Anti-electrical shaking device and method based on magnetic switch

Abstract

The present invention discloses an anti-electrical sway device and method based on a magnetic switch, which relates to the technical field of anti-electrical sway. The present invention adopts a sliding average filter to reduce the interference of instantaneous voltage fluctuations, and combines the short-time Fourier transform STFT to extract the instantaneous change of the low-frequency component, so as to more accurately identify the voltage drop of the power grid and effectively avoid the problem of misjudgment or omission of the traditional method due to short-term fluctuations; in the AC / DC switching strategy, the current voltage phase is calculated and matched with the optimal switching phase to ensure that the AC / DC voltage difference is minimized during switching, thereby reducing current shock and avoiding vibration of the contactor contacts caused by phase deviation; at the same time, the DC support voltage is dynamically adjusted in combination with the exponential smoothing function, and the voltage change during the switching process is more stable; in the DC support mode, the magnetic locking technology is adopted to enhance the stability of the contactor contacts, and by real-time monitoring of the contact state quantity, the contacts will not be mistakenly released due to fluctuations in electromagnetic attraction during the electric sway.

Description

Technical Field

[0001] The present invention relates to the field of anti-electrical shaking technology, and in particular to an anti-electrical shaking device and method based on a magnetic switch. Background Art

[0002] Power sloshing is a common phenomenon in industrial production and power systems. Power sloshing is caused by transmission line failures, large load shocks, or remote grid disturbances. Although it lasts for a short time, it can still cause equipment tripping, production interruptions, and even equipment damage.

[0003] Traditional anti-power sway methods primarily address the power supply and load sides, such as dynamic VAR compensation (SVG), dual power switching, low-voltage ride-through inverters, or contactor retention modules. These methods struggle to balance the characteristics of diverse loads. For devices that rely on electromagnetic attraction, such as AC contactors, even if power is quickly restored, electromagnetic force fluctuations can cause them to release unexpectedly, leading to unexpected power outages.

[0004] To reduce such risks, a common solution uses a DC support module to provide short-term DC to maintain contactor coil excitation when the voltage drops. However, different contactors respond differently to the DC support, and phase mismatch during the switching process may cause short-term current mutations, resulting in slight contact vibration. This vibration will not immediately cause equipment shutdown, but it may affect the life of the contactor and cause relay mistriggers or control system abnormalities in highly sensitive load scenarios, such as continuous production lines or data centers. Existing flexible switching solutions use fixed logic to calculate the optimal switching phase, reducing impact. However, when faced with different load characteristics, especially high-power contactors, slight vibrations may still occur, affecting system stability. Therefore, how to optimize the contactor's anti-electrical shaking capability and prevent contact vibration during switching without increasing additional hardware costs has become an important optimization direction for anti-electrical shaking technology. Summary of the Invention

[0005] In view of the above existing problems, the present invention is proposed.

[0006] The present invention provides an anti-sway device and method based on a magnetic switch to solve the problems that the contactor may still be released incorrectly after power supply is restored, the DC support solution responds unstablely under different loads, and the switching phase mismatch causes contact vibration, which affects the equipment life and system stability.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides an anti-electrical shaking device based on a magnetic switch, which includes:

[0009] Voltage detection module, switching control module, DC support module, magnetic stabilization module, status monitoring module and power recovery module:

[0010] The voltage detection module is used to detect grid voltage changes, determine whether power fluctuations occur, and output a power fluctuation signal when the voltage is lower than a set threshold;

[0011] The switching control module receives the power shaking signal, calculates the optimal AC / DC switching phase, and outputs a phase control signal;

[0012] The DC support module receives the phase control signal, dynamically adjusts the DC support voltage, and outputs a DC control signal;

[0013] The magnetic stabilization module receives the DC control signal, switches to the DC support mode, and provides additional magnetic attraction force through magnetic locking technology to stabilize the contact state of the contactor;

[0014] The state monitoring module receives the stability signal and determines whether the grid voltage has recovered;

[0015] The power supply recovery module receives the recovery signal and switches back to AC power supply according to the optimal phase calculated by the switching control module to avoid current shock, prevent contact vibration, complete AC / DC switching, and restore normal power supply status.

[0016] As a preferred solution of the anti-electrical shaking device based on a magnetic switch described in the present invention, wherein:

[0017] The magnetic stabilization module monitors the contact state and outputs a stability signal;

[0018] The magnetic locking technology is specifically a magnetic switch or an electromagnetic lock.

[0019] As a preferred solution of the anti-electrical shaking device based on a magnetic switch described in the present invention, in which: in the state monitoring module, when the voltage recovers to the set threshold and continues to operate stably for more than a preset time, a recovery signal is output.

[0020] In a second aspect, the present invention provides an anti-electrical shaking method based on a magnetic switch, comprising:

[0021] Step S1: Detect grid voltage changes and determine whether power fluctuations occur; when the voltage is lower than a set threshold, output a power fluctuation signal;

[0022] Step S2, calculating the optimal AC / DC switching phase based on the power sway signal and outputting a phase control signal;

[0023] Step S3, adjusting the DC support voltage according to the phase control signal and outputting a DC control signal;

[0024] Step S4: receiving a DC control signal, switching to a DC support mode, and stabilizing the contact state through magnetic locking technology to prevent contact vibration; simultaneously monitoring the contact state and outputting a stability signal;

[0025] Step S5, receiving a stability signal and determining whether the grid voltage has recovered; when the voltage is restored to stability, outputting a recovery signal;

[0026] Step S6: receiving the restoration signal, switching back to AC power supply according to the optimal phase to avoid current shock and prevent contact vibration; and restoring normal power supply after completing the AC / DC switching.

[0027] As a preferred solution of the anti-electrical shaking method based on a magnetic switch described in the present invention, the step of detecting the grid voltage change, determining whether an electric shaking occurs, and outputting an electric shaking signal when the voltage is lower than a set threshold is as follows:

[0028] The collected grid voltage signal is defined as V(t):

[0029] V(t)={v1,v2,…,v n},

[0030] Among them, V(t) represents the grid voltage signal at time t, v i represents the voltage value of the i-th sampling point, n is the total number of sampling points, t represents the current time point,

[0031] Apply a sliding average filter to the sample sequence, the formula is:

[0032]

[0033] in, represents the smoothed voltage value with a window length of m, where m represents the length of the sliding window, and v i represents the voltage value of the i-th sampling point, and t represents the current time point;

[0034] The frequency change is calculated using the short-time Fourier transform (STFT). The STFT transform is performed on the signal. The formula is:

[0035]

[0036] Where X(t,f) represents the short-time Fourier transform amplitude at time t and frequency f, v i is the voltage value of the i-th sampling point, w(it) is the window function, f is the analysis frequency, j is the imaginary unit,

[0037] Calculate the voltage change rate and extract the amplitude of the low-frequency component at f = 0 based on STFT, which is expressed as:

[0038] ΔV(t)=|X(t,0)|-|X(t-1,0)|,

[0039] Where ΔV(t) represents the instantaneous change in voltage, X(t,0) and X(t-1,0) represent the amplitude of the STFT low-frequency component at the current and previous moments, respectively.

[0040] When the following conditions are met, it is determined that a power surge has occurred:

[0041]

[0042] Among them, V th is the set voltage threshold,

[0043] like Duration T d Exceeds the set time threshold T th , then the output power shaking signal:

[0044] when S d =1,

[0045] Among them, S d For power shake signal, when S d =1, indicating that power shaking is detected, T d Indicates the duration of low voltage, T th The time threshold is set.

[0046] As a preferred solution of the anti-electrical shaking method based on a magnetic switch of the present invention, the step of calculating the optimal AC / DC switching phase based on the electric shaking signal and outputting the phase control signal is as follows:

[0047] Collect the AC grid voltage signal and define the grid voltage signal time domain expression as:

[0048] V ac (t) = V m cos(ωt+φ),

[0049] Among them, V ac (t) is the instantaneous voltage of the AC grid, V m is the maximum amplitude of the grid voltage, ω is the grid angular frequency, t is the current time, φ is the current voltage phase,

[0050] The current phase is calculated based on the sampled signal. The calculation formula is:

[0051]

[0052] Among them, φ(t) represents the voltage phase at the current moment, Δt is the sampling time interval,

[0053] Set the optimal AC / DC switching phase φ opt Minimize switching shock, φ opt The calculation formula is:

[0054]

[0055] Among them, φ opt is the optimal switching phase, V dc is the DC support voltage, |V ac (t)-V dc | is the AC / DC voltage difference,

[0056] Calculate the optimal switching time, the formula is:

[0057]

[0058] Among them, t opt is the optimal switching time,

[0059] When t = t opt , S φ =1, generates phase control signal,

[0060] Among them, S φ is the phase control signal, when S φ =1, output phase synchronization trigger signal.

[0061] As a preferred solution of the anti-electrical shaking method based on a magnetic switch of the present invention, the step of adjusting the DC support voltage according to the phase control signal and outputting the DC control signal is as follows:

[0062] DC support voltage V dc Dynamic adjustment is required to match the optimal AC / DC switching phase φ opt , and the adjustment formula is:

[0063] V dc (t)=αV ac (t opt ),

[0064] Among them, V dc (t) is the DC support voltage at time t, α is the DC support proportional coefficient, 0<α≤1, set according to the load characteristics, V ac 9t opt ) is the optimal switching time t opt The AC voltage,

[0065] For the DC support voltage, in order to avoid voltage mutation, an exponential smoothing function is used to adjust V dc , the adjustment formula is:

[0066] V dc(t)=λV dc (t-1)+(1-λ)αV ac (t opt ),

[0067] Where λ is a smoothing factor (0<λ<1), which is used to control the adjustment rate of the DC support voltage.

[0068] When V dc Reaching a stable state, the change is less than the set threshold ΔV th When , the output DC control signal is:

[0069] When |V dc (t)-V dc (t-1)|<ΔV th , S dc =1,

[0070] Among them, S dc is the DC control signal, when S dc =1, indicating that the DC support voltage has reached a stable state, ΔV th The threshold value for the voltage change allowed.

[0071] As a preferred solution of the anti-electrical shaking method based on a magnetic switch of the present invention, the step of switching to the DC support mode and stabilizing the contact state by magnetic locking technology is as follows:

[0072] When S dc =1,M s =1, when receiving the DC control signal S dc =1, switches to DC support mode, where M s It is the DC support mode indication signal. When M s =1, it means it has switched to DC support mode.

[0073] Magnetic locking technology is used to enhance contact stability. The formula for calculating the magnetic attraction force is:

[0074]

[0075] Among them, F m is the magnetic attraction force, β is the electromagnetic attraction coefficient, I dc is the DC support current, and the calculation formula is:

[0076] I dc =P / V dc , where P is the load power,

[0077] Monitor the contact state and define the contact vibration state quantity as D c :

[0078]

[0079] Among them, D c is the contact vibration amount, reflecting the degree of change of the contact state, C(i) represents the contact position state at time i, T w is the monitoring window length,

[0080] If the vibration level is lower than the set threshold D th , output stability signal:

[0081] When D c <D th , S s =1,

[0082] Among them, S s is the contact stability signal, when S s =1, indicating that the contact is stable.

[0083] As a preferred solution of the anti-electrical shaking method based on a magnetic switch described in the present invention, the steps of receiving a stability signal and judging whether the grid voltage has recovered; and outputting a recovery signal when the voltage has recovered and stabilized are as follows:

[0084] Collect the grid voltage signal, which is represented by V ac (t):

[0085] V ac (t) = V m cos(ωt+φ),

[0086] Among them, V ac (t) is the AC voltage at time t, V m is the maximum voltage amplitude, ω is the grid angular frequency, φ is the voltage phase,

[0087] The voltage mean is calculated using the sliding average method. The calculation formula is:

[0088]

[0089] in, is the mean voltage at time t, N is the sliding window length,

[0090] Determine whether the voltage has recovered and set the voltage recovery threshold V th , the grid voltage is considered to be restored when the following conditions are met:

[0091]

[0092] Among them, V th is the set recovery threshold,

[0093] To prevent misjudgment, the recovery time T is introducedr , the calculation formula is:

[0094]

[0095] Among them, T v T is the cumulative time for voltage recovery. r is the set recovery time threshold,

[0096] When the voltage recovery time exceeds the threshold, T v >T r , S r =1, output recovery signal, where S r To restore the signal, when S r =1, it indicates that the grid voltage has returned to stability.

[0097] As a preferred solution of the anti-electrical shaking method based on a magnetic switch of the present invention, the step of receiving the recovery signal and switching back to AC power supply according to the optimal phase is as follows:

[0098] Collect the current AC voltage phase information, the grid voltage expression is:

[0099] V ac (t) = V m cos(ωt+φ),

[0100] Among them, V ac (t) is the AC voltage at time t, V m is the maximum voltage amplitude, ω is the grid angular frequency, φ is the voltage phase,

[0101] The phase calculation formula at the current moment is:

[0102]

[0103] Where φ(t) is the voltage phase at time t, Δt is the sampling time interval,

[0104] Calculate the optimal phase switching time, the formula is:

[0105]

[0106] Among them, φ opt is the optimal switching phase, V dc is the current DC support voltage,

[0107] Calculate the optimal switching time, the calculation formula is:

[0108]

[0109] Among them, t sw is the optimal phase switching time,

[0110] When receiving the recovery signal S r =1 and the optimal phase switching time t=t sw When the switch is executed:

[0111] When t = t sw And S r =1, S ac =1,

[0112] Among them, S ac It is the AC switching trigger signal. When S ac =1, AC / DC switching is performed.

[0113] When the AC switching is successful and the current impact is less than the set threshold I th Normal power supply is restored when:

[0114] When|I ac -I dc | th , M s =0,

[0115] Among them, M s It is the DC support mode status indication signal, M s =0 means exiting DC support mode, I ac is the AC current, I dc is the DC support current, I th It is the maximum threshold allowed for current surge.

[0116] The beneficial effects of the present invention are as follows: the present invention adopts a sliding average filter to reduce the interference of instantaneous voltage fluctuations, and combines the short-time Fourier transform STFT to extract the instantaneous changes of the low-frequency component, so as to more accurately identify the voltage drop of the power grid, and effectively avoid the problem of misjudgment or omission due to short-term fluctuations in traditional methods.

[0117] In the AC / DC switching strategy of the present invention, the current voltage phase is calculated and matched with the optimal switching phase to ensure that the AC / DC voltage difference is minimized during switching, thereby reducing current shock and avoiding vibration of the contactor contacts caused by phase deviation; at the same time, the DC support voltage is dynamically adjusted in combination with the exponential smoothing function, and the voltage change is more stable during the switching process; in the DC support mode, magnetic locking technology is used to enhance the stability of the contactor contacts, and by real-time monitoring of the contact status, the contacts will not be mistakenly released due to fluctuations in electromagnetic attraction during power shaking.

[0118] ​The present invention uses a sliding average to calculate the voltage mean value for judging the recovery of the power grid voltage, combined with a cumulative calculation method for the recovery time, and performs AC / DC switching only after the voltage stability reaches a set threshold, thereby reducing the interference of short-term voltage fluctuations on the system and avoiding malfunctions caused by premature switching; during the power supply recovery process, the optimal phase matching switching time is calculated so that no excessive current shock is generated when the AC power supply is restored, avoiding mechanical jitter of the contacts due to instantaneous shock.

[0119] In summary, the present invention improves the stability of the contactor during power shaking, reduces the risk of false triggering, and effectively overcomes the shortcomings of traditional anti-power shaking solutions in load adaptability, contact vibration suppression, and power supply switching stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0120] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0121] Figure 1 Schematic diagram of the framework of the anti-electrical shaking device based on the magnetic switch of the present invention.

[0122] Figure 2 Schematic diagram of the flow of the anti-electrical shaking method based on the magnetic switch of the present invention. DETAILED DESCRIPTION

[0123] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0124] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0125] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0126] Example 1, with reference to Figure 1 and Figure 2 This embodiment provides an anti-electrical shaking device based on a magnetic switch, comprising:

[0127] Voltage detection module, switching control module, DC support module, magnetic stabilization module, status monitoring module and power supply recovery module;

[0128] The voltage detection module is used to detect grid voltage changes, determine whether power fluctuations occur, and output a power fluctuation signal when the voltage falls below a set threshold.

[0129] The switching control module receives the power shaking signal, calculates the optimal AC / DC switching phase, and outputs a phase control signal;

[0130] The DC support module receives the phase control signal, dynamically adjusts the DC support voltage, and outputs a DC control signal;

[0131] The magnetic stabilization module receives the DC control signal, switches to the DC support mode, and provides additional magnetic attraction force through magnetic locking technology to stabilize the contactor contact state;

[0132] The magnetic stabilization module monitors the contact status and outputs a stability signal;

[0133] Magnetic locking technology is specifically a magnetic switch or electromagnetic lock;

[0134] The status monitoring module receives the stability signal and determines whether the grid voltage has recovered;

[0135] In the status monitoring module, when the voltage returns to the set threshold and continues to operate stably for more than the preset time, a recovery signal is output;

[0136] The power supply recovery module receives the recovery signal and switches back to AC power supply according to the optimal phase calculated by the switching control module to avoid current shock, prevent contact vibration, complete AC / DC switching, and restore normal power supply status.

[0137] This embodiment further provides an anti-electrical shaking method for the above-mentioned anti-electrical shaking device based on a magnetic switch, comprising:

[0138] Step S1: Detect grid voltage changes and determine whether power fluctuations occur; when the voltage is lower than a set threshold, output a power fluctuation signal;

[0139] Detect grid voltage changes and determine whether power shake occurs. When the voltage is lower than the set threshold, the steps of outputting power shake signal are as follows:

[0140] The collected grid voltage signal is defined as V(t):

[0141] V(t)={v1,v2,…,v n},

[0142] Among them, V(t) represents the grid voltage signal at time t, v irepresents the voltage value of the i-th sampling point, n is the total number of sampling points, t represents the current time point,

[0143] Apply a sliding average filter to the sample sequence, the formula is:

[0144]

[0145] in, represents the smoothed voltage value with a window length of m, where m represents the length of the sliding window, and v i represents the voltage value of the i-th sampling point, and t represents the current time point;

[0146] The frequency change is calculated using the short-time Fourier transform (STFT). The STFT transform is performed on the signal. The formula is:

[0147]

[0148] Where X(t,f) represents the short-time Fourier transform amplitude at time t and frequency f, v i is the voltage value of the i-th sampling point, w(it) is the window function, f is the analysis frequency, j is the imaginary unit,

[0149] Calculate the voltage change rate and extract the amplitude of the low-frequency component at f = 0 based on STFT, which is expressed as:

[0150] ΔV(t)=|X(t,0)|-|X(t-1,0)|,

[0151] Where ΔV(t) represents the instantaneous change in voltage, X(t,0) and X(t-1,0) represent the amplitude of the STFT low-frequency component at the current and previous moments, respectively.

[0152] When the following conditions are met, it is determined that a power surge has occurred:

[0153]

[0154] Among them, V th is the set voltage threshold,

[0155] like Duration T d Exceeds the set time threshold T th , then the output power shaking signal:

[0156] when

[0157] Among them, S d For power shake signal, when S d =1, indicating that power shaking is detected, T d Indicates the duration of low voltage, T this the set time threshold,

[0158] Specifically, the sliding window filtering method is used to smooth the original voltage signal to reduce the interference of instantaneous fluctuations on the judgment. Then, the short-time Fourier transform (STFT) is used to perform time-frequency analysis on the voltage signal to extract the instantaneous change information of the low-frequency component, thereby obtaining more accurate voltage change characteristics and improving detection robustness. The voltage threshold V is defined here as th and time threshold T th Only when the voltage is lower than the set threshold and the duration exceeds the set threshold, the power shake signal S will be triggered. d Output to prevent misjudgment;

[0159] Step S2, calculating the optimal AC / DC switching phase based on the power sway signal and outputting a phase control signal;

[0160] Based on the power sway signal, the steps of calculating the optimal AC / DC switching phase and outputting the phase control signal are as follows:

[0161] Collect the AC grid voltage signal and define the grid voltage signal time domain expression as:

[0162] V ac (t) = V m cos(ωt+φ),

[0163] Among them, V ac (t) is the instantaneous voltage of the AC grid, V m is the maximum amplitude of the grid voltage, ω is the grid angular frequency, t is the current time, φ is the current voltage phase,

[0164] The current phase is calculated based on the sampled signal. The calculation formula is:

[0165]

[0166] Among them, φ(t) represents the voltage phase at the current moment, Δt is the sampling time interval,

[0167] Set the optimal AC / DC switching phase φ opt Minimize switching shock, φ opt The calculation formula is:

[0168]

[0169] Among them, φ opt is the optimal switching phase, V dc is the DC support voltage, |V ac (t)-V dc | is the AC / DC voltage difference,

[0170] Calculate the optimal switching time, the formula is:

[0171]

[0172] Among them, t opt is the optimal switching time,

[0173] When t = t opt , S φ =1, generates phase control signal,

[0174] Among them, S φ is the phase control signal, when S φ =1, output phase synchronization trigger signal,

[0175] Specifically, based on the time domain expression of the AC voltage signal of the power grid, the current phase information is calculated by sampling, and on this basis, the optimal AC / DC switching phase φ is determined. opt , so that the switching impact of AC and DC voltages is minimized, and the optimal switching time t is calculated based on the current phase information opt , and is used to trigger the phase control signal S φ , ensuring the stability of the AC / DC switching process and improving the reliability of the anti-sway system;

[0176] Step S3, adjusting the DC support voltage according to the phase control signal and outputting a DC control signal;

[0177] Step S4: receiving a DC control signal, switching to a DC support mode, and stabilizing the contact state through magnetic locking technology to prevent contact vibration; simultaneously monitoring the contact state and outputting a stability signal;

[0178] The steps of adjusting the DC support voltage and outputting the DC control signal according to the phase control signal are as follows:

[0179] DC support voltage V dc Dynamic adjustment is required to match the optimal AC / DC switching phase φ opt , and the adjustment formula is:

[0180] V dc (t)=αV ac (t opt ),

[0181] Among them, V dc (t) is the DC support voltage at time t, α is the DC support proportional coefficient, 0<α≤1, set according to the load characteristics, V ac (t opt ) is the optimal switching time t opt The AC voltage,

[0182] For the DC support voltage, in order to avoid voltage mutation, an exponential smoothing function is used to adjust Vdc , the adjustment formula is:

[0183] V dc (t)=λV dc (t-1)+(1-λ)αV ac (t opt ),

[0184] Where λ is a smoothing factor (0<λ<1), which is used to control the adjustment rate of the DC support voltage.

[0185] When V dc Reaching a stable state, the change is less than the set threshold ΔV th When , the output DC control signal is:

[0186] When |V dc (t)-V dc (t-1)|<ΔV th , S dc =1,

[0187] Among them, S dc is the DC control signal, when S dc =1, indicating that the DC support voltage has reached a stable state, ΔV th is the threshold value for voltage change allowed,

[0188] The steps to switch to DC support mode and stabilize the contact state through magnetic locking technology are as follows:

[0189] When S dc =1,M s =1, when receiving the DC control signal S dc =1, switches to DC support mode, where M s It is the DC support mode indication signal. When M s =1, it means it has switched to DC support mode.

[0190] Magnetic locking technology is used to enhance contact stability. The formula for calculating the magnetic attraction force is:

[0191]

[0192] Among them, F m is the magnetic attraction force, β is the electromagnetic attraction coefficient, I dc is the DC support current, and the calculation formula is:

[0193] I dc =P / V dc , where P is the load power,

[0194] Monitor the contact state and define the contact vibration state quantity as D c :

[0195]

[0196] Among them, D c is the contact vibration amount, reflecting the degree of change of the contact state, C(i) represents the contact position state at time i, T w is the monitoring window length,

[0197] If the vibration level is lower than the set threshold D th , output stability signal:

[0198] When D c <D th , S s =1,

[0199] Among them, S s is the contact stability signal, when S s =1, indicating that the contact is stable.

[0200] Specifically, in the DC support mode, according to the optimal switching phase φ opt Calculate the adaptive DC support voltage V dc , and adopt exponential smoothing adjustment to ensure the stability of the voltage switching process; when V dc After reaching stability, a DC control signal S is generated dc , triggering DC support mode M s At the same time, the magnetic attraction force F is applied through the magnetic locking technology m , enhance the stability of the contact and prevent contact vibration; finally, based on the contact vibration state quantity D c Perform real-time monitoring and output stability signal S when the contact state tends to be stable s ;

[0201] Step S5, receiving a stability signal and determining whether the grid voltage has recovered; when the voltage is restored to stability, outputting a recovery signal;

[0202] Receive the stability signal and determine whether the grid voltage has recovered; when the voltage is restored to stability, output the recovery signal in the following steps:

[0203] Collect the grid voltage signal, which is represented by V ac (t):

[0204] V ac (t) = V m cos(ωt+φ),

[0205] Among them, V ac (t) is the AC voltage at time t, V m is the maximum voltage amplitude, ω is the grid angular frequency, φ is the voltage phase,

[0206] The voltage mean is calculated using the sliding average method. The calculation formula is:

[0207]

[0208] in, is the mean voltage at time t, N is the sliding window length,

[0209] Determine whether the voltage has recovered and set the voltage recovery threshold V th , the grid voltage is considered to be restored when the following conditions are met:

[0210]

[0211] Among them, V th is the set recovery threshold,

[0212] To prevent misjudgment, the recovery time T is introduced r , the calculation formula is:

[0213]

[0214] Among them, T v T is the cumulative time for voltage recovery. r is the set recovery time threshold,

[0215] When the voltage recovery time exceeds the threshold, T v >T r , S r =1, output recovery signal, where S r To restore the signal, when S r =1, indicating that the grid voltage has returned to stability;

[0216] Specifically, the voltage mean is calculated based on the sliding average Determine whether the grid voltage has recovered to ensure that short-term fluctuations will not lead to misjudgment. Then set the recovery threshold V th Determine whether the voltage is restored, and further use the recovery time T r The cumulative calculation improves voltage stability; when the recovery time exceeds the threshold T r , output recovery signal S r ;

[0217] Step S6: receiving the restoration signal, switching back to AC power supply according to the optimal phase to avoid current shock and prevent contact vibration; after completing the AC / DC switching, normal power supply is restored;

[0218] The steps for receiving the recovery signal and switching back to AC power supply according to the optimal phase are as follows:

[0219] Collect the current AC voltage phase information, the grid voltage expression is:

[0220] V ac (t) = V m cos(ωt+φ),

[0221] Among them, V ac (t) is the AC voltage at time t, V m is the maximum voltage amplitude, ω is the grid angular frequency, φ is the voltage phase,

[0222] The phase calculation formula at the current moment is:

[0223]

[0224] Where φ(t) is the voltage phase at time t, Δt is the sampling time interval,

[0225] Calculate the optimal phase switching time, the formula is:

[0226]

[0227] Among them, φ opt is the optimal switching phase, V dc is the current DC support voltage,

[0228] Calculate the optimal switching time, the calculation formula is:

[0229]

[0230] Among them, t sw is the optimal phase switching time,

[0231] When receiving the recovery signal S r =1 and the optimal phase switching time t=t sw When the switch is executed:

[0232] When t = t sw And S r =1, S ac =1,

[0233] Among them, S ac It is the AC switching trigger signal. When S ac =1, AC / DC switching is performed.

[0234] When the AC switching is successful and the current impact is less than the set threshold I th Normal power supply is restored when:

[0235] When|I ac -I dc | th , M s ​=0,

[0236] Among them, M s It is the DC support mode status indication signal, M s =0 means exiting DC support mode, I ac is the AC current, I dc is the DC support current, I th is the maximum threshold allowed by the current surge,

[0237] Specifically, after the AC grid is restored, it is necessary to opt Perform AC / DC switching to reduce current shock. Here, calculate the current phase φ(t) and match the optimal switching time t sw , to ensure smooth switching; when the signal S is restored r When the trigger is triggered and the system reaches the optimal switching phase, the AC switching signal S is output ac , complete the switch from DC support mode to AC power supply, and ensure the current surge |I ac -I dc |Below the set threshold I th , to prevent contact vibration and equipment damage.

[0238] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An anti-electrical shaking device based on a magnetic switch, characterized in that: The device includes a voltage detection module, a switching control module, a DC support module, a magnetic stabilization module, a status monitoring module and a power supply recovery module: The voltage detection module is used to detect grid voltage changes, determine whether power fluctuations occur, and output a power fluctuation signal when the voltage is lower than a set threshold; The switching control module receives the power shaking signal, calculates the optimal AC / DC switching phase, and outputs a phase control signal; The DC support module receives the phase control signal, dynamically adjusts the DC support voltage, and outputs a DC control signal; The magnetic stabilization module receives the DC control signal, switches to the DC support mode, and provides additional magnetic attraction force through magnetic locking technology to stabilize the contact state of the contactor; The state monitoring module receives the stability signal and determines whether the grid voltage has recovered; The power supply recovery module receives the recovery signal, switches back to AC power supply according to the optimal phase calculated by the switching control module, completes AC / DC switching, and restores the normal power supply state.

2. The anti-electrical shaking device based on a magnetic switch according to claim 1, characterized in that: The magnetic stabilization module monitors the contact state and outputs a stability signal; The magnetic locking technology is specifically a magnetic switch or an electromagnetic lock.

3. The anti-electrical shaking device based on a magnetic switch according to claim 2, characterized in that: In the state monitoring module, when the voltage recovers to the set threshold and continues to operate stably for more than a preset time, a recovery signal is output.

4. A method for preventing electric sway based on a magnetic switch, based on the anti-electric sway device based on a magnetic switch according to any one of claims 1 to 3, characterized in that: include: Step S1, detecting grid voltage changes and determining whether power shaking occurs; When the voltage is lower than the set threshold, a power shake signal is output; Step S2, calculating the optimal AC / DC switching phase based on the power sway signal and outputting a phase control signal; Step S3, adjusting the DC support voltage according to the phase control signal and outputting a DC control signal; Step S4: receiving a DC control signal, switching to a DC support mode, and stabilizing the contact state through magnetic locking technology to prevent contact vibration; simultaneously monitoring the contact state and outputting a stability signal; Step S5, receiving a stability signal and determining whether the grid voltage has recovered; when the voltage is restored to stability, outputting a recovery signal; Step S6: receiving a restoration signal, switching back to AC power supply according to the optimal phase, and restoring normal power supply after completing the AC / DC switching.

5. The anti-electrical shaking method based on a magnetic switch according to claim 4, characterized in that: The steps of detecting the grid voltage change, determining whether power shaking occurs, and outputting a power shaking signal when the voltage is lower than a set threshold are as follows: The collected grid voltage signal is defined as V(t): V(t)={v1,v2,…,v n }, Among them, V(t) represents the grid voltage signal at time t, v i represents the voltage value of the i-th sampling point, n is the total number of sampling points, t represents the current time point, Apply a sliding average filter to the sample sequence, the formula is: in, represents the smoothed voltage value with a window length of m, where m represents the length of the sliding window, and v i represents the voltage value of the i-th sampling point, and t represents the current time point; The frequency change is calculated using the short-time Fourier transform (STFT). The STFT transform is performed on the signal. The formula is: Where X(t, f) represents the short-time Fourier transform amplitude at time t and frequency f, v i is the voltage value of the i-th sampling point, w(it) is the window function, f is the analysis frequency, j is the imaginary unit, Calculate the voltage change rate and extract the amplitude of the low-frequency component at f = 0 based on STFT, which is expressed as: ΔV(t)=|X(t,0)|-|X(t-1,0)|, Where ΔV(t) represents the instantaneous change in voltage, X(t,0) and X(t-1,0) represent the amplitude of the STFT low-frequency component at the current and previous moments, respectively. When the following conditions are met, it is determined that a power surge has occurred: Among them, V th is the set voltage threshold, like Duration T d Exceeds the set time threshold T th , then the output power shaking signal: when S d =1, Among them, S d For power shake signal, when S d =1, indicating that power shaking is detected, T d Indicates the duration of low voltage, T th The time threshold is set.

6. The anti-electrical shaking method based on a magnetic switch according to claim 5, characterized in that: The steps of calculating the optimal AC / DC switching phase based on the power shaking signal and outputting the phase control signal are as follows: Collect the AC grid voltage signal and define the grid voltage signal time domain expression as: V ac (t)=V m cos(ωt+φ), Among them, V ac (t) is the instantaneous voltage of the AC grid, V m is the maximum amplitude of the grid voltage, ω is the grid angular frequency, t is the current time, φ is the current voltage phase, The current phase is calculated based on the sampled signal. The calculation formula is: Among them, φ(t) represents the voltage phase at the current moment, Δt is the sampling time interval, Set the optimal AC / DC switching phase φ opt Minimize switching shock, φ opt The calculation formula is: Among them, φ opt is the optimal switching phase, V dc is the DC support voltage, |V ac (t)-V dc | is the AC / DC voltage difference, Calculate the optimal switching time, the formula is: Among them, t opt is the optimal switching time, When t = t opt , S φ =1, generates phase control signal, Among them, S φ is the phase control signal, when S φ =1, output phase synchronization trigger signal.

7. The anti-electrical shaking method based on a magnetic switch according to claim 6, characterized in that: The steps of adjusting the DC support voltage according to the phase control signal and outputting the DC control signal are as follows: DC support voltage V dc Dynamic adjustment is required to match the optimal AC / DC switching phase φ opt , and the adjustment formula is: V dc (t)=αV ac (t opt ), Among them, V dc (t) is the DC support voltage at time t, α is the DC support proportional coefficient, 0<α≤1, set according to the load characteristics, V ac (t opt ) is the optimal switching time t opt The AC voltage, For the DC support voltage, use the exponential smoothing function to adjust V dc , the adjustment formula is: V dc (t)=λV dc (t-1)+(1-λ)αV ac (t opt ), Where λ is a smoothing factor, where 0<λ<1, which is used to control the adjustment rate of the DC support voltage. When V dc Reaching a stable state, the change is less than the set threshold ΔV th When , the output DC control signal is: When |V dc (t)-V dc (t-1)|<ΔV th , S dc =1, Among them, S dc is the DC control signal, when S dc =1, indicating that the DC support voltage has reached a stable state, ΔV th The threshold value for voltage change allowed.

8. The anti-electrical shaking method based on a magnetic switch according to claim 7, characterized in that: The steps of switching to the DC support mode and stabilizing the contact state through magnetic locking technology are: When S dc =1,M s =1, when receiving the DC control signal S dc =1, switches to DC support mode, where M s It is the DC support mode indication signal. When M s =1, it means it has switched to DC support mode. Magnetic locking technology is used to enhance contact stability. The formula for calculating the magnetic attraction force is: Among them, F m is the magnetic attraction force, β is the electromagnetic attraction coefficient, I dc is the DC support current, and the calculation formula is: I dc =P / V dc , where P is the load power, Monitor the contact state and define the contact vibration state quantity as D c : Among them, D c is the contact vibration amount, reflecting the degree of change of the contact state, C(i) represents the contact position state at time i, T w is the monitoring window length, If the vibration level is lower than the set threshold D th , output stability signal: When D c <D th , S s =1, Among them, S s is the contact stability signal, when S s =1, indicating that the contact is stable.

9. The anti-electrical shaking method based on a magnetic switch according to claim 8, characterized in that: The steps of receiving the stability signal and judging whether the grid voltage has recovered; and outputting the recovery signal when the voltage has recovered and stabilized are as follows: Collect the grid voltage signal, which is represented by V ac (t): V ac (t)=V m cos(ωt+φ), Among them, V ac (t) is the AC voltage at time t, V m is the maximum voltage amplitude, ω is the grid angular frequency, φ is the voltage phase, The voltage mean is calculated using the sliding average method. The calculation formula is: in, is the mean voltage at time t, N is the sliding window length, Determine whether the voltage has recovered and set the voltage recovery threshold V th , the grid voltage is considered to be restored when the following conditions are met: Among them, V th is the set recovery threshold, To prevent misjudgment, the recovery time T is introduced r , the calculation formula is: Among them, T v T is the cumulative time for voltage recovery. r is the set recovery time threshold, When the voltage recovery time exceeds the threshold, T v >T r , S r =1, output recovery signal, where S r To restore the signal, when S r =1, it indicates that the grid voltage has returned to stability.

10. The anti-electrical shaking method based on a magnetic switch according to claim 9, characterized in that: The steps of receiving the recovery signal and switching back to AC power supply according to the optimal phase are: Collect the current AC voltage phase information, the grid voltage expression is: V ac (t)=V m cos(ωt+φ), Among them, V ac (t) is the AC voltage at time t, V m is the maximum voltage amplitude, ω is the grid angular frequency, φ is the voltage phase, The phase calculation formula at the current moment is: Where φ(t) is the voltage phase at time t, Δt is the sampling time interval, Calculate the optimal phase switching time, the formula is: Among them, φ opt is the optimal switching phase, V dc is the current DC support voltage, Calculate the optimal switching time, the calculation formula is: Among them, t sw is the optimal phase switching time, When receiving the recovery signal S r =1 and the optimal phase switching time t=t sw When the switch is executed: When t = t sw And S r =1, S ac =1, Among them, S ac It is the AC switching trigger signal. When S ac =1, AC / DC switching is performed. When the AC switching is successful and the current impact is less than the set threshold I th Normal power supply is restored when: This | I ac -I dc | th , M s = 0,​ Among them, M s It is the DC support mode status indication signal, M s =0 means exiting DC support mode, I ac is the AC current, I dc is the DC support current, I th The maximum threshold allowed for current surge.

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