| Electric vehicles use wireless charging technology to charge the power battery,which has many advantages,such as convenient charging,small equipment area,easy maintenance and so on.At the same time,the technology can better solve the problem of electric vehicle endurance.Therefore,the application of this technology can further promote the popularization of electric vehicles,and can better alleviate the problems of energy shortage and environmental pollution.At present,electric vehicles use magnetic coupling resonance technology to achieve wireless power transmission.However,this method still has some shortcomings.For example,the circuit parameters will change during the operation of the system,resulting in detuning of the system frequency.At this time,the transmission characteristics of the system will be greatly affected.This article focuses on the frequency detuning of MCRWPT system.In the case of system frequency detuning,a method based on fuzzy neural network PI control is proposed to realize the resonant frequency tracking of the system,so that the system can operate stably under resonance,thereby maintaining a relatively high transmission efficiency.First,briefly explain the composition and working principle of the MCRWPT system.Choosing string resonance topology to build the circuit model of the system.Next,the system transmission efficiency is analyzed,and the system transmission efficiency formula is derived through the simplified circuit model,and the system transmission efficiency formula is derived from the simplified circuit model,and the influence of the circuit parameters on the system transmission efficiency is analyzed.Immediately afterwards,the detuning mechanism of the system was studied.After analysis,it is known that when the circuit parameters of the system change,corresponding control methods need to be adopted to make the system work stably in resonance,so that the MCRWPT system can maintain a high transmission efficiency.Secondly,aiming at the problem of frequency detuning of MCRWPT system,a frequency tracking method based on PI control of fuzzy neural network is proposed.And it is verified that the proposed method can realize the fast tracking of the system resonance frequency,and at the same time can improve the anti-interference ability of the system.Then,the MCRWPT system circuit was designed,including the design of the main circuit and the frequency tracking circuit,and the principles and requirements of the structure of each part and the model selection of the main components were explained,which is conducive to the subsequent further research.Finally,an experimental platform for the wireless power transmission system was built,and the experiment verified that the proposed frequency tracking method can keep the system high transmission efficiency when the load resistance and the transmission distance of the coil change.The research content of this paper has certain theoretical value and reference significance for improving the transmission efficiency of MCRWPT system. |
