| With the current progress and development of industrialization and human society,people’s requirements for the convenience of production and life are getting higher and higher.In traditional industrial production and daily life,machinery,equipment,and electrical appliances often provide electrical energy through cables.The use of wires not only limits the freedom of equipment used but also lays a safety hazard for fire protection issues.For this reason,wireless power transfer technology is gradually becoming known as a new method,among which the Electric-field Coupled Power Transfer(ECPT)technology has a more flexible coupling mechanism and no eddy current loss compared with other technologies.And other advantages,it has been valued by domestic and foreign scientific researchers.This paper focuses on the coupling mechanism offset characteristics of the ECPT system and the system performance improvement.The coupling mechanism,as an important part of the ECPT system,has a certain influence on the effectiveness of the system in transmitting electrical energy.In this paper,the common coupling mechanism is compared and analyzed in various applications,and the circular flat plate coupling mechanism model is selected according to the actual requirements.And the coupled pole plate is modelled as a four-pole plate six-capacitance circuit by combining the theory and solving for the π-type equivalent circuit expression.For the common coupling pole plate variations that cause the system transmission efficiency,two systems,horizontal and vertical,are analyzed.Through comparing the two offset methods,the horizontal type with better resistance to offset is selected for analysis.Then the influence of the offset on the coupling capacitance is analyzed by theoretical calculation and Matlab software.Finally,the electric field distribution of the coupling mechanism is analyzed by applying Maxwell simulation software.In order to analyze the problem of the effect of the horizontal offset case on the system transmission,the overall resonance principle of the compensation circuit will be analyzed theoretically in this paper.Then,the mathematical model established for the LCLC compensation network is derived using the circuit knowledge to obtain the system power and efficiency expressions,which were linked to the offset distance and coupling capacitance.After that,the problem of the offset situation of the system is simulated and analyzed by Matlab software.The simulations show that when the coupling poles are close together,the offset causes cross-coupling phenomena that can reduce the transmission effectiveness of the system.When the coupling capacitance is reduced to the first 60%,the system can maintain 80% transmission effectiveness.And depending on the equipment application scenario,the choice of appropriate bypass shunt capacitors can maintain good system efficiency.In this regard,the ECPT system’s whole transmission efficiency can be improved.Based on the analysis of each part of the system,the prototype was selected and fabricated.And the experimental platform of the ECPT system is constructed.The experimental verification of the offset phenomenon of the coupling mechanism and the system output is carried out.The system can maintain a certain stability of transmission efficiency when the coupling mechanism is shifted before 60% of the design value of the equivalent capacitance.However,as the degree of offset increases,the transmission effect decreases sharply.Choosing the right bypass capacitor size,depending on the device application scenario,will help maintain the best transmission efficiency of the system.There are 49 figures,4 tables and 67 references in this paper. |
