements. The core basis is the relationship between electromagnetic force and current and the integral definition of impulse.

[0058] The electromagnetic force F of the repulsion coil is related to the coil current iL by F = (1 / 2)iL² × Lx. The third discharge pulse is powered by the energy storage capacitor. Under engineering conditions where the equivalent resistance R of the circuit is small and the pulse duration τ3 is much smaller than L / R (L is the equivalent inductance of the repulsion coil), the coil current rises approximately linearly, i.e., iL(t) ≈ (U3 / L)(t-tp3), where U3 is the initial voltage of the third discharge and t is the duration of the third discharge pulse.

[0059] The electromagnetic impulse J3 is the integral of the electromagnetic force over time, that is: Substituting the current approximation into the integral, we get: Let the required equivalent electromagnetic impulse J3,req be equal to the actual electromagnetic impulse J3, and the target duration be obtained: If the calculated target duration exceeds the safe upper limit duration allowed by the vacuum switch (the safe upper limit duration is limited by the electrothermal characteristics), then take... Equal to the maximum safe duration.

[0060] In detail, at the trigger time tp3 of the third discharge pulse, the third branch switch is turned on, causing the third energy storage capacitor to discharge to the repulsion coil. The pulse duration is the calculated τ3. After the duration is reached, the switch is turned off, terminating the discharge. The formula for calculating the pulse termination time tp3 is tp3 = tp3 + τ3. The pulse peak current I3,pk is the maximum value of the current rising segment, which can be approximated by the current approximation formula: I3,pk ≈ (U3 / L) × τ3. Recorded parameters include pulse termination time tp3, duration τ3, and peak current I3,pk.

[0061] In one embodiment of the present invention, if there is no response to pre-breakdown, then when the detected displacement reaches a preset second displacement threshold, a third discharge pulse is generated based on a preset soft landing velocity threshold, including: When the displacement of the moving contact reaches the preset second displacement threshold, the corresponding second arrival speed and second arrival time are determined. The equivalent electromagnetic impulse of the third discharge pulse is calculated based on a preset soft landing speed threshold. The target duration of the third discharge pulse is calculated based on the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent resistance of the loop, and the initial voltage of the third discharge. A third discharge pulse is applied at the second arrival time, and terminated when the target duration of the third discharge pulse is reached.

[0062] In detail, the preset second displacement threshold is a fixed parameter determined during the calibration phase of the vacuum switch to define the starting position of the final stage deceleration control. The displacement of the moving contact is continuously measured in real-time using a displacement sensor to obtain a continuous function of displacement over time. When the real-time measured displacement value first equals or exceeds the preset second displacement threshold, the control system immediately records that moment; this moment is the second arrival time.

[0063] In detail, the specific process for determining the second arrival time is as follows: The displacement of the moving contact is collected in real time by a displacement sensor. This displacement changes continuously with time. When the real-time collected displacement is equal to or exceeds the preset second displacement threshold, the control system immediately records the time at this moment. This moment is the second arrival time, which represents the time node when the moving contact moves to the preset end deceleration start position.

[0064] In detail, the process of determining the second arrival velocity is based on the second arrival time and is implemented using the differential method. Specifically, within a fixed sampling interval Ts before and after the second arrival time, two adjacent displacement data are collected. The displacement corresponding to the time before the second arrival time is tp3-Ts is x(tp3-Ts), and the displacement corresponding to the time after the second arrival time is tp3+Ts is x(tp3+Ts). The formula for calculating the second arrival velocity v(tp3) is as follows: v(tp3)=[x(tp3+Ts)-x(tp3-Ts)] / 2Ts The calculation formula obtains the instantaneous velocity through a local linear approximation to ensure that the movement velocity of the moving contact can be accurately obtained when the displacement threshold is reached.

[0065] In detail, after obtaining the second arrival speed and the preset soft landing speed threshold, it is necessary to calculate the equivalent electromagnetic impulse of the third discharge pulse. First, it is clear that the preset soft landing speed threshold represents the maximum speed allowed when the moving contact and the stationary contact are in contact. Exceeding the preset soft landing speed threshold will cause the closing bounce to intensify. Therefore, it is necessary to decelerate the moving contact through the electromagnetic force generated by the third discharge pulse. The calculation process consists of two steps: First, the required speed correction is determined. This required speed correction is the difference between the second arrival speed and the preset soft landing speed threshold. If the second arrival speed is less than or equal to the preset soft landing speed threshold, the required speed correction is 0, indicating no deceleration is needed. If the second arrival speed is greater than the preset soft landing speed threshold, the required speed correction is the difference between the two, representing the extent to which the moving contact speed needs to be reduced. Second, the required speed correction ΔV3 is converted into an equivalent electromagnetic impulse. According to the momentum theorem, the change in momentum equals the impulse of the net external force. Considering only the electromagnetic force generated by the third discharge pulse, the electromagnetic impulse must be equal to the product of the moving contact mass and the required speed correction, as follows: J3,req=m×ΔV3 Among them, the equivalent electromagnetic impulse J3,req is the minimum impulse that the third discharge pulse needs to provide.

[0066] In detail, under the condition that no pre-breakdown is detected, the calculation of the target duration of the third discharge pulse needs to be based on the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent resistance of the circuit, and the initial voltage of the third discharge, and is achieved through analytical derivation; its core is to establish a quantitative relationship between electromagnetic impulse and pulse duration to ensure that the impulse provided by the pulse just meets the deceleration requirements: First, the equivalent inductance of the repulsion coil, L, reflects the coil's resistance to changes in current. The inductance gradient at the end of the repulsion coil, Lx, describes the rate of change of the coil inductance as the moving contact moves. The equivalent resistance of the parameter loop, R, includes the coil resistance and the sum of other loop resistances. The initial voltage of the third discharge, U3, is the voltage value when the third energy storage capacitor begins to discharge.

[0067] Next, the current characteristics of the discharge process are analyzed. In engineering applications, the duration τ3 of the third discharge pulse is much smaller than the loop time constant L / R. At this time, the current increases approximately linearly with time, and its expression is: iL(t)≈(U3 / L)(t-tp3) The rationale for this approximation is that the energy loss of the resistor during the current rise phase under short pulse conditions is extremely small, and it can be simplified to a pure inductor circuit model. Then, the relationship between electromagnetic impulse and pulse duration is derived: Electromagnetic force is the direct cause of the deceleration effect, and the magnitude of the electromagnetic force is related to the square of the current and the inductance gradient by the following expression: The electromagnetic impulse J3 is the integral of the electromagnetic force over the pulse duration, that is, the integral of the electromagnetic force from tp3 to tp3+τ3: Substituting the current expression into the integral, we get: After solving the integral, the relationship between the electromagnetic impulse and the pulse duration is as follows: Let J3 equal J3,req, then the target duration τ3 is: If the calculated target duration exceeds the safe upper limit duration allowed by the vacuum switch (the safe upper limit duration is limited by the electrothermal characteristics), then take... Equal to the maximum safe duration.

[0068] In detail, the application time of the third discharge pulse is strictly tied to the second arrival time. When the displacement of the moving contact reaches the preset second displacement threshold, the control system records this moment as the second arrival time tp3. At this moment, the control system immediately triggers the third branch switch to conduct, causing the third energy storage capacitor to begin discharging to the repulsion coil, that is, the start time of the third discharge pulse is tp3.

[0069] The termination time of the third discharge pulse is determined by the target duration. Based on the target duration τ3, when the pulse application time reaches τ3, the control system immediately shuts off the third branch switch, terminating the discharge.

[0070] The formula for calculating the pulse termination time is: t3 = tp3 + τ3. Where t3 is the termination time of the third discharge pulse. This termination logic ensures that the electromagnetic impulse provided by the pulse precisely meets the deceleration requirements, preventing insufficient deceleration due to an excessively short pulse, and avoiding excessively long pulses that cause excessively low speed or device overload.

[0071] In one embodiment of the present invention, a fourth discharge pulse is generated until the moving contact is detected to close for the first time, including: The voltage and displacement of the moving contact in the vacuum interrupter are collected at fixed time intervals. If the voltage of the vacuum interrupter is less than or equal to the preset contact voltage threshold, and the displacement of the moving contact is greater than or equal to the preset contact displacement threshold, then the first closing of the moving contact is determined, and the first closing time is recorded simultaneously. The rise time and total duration of the fourth discharge pulse are calculated based on the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, and the initial voltage of the fourth discharge. A fourth discharge pulse is applied during the initial closing time and terminated when the total duration of the fourth discharge pulse is reached.

[0072] In detail, the voltage uVI[k] of the vacuum interrupter represents the voltage value at the kth sampling moment, reflecting the electrical connection state between the moving contact and the stationary contact; the displacement x[k] of the moving contact represents the displacement value at the kth sampling moment, reflecting the mechanical position state of the moving contact.

[0073] In detail, the initial closing determination must meet both electrical and mechanical conditions to eliminate false triggering caused by interference from a single signal: Electrical conditions: The voltage of the vacuum interrupter is reduced to below the preset contact voltage threshold, i.e., uVI[k]≤Uc,th, where Uc,th is the contact voltage threshold, which is determined by the contact material and the rated voltage, and represents the voltage characteristic value after the contact is made. Mechanical conditions: The displacement of the moving contact reaches or exceeds the preset contact displacement threshold, i.e., x[k]≥Xc,th, where Xc,th is the contact displacement threshold, which is determined by the mechanical structure of the switch and represents the displacement characteristic value at which the contacts begin to make contact.

[0074] When the above electrical and mechanical conditions are met simultaneously, the system determines that the first closing of the moving contact is successful and immediately records the moment as the first closing time tc.

[0075] In detail, to suppress closing bounce, the kinetic energy of the moving contact before contact needs to be absorbed. The velocity at the sampling moment before contact is vc*. The kinetic energy that needs to be absorbed is: ; To ensure sufficient magnetic work is provided within the micro-clamping stroke Δc (where Δc represents the calibrated allowable minute displacement after contact), and considering a safety factor γ≥1, the lower limit of the current must meet the following requirements: The current of the fourth discharge pulse needs to rise to Based on the circuit characteristics, when the pulse duration is much smaller than the loop time constant (τ4≪L / R, where L is the equivalent inductance of the repulsion coil and R is the equivalent resistance of the loop), the current increases approximately linearly. iL(t)=(U4 / L)(t-tc) Wherein, U4 represents the fourth discharge initial voltage, that is, the initial voltage of the fourth energy storage capacitor.

[0076] When the current reaches When the rise time is: .

[0077] The total duration of the fourth discharge pulse must include both the current rise phase and the holding phase. The holding phase time must ensure sufficient decay of the initial vibration after contact. Based on the inherent characteristics of the vacuum switch: its inherent angular frequency ωn and damping ratio ζ, the lower limit of the holding time is: ≥3 / ζ×ωn, Therefore, the total duration of the fourth discharge pulse is: .

[0078] At the initial closing time tc, the control system immediately activates the fourth branch switch via the fourth energy storage capacitor, initiating the fourth discharge pulse: forward Within a time period, the current increases linearly from 0 to The above steps quickly establish sufficient electromagnetic force. The following During the time period, the maintaining current is not lower than To ensure stable contact between the contacts; When the pulse duration reaches When the discharge is stopped, immediately turn off the fourth branch switch to terminate the discharge. The termination time is: t4off = tc + τ4.

[0079] The embodiments of this example have been described above. However, this example is not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this example, and all of them are within the protection scope of this example.

Claims

1. A control method for a fast repulsive vacuum switch, characterized in that, include: S1, in response to the closing command, generates the first discharge pulse, causing the moving contact to move towards the target middle section. S2, when the detected displacement reaches the preset first displacement threshold, a second discharge pulse is generated, causing the moving contact to move towards the target mid-section velocity; S3: Real-time acquisition of the voltage of the vacuum interrupter and the current of the repulsion coil. If either the voltage or the current exceeds the limit, it is determined that a pre-breakdown has occurred, and the corresponding phase of occurrence is recorded simultaneously. S4, in response to pre-breakdown, executes the third discharge pulse according to the occurrence phase; S5, if there is no response to pre-breakdown, then when the displacement is detected to reach the preset second displacement threshold, a third discharge pulse is generated according to the preset soft landing speed threshold; S6 continues until the first closing of the moving contact is detected, at which point the fourth discharge pulse is generated.

2. The control method for a fast repulsion vacuum switch according to claim 1, characterized in that, In response to the closing command, a first discharge pulse is generated, causing the moving contact to move towards the target middle section, including: Determine the timing of sending the closing command; The target duration of the first discharge pulse is calculated based on the target mid-section displacement, the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent mass of the moving contact, the equivalent resistance of the circuit, and the initial voltage of the first discharge, and the safe duration threshold of the first discharge pulse is determined. The first discharge pulse is applied at the moment the command is sent, and the current of the repulsion coil and the displacement of the moving contact are collected in real time. The first discharge pulse is terminated when the displacement of the moving contact reaches the target mid-section displacement. If the displacement of the moving contact does not reach the target mid-section displacement when the target duration of the first discharge pulse is reached, the pulse is terminated after a delay, provided that the safe duration threshold of the first discharge pulse is not exceeded.

3. The control method for a fast repulsion vacuum switch according to claim 2, characterized in that, When the detected displacement reaches a preset first displacement threshold, a second discharge pulse is generated, causing the moving contact to move towards the target mid-section velocity, including: When the displacement of the moving contact reaches the preset first displacement threshold, the corresponding first arrival speed and first arrival time are determined. The speed increment is obtained by subtracting the target's mid-section speed from its initial arrival speed. The equivalent electromagnetic impulse of the second discharge pulse and the safe duration threshold of the second discharge pulse are determined based on the velocity increment. Based on the second discharge initial voltage, the equivalent inductance of the repulsion coil, the equivalent resistance of the loop, and the inductance gradient at the end of the repulsion coil, the target duration of the second discharge pulse is calculated. A second discharge pulse is applied at the first arrival time, and terminated when the target duration of the second discharge pulse is reached.

4. The control method for a fast repulsion vacuum switch according to claim 3, characterized in that, If either voltage or current exceeds its limit, a pre-breakdown is determined to have occurred, and the corresponding timestamp, occurrence gap, occurrence speed, and occurrence phase are recorded simultaneously, including: The voltage of the vacuum interrupter and the current of the repulsion coil are collected at fixed time intervals; The rate of change of current is determined based on the current in the repulsive coil; If the voltage of the vacuum interrupter is less than the preset voltage threshold and the current of the repulsion coil is greater than the preset current change rate threshold, then a pre-breakdown is determined to have occurred, and the pre-breakdown time is recorded. The occurrence time, occurrence gap, occurrence speed, and occurrence phase are determined at the pre-breakdown time.

5. The control method for a fast repulsion vacuum switch according to claim 4, characterized in that, In response to pre-breakdown, a third discharge pulse is executed according to the occurrence phase, including: The phase alignment delay is calculated based on the occurrence phase and the natural angular frequency of the moving contact, and the triggering time of the third discharge pulse is determined by the sum of the occurrence time and the phase alignment delay. The initial velocity of the third discharge pulse is calculated based on the displacement and velocity of the moving contact at the time of occurrence. The equivalent electromagnetic impulse required for the third discharge pulse is determined based on the initial velocity. The target duration of the third discharge pulse is calculated by combining the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent resistance of the circuit, and the initial voltage of the third discharge. The third discharge pulse is applied at the triggering time of the third discharge pulse and terminated when the target duration of the third discharge pulse is reached.

6. The control method for a fast repulsion vacuum switch according to claim 5, characterized in that, If there is no response to pre-breakdown, then when the detected displacement reaches a preset second displacement threshold, a third discharge pulse is generated based on a preset soft landing velocity threshold, including: When the displacement of the moving contact reaches the preset second displacement threshold, the corresponding second arrival speed and second arrival time are determined. The equivalent electromagnetic impulse of the third discharge pulse is calculated based on a preset soft landing speed threshold. The target duration of the third discharge pulse is calculated based on the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, the equivalent resistance of the loop, and the initial voltage of the third discharge. A third discharge pulse is applied at the second arrival time, and terminated when the target duration of the third discharge pulse is reached.

7. The control method for a fast repulsion vacuum switch according to claim 6, characterized in that, The fourth discharge pulse is generated only when the moving contact is detected to be closed for the first time, including: The voltage and displacement of the moving contact in the vacuum interrupter are collected at fixed time intervals. If the voltage of the vacuum interrupter is less than or equal to the preset contact voltage threshold, and the displacement of the moving contact is greater than or equal to the preset contact displacement threshold, then the first closing of the moving contact is determined, and the first closing time is recorded simultaneously. The rise time and total duration of the fourth discharge pulse are calculated based on the equivalent inductance of the repulsion coil, the inductance gradient at the end of the repulsion coil, and the initial voltage of the fourth discharge. A fourth discharge pulse is applied during the initial closing time and terminated when the total duration of the fourth discharge pulse is reached.

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