| The research of micro-robot capsules based on electromagnetic coupling wireless power transmission(WPT) is one of the hottest topics in medical diagnosis and treatment. Many scholars are doing a lot of research work on this issue.Based on the previous work of our research group, the characteristics of micro-robot capsule WPT system is discussed, and a comprehensive optimization model of the system is established. The performance of the WPT system is optimized with intelligent algorithm, and the processing circuit is also improved.Firstly, the composition and basic principle of micro robot WPT system is analyzed. The circuit of the outer energy emitting portion is designed, and simulation experiment is conducted. An experimental platform with full bridge inverter circuit and rectifier filter circuit is established to verify the validity of the design, and the relationship between frequency,input voltage and circuit conversion efficiency is then analyzed. The reaction impedance and the reactive reactance model are studied to find out the connection between reaction impedance and frequency or load.Secondly, the mutual inductance model of the system in arbitrary pose is established. The influence of frequency, coil spacing, power supply voltage, center offset, deflection angle and other parameters on output power as well as transmission efficiency is discussed.Thirdly, in reference to the design parameters of turns, radius and resonant frequency, a new comprehensive energy efficiency model is put forward. The constraints of frequency, coil parameters, energy consumption, electromagnetic safety and temperature rise safety condition are all taken in to consideration. Genetic algorithm is utilized to optimize the micro-robot capsule WPT system, and experiment results show the correctness of optimization.Fourthly, frequency detuning in the micro-robot capsule WPT system is studied. High frequency parasitic capacitance and distributed capacitance are found to be the primary causes of frequency detuning. Dynamic capacitance compensation is proposed to solve the problem,so the system can remain resonant with the former frequency. Moreover, a novel three-dimensional rectification processing circuit is developed to improve the electric energy conversion performance of the receiving portion. Therefore, the synthesis problem of the multi-dimensional rectifier circuit is solved.Lastly, The new WPT system, together with the improved rectifier circuit are tested and verified by experiments. When the location and pose of the receiving coils is changed, the WPT system can continue providing stable electrical energy supply for the load. The outcomeof the experiments indicates that the performance of the whole system meets initial goal. |
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