Research On The Integrated Control Strategy Of Optimal Efficiency Tracking And Constant Voltage Output Of ICPT System With Dual LCL Topology

Inductively coupled power transfer(ICPT)technology uses the principle of electromagnetic induction to realize the wireless transmission of electric energy from the power supply to the load,which has the advantages of reliability of safety,operational flexibility and using convenience.Its advantages in terms of power transmission and efficiency aspects make it have a good prospect in theoretical research and market application.In the practical application of ICPT system,the uncertainty of load will have an impact on the system,which is prone to output instability,degradation of power quality and transmission efficiency,etc.Facing the load changes,how to ensure the system to simultaneously meet the requirements of stable output,higher efficiency,strong load compatibility and so on is the key issues of ICPT technology research.Therefore,this thesis focuses on the load variations,and proposes a multi-performance integrated control strategy with high efficiency tracking,output voltage regulation and strong robustness by combining robust H_?control and the optimal efficiency tracking control.The main research work is as follows:Firstly,the research background and the basic principle of ICPT system are introduced.Then,the research status of modeling methods,voltage stabilizing control strategies and efficiency improvement of ICPT system are elaborated in detail.Secondly,starting with the LCL topology circuit,the principle and characteristics are studied and analyzed.The LCL resonant network is chosen as the primary compensation topology.The LCL-S topology,LCL-P topology and dual LCL topology structures are selected for comparative analysis from the aspects of voltage gain,current gain,transmission power and efficiency respectively.The research shows that dual LCL topology has strong parameter compatibility,and can maintain stable,higher efficiency in a relatively wider load variation range.Therefore,this thesis takes the dual LCL compensation topology as the object of design and analysis.Thirdly,for the ICPT system with dual LCL topology,the AC impedance method is adopted to build the system efficiency model.The optimal efficiency tracking control of the Buck-Boost impedance converter is designed,and the optimal efficiency can be tracked by regulating the duty cycle of the converter.On the basis of the optimal efficiency tracking control,in order to meet multiple performance requirements such as high efficiency,constant voltage and so on at the same time,a double closed-loop integrated control method is proposed in combination with the robust H_?control.According to the decoupling conditions,two design methods can be controlled independently,so the design complexity is reduced.Fourthly,by generalized state space averaging(GSSA)modeling method and linear fraction transformation(LFT)principle to establish the uncertainty model of load perturbation,a robust H_?controller for the closed-loop feedback system is designed.For the frequency domain,the nominal performance,the robust stability against parameter perturbation and the robust performance of suppressing external disturbances are verified by using structure singular value,and the dynamic tracking performance and anti-interference performance of the system are also verified in time domain.Finally,the experimental prototype of the double closed-loop feedback control system is set up to analyze the dynamic and static performance of the system under parameter perturbation and external interference.The experimental results show that the integrated control method proposed can not only track higher efficiency in a large range of load changes,but also ensure that the system has good dynamic reference tracking performance,disturbance suppression performance,voltage regulation performance and robustness when load and input voltage changes.