Research On Passivity-Based Control Strategy For AGV Wireless Power Transfer System

With the rapid development of industrialization,AGV(Automated Guided Vehicle)has been widely applied in automated and intelligent logistics management systems.However,the traditional charging equipment of AGV has some shortcomings,such as fixed charging position and long charging time,result in low utilization rate and high using cost.Therefore,in order to solve these problems,an AGV wireless power transfer system is proposed,and the working principle and control strategy of this system have been deeply studied.The main research contents are as follows:In this paper,an AGV wireless power transfer system is proposed.In order to improve the transfer power,a high frequency transformer is added at the output of this system to increase the output voltage,while the battery voltage of AGV is 24 V;combined with the working characteristics of AGV,the intermittent pulse charging method is adopted at its temporary stop point to realize 24-hour full-automatic work.The impedance matching analysis method is proposed.With the change of SOC,the internal resistance characteristics of AGV vehicle battery changes dynamically.In order to guarantee the stability of this system,the impedance matching method is proposed to design the parameters of LCC,so the resonant working point is independent of the load.Considering the influence of high frequency components on LCC resonant network,the conditions for soft switch of inverter are deduced.The overall model of the system is established.While the interaction between high frequency transformer and LCC resonant compensation network,the transfer efficiency of the system is reduced.The principle and modeling analysis of the main modules in this system are carried out,and the overall power transfer model is established.The influence of transformer leakage inductance on this system is emphatically analyzed,and the correctness of the theoretical analysis is verified by simulation.The passivity-based control strategy of PI-PBC is proposed.The PI-PBC controller is designed to reduce the regulation time,resulting in more transmitting energy in each parking gap.While the complexity of the output load of DC/DC converter and the characteristics of dynamic change with SOC,the theory and simulation verify that the PI-PBC control strategy is independent of the load conditions.The experimental platform of 1.5kW AGV-based wireless power transfer system is built,simulation and experimental results are provided to further validate the realization of soft-switching inverter and the stability under different SOC conditions.Compared with the traditional PI control strategy,the output voltage of the proposed control strategy has no steady-state error,and its dynamic performance is much better than that of PI control strategy.As a result,the time to reach steady state is less than half of that of PI control strategy.