| Contactless Power Transmission(CPT)systems use electromagnetic fields as a medium to convert electrical energy into magnetic energy for energy transmission.This power transmission method has physical isolation and can effectively overcome problems such as electrical sparks caused by wire transmission,which has strong practical value.Magnetic Coupling Resonant(MCR)contactless power transmission system is a high-frequency,high-order system.Under the interference of factors such as coil position offset,load dynamic changes,and other factors,the system output voltage is unstable,resulting in reduced power transmission efficiency.In order to improve the power transmission quality of the MCR-CPT system in the context of energy storage,the hardware circuit structure of the system is designed,and the control strategy of the system is emphatically studied.The specific work content is as follows:Firstly,for the application scenario of battery load,the circuit structure of a series to series(SS)compensated MCR-CPT system is adopted,and the circuit model is established to derive the output voltage expression.Based on the analysis results,phase shift control is selected as the closed-loop voltage stabilizing strategy of the system.The CPT system framework based on phase shift control is constructed,and the working principle of phase shift voltage regulation is analyzed in detail.Propose an optimization strategy for non-contact chargers for energy storage scenarios,design a constant current constant voltage float charging mode based on the characteristics of lithium batteries,and design an intelligent load detection mode for no-load load measurement based on practical applications,making the system more environmentally friendly and intelligent.The closed-loop feedback performance and power transmission performance of the phase shifted CPT system are verified through simulation and experiments.Secondly,based on the phase shift closed-loop control strategy,a three input fuzzy PID algorithm is proposed.This algorithm combines two control schemes,PID control and fuzzy control,using fuzzy control to adjust the control parameters of the PID controller,thereby adjusting the phase shift angle of the system and controlling the output voltage of the system.A fuzzy neural network algorithm is proposed for parameter iterative optimization to achieve the goal of self-learning of system fuzzy rules.The superiority of the three input fuzzy PID algorithm in the phase shift control CPT system is verified through simulation and experiments.Finally,a power and signal synchronous transmission(PSST)strategy for the CPT system is proposed to meet the wireless communication requirements between the primary and secondary sides of the CPT system.This thesis analyzes several common signal modulation and demodulation principles,and designs a modulation and demodulation strategy based on 2FSK/FFT according to the characteristics of phase shifted CPT systems.After that,two PSST optimization strategies,namely,the direct sequence spread spectrum based 2FSK signal transmission strategy and the orthogonal frequency division multiplexing based 2PSK signal transmission strategy,are proposed in the CPT system,effectively improving the accuracy and anti-interference ability of the CPT system signal transmission.The feasibility of the above three PSST strategies in the CPT system is verified through simulation and experiments.There are 66 figures,6 tables and 84 references in this thesis. |
