Comparative Study of Autonomous Magnetically Coupled Wireless Power Transfer Characteristics between S-S and S-P Types Based on Negative Resistance
The magnetically coupled wireless power transfer(WPT)system based on negative resistance is a typi-cal autonomous system that has been proven to exhibit constant output characteristics.This paper compares and studies the transmission characteristics of two commonly used topological structures,namely the S-S type and S-P type,based on negative resistance.Firstly,the working frequency and critical coupling coefficient of the magnetically coupled WPT system based on negative resistance are solved using the coupling model equation.Then,a comparative study of the output power and transmission efficiency of the two topologies is conducted using analytical and numeri-cal analysis methods.Theoretical analysis indicates that,when the coupling coefficient is the same,the S-S type to-pology based on negative resistance can only operate in a constant output state when the load resistance is small,while the S-P type topology can only operate in a constant output state when the load resistance is large.Finally,cir-cuit simulation is performed to validate the theoretical analysis,providing valuable reference for the design of mag-netically coupled WPT systems based on negative resistance.