| By reducing the over-dependence on current battery technologies,the wireless power transfer(WPT)offers a brand-new power-supply solution and changes the traditional style of the energy utilization for electric-driven devices,which shows significant meanings for realizing the energy supplement in the extreme environment,reducing the pollution of waste batteries,and promoting the development of clean renewables.Related fields have become a hot spot in research institute.Based on the principle of magnetic resonance coupling,the radial induced magnetic field generated by the primary coil presents an inherent advantage to the multiple-pickup WPT transmission.Therefore,this paper mainly focuses on the single primary coil to multiple-pickup coils WPT transmission("single-to-multiple"),and the content mainly includes the following three aspects:Firstly,the parameters of four traditional impedance matching compensation topologies are calculated,and the reason for selecting series-series compensation topology is elaborated and given in this part.Then,the system detuning(frequency shifting)caused by varieties reasons,for example,the random access of multiplepickups,the dynamic change of refracted impedance,the load characteristics,the quantity of multiple-pickups,the cross-coupling effect between multiple-pickups and the parameter drift on different devices,are studied and analysis regarding to multiplepickup WPT systems.Based on the above research,the impact of the complex working condition on the transmission performances of multiple-pickup WPT systems as well as the quantitative relationship with the transmission efficiency and power are depicted.Secondly,this paper proposes a self-balancing electronic-based virtual impedance technique for multiple-objective WPT systems,which could realize the dynamic impedance adjustment by injecting the current into the primary resonance compensation capacitor.Then the mathematical model of the proposed topology is established,the feasibility and stability analysis of the proposed strategy is carried out,and the control ratio is given.Besides,the simulation by MATLAB/SIMULINK is built to verify the proposed strategy.The results show that the proposed self-balancing electronic-based virtual impedance technique can effectively improve the total transmission power of the "single-to-multiple" WPT systems by compensating the attenuation of the primary side excitation current to the value of resonant state.Finally,the experimental platform is built to verify the effectiveness,reliability and dynamic performance of the proposed self-balancing electronic-based virtual impedance technique in multiple-pickup WPT systems.In summary,this paper combines the theoretical analysis,simulation with the experimental verification to analyzes the impact of the complex working condition on the transmission performances of multiple-pickup WPT systems as well as the quantitative relationship with the resonant frequency.Then the self-balancing electronic-based virtual impedance technique are proposed,which is able to recover the primary exciting current back to the expected values thus improving the transmission power.This study improves the environmental adaptability and the performance reliability for multiple-objective WPT systems. |
