Research Of An IPT System Based On PS/SP Compensation Topology With High Misalignment-tolerant Capability

In recent years,charging devices are more and more widely used by people.In some specific charging situations that need to be moved,the traditional cable connection is very troublesome and the cost is relatively high.So the wireless power transfer technology is widely concerned with its advantages of quick and convenient.Since there is no physical contact between the two sides of the wireless power transfer system,the transmission efficiency of the system will be greatly reduced under the condition of deviation or misalignment.In order to further improve the misalignment-tolerant capability of the system,this paper proposes a solution to optimize the system performance from the compensation network,magnetic coupled structure,parameter optimization design method.A compensation topology with high misalignment-tolerant capability named PS/SP(parallel-series/series-parallel)compensation topology is proposed in this paper.This topology has high misalignment-tolerant capability compared with traditional S/S and LCC/S constant voltage output compensation topology,which keeps the output voltage constant in a certain range.Firstly,this paper presents the conditions that the PS/SP compensation topology needs to be satisfied with its misalignment-tolerant capability,and introduces its parameter design method.Secondly,the impedance characteristics of the compensation topology are analyzed.When the coupling coefficient of the PS/SP compensation topology is the central coupling coefficient,the angle of input impedance is zero.In order to realize the zero voltage switch,the circuit parameters are optimized to effectively reduce the switching loss and improve the system efficiency.Finally,the sensitivity of the output voltage to the compensation parameters is analyzed.In order to further improve the misalignment-tolerant capability,this paper proposes an optimized design method for planar circular loosely coupled transformer,which improves the misalignment-tolerant capability of the system.Firstly,the coupling coefficient and the misalignment-tolerant ability of loosely-coupled transformer with different air gap distance,different primary side dimensions,symmetrical and asymmetric coils are simulated and analyzed by Maxwell software.Secondly,the laws of coupling coefficient and the misalignment-tolerant ability change with the above parameters are obtained by analysis,and an optimized system parameter design method is proposed accordingly.Finally,a magnetic coupling mechanism with high coupling coefficient and high misalignment-tolerant capability is designed according to the above analysis.Based on the above theoretical analysis,calculation and simulation results,an inductively power transfer system with high misalignment-tolerant capability is designed and its performance is vetified by simulation and experiment.The maximum efficiency of the system is 94.41%,and the efficiency of the whole load range is more than 82%,achieving a high transmission efficiency.The experimental results show that the voltage fluctuation range is 6.4%,and the range of simulation is 1.7%.The system has high misalignment-tolerant capability.