Optimization Design Of Compensation Network Parameters For Wireless Power Transmission System With Anti-migration Characteristics

Wireless Power Transmission（WPT）has effectively improved the convenience of charging by its non-contact charging method.In recent years,it has gradually begun to be applied to electric vehicles,implantable medical equipment,underwater equipment,consumer electronics and other fileds.Usually,it is difficult to achieve complete alignment between the transmitter coil and the receiver coil,which will cause the coupling coefficient between the coils to deviate from the standard operating conditions,resulting in severe fluctuations in the output power of the system.Effectively improving the anti-offset performance of the WPT system has become a particularly critical step for its promotion and application.Most of the time,users hope that the system has strong anti-coil offset ability without using complex coil structure and complex topology.Therefore,the method of optimizing the design of compensation network parameters to improve the system’s anti-offset ability becomes a quite good choice.The method to solve the anti-offset ability of the WPT system through the compensation network parameter design is mainly to introduce free variables that can be used to adjust the compensation component parameters.And then obtain the system through the enumeration method or the traversal optimization method to get the value of free variables that minimize the output power fluctuation rate in the expected coupling coefficient working range.Then determine the actual value of each compensation component.This paper first analyzes the mathematical model of the common compensation topology,and discusses the output power fluctuation characteristics of the conventional SS topology and LCL topology when facing the coil offset.Then,based on the new universal compensation network parameter design method proposed in this paper,the LCC type compensation topology is taken as an example to verify the anti-offset parameter design method.Moreover,the anti-offset parameter design method for general compensation topology is derived.The main research contents are as follows.1)The anti-offset parameter design method of LCC type compensation topology.First,study the offset output characteristics of the conventional LCC compensation topology.Then,starting from the parameter optimization design,two free variables K₁ and K₂ are introduced to optimize the parameters of the LCC compensation topology.When the coupling coefficient changes and the reflection impedance changes,The LCC compensation network on the transmitter side realizes the adaptive adjustment of the transmitter coil current,so that the transmission power of the magnetic coupler remains stable within a wide range of coupling coefficients.Finally,an experimental prototype is built to verify the anti-offset parameter design method.The experimental results show that the maximum fluctuation rate of the output power of the system is kept within 10%in the range where the lateral deviation percentageδof the coil is less than 35%.2)The anti-offset parameter design method for general compensation topology.First,the design ideas of compensation network parameters that can make the WPT system of general compensation topology have anti-offset performance are introduced,and the essence of the anti-offset parameter design is analyzed.Then,PSS topology and CCC-S topology are taken as examples for this universal parameter design method.The improvement effect of the anti-offset ability is verified through simulation,and it is found that increasing the number of free variables can further improve the anti-offset performance of the WPT system.Finally,the experimental prototype is built for verifiing this universal parameter design method.The CCC-S topology with two free variables can realize the fluctuation rateΔ≤7.65%within the range of coil offsetδ≤45%,and the maximum efficiency is 91.7%,while the PSS topology with one free variable can realize the fluctuation rateΔ≤13.33%under the same condition,the maximum efficiency is 90.2%.