| Wireless power transfer technology is to achieve efficient transmission of electrical energy without conductor contact,which overcomes many problems caused by the traditional wired transmission method,making people more convenient and flexible when using electrical equipment.It makes the system safer,more reliable and easier to maintain.WPT technology is being popularized and applied in many fields such as rail transit and biomedicine.Even if the application range is getting more wider,there are still some critical problems in the WPT system.For example,the design system is optimized for a specific application object application scenario by comprehensively considering multiple factors,which can ensure that the system has good robustness within a certain range of parameter changes and improve transmission energy and efficiency of the system as much as possible.For the optimization design of WPT system,it can usually be considered from the aspects of circuit topology,coupling mechanism,and maximum energy efficiency tracking control.In this article,it starts directly from the system parameters for a specific topology.It optimizes the system dynamic and steady-state performance and improves transmission efficiency and power by optimizing the system parameters.This article mainly does the following work:First,it analyzes how the WPT system works and its related topological characteristics.Aiming at the optimization design problem of WPT system,the LCC-S type WPT system is taken as the research object.It establishes the mathematical model of WPT system with circuit theory.According to the AC impedance method,the working principle and structural characteristics of the system are analyzed to determine the influencing factors that can effectively improve the transmission power and transmission efficiency of the system,and the characteristics are verified by combining a set of simulation parameters.Second,it establishes NLP model of WPT system.As we all know,the WPT system is a complex high-order nonlinear system,and its performance is under the influence of many factors.Considering the problems of frequency stability,soft-switching control mode,inter-relationship between parameters,and actual device constraints in WPT system,the article adopts generalized state space averaging method and time-domain differential method to establish multi-objective multi-constrained nonlinearity Planning model.Compared with the pros and cons of two methods,it is found that the time-domain differential method is more general and reduces the difficulty of the solution.Taking transmission energy efficiency as the goal,the NLP model of the LCC-S WPT system is established by the time-domain differential method.Finally,it improves NGSA-II multi-objective optimization algorithm.Firstly,the commonly used optimization methods for solving nonlinear programming models are compared and analyzed.The appropriate NSGA-II multi-objective genetic optimization method is selected according to the characteristics of each method.After improvement,the non-linear model established above is subjected to multi-objective multi-constraint optimization.Then,a set of test samples are given to compare and improve the performance of the NSGA-II multi-objective optimization algorithm.Finally,given the specific design requirements,an LCC-S type WPT system is optimally designed using the above model and model optimization solution method,a MATLAB / Simulink platform is built by optimized parameters obtained by the improved NSGA-II multiobjective optimization algorithm.It can analyze the system characteristics and verify the feasibility and effectiveness of the multi-objective optimization method to improve the overall performance of the system. |
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