CN110045277A - Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method, system and medium - Google Patents

Abstract

The invention discloses a method for analyzing the dynamic characteristics of a built-in load switch of a smart electric energy meter, comprising: S01. Obtaining the coil magnetic flux φ ₂ and the electromagnetic suction under the conditions of different angular displacements α of the armature of the built-in load switch of the intelligent electric energy meter and different coil current values i Moment M _x , obtain the static data of the electromagnetic system; S02, obtain the reed deformation displacement Δx, reaction force F _f and reaction torque M _f under the condition of different angular displacement α of the armature, and obtain the static data of the reaction force of the contact spring system; S03, based on the electromagnetic The static data of the system and the static data of the reaction force of the contact spring system are analyzed by using the fourth-order Runge-Kutta method to obtain dynamic characteristic data under the condition of dynamic characteristic parameters; S04, analyze the dynamic characteristic data obtained in step S03 to evaluate the load switch reliability. The present invention also discloses a system and a medium corresponding to the above method. The method, system and medium of the present invention all have the advantages of accurate and reliable analysis.

Description

Dynamic characteristic analysis method, system and medium of built-in load switch of smart energy meter

technical field

The invention mainly relates to the technical field of electric energy meters, in particular to a dynamic characteristic analysis method, system and medium of a built-in load switch of a smart electric energy meter.

Background technique

The quality of the built-in load switch for electric energy meters is directly related to the quality of customer service and the safety of power grid operation. Since the large-scale construction of low-voltage centralized reading has been carried out across the country, the State Grid Corporation has had a huge amount of traffic. Among the metering fault repair services accepted, the built-in load switch for electric energy meters has a high proportion of faults, accounting for 60% of the entire metering fault repairs. The built-in load switch The quality problem has brought huge economic losses and bad social impact to power grid companies. Therefore, improving the reliability of the built-in load switch, essentially improving the quality of the built-in load switch, reducing the failure caused by the failure of the built-in load switch, for improving the quality of service level, ensuring the stability of the power grid, and saving the manpower, material and financial resources of enterprises, it has significant social and economic significance.

Through analysis, the built-in load switch for electric energy meters has a low operating frequency, but has high reliability requirements. Generally, the open switch will be operated under special circumstances such as user arrears or short-circuit, and the operation will be closed after the user's payment is completed or when it returns to normal. brake. At the same time, when the user's electricity bill is sufficient and the state is normal, the built-in load switch should not act to ensure the normal power consumption of the user; when the line is overloaded or short-circuited, it should act in time to disconnect the fault current to protect the line and electrical equipment. The dynamic characteristics (such as angular velocity, angular acceleration, etc.) of the built-in load switch of the electric energy meter during the action process are important indicators to measure its performance and reliability. In various static states, the coordination of suction and reaction force characteristics directly affects the quality of dynamic characteristics, and ultimately affects the life of the built-in load switch. The contact breaking arc erosion is the main reason for the contact failure and the short life of the built-in load switch. Another important reason that affects the contact erosion and failure is the contact closure bounce. For the application scenario of AC load, the built-in load switch of the electric energy meter that only relies on contact separation to pull out the arc, increasing the contact separation speed is an important means to reduce the erosion of the breaking arc and suppress or prevent the closing bounce. At present, there is no corresponding attention to this characteristic of the load switch, and there is no corresponding measurement device, and the above results cannot be accurately obtained through the measurement device, so that the monitoring and improvement of its reliability cannot be realized.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is as follows: in view of the technical problems existing in the prior art, the present invention provides a method, system and medium for analyzing the dynamic characteristics of a built-in load switch of a smart electric energy meter with simple analysis process and accurate analysis results.

In order to solve the above-mentioned technical problems, the technical scheme proposed by the present invention is:

A method for analyzing the dynamic characteristics of a built-in load switch of a smart electric energy meter, comprising the following steps:

S01. Obtain the coil magnetic flux φ ₂ and the electromagnetic suction torque M _x under the conditions of different angular displacements α of the armature of the built-in load switch of the smart energy meter and different coil current values i, and obtain the static data of the electromagnetic system;

S02, obtain the reed deformation displacement Δx, reaction force F _f and reaction moment M _f under different angular displacement α conditions of the armature, and obtain the static data of the reaction force of the contact spring system;

S03. Based on the static data of the electromagnetic system and the static data of the reaction force of the contact spring system, the fourth-order Runge-Kutta method is used for analysis to obtain the dynamic characteristic data under the condition of dynamic characteristic parameters;

S04, analyze the dynamic characteristic data obtained in step S03 to evaluate the reliability of the load switch.

Preferably, the specific process of the step S01 is:

S11. According to the magnetic system structure of the load switch, according to the equivalent magnetic circuit method, establish an equivalent magnetic circuit model of the load switch that takes into account the leakage magnetic resistance between the iron core and the armature;

S12. Calculate the magnetic flux value φ _pi of each working air gap in the equivalent magnetic circuit model of the load switch according to the equivalent magnetic circuit model of the load switch that takes into account the leakage magnetic resistance between the iron core and the armature;

S13 , calculating the electromagnetic suction force F _i corresponding to each working air gap through the cross-sectional area S _pi corresponding to the working air gap, thereby obtaining the electromagnetic suction torque M _x .

Preferably, in step S13, the electromagnetic attraction force F _i is calculated by Maxwell's electromagnetic force calculation formula:

where φ _pi represents the magnetic flux passing through the working air gap, S _pi represents the cross-sectional area corresponding to the working air gap, μ ₀ represents the vacuum permeability, μ0=4π×10-7Wb/(A m);

The electromagnetic attraction torque Mx is:

M _x =F ₂ r ₁₂ +F ₃ r ₂₁ -F ₁ r ₁₁ -F ₄ r ₂₂ ;

The length of the long left armature is r ₁₁ ; the length of the long right armature is r ₂₁ ; the length of the short left armature is r ₁₂ ; the length of the short right armature is r ₂₂ .

Preferably, the concrete process that obtains reaction torque in described step S02 is:

S21. Divide each layer of reeds in the built-in load switch of the smart energy meter into n segments, and establish a mathematical function model corresponding to each layer and each segment;

S22. Obtain the bending moments of the sections in the reeds of each layer and section, and combine the corresponding mathematical models to obtain the sub-compliance of the reeds of each layer and section;

S23. Obtain the flexibility of each layer of reeds at the point of force through the sub-compliance of each layer and each section of the reed;

S24, through the flexibility and stiffness of each layer of reeds at the point where the force is applied, combined with the different angular displacements α of the armature, the reaction moment of the whole reed acting on the armature is obtained.

Preferably, in the step S21, each layer of reeds in the built-in load switch of the smart energy meter is divided into three sections, which are respectively a straight section S1, a curved section S2 and a straight section S3 connected in sequence.

Preferably, in the step S22, the sub-compliance of each layer and each segment of the reed is:

Where M _wf represents the bending moment of the reed, E represents the elastic modulus of the reed material, I represents the moment of inertia of the reed section, s represents the arc length of the reed, and P _f is the force at the point of force.

Preferably, in the step S24, the reaction force of each layer of reeds at the point of force is obtained through the flexibility of each layer of reeds at the point of force, so as to obtain that the whole reed acts on the load switch inside the smart energy meter reaction torque on the armature.

Preferably, the reaction force of the three-layer reed at the force point:

Among them, Δx is the deformation displacement of the reed at f, wherein the flexibility of the three-layer reed is C _ff1 , C _ff2 , and C _ff3 , and the stiffnesses are G ₁ , G ₂ , and G ₃ ;

Δx=α·r ₁₁ -x _c0

where x _c0 is the initial value of the deformation and displacement of the reed, α is the angular displacement of the armature, and αr ₁₁ is the displacement of the armature wire;

The reaction torque of the reaction force of the three-layer reed acting on the armature:

The first module is used to obtain the coil magnetic flux φ ₂ and the electromagnetic suction torque M _x under the conditions of different angular displacements α of the armature of the built-in load switch of the smart energy meter and different coil current values i, and form the static data of the electromagnetic system;

The second module is used to obtain the reed deformation displacement Δx, the reaction force F _f and the reaction moment M _f under the condition of different angular displacement α of the armature, and obtain the static data of the reaction force of the contact spring system;

The third module is used to analyze the fourth-order Runge-Kutta based on the static data of the electromagnetic system and the static data of the reaction force of the contact spring system to obtain the dynamic characteristic data under the condition of the dynamic characteristic parameters;

The fourth module is used to analyze the dynamic characteristic data obtained in step S03 to evaluate the reliability of the load switch.

The present invention further discloses a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the above-mentioned method for analyzing the dynamic characteristics of a built-in load switch of a smart electric energy meter is realized. A step of.

Compared with the prior art, the advantages of the present invention are:

The intelligent electric energy meter of the present invention has a built-in load switch dynamic characteristic analysis method, system and medium. The fourth-order Runge-Kutta method is used to analyze the static data of the electromagnetic system and the static data of the reaction force of the contact spring system to obtain the dynamic characteristic parameters under the condition of dynamic characteristic parameters. The characteristic data is then compared with the set standard value to judge the reliability of the load switch operation, and it is also convenient for the subsequent optimization of the parameters of the load switch to form a closed loop; in addition, the above process of obtaining dynamic characteristic data is simple and the result is accurate.

Description of drawings

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is a flow chart of the quality characteristic analysis of the present invention.

FIG. 3 is a schematic structural diagram of the load switch magnetic system of the present invention.

FIG. 4 is an equivalent magnetic circuit diagram of the present invention considering magnetic flux leakage.

FIG. 5 is a schematic diagram of the working air gap of the present invention.

FIG. 6 is a diagram of a segmented calculation model of the self-compliance and mutual compliance of the reed according to the present invention.

FIG. 7 is a schematic diagram of the sub-compliance section of the single-layer reed in the present invention.

FIG. 8 is a flow chart of dynamic characteristic analysis based on static data in the present invention.

FIG. 9 is an equivalent circuit diagram of the built-in load switch coil in the present invention.

FIG. 10 is a flow chart of dynamic characteristic calculation in the present invention.

FIG. 11 is a schematic diagram of the angular velocity of the armature in the present invention.

FIG. 12 is a schematic diagram of the angular acceleration of the armature in the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 1 , the method for analyzing the dynamic characteristics of a built-in load switch of a smart electric energy meter in this embodiment includes the following steps:

S01. Obtain the coil magnetic flux φ ₂ and the electromagnetic suction torque M _x under the conditions of different angular displacements α of the armature of the built-in load switch of the smart energy meter and different coil current values i, and obtain the static data of the electromagnetic system;

S02, obtain the reed deformation displacement Δx, reaction force F _f and reaction moment M _f under different angular displacement α conditions of the armature, and obtain the static data of the reaction force of the contact spring system;

S03. Based on the static data of the electromagnetic system and the static data of the reaction force of the contact spring system, the fourth-order Runge-Kutta method is used for analysis, and the dynamic characteristic data (such as armature angular velocity, armature angular acceleration, etc.) under the condition of dynamic characteristic parameters are obtained;

S04, analyze the dynamic characteristic data obtained in step S03 to evaluate the reliability of the load switch.

The intelligent electric energy meter built-in dynamic characteristic analysis method of the load switch of the present invention adopts the fourth-order Runge-Kutta method to analyze the static data of the electromagnetic system and the static data of the reaction force of the contact spring system, and obtains the dynamic characteristic data under the condition of the dynamic characteristic parameters, and then It is compared with the set standard value to judge the reliability of the load switch operation, and it is also convenient for subsequent optimization of the parameters of the load switch to form a closed loop; in addition, the above process of obtaining dynamic characteristic data is simple and the result is accurate.

The design parameters of the built-in load switch of the electric energy meter include electromagnetic system parameters and contact spring system parameters. The values of these parameters have an important impact on the suction characteristics, reaction force characteristics and the matching characteristics of suction and reaction forces. It is reflected, which in turn affects the performance indicators of the load switch. Therefore, the final value of the design parameters needs to be optimized with the goal of the best performance index. To complete the parameter optimization task, it is first necessary to study the relationship between each design parameter and the static and dynamic characteristics when a single factor changes, so as to screen out the key parameters that have a significant impact on the static and dynamic characteristics from many design parameters. One-step parameter design and parameter optimization work to lay the foundation. The quality characteristic analysis process is shown in Figure 2.

Below in conjunction with a specific embodiment, above-mentioned method is described in detail:

1. Establishment of static suction model:

The magnetic circuit method and the magnetic field method are commonly used analytical methods for solving electromagnetic systems. The magnetic circuit method has a simple operation method and a small amount of calculation data, but the accuracy is not high enough, and it can only reflect the mechanical properties of the electromagnet relatively shallowly. The magnetic field method has high precision, but a large amount of calculation. The most commonly used representative method of the magnetic field method is the finite element method.

For the analysis of the quality characteristics of the built-in load switch of the electric energy meter, if the magnetic field method is used for simulation calculation, the number of calculations is huge, which cannot be completed in ordinary laboratories. Therefore, an equivalent magnetic circuit of the built-in load switch must be established based on the equivalent magnetic circuit method, taking into account the magnetic flux leakage, taking into account the calculation speed and calculation accuracy, so as to realize the rapid calculation of the static characteristics of the built-in load switch of the electric energy meter.

Based on the structure of the load switch magnetic system (as shown in Figure 3) and based on the equivalent magnetic circuit method, an equivalent magnetic circuit model of the load switch (as shown in Figure 4) is established that takes into account the leakage magnetic resistance between the iron core and the armature.

In Figure 4, F _m is the equivalent magnetic potential of the permanent magnet, R _m is the equivalent magnetic resistance of the permanent magnet; IW is the magnetic potential of the coil winding; R ₁ , R ₂ , R ₃ , and R ₄ are the gap between the armature and the yoke, respectively The formed working air gap magnetoresistance; R _a1 , R _a2 , R _b1 , R _b2 , R _c1 , R _c2 , R _d are the equivalent pure iron material magnetoresistance respectively; R _s is the leakage between the iron core and the armature Magnetic resistance, leakage coefficient k ₁ =k ₂ =0.5 (system structure is symmetrical); φ ₁ , φ ₂ , φ ₃ , φ ₄ , φ ₅ are the magnetic fluxes of each circuit, and the calculation methods of each parameter are as follows:

(1) Equivalent magnetic potential and equivalent reluctance of permanent magnets

The permanent magnet in the magnetic circuit model is equivalent to the combination of the magnetic potential F _m and the reluctance R _m (see Figure 4). The permanent magnet material of the permanent magnet is NdFeB, the return line of NdFeB coincides with the demagnetization curve and is basically a straight line, so the equivalent magnetic potential of the built-in load switch permanent magnet in the equivalent magnetic circuit is the same as the equivalent magnetic field. resistance is:

where H _c and μ _m represent the coercivity and permeability of the permanent magnet, respectively, and _{lm and S m represent} the length and cross-sectional area of the permanent magnet, respectively.

(2) Coil magnetic potential

The coil magnetic potential IW is the magnetic pressure generated by the coil itself. The calculation formula of the coil magnetic potential is:

IW=U ₀ ·W/R(2)

In the formula, U ₀ represents the operating voltage of the coil, W represents the inherent number of turns of the coil, and R represents the inherent resistance of the coil.

(3) Air gap magnetoresistance

Four symmetrical working air gaps are formed between the left and right ends of the built-in load switch armature and the yoke, and the air gap structure is a bridge-type symmetrically distributed ladder-type structure. The schematic diagram of the working air gap is shown in Figure 5. The calculation formula of the ladder-type air gap reluctance is:

In the formula, R is the magnetoresistance, G is the permeability, μ ₀ is the vacuum permeability, and r is the air gap length. In the calculation of the magnetic resistance R ₁ of the working air gap 1, the value of r is r11-r13; in the calculation of the magnetic resistance R ₂ of the working air gap 2, the value of r is r12-r13; in the magnetic resistance R of the working air gap 3 In the calculation of ₃ , the value of r is r21-r23; in the calculation of the magnetic resistance R4 of the working air gap ₄ , the value of r is r22-r23. r1 is the armature width, r2 is the yoke width ke, in the calculation of R ₁ and R ₃ , r1 refers to the long armature width kl; in the calculation of R ₂ and R ₄ , r1 refers to the short armature width ks (yoke width ke, short armature width ks) armature width ks). θ is the angle between the armature and the pole face of the yoke. When the built-in load switch is disconnected, θ=0.09; when the built-in load switch is closed, θ=0.11; when the angular displacement α≤0.09, θ=0.09 -α; when 0.09<α≤0.11, θ=α-0.09 (angle unit: rad).

According to formula (3), the reluctance of each air gap can be calculated after measuring the key parameters.

(4) leakage magnetic resistance

The formula for calculating the leakage magnetic resistance between the armature and the iron core is as follows:

R _s =L _pa /(μ _{0 Spa} )(4)

In the formula, L _pa represents the distance from the outer diameter of the iron core to the armature, and S _pa represents the bottom area of the short armature.

(5) magnetoresistance

R _a1 , R _a2 , R _b1 , R _b2 , R _c1 , R _c2 , R _d are the equivalent reluctance of each component of the electromagnetic system, respectively, where R _a1 and R _a2 represent the upper left and upper right armature reluctance, respectively, R _b1 and R _b2 represent the lower left and lower right armature magnetoresistance respectively, R _c1 and R _c2 respectively represent the magnetoresistance of the left and right yokes, and R _d represent the iron core magnetoresistance. The following formula can be used to calculate the reluctance of the magnetic conductor of each component of the electromagnetic system.

R=L/(μS)(5)

In the formula, S and L represent the cross-sectional area and length of the magnetizer, respectively, and μ represents the magnetic permeability of the magnetizer.

Because the built-in load switch magnetizers are all soft magnetic materials, and their permeability is closely related to the magnetic flux and changes non-linearly, the magnetization curve based on electrical pure iron is used to calculate the permeability of each magnetizer. First, mark the magnetization curve (H, B) of electrical pure iron with sufficient density in the table, and then use the Lagrangian interpolation method to obtain the permeability μ value corresponding to the B value at any point on the curve. For example, the specific method for solving the μ value corresponding to B falling between (H _i-1 ,B _i-1 ) and (H _i ,B _i ) is:

(6) Working air gap magnetic flux

According to the equivalent magnetic circuit model and the loop current method considering the leakage flux in Fig. 3, the following equations can be obtained:

Its matrix form is expressed as:

RФ _n =F _b

In the formula, R represents the loop magnetoresistance matrix; Ф _n represents the loop magnetic flux matrix; F _b represents the loop magnetic potential vector matrix.

Since the equation system (7) is a multivariate first-order equation system, when the loop magnetoresistance matrix R and the loop magnetic potential vector matrix F _b are known, the Gaussian column pivoting rule can be used to solve Ф _n . The permanent magnet equivalent reluctance, leakage reluctance, and working air-gap reluctance in R can be obtained by using known parameters, and the reluctance of each magnet conductor related to the magnetic flux to be determined needs to be solved iteratively. First, set the reluctance of all magnetizers to zero, and substitute them into equation (7) to obtain the magnetic flux φ(i) of each branch. Divide φ(i) by the cross-sectional area of the corresponding magnetizer to obtain the corresponding Magnetic induction B _i , H _{i can be obtained by querying the magnetization curve of B i .} Then find the magnetoresistance R _i from H _i l _i =φ(i)R _i , substitute it into the loop equation system again, and perform Gaussian iteration to find a new φ(i+1) until up to (ε represents the calculation accuracy, usually 0.001).

According to the obtained magnetic flux value of each circuit, the magnetic flux value of each working air gap is calculated.

(7) Electromagnetic suction

The electromagnetic attraction force F _i (i=1, 2, 3, 4) is calculated by Maxwell's electromagnetic force calculation formula.

In the formula, φ _pi represents the magnetic flux passing through the working air gap, S _pi represents the cross-sectional area corresponding to the working air gap, μ ₀ represents the vacuum permeability, and μ0=4π×10-7Wb/(A·m).

The synthetic suction moment Mx is:

M _x =F ₂ r ₁₂ +F ₃ r ₂₁ -F ₁ r ₁₁ -F ₄ r ₂₂ (10)

The resultant force F at the working air gap 1 can be calculated by M=Fr ₁₁ :

According to the above formula, the reduced resultant force of different working air gaps can be obtained.

Referring to the fast calculation model of static suction of built-in load switch of electric energy meter established above, the following methods are adopted:

1). Calculation of the equivalent magnetic potential and equivalent magnetic resistance of the permanent magnet: Calculate the cross-sectional area of the permanent magnet sc=hc×kc; calculate the equivalent magnetic potential Fm and equivalent magnetic resistance Rm of the permanent magnet according to formula (1);

2). Use formula (2) to calculate the coil magnetic potential IW;

3). Using the ladder-type air gap calculation formula (3), calculate the 4 air gap magnetic resistances R1, R2, R3, R4 under static conditions respectively;

4). Based on the magnetic circuit model considering the magnetic flux leakage, the leakage magnetic resistance Rs between the electromagnetic coil and the lower armature is calculated by using the formula (4);

5). Considering that the armature, yoke and iron core can be equivalent to pure iron materials when calculating the magnetic resistance, using the magnetization curve of electric pure iron and the Lagrangian interpolation method, according to formula (6), the corresponding According to formula (5), the magnetic permeability μ under the value of magnetic field strength can be obtained respectively by obtaining the left and right magnetoresistances Ra1 and Ra2 of the long armature, the left and right magnetoresistances Rb1 and Rb2 of the short armature, and the magnetoresistance Rc1 of the left and right yokes. , Rc2, iron core magnetoresistance Rd.

6). According to the equivalent magnetic circuit model, establish a magnetic circuit circuit equation system, and obtain the relationship matrix RmnΦn=Fb between the circuit magnetoresistance matrix R, the circuit magnetic flux matrix Φn, and the circuit magnetic potential vector matrix Fb. Under the condition of Fb, the Gaussian column pivoting method can be used to solve Φn.

7). Solve the loop magnetoresistance matrix R. Since the elements Rm, R1, R2, R3, R4, and Rs in R are known, it is only necessary to solve the magnetoresistance of each magnetizer. ,5), it needs to be calculated and solved in an iterative way.

① First, set the magnetic resistance of each magnet conductor to zero, and substitute it into the equation system (7) to obtain the corresponding magnetic flux Φn(0) of each loop (n=1, 2, 3, 4 5);

②Calculate the cross-sectional area of each magnet conducting body. Use sc=hl×kl to calculate the cross-sectional area of the long armature; use ss=hs×ks to calculate the cross-sectional area of the short armature; use se=heh×ke to calculate the cross-sectional area of the yoke;

③Using B(i)=φ(i)/S (S are sc, ss, se respectively; φ(i) is the magnetic flux of the corresponding magnetic conductor; i=0, 1, 2...) to solve the corresponding magnetic conductor respectively The magnetic induction intensity of , and the corresponding magnetic field intensity Hi is obtained by querying the magnetization curve of pure iron.

④Using H(i)L=φ(i)R(i) to obtain the magnetoresistance of the magnetizer under the corresponding conditions respectively (when obtaining Ra1 and Ra2, L = cl/2; when obtaining Rb1 and Rb2, L = cs/2; when finding Rc1 and Rc2, L=ce+heg; when finding Rd, L=ct);

⑤ Substitute the obtained magnetoresistance matrix Rmn(i) (i is the number of iterations) back into the equation system, and use the Gauss iteration method to obtain a new magnetic flux matrix Φn(i+1);

⑥ Judgment: If (ε is the calculation accuracy, generally 0.001), the calculation is terminated; if Then repeat steps ③, ④, ⑤ until

8) Calculation of the resultant moment of electromagnetic attraction:

①Calculate the magnetic flux value of the working air gap. According to the magnetic circuit model considering magnetic flux leakage, the magnetic flux value of working air gap 1 is Φp1=Φ4; the magnetic flux value of working air gap 2 is Φp2=Φ1-Φ4; the magnetic flux value of working air gap 3 is Φp3=Φ5; The magnetic flux value of gap 4 is Φp4=ΦΦ5;

② Calculate the cross-sectional area corresponding to the working air gap;

③Using formula (9) to calculate the suction corresponding to the four working air gaps

④ Use formula (10) to calculate the resultant moment Mx of the suction.

Corresponding model input: built-in load switch electromagnetic system physical parameter vector D {permanent magnet width kc; permanent magnet length cc; permanent magnet thickness hc; permanent magnet coercive force (corrected value) Hc; permanent magnet permeability um; length armature length cl; long armature width kl; long armature thickness hl; long left armature length r11; long right armature length r21; short armature length cs; short armature width ks; short armature thickness hs; short left armature length r12; short right armature Length r22; yoke length ce; yoke width ke; yoke thickness heh; yoke height heg; left yoke to center distance r13; right yoke to center distance r23; core length ct; core outer diameter to short The distance from the bottom of the armature Lpa};

Output: Electromagnetic attraction force torque Mx.

2. Establishment of static reaction force model:

Based on the discrete unified numerical calculation model and deformation energy method, which can be used to calculate any complex reeds, the established calculation model is segmented a little under the condition of ensuring high calculation accuracy.

In Figure 6, the self-compliance C _ee , C _ff and mutual compliance C _ef at the specified points e and f on the reed can be calculated by the deformation energy method:

where P _e represents the force at point e, M _we represents the bending moment of the reed produced by the force; P _f represents the force at point f, M _wf represents the bending moment of the reed produced by the force; E represents the material of the reed The elastic modulus, I represents the moment of inertia of the reed section, and s represents the reed arc length. These three quantities are all fixed values in the calculation.

If the reed is divided into _n segments: S ₁ , S ₂ , ..., Sn , the calculation formulas of self-compliance and mutual compliance can be obtained:

In the formula, _{Respectively expressed} as the i-section sub- _compliances (i=1, 2, .

The reed sub-compliance segment of the built-in load switch of the electric energy meter can be classified into two types: linear and curved, which can simplify its mathematical model for compliance calculation. The built-in load switch reed of the electric energy meter is composed of two straight sections and one curved section. It can be equivalent to three sections, that is, it is equivalent to two straight sections and one curved section for calculation. Since there is only one force action point, there is only self-compliance and no mutual compliance in the modeling and calculation process. The single-layer reed sub-compliance segment S _i (i=1, 2, 3) is shown in Figure 7, and its mathematical model is as follows.

The mathematical function model of the sub-flexibility segment S1 is:

y=-y ₀ (x _f ≤x≤x _a ) (14)

The mathematical function model of the sub-flexibility segment S2 is:

The mathematical function model of the sub-flexibility segment S3 is:

y=-y ₀ (x _b ≤x≤x _b +x ₁ ) (16)

where x _a =-x _b , x _f =x _a -x ₀ .

Since the action point of the force P _f is the contact point, that is, the end point of S1, the bending moment of the reed section at the sub-flexibility section x of the three-section reed Si (i=1, 2, 3) is:

M _wf =P _f |xx _f | (17)

Therefore, the flexibility of the i segment of the self-compliance Cff is:

Since the cross-sections of the three-section reeds are all rectangular, the formula for calculating the cross-section moment is:

where c _hp is the length of the reed section, and h _hp is the thickness of the reed section.

For S1 segment:

For S2 segment:

Among them, it can be calculated according to formula (14):

Substitute equation (20) into equation (19) to calculate:

For S3 segment:

The overall flexibility of the reed at the moving contact f:

Stiffness of the reed:

According to the above formula, the design parameters of the three-layer reed are respectively substituted, and the flexibility C _ff1 , C _ff2 , C _ff3 , and the stiffness G ₁ , G ₂ , and G ₃ of the three-layer reed are calculated.

The reaction force of the three-layer reed at f:

Among them, Δx is the deformation displacement of the reed at f:

Δx=α·r ₁₁ -x _c0 (28)

In the formula, x _c0 is the initial value of the deformation and displacement of the reed, α is the angular displacement of the armature, and αr ₁₁ is the displacement of the armature wire (ie the armature stroke).

The reaction torque of the reaction force of the three-layer reed acting on the armature:

Referring to the fast calculation model of the static reaction force of the built-in load switch of the electric energy meter established above, perform the following steps:

1. Divide the three-layer reeds into two straight line segments S1, S3 and one curved segment S2 according to Figure 7, respectively, and establish mathematical models (3), (4), (5) for each layer and each segment of the reeds;

2. Calculation of self-compliance _Cff :

①Using formula (6) to calculate the bending moment M _wf of the reed section at the sub-compliance section x;

②Substitute (6) into (2) to get the self-compliance of the i-section reed The general calculation formula (7) of ;

③Using Equation (6), combined with the mathematical model of the three-section reed, obtain the sub-compliance of the three-section reed respectively

④ Flexibility of the three-section reed Substitute into formula (14) to obtain the self-compliance _Cff of the whole reed at the force point f;

3. Use formula (15) to obtain the stiffness G of the reed;

4. Using steps 2 and 3, respectively substitute the design parameters of the three-layer reed, and calculate the flexibility C _ff1 , C _ff2 , C _ff3 , and the stiffness G ₁ , G ₂ , and G ₃ of the three-layer reed;

5. Use formula (16) to obtain the reaction force F _{f of the three-layer reed at f} ;

6. Use formula (18) to obtain the reaction moment M _f of the three-layer reed reaction force acting on the armature.

The input of the mathematical model: physical parameter vector C{reed material elastic modulus E; upper reed section length c _hp1 ; upper reed section thickness h _hp1 ; middle layer reed section length c _hp2 ; middle layer reed section Thickness h _hp2 ; section length of lower reed c _hp3 ; section thickness of lower reed h _hp3 ; the length of the first straight reed of the upper layer x ₀₁ ; the length of the second straight reed of the upper layer x ₁₁ ; the upper Ω curved reed Height y ₀₁ +R ₁ ; the length of the first straight reed in the middle layer x ₀₂ ; the length of the second straight reed in the middle layer x ₁₂ ; the height of the Ω curved reed in the middle layer y ₀₂ +R ₂ ; the first straight reed in the lower layer Length of reed x ₀₃ ; length of the second straight reed of the lower layer x ₁₃ ; height of the Ω curved reed of the lower layer y ₀₃ +R ₃ }

The output of the mathematical model: the reaction torque M _f

Finally, use the fast calculation method of the static suction and reaction force characteristics of the built-in load switch of the electric energy meter to calculate the corresponding static data table, and then input it into the dynamic characteristic analysis model for calculation, the armature acceleration of the built-in load switch of the electric energy meter can be obtained. , angular acceleration and other dynamic characteristics calculation results. As shown in Figure 8.

3. Establish a mathematical model of dynamic characteristics:

During the action of the built-in load switch of the electric energy meter, the coil loop of the load switch can be equivalent to the equivalent circuit shown in Figure 9.

Its voltage balance equation is:

Since L is a fixed value, Then there are:

In the above formula, U, i and R are the coil voltage, current and resistance, respectively; I _s is the steady-state current of the coil; L is the inductance; T is the electromagnetic time constant,

It can be seen that from the moment the coil is energized to the end of the armature action, the coil current increases exponentially, and finally reaches a stable state. The dynamic characteristic equation system of the built-in load switch of the electric energy meter is a typical first-order differential equation system, which is divided into the coil loop differential equation, the armature mechanical motion differential equation, the differential relationship equation between the armature angular displacement and the angular velocity, and the initial value:

where φ ₂ is the magnetic flux of the coil; U, i, R are the coil voltage, current and resistance, respectively; α, ω are the angular displacement and angular velocity of the armature, respectively; J is the moment of inertia of the armature; M _x , M _f are the suction force of the electromagnetic system, respectively The torque and the reaction force torque of the contact spring system; φ ₀ and α ₀ are the coil magnetic flux and the angular displacement of the armature at the moment of t=0, respectively.

The above equation system (33) is solved by the fourth-order Runge-Kutta method, as follows:

At present, the dynamic characteristics are mainly solved by numerical methods based on static data, multi-software co-simulation methods and finite element transient solution methods. Numerical values based on static data are used for dynamic calculations, while the fourth-order Runge-Kutta method is mainly used for dynamic equation solving. The solution process of the fourth-order Runge-Kutta method is as follows:

The initial value of the first-order ordinary differential equation:

The representation of the fourth-order Runge-Kutta method:

In the formula, b _i , c _i , a _ij are all constants, c ₁ =0, a _1j =0, j=1, 2,...,s-1. In the fourth-order Runge-Kutta method, s=4, and its classical formula is:

When solving the differential equation system of dynamic characteristics of the built-in load switch of the electric energy meter, the time variable t is first discretized, and the step size Δt is iterated for each period of time:

where Δt=t _i+1 -t _i , K _φj , L _ωj and M _αj (j=1, 2, 3, 4) are the rate of change at four time points within Δt Its specific calculation formula is as follows:

In the formula, h _j represents the iteration time step, h1=0, h4=Δt.

Considering that the dynamic characteristics of the built-in load switch such as speed, acceleration, and suction torque change relatively slowly in the triggering and closing stages during the pull-in process, but change rapidly during the movement process, so by setting different iteration times at different stages. method to improve computational accuracy and computational efficiency. The dynamic characteristic calculation process is shown in Figure 10. First determine the parameters to be calculated and the number of iterative calculations, calculate the moment of inertia of the armature, and then use the Runge-Kutta method to iteratively solve the differential equation. Among them, the time step of the trigger stage and the time step of the closing stage are set to 0.02ms, and the time step of the movement stage is set to 0.01ms. When the suction torque is greater than the reaction torque, the armature starts to move, and the system enters the movement stage from the trigger stage; when the angle of the armature changes to zero, the armature movement ends, and the system enters the closed stage from the movement stage; when the current change in the solenoid coil is less than When it is 1/10,000, it means that the built-in load switch is completely closed, and the iterative calculation process ends.

The 4th-order Runge-Kutta method iteratively solves the dynamic characteristics based on the static data table of the electromagnetic system and the contact spring system. For this purpose, firstly divide the current i and angular displacement α into equal parts of n and m respectively within the range of coil current and armature angular displacement, i∈[0,Is], α∈[ _0,0.2 ] (unit: rad ), and then use the fast algorithm of the static suction of the built-in load switch of the electric energy meter considering the magnetic flux leakage to obtain M _x and the loop magnetic flux matrix Ф _n under different i and α, as shown in Table 1. According to this table, for the known i _z and α _z can be obtained through table look-up and linear interpolation to obtain the corresponding electromagnetic attraction moment Mxz.

Table 1 Coil magnetic flux and electromagnetic attraction torque data table

Based on the angular displacement data of the armature in Table 1, according to formulas (25), (26) and (27), respectively calculate the reed deformation displacement, reaction force and reaction torque of the corresponding point to obtain the static data table 2 of the reaction force of the contact spring system. According to this table, for the known α _z , the corresponding contact spring reaction torque M _fz can be obtained through table look-up and linear interpolation.

Table 2 Angular displacement corresponding to the contact spring reaction torque data table

The specific steps of the dynamic characteristic analysis process based on static data shown in Figure 8 are as follows:

Input: dynamic characteristic parameter vector T{armature moment of inertia J; coil voltage U; coil magnetic flux initial value φ ₀ ; armature angular velocity initial value ω ₀ ; armature angular displacement initial value α ₀ };

Output: Dynamic characteristic data (α,ω,t)

1. Obtain the coil magnetic flux φ ₂ and the electromagnetic attraction moment M _x under the conditions of different angular displacement α and current value i to form the static data of the electromagnetic system, as shown in Table 1;

2. Obtain the reed deformation displacement Δx, reaction force F _f and reaction moment M _f under different angular displacement α conditions, and obtain the static data of the reaction force of the contact spring system, as shown in Table 2;

3. Based on the static data of the electromagnetic system and the static data of the reaction force of the contact spring system, the fourth-order Runge-Kutta method is used to solve the equation (33), and the dynamic characteristic data (α, ω, t) under the condition of the dynamic characteristic parameters are obtained.

The dynamic characteristics simulation and analysis are as follows:

Using the above method, calculate the dynamic characteristics of the built-in load switch of the standard designed smart energy meter based on static data (see Tables 3 and 4 for standard design parameters). This process method is implemented by programming in Matlab software, and the static suction and reaction force data obtained through the rapid calculation of the static suction and reaction force characteristics are imported into the dynamic characteristic calculation program, and the built-in electric energy meter based on the static suction and reaction force data can be obtained. The dynamic characteristics of the load switch mainly include the curves of angular velocity and angular acceleration changing with time, as shown in Figures 11-12.

It can be seen from Figure 11 that the upward trend of the angular velocity of the armature rotation is smooth, and its maximum value can reach 1.45×102rad/s; at the same time, the descending speed is extremely fast, indicating that the stability of the armature after the pull-in is good. The calculation result of the characteristic curve of the angular acceleration of the armature rotation is shown in Figure 12. From the analysis of the above calculation results, it can be seen that the angular velocity and angular acceleration of the armature rise with time from the time the coil is energized, and return to zero at the pull-in point, indicating that the pull-in process has been completed, the action time is between 10ms-12ms, and the waveform is consistent with the actual expectation. It can be seen from the simulation curve that the dynamic characteristic simulation model can correctly reflect the transformation of armature stroke, armature angular velocity and armature acceleration under dynamic conditions.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above, or modify it into an equivalent implementation of equivalent changes. example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention should fall within the protection scope of the technical solutions of the present invention.

Claims (10)

1. a kind of Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method, which comprises the following steps:

Under the conditions of S01, the armature difference angular displacement alpha for obtaining Intelligent electric energy meter built-in load switch and different coil current value i Coil flux amount φ₂With electromagnetic attraction square M_x, obtain electromagnetic system static data；

Reed deformational displacement Δ x, counter-force F under the conditions of S02, acquisition armature difference angular displacement alpha_fWith countertorque M_f, obtain touching spring system System counter-force static data；

S03, it is based on electromagnetic system static data and contact spring system counter-force static data, is carried out using four step Runge-Kutta Analysis, obtains the dynamic Characteristic Data under the conditions of dynamic characteristic parameter；

S04, dynamic Characteristic Data obtained in step S03 is analyzed to assess the reliability of on-load switch.

2. Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method according to claim 1, which is characterized in that institute State the detailed process of step S01 are as follows:

S11, by on-load switch magnetic system structure, according to magnetic equivalent circuit method, establish the negative of leakage field resistance between meter and iron core and armature Lotus switchs equivalent magnetic circuit modeling；

The on-load switch equivalent magnetic circuit modeling of leakage field resistance, calculated load switch equivalent magnetic between S12, foundation meter and iron core and armature The flux value φ of each working gas gap in the model of road_pi；

S13, pass through the corresponding sectional area S of working gas gap_pi, calculate the corresponding electromagnetic attraction F of each working gas gap_i, to obtain electricity Magnetic torque M_x。

3. Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method according to claim 2, which is characterized in that In step S13, electromagnetic attraction F_iIt is calculated by Maxwell's electromagnetic force calculation formula:

φ in formula_piIndicate the magnetic flux by working gas gap, S_piIndicate the corresponding sectional area of working gas gap, μ₀Indicate vacuum magnetic conductance Rate, μ 0=4 π × 10-7Wb/ (Am)；

Electromagnetic attraction square Mx are as follows:

M_x=F₂r₁₂+F₃r₂₁-F₁r₁₁-F₄r₂₂；

Wherein grow the long r of left armature₁₁；The long right long r of armature₂₁；The short long r of left armature₁₂；The short long r of right armature₂₂。

4. Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method according to claim 1 or 2 or 3, feature It is, obtains the detailed process of countertorque in the step S02 are as follows:

S21, layer reed each in Intelligent electric energy meter built-in load switch is divided into n sections, establishes each section of corresponding mathematical function of each layer Model；

Section turn moment in S22, each each section of reed of layer of acquisition, and corresponding mathematical model is combined, obtain the son of each section of reed of each layer Flexibility；

S23, by the sub- flexibility of each section of reed of each layer, obtain flexibility of each layer reed at receptor site power；

S24, flexibility and rigidity by each layer reed at receptor site power obtain whole reed in conjunction with armature difference angular displacement alpha Act on the countertorque on armature.

5. Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method according to claim 4, which is characterized in that institute It states in step S21, layer reed each in Intelligent electric energy meter built-in load switch is divided into three sections, respectively sequentially connected straightway S1, curved section S2 and straightway S3.

6. Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method according to claim 5, which is characterized in that institute It states in step S22, the sub- flexibility of each section of reed of each layer are as follows:

Wherein M_wfIndicate that reed moment of flexure, E indicate that the elasticity modulus of materials of reed, I indicate that reed cross sectional moment of inertia, s indicate reed Arc length, P_fFor the active force of stress point.

7. Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method according to claim 6, which is characterized in that institute It states in step S24, by flexibility of each layer reed at receptor site power, obtains counter-force of each layer reed at receptor site power, thus The countertorque on armature for acting on Intelligent electric energy meter built-in load switch to whole reed.

8. Intelligent electric energy meter built-in load switch Dynamic Characteristics Analysis Method according to claim 7, which is characterized in that three Counter-force of the layer reed in stress point:

Wherein, Δ x is deformational displacement of the reed at f, wherein the flexibility of three layers of reed is respectively C_ff1、C_ff2、C_ff3, rigidity point It Wei not G₁、G₂、G₃；

Δ x=α r₁₁-x_c0

X in formula_c0For reed deformational displacement initial value, α is armature angular displacement, α r₁₁For armature displacement of the lines；

The counter-force of three layers of reed acts on the countertorque on armature:

9. a kind of Intelligent electric energy meter built-in load switch dynamic characteristic analysis system, which is characterized in that including

First module, for obtain Intelligent electric energy meter built-in load switch armature difference angular displacement alpha and different coil current value i Under the conditions of coil flux amount φ₂With electromagnetic attraction square M_x, form electromagnetic system static data；

Second module, for obtaining reed deformational displacement Δ x, counter-force F under the conditions of armature difference angular displacement alpha_fWith countertorque M_f, Obtain contact spring system counter-force static data；

Third module, for being based on electromagnetic system static data and contact spring system counter-force static data, using quadravalence Runge- Kutta is analyzed, and the dynamic Characteristic Data under the conditions of dynamic characteristic parameter is obtained；

4th module, for being analyzed dynamic Characteristic Data obtained in step S03 to assess the reliability of on-load switch.

10. a kind of computer readable storage medium, which is characterized in that be stored with computer on the computer readable storage medium Program is realized when the computer program is executed by processor in intelligent electric energy meter described in any one of claim 1 to 8 The step of setting on-load switch Dynamic Characteristics Analysis Method.