Research On Effect Analysis And Efficiency Optimization Of DC/DC Topology On LCC-WPT System

Wireless power transfer(WPT)technology is widely used due to its advantages in flexibility,safety,and aesthetics.AGV charging adopts wireless energy transmission technology to avoid excessive wiring,and it can realize charging at any time while stopping.It is very convenient,safe and efficient.Even in rainy and snowy weather,it will not affect the charging effeciency.Based on AGV's wireless energy transmission technology,this paper studies the influence of the receiving side DC/DC topology on the entire wireless energy transmission system.And on this basis,the secondary side DC/DC topology is optimized to achieve the high efficiency and stability of the entire AGV wireless energy transmission system.The paper first introduces the main circuit structure and working principle of the AGV wireless energy transmission system.The main circuit includes the inverter,the compensation structure and the coupling coil,the secondary side rectification and the DC/DC conversion part,and models the wireless energy transmission system.Using the mutual inductance model,a steady-state model of the LCC-S wireless energy transmission system is established,and then the circuit topology is analyzed,and the voltage gain and transmission of the LCC-S compensation topology are investigated by changes in parameters such as resonance frequency and equivalent load.Effects on efficiency,system robustness,etc.Secondly,the paper discusses the influence of different DC/DC topologies on the system stability and efficiency,and analyzes how to choose the DC/DC topology under different working conditions.The choice of DC/DC topology directly affects the equivalent load on the secondary side of the wireless energy transmission system.If the actual equivalent load differs too much from the optimal equivalent load,the inverter output current waveform will be seriously distorted,affecting the overall system Efficiency,at the same time,will also affect the voltage gain of the LCC compensation and directly affect the efficiency of the wireless energy transmission system.Through the above analysis,the choice of the secondary DC/DC topology under specific working conditions is given,so that the inverter harmonic content and other parameters meet the requirements,and the efficiency and stability of the entire wireless energy transmission system are optimized.Thirdly,under certain operating conditions,the secondary DC/DC topology selects a four-switch Buck-Boost converter and optimizes it.In order to solve the problem of unstable output when the input and output voltages of the four-switch Buck-Boost converter are close to each other,the mode switching method is optimized,multi-stage control is adopted and the buffer area is increased.In response to the problem that the number of switching tubes of the converter is large and the switching loss is large,the chronological sequence of the switching tubes is optimized,so that all four switching tubes of the converter can realize soft switching,greatly reducing or even eliminating switching losses Higher efficiency of wireless energy transmission system.Finally,related experiments of AGV 3.3k W wireless energy transmission system were carried out,and the influence of the secondary DC/DC topology selection on the wireless energy transmission system was partially verified.