CN-115795957-B - Semi-analytic mutual inductance calculation method of dynamic wireless power transmission magnetic coupling mechanism

CN115795957BCN 115795957 BCN115795957 BCN 115795957BCN-115795957-B

Abstract

The invention provides a semi-analytic mutual inductance calculation method of a dynamic wireless power transmission magnetic coupling mechanism. In the process of designing and optimizing the magnetic coupling mechanism, the mutual inductance calculation method disclosed by the invention can be used for rapidly calculating the mutual inductance of the magnetic coupling mechanism at different receiving end positions and under different receiving end structural parameters only by one time of finite element simulation, so that the problems of overlong calculation time, large simulation workload, overlarge occupied computer memory, unclear physical concept and the like in the traditional simulation calculation method in the process of calculating the mutual inductance of the magnetic coupling mechanism in the dynamic wireless power transmission process can be solved, and the mutual inductance calculation speed and the design speed of the magnetic coupling mechanism are greatly improved. Meanwhile, the method of the invention provides the analytic function relation between each structural parameter of the receiving end and the mutual inductance, reveals the influence of different structural parameters of the receiving end of the magnetic coupling mechanism on the mutual inductance, and can provide theoretical guidance for the structural design of the magnetic coupling mechanism.

Inventors

SONG BEIBEI
CUI SHUMEI
DU BOCHAO
ZHU CHUNBO

Assignees

哈尔滨工业大学
哈工大郑州研究院

Dates

Publication Date: 20260505
Application Date: 20221129

Claims (8)

1. A semi-analytic mutual inductance calculation method of a dynamic wireless power transmission magnetic coupling mechanism is characterized by comprising the following steps: Step 1, establishing a finite element simulation model of a magnetic core of a transmitting end and a transmitting coil, and obtaining simulation distribution results of magnetic induction intensity B generated by the transmitting coil on a straight line x=0 and a straight line y=0 of a receiving end plane z=h under rated transmitting current excitation I T through single finite element simulation, wherein the receiving end plane refers to a horizontal plane where the receiving coil is positioned, namely an xy plane, and rated transmitting current I T is an effective value of current I T in the transmitting coil when a magnetic coupling mechanism works in a rated state, and h is a vertical distance between the upper surface of the transmitting end and the receiving end plane; Step 2, extracting a vertical component B z of the magnetic induction intensity on the plane of the receiving end, extracting the maximum value of the vertical component B z of the magnetic induction intensity on the plane of the receiving end through numerical analysis software, and extracting a magnetic field shape function lambda through Gaussian function fitting; Wherein the magnetic induction is a space vector with a direction that can be decomposed into a horizontal component B x ,B y and a vertical component B z of the magnetic induction along the x-axis, the y-axis, and the z-axis; step 3, carrying out corresponding position x of the receiving coil on the x axis, and solving a mutual inductance position function M x (x); step 4, carrying the length l R of the receiving coil, and solving a mutual inductance length function M l (l R ); step 5, the width W R of the receiving coil is brought in, and a mutual inductance width function M W (W R is solved; Step 6, carrying out turns N R of the receiving coil, and solving a mutual inductance turn function M N (N R ); step 7, carrying the number n of the receiving coils and the center distance d between two adjacent receiving coils, and solving a mutual inductance distance function M dn (d, n); Step 8, carrying the length of the receiving end flat magnetic core, and solving a mutual inductance magnetic core function M core (l c ,W c ), wherein the size of the receiving end magnetic core is larger than the outer sizes of the plurality of receiving coils; and 9, solving the mutual inductance M of the magnetic coupling mechanism by the product of the amplitude of the vertical component of the magnetic induction intensity and each mutual inductance calculation function, wherein the solved expression is specifically as follows: And 10, substituting the new structural parameters and the position parameters into the steps 3 to 9 when the position of the receiving end, the structural parameters of the receiving coil and the receiving end magnetic core are changed, and calculating to obtain the mutual inductance under the new structural parameters.
2. The method of claim 1, wherein the semi-analytical calculation method is applied to a longitudinal magnetic flux type magnetic coupling mechanism, that is, a magnetic coupling mechanism in which a transmission coil generates an empty magnetic field to form N, S alternating magnetic poles along a traveling direction, and a main magnetic flux direction is parallel to the traveling direction.
3. The method of claim 1, wherein the mutual inductance location function M x (x) represents a function of mutual inductance and receiving coil location, and the expression is as follows: where τ represents the pole pitch of the transmit coil, i.e., the distance between two adjacent equivalent magnetic poles in the magnetic field generated by the transmit coil.
4. The method of claim 1, wherein the mutual inductance length function represents a mutual inductance as a function of a length of the receiving coil, and is expressed as follows:
5. the method of claim 1, wherein the mutual inductance width function represents a mutual inductance as a function of a receiving coil width, expressed as follows: where Φ (x) represents the distribution function of a standard normal distribution.
6. The method of claim 1, wherein the mutual inductance turns function represents a mutual inductance as a function of the number of turns of the receiving coil, expressed as follows: where i represents the ith turn of the receiving coil and delta represents the inter-turn distance between two adjacent turns of the receiving coil.
7. The method of claim 1, wherein the mutual inductance distance function represents a function of the number of the mutual inductance and the receiving coils and a center distance between two adjacent receiving coils, and the expression is as follows:
8. The method of claim 1, wherein the mutual inductance core function represents a functional relationship between mutual inductance and a receiving end planar core structural parameter, and the expression is as follows:

Description

Semi-analytic mutual inductance calculation method of dynamic wireless power transmission magnetic coupling mechanism Technical Field The invention belongs to the technical field of wireless power transmission, and particularly relates to a semi-analytic mutual inductance calculation method of a dynamic wireless power transmission magnetic coupling mechanism. Background The dynamic wireless power transmission technology can effectively improve the endurance mileage of the electric automobile, reduce the time of parking and charging, improve the flexibility, safety and environmental adaptability of vehicle charging, and fundamentally solve the bottleneck problem of limiting the popularization and application of the electric automobile at present. In a dynamic wireless power transmission system, a magnetic coupling mechanism is a core component for wireless transmission of electromagnetic energy. The mutual inductance directly determines the most important factors of the output power of the magnetic coupling mechanism, is related to the structure of the transmitting coil, the receiving coil, the relative position of the transmitting coil and other parameters, and directly determines various key performances of the dynamic wireless electric energy transmission system. Therefore, the calculation of the mutual inductance and the relationship between the mutual inductance and the parameters of the magnetic coupling mechanism are important problems in the design process of the magnetic coupling mechanism. At present, 2 calculation methods are mainly used for mutual inductance in a dynamic wireless power transmission magnetic coupling mechanism. The first is an analytical calculation method, which calculates the mutual inductance by calculating the mutual inductance flux passing through the coil based on the law of pioshal. For example, literature [S.Raju,R.Wu,M.Chan and C.P.Yue,"Modeling ofMutual Coupling Between Planar Inductors in Wireless Power Applications,"IEEE Transactions on Power Electronics,2014] gives a method of calculating the mutual inductance of a circular air-core coil based on the neumann equation. However, analytical calculation methods are only applicable to magnetic coupling mechanisms without a magnetic core. When the structure of the magnetic core or the coil is complex, the magnetic field distribution is difficult to describe through a formula, so that the mutual inductance cannot be calculated in an analytic way. The second method is a finite element simulation calculation method. The method obtains mutual inductance through simulation by means of finite element simulation software. The simulation calculation method can calculate the mutual inductance in the complex magnetic coupling mechanism and is widely applied to dynamic wireless power transmission systems. However, in the process of designing or optimizing the magnetic coupling mechanism, the finite element simulation calculation method needs to obtain the variation relation of mutual inductance along with the structural parameters of the magnetic coupling mechanism through parameterized scanning simulation. The three-dimensional field simulation needs to occupy a large amount of memory of a computer for thousands of times, consumes more time, and greatly increases the design period. Meanwhile, the quantitative relation between the mutual inductance and the structural parameters cannot be established by the method, so that the design of the magnetic coupling mechanism lacks theoretical design guidance. Disclosure of Invention The invention aims to solve the problems of large simulation workload, low calculation speed, lack of theoretical basis and the like of the traditional finite element calculation method in the process of calculating mutual inductance of the traditional dynamic wireless power transmission magnetic coupling mechanism, and provides a semi-analytic mutual inductance calculation method of the dynamic wireless power transmission magnetic coupling mechanism. The invention is realized by the following technical scheme, and provides a semi-analytic mutual inductance calculation method of a dynamic wireless power transmission magnetic coupling mechanism, which specifically comprises the following steps: Step 1, establishing a finite element simulation model of a magnetic core of a transmitting end and a transmitting coil, and obtaining simulation distribution results of magnetic induction intensity B generated by the transmitting coil on a straight line x=0 and a straight line y=0 of a receiving end plane z=h under rated transmitting current excitation I T through single finite element simulation, wherein the receiving end plane refers to a horizontal plane where the receiving coil is positioned, namely an xy plane, and rated transmitting current I T is an effective value of current I T in the transmitting coil when a magnetic coupling mechanism works in a rated state, and h is a vertical distance between the upper surface