Research On Magnetic Coupling Resonant Wireless Powr Transfer Method Based On Nonlinear Vibration Theory

Wireless power transfer(WPT)provides a new way of power transmission,which has attracted much attention in application fields such as drone power supplies and portable electronics.WPT can be divided into two types of near-field and far-field energy transmission.WPT can be divided into two types of near-field and far-field power transmission.In near-field power transfer,magnetic coupling resonance wireless power transfer(MCR-WPT)has the characteristics of high efficiency,large power and longer transfer distance.MCR-WPT is currently one of the most promising WPT technologies.For efficient power transfer,the transmitting and resonator resonators of MCR-WPT system should be worked at the same resonant frequency.However,due to aging of components or impact of environment,circuit parameters of the resonator may change and frequency drift occurs.In addition,the quality factor of the resonator in a MCR-WPT system should be kept at a relatively high value so as to reduce the transmission loss.However,the bandwidth is limited to a narrow range under the high quality factor which reduces the system tolerance to frequency drift.In order to solve the problem that the MCR-WPT system is sensitive to the frequency drift of the resonator,in this paper,a magnetic coupling resonance wireless power transmission method based on the nonlinear vibration theory is proposed.First,a two-coil MCR-WPT system circuit model including a power supply,a transmitting resonator,a receiving resonator and the load is established,and nonlinear components are introduced into the receiving resonator to make it have nonlinear resonant circuit characteristics.On this basis,by reflecting the transmitting side to the receiving side,the mathematical model of the MCR-WPT system with nonlinear vibration characteristics is established,and the nonlinear equation describing its operating characteristics is deduced.By solving the equation,the system amplitude-frequency characteristic expression is obtained.Next,the influence of different nonlinear parameters on the system amplitude-frequency characteristic is analyzed,and the nonlinear parameter corresponding to the maximum nonlinear hysteresis region under a certain vibration amplitude is obtained.Then,the output voltage of the system under different operating frequencies is analyzed,the relationship between loop impedance and operating frequency is studied,and the influence of circuit parameter changes caused by external disturbances on power transmission performance is analyzed.Finally,the experimental setup of the MCR-WPT system with nonlinear vibration characteristics is built.The result shows that compared with the traditional MCR-WPT method,the proposed method can maintain a stable voltage output in a wider frequency band.In the case that the capacitance value of the resonance circuit has a deviation of ±15%,the voltage output can still be maintained higher than that of the traditional MCR-WPT system.Compared with the traditional method,the proposed method has a better ability to suppress the influence of frequency drift.