Research On Wireless Power Transfer Technology With S/LCC Compensation Topology

Wireless Power Transfer(WPT)is an active research direction in recent years.Because of its convenience,efficience and safety,it is conducive to the reliability and economy of the equipment.It has been increasingly used in consumer electronics,medical electronics,lighting,transportation and other fields.Because of the inapplicability of the traditional transformer model for wireless power transfer system,this paper first deduces the leakage inductance model and the controlled source model of loosely coupled transformers.Through the theoretical derivation and software simulation,the coil parameters under different winding methods and shapes are analyzed and compared.The structure of different loosely coupled transformers is studied and designed.A loosely coupled transformer with low transmission loss that meets the requirements for larger power transmission is designed to improve the overall performance of the wireless power transmission system.To sove the disadvantages of traditional low-order compensation,a new S/LCC compensation topology is obtained by combining a T-circuit with a conventional series compensation topology.This topology has constant-voltage output characteristics over the full load range when the T-circuit is symmetric.The basic wave analysis method was used to study the properties of the S/LCC compensation topology.After asymmetric processing,the circuit obtained the ZVS soft-switching characteristics.Finally,the influence of higher harmonics on the circuit was discussed.In order to improve the output accuracy of system and realize the constant voltage output of load,this paper analyzes the small-signal modeling of the Buck circuit and adopts a continuous-mode Buck DC-DC converter.Digital control is used to ensure the constant-voltage output.Using the PI compensation method,the dynamic and steady-state performance of the system is compensated and adjusted,and the output voltage of the load is adjusted to be constant,thereby realizing closedloop control.Finally,according to the theoretical calculations and simulation results,a prototype of a wireless power transmission system with a power of 200 W was built with a transmission distance of 5 cm and an efficiency of 82%.