The Research On Segmentated Dynamic Wireless Power Transfer System Based On LCL-SS Compensation

Wireless power transfer(WPT)technology can realize the transmission of electrical energy between the transmitter and the receiver with out physical contact through the coupling of the electromagnetic field.Compared with the traditional contact(wired)power transmission,it allows the receiver to move within a certain distance.This technology makes it possible that the electric vehicle(EV)can charge anywhere at anytime.For example,through the application of dynamic wireless charging technology can realize EV charging while moving.In the dynamic WPT system,the power of the receiver depends on the mutual inductance of the coil.In the applicaition for EV,the transmitter and receiver are relatively mobile,the mutual inductance varies with the EV movement,which results in the transmission power fluctuations,furthermore the overall efficiency of the system will decrease.To solve this problem,this paper designs a WPT system based on the LCL-SS compensation.The system can ensure that the transmission power will maintain a stable while the EV is moving.Firstly,this paper analyse the working principle of capacitance compensation WPT system by using of loosely coupled transformer transformer model,discusses the output power and the transmission efficiency of system Secondly,in order to improve the dynamic stability of WPT system,this paper present a topology with LCL-SS compensation network.Then it will be analysed,that this topology can inhibit the system harmonic current and stable output voltage and increase the load capacity of the system.It is proved that the LCL-SS compensation network has an important application in dynamic WPT system.Through the transfer function derived by LCL-SS compensation network,by means of the pole zero plot and the amplitude frequency characteristic of the system diagram,this paper will present how the key design parameters of LCL-SS network influence the transient response of sysem in detail,and the theoretical results are verified by PLEC circuit simulation software.Finally,the parameter design method of WPT system based on LCL-SS compensation network is proposed.In addition,aiming at the application of the LCL-SS compensation network in the segmented dynamic WPT system,this paper proposes a topology which uses the same LCL-SS compensation network parameters and the primary side coils are connected in parallel.Two primary coils and one receiving coil are studied in detail.The multi-coil mutual inductance model of the LCL-SS compensation network is presented in this paer.The output power and transmission efficiency of system will be discussed combined with the mutual inductance characteristics of coil.Finally,it will be proved that the LCL-SS can be used to realize the smooth transfer power in the dynamic WPT system by designing a proper transmitting coil.Finally,according to the theoretical analysis and simulation results proposed in this paper,an experimental platform based on LCL-SS parallel compensation is designed,which can achieve 100 W power output,the transmission distance is 15 cm,the transmission efficiency can reach more than 71%.Through the experiment and analyzing he characteristics of the WPT system with parallel LCL-SS compensation,it is verified that the system can achieve the function of maintaining the power of the secondary side in dynamic.The effectiveness of the segmented multi-coil WPT system based on LCL-SS compensation is proved.