阅读说明：本技术 常导磁浮列车悬浮电磁铁电感参数的在线辨识方法及系统 (Online identification method and system for inductance parameters of suspension electromagnet of normally-conductive magnetic-levitation train ) 是由 张文跃 佟来生 周源 蒋毅 汤彪 石昊翔 曾颖丰 于 2019-07-29 设计创作，主要内容包括：本发明公开了一种常导磁浮列车悬浮电磁铁电感参数的在线辨识方法及系统,采用如下公式计算悬浮电磁铁的电感参数：<Image he="124" wi="325" file="DDA0002147115230000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中,N为悬浮电磁铁线圈匝数；i为悬浮电磁铁电流；S为悬浮电磁铁磁极面积；F为悬浮力；μ<Sub>0</Sub>为真空磁导率。本发明提出的电感参数辨识方法,充分考虑的漏磁、铁芯磁阻以及磁饱和的影响,可获取准确的电感参数,而且在悬浮系统工作过程中,通过控制器内部软件实现查表,在通过插值计算即可在线获取,易于实现。(The invention discloses an online identification method and system for inductance parameters of a suspension electromagnet of a normally-conducting magnetic-levitation train, which adopts the following formula to calculate the inductance parameters of the suspension electromagnet: wherein N is the number of turns of the suspension electromagnet coil; i is the current of the suspension electromagnet; s is the area of a suspended electromagnet pole; f is the suspension force; mu.s 0 Is a vacuum magnetic permeability. The inductance parameter identification method provided by the invention can obtain accurate inductance parameters by fully considering the influences of magnetic flux leakage, iron core magnetic resistance and magnetic saturation, realizes table look-up through internal software of the controller in the working process of the suspension system, can obtain the inductance parameters on line through interpolation calculation, and is easy to realize.)

1. The online identification method for the inductance parameter of the levitation electromagnet of the normally-conducting magnetic-levitation train is characterized in that the inductance parameter of the levitation electromagnet is calculated by adopting the following formula:wherein N is the number of turns of the suspension electromagnet coil; i is the current of the suspension electromagnet; s is the area of a suspended electromagnet pole; f is the suspension force; mu.s₀Is a vacuum magnetic permeability.

2. The on-line identification method for the inductance parameters of the levitation electromagnet of the normally-conductive magnetic-levitation train as recited in claim 1, wherein a levitation gap δ and a current i are obtained, and the levitation force is determined by using a linear interpolation method.

3. The on-line identification method for the inductance parameter of the levitation electromagnet of the normally-conducting magnetic-levitation train as recited in claim 2, wherein the levitation force F (δ, i);

(ii) a Delta (x) is more than or equal to delta (x + 1); i is more than or equal to i (y + 1); x is more than or equal to 1 and less than or equal to m-1; y is more than or equal to 1 and less than or equal to n-1; δ is the levitation gap, i is the current, F is the levitation force, m is the number of levitation gap data, n is the number of current data, δ(x) The current data is the x-th suspension gap data, the delta (x +1) is the x + 1-th suspension gap data, the i (y) is the y-th current data, the i (y +1) is the y + 1-th current data, the F (x, y) is the suspension force corresponding to the x-th suspension gap data and the y-th current data, the F (x +1, y) is the suspension force corresponding to the x + 1-th suspension gap data and the y-th current data, and the F (x +1, y +1) is the suspension force corresponding to the x + 1-th suspension gap data and the y + 1-th current data.

4. The utility model provides an online identification system of normally leading maglev train suspension electro-magnet inductance parameter which characterized in that includes:

the suspension sensor is used for acquiring a magnetic suspension gap between the suspension electromagnet and the guide rail in real time and sending the magnetic suspension gap to the magnetic suspension controller;

the magnetic levitation controller is internally provided with a current sensor for collecting the current of a levitation electromagnet in real time and is used for calculating levitation force F (delta, i) according to the following formula:

Technical Field

The invention relates to a maglev train, in particular to an online identification method and system for inductance parameters of a levitation electromagnet of a normally-conductive maglev train.

Background

The suspension system of the normally-conducting magnetic-levitation train comprises a suspension sensor, a suspension controller and a suspension electromagnet. The suspension sensor detects the suspension gap between the suspension electromagnet and the rail in real time and sends a gap signal to the suspension controller, and the suspension controller adjusts the current in the suspension electromagnet coil in real time according to the gap signal and adjusts the electromagnetic force generated by the suspension electromagnet, so that the suspension gap between the suspension electromagnet and the rail is controlled to be kept stable.

The inductance parameter of the suspension electromagnet is an important parameter required by the suspension controller, and during the operation of the suspension system, the control parameters of the suspension control algorithm and the digital current loop algorithm need to be adjusted according to the actual inductance parameter so as to achieve the effects of quick current response and stable suspension control.

In practice, the inductance of the levitation electromagnet varies with the current and the levitation gap, and the variation range of the inductance is large because the variation range of the current and the levitation gap is large. The existing methods for obtaining inductance parameters include three methods: one method is calculated by an approximate formula, and the method has poor accuracy because the influence of factors such as magnetic flux leakage and magnetic saturation is ignored; the second method is obtained by adopting electromagnetic field finite element analysis, the method considers the influence of magnetic leakage and magnetic saturation to a certain extent, so the precision is higher than that of the first method, but the method has 10-20% of error through practice verification; the third method is to superpose a Pulse Width Modulation (PWM) signal on the voltage signal output by the suspension controller, and calculate inductance parameters by detecting the voltage and current information in a PWM period.

Taking the simplified electromagnet model shown in fig. 1 as an analysis object, if neglecting the magnetic flux leakage and the magnetic resistance of the electromagnet core and the guide rail, and neglecting the magnetic saturation effect of the core, the air gap flux is:

the air gap flux density is:

the inductance of the electromagnet is then:

in the above formula,. phi_mIs an air gap flux, B_mIs air gap flux density, F_mIs magnetomotive force, R_mIs air gap reluctance, N is the number of turns of the electromagnet coil, S is the electromagnet pole area, i is the electromagnet current, δ is the levitation gap, μ₀Is a vacuum magnetic conductivity, and L is an electromagnet inductance.

It can be seen from equation (3) that, neglecting the factors of magnetic leakage and magnetic saturation, the derived inductance formula is only related to the levitation gap, and in practice, due to the influence of the magnetic leakage and the magnetic saturation, when the current changes, the magnetic leakage and the magnetic saturation of the electromagnet are different, so that in practice, the inductance is related to both the levitation gap and the current.

By adopting electromagnetic field three-dimensional finite element analysis, the influence of magnetic leakage, magnetic saturation and other factors can be reflected to a certain extent, and fig. 2 also shows that the inductance is not only related to the levitation gap like the formula (3), but is related to the levitation gap and the current at the same time.

However, the finite element analysis considers the factors such as magnetic flux leakage and magnetic saturation to a certain extent, but the finite element analysis is different from the actual situation, and the finite element analysis result and the test data have errors of 10% -20% proved by tests.

Disclosure of Invention

The invention aims to solve the technical problem that the prior art is insufficient, and provides an online identification method and system for the inductance parameter of a levitation electromagnet of a normally-conducting magnetic-levitation train, so that the inductance parameter of the levitation electromagnet can be accurately identified online.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: an online identification method for inductance parameters of a levitation electromagnet of a normally-conducting magnetic-levitation train is characterized in that the inductance parameters of the levitation electromagnet are calculated by adopting the following formula:wherein N is the number of turns of the suspension electromagnet coil; i is the current of the suspension electromagnet; s is the area of a suspended electromagnet pole; f is the suspension force; mu.s₀Is a vacuum magnetic permeability.

And acquiring a suspension gap delta and a current i, and determining the suspension force by using a linear interpolation method.

Suspension force F ═ δ, F;

i is more than or equal to i (y + 1); x is more than or equal to 1 and less than or equal to m-1; y is more than or equal to 1 and less than or equal to n-1; δ is a suspension gap, i is a current, F is a suspension force, m is the number of suspension gap data, n is the number of current data, δ (x) is the x-th suspension gap data, δ (x +1) is the x + 1-th suspension gap data, i (y) is the y-th current data, i (y +1) is the y + 1-th current data, F (x, y) is the suspension force corresponding to the x-th suspension gap data and the y-th current data, F (x +1, y) is the suspension force corresponding to the x + 1-th suspension gap data and the y-th current data, and F (x +1, y +1) is the suspension force corresponding to the x + 1-th suspension gap data and the y + 1-th current data.

An online identification system of inductance parameters of a levitation electromagnet of a normally-conducting magnetic-levitation train comprises:

the suspension sensor is used for acquiring a magnetic suspension gap between the suspension electromagnet and the guide rail in real time and sending the magnetic suspension gap to the magnetic suspension controller;

the magnetic levitation controller is internally provided with a current sensor for collecting the current of a levitation electromagnet in real time and is used for calculating levitation force F (delta, i) according to the following formula:

compared with the prior art, the invention has the beneficial effects that: the inductance parameter identification method provided by the invention can obtain accurate inductance parameters by fully considering the influences of magnetic flux leakage, iron core magnetic resistance and magnetic saturation, realizes table look-up through internal software of the controller in the working process of the suspension system, can obtain the inductance parameters on line through interpolation calculation, and is easy to realize.

Drawings

FIG. 1 is a simplified analysis model of an electromagnet;

FIG. 2 is a result of finite element analysis of inductance parameters of a levitation electromagnet of a certain medium-low speed maglev train;

FIG. 3 is an analysis diagram of the linear interpolation method of the present invention.

Detailed Description

The analysis process and the basic steps of the present invention are described below.

Because magnetic leakage and magnetic saturation are neglected, calculation errors are caused by the derivation processes of the second steps in the formulas (1) to (3), and in order to ensure the accuracy, the derivation of the first steps in the formulas (2) to (3) is reserved:

the relationship between the suspension force and the air gap flux density is as follows:

bringing formula (5) into formula (4):

the inductance parameters of the suspension electromagnet are inconvenient to directly measure, but the electromagnetic attraction (namely the suspension force) between the suspension electromagnet and the guide rail can be obtained through a special test device. In the working process of the suspension system, a data table of the relation among the suspension gap, the current and the suspension force is stored in the controller, after the suspension gap and the current are obtained through the sensor, the suspension force can be obtained in real time by looking up the table and using an interpolation method in a matching way, and then the inductance of the suspension electromagnet can be calculated through the formula (6).

In summary, the online identification method for inductance parameters of the levitation electromagnet of the normally-conducting magnetic-levitation train provided by the invention comprises the following steps:

(a) obtaining a relation data table of suspension clearance, suspension electromagnet current and suspension force through tests;

(b) acquiring a suspension gap of a suspension electromagnet through a suspension sensor;

(c) acquiring the current of the suspension electromagnet through a current sensor;

(d) obtaining the suspension force by combining an interpolation method through the suspension gap, the current and the relation data table;

(e) the suspension force obtained by the above method is calculated according to the formulaAnd calculating to obtain the inductance parameter of the suspension electromagnet.

Fig. 1 is a simplified analysis model of an electromagnet, after a coil of the electromagnet is electrified, an electromagnetic attraction force, namely a suspension force, is generated between the coil of the electromagnet and a track, and a gap between the electromagnet and the track is a suspension gap.

Fig. 2 is an inductance parameter analysis result of a levitation electromagnet of a certain medium-low speed maglev train obtained by adopting an electromagnetic field finite element analysis method, and it can be seen that the inductance parameter is related to a levitation gap and a current at the same time.

Fig. 3 is an analysis diagram of linear interpolation based on the test data in table 1, and F (δ, i) is the suspension force at the current suspension gap δ and current i, and can be obtained by geometric calculation.

Table 1 is a data table of the relationship between the levitation gap δ, the current i, and the levitation force F, which is obtained by a dedicated test apparatus.

TABLE 1 data table of nonlinear relationship between levitation gap delta, current i and levitation force F

The working of the present invention is further described below.

(a) Obtaining a relation data table of suspension clearance, suspension electromagnet current and suspension force through tests;

as shown in table 1, where i (1) to i (n) are current data points, δ (1) to δ (m) are levitation gap data points, and F (1,1) to F (m, n) are levitation force data points.

The data of the relational data table can be stored in the floating controller in advance.

(b) Acquiring a suspension gap of a suspension electromagnet through a suspension sensor;

in the working process of the suspension system, the suspension sensor collects the suspension gap between the suspension electromagnet and the guide rail in real time and sends the suspension gap to the suspension controller in the form of an electric signal, so that the suspension controller can acquire a suspension gap signal in real time.

(c) Acquiring the current of the suspension electromagnet through a current sensor;

the suspension controller is internally provided with a current sensor which can collect the current of the suspension electromagnet in real time, so that the current is a signal which can be acquired in real time.

(d) Obtaining the suspension force by combining an interpolation method through the suspension gap, the current and the relation data table (table 1);

after the suspension controller acquires the current suspension gap δ and the current signal i, on the basis of the relational data table, a linear interpolation method can be adopted to further determine the suspension force F (δ, i) at the moment.

With reference to FIG. 3 and Table 1, it is first necessary to determine the ranges of δ and i, i.e., δ (x) in the formula δ (x) ≦ δ (x +1) (1 ≦ x ≦ m-1) and i (y) ≦ i (y +1) (1 ≦ x ≦ n-1), δ (x +1), i (y +1), and then from the geometric relationships:

(e) the levitation force F obtained as described above is F (δ, i), and calculated according to the formulaAnd calculating to obtain the inductance parameter L of the suspension electromagnet.