Parameter Design And Frequency Switching Control Strategy Of LCC-S WPT System

Wireless power transmission technology is a non-contact power supply based on electromagnetic induction principle through a series of power electronic changes.Nowadays,WPT technology has been widely used in various fields.Compared with traditional wired power supply,it is more secure and convenient.There is a research upsurge of WPT technology at home and abroad.In the practical application of wireless charging system,WPT system often needs to output load independent constant voltage or current,such as LED power supply and lithium battery charging.At present,constant current and voltage of the system are realized mainly by these methods: adding DC-DC converter circuit at the secondary side,and control the output voltage to the load through PID algorithm;Detecting the status of the load and control the transmission power of the primary side according to the status of the load;Switching the compensation network and use the output characteristics of the compensation network to achieve constant current and voltage;Adjusting the working frequency of the system.Compared with these methods to achieve constant current and voltage,adjusting the working frequency of the inverter is the simplest and easiest.the advantage is that it does not need to add additional conversion and driving circuits,nor complex control algorithm.In this paper,LCC-S structure is selected as the resonance network of frequency modulation.The reason is that compared with the low-order compensation network,the original side has compensation inductance,and the parameters of the circuit are more controllable and adjustable.Compared with some high-order compensation networks such as LCC-LCC,its analysis process and frequency calculation are more convenient and simple,which is conducive to parameter design.The research content of this paper is mainly divided into four aspects.The first part is how to find the constant current and constant voltage frequency point of LCC-S compensation network,putting forward an analysis method,and giving the program of frequency calculation,which makes the parameter design easier.The second part is to give the flow and method of parameter design,according to the simulation parameters,this part studyed the effect of current stabilizing and voltage stabilizing.The third part is to develop the control strategy of frequency switching,and analyzing The influence of frequency switching conditions and modes on the system.The fourth part is to build the model based on the MATLAB simulation platform,analysising the frequency switching mode and the system characteristic such as Zero Phase Angle condition,the transmission efficiency,the device stress and the inverter output current characteristic,finally this paper proved the correctness of the scheme design and the parameter configuration from the simulation angle.