Research On Wireless Energy Transmission Technology Of Pacemaker

With the rapid development of electronic technology and chip field,biological engineering technology also reforms as application of more and more implanted medical equipment raises the cure rate and survival rate of patients.As the most frequently used medical equipment which can be implanted into human bodies,pacemakers' technology and functions have become relatively complete.However,pacemakers currently in clinical use still adopt traditional power supply way of using lithium-iodine battery.As pacemakers' power supply system is integrated with the pacing part,when the electricity runs outs,the whole pacemaker must be replaced by conducting another operation.Once installed,the implanted pacemaker will accompany patients for their whole life.During treatment,repeated operations will not only be easy to cause inflation,wounds hard to heal and other complications but also bring psychological stress to patients.To solve this practical problem,this thesis takes pacemakers' power supply system as its study object to establish a model of resonant coupled wireless energy transmission system and based on the law of electromagnetic induction and coupled-mode theory,it analyzes the system's energy transmission mechanism.It studies the system's circuit structure and analyzes influence of different compensation topology on the system's resonance compensation performance.According to the characteristics of pacemakers' small size and high biosecurity requirements,the designed study is applicable for the resonant coil structure of pacemakers' wireless energy transmission system and analyzes different parameters so as to select the optimal operating parameter for the system.It inputs the designed system into the human body model to conduct electromagnetic exposure safety assessment so as to determine the system's biosecurity.The main study contents are as follows:(1)It applies electromagnetic induction theory and coupled-mode theory to analyze energy transmission principles of the system and uses mathematical modeling to analyze and determine the basic characteristics and premises of resonant coupled wireless energy transmission.(2)By analyzing the mathematical modeling of four different compensation topology,comparing the results of emulsion proof and combined with the biosecurity requirement of pacemakers,it finally finds the most applicable resonant compensation topology for pacemakers' wireless energy transmission system after comprehensive consideration.(3)Based on finite element simulation software and giving comprehensive consideration to the system's structural characteristics and transmission performance requirements,it designs four different resonant coil structures.It uses finite element simulation analysis to compare the transmission performance and characteristics of the four coils with different structures and analyzes their influence on the system's output power,output voltage and magnetic flux density in the ambient environment and at last,it decides to adopt 8 shaped-round coil as the resonant coil.(4)It studies and analyzes different parameters' influence on the system's output performance.It uses parametric scanning to change various parameter values within a reasonable range to determine the influence of resonance frequency,operating frequency,operation voltage,primary coil transmission distance and turns per coil and other parameters on output power.Based on parametric scanning,it selects the optimal operating parameter for the system.(5)It establishes a 3D simulation model of human body and inputs the pacemaker's wireless energy transmission system into the model to conduct numerical value simulation and analysis in a electromagnetic field so as to evaluate the influence of pacemaker's wireless energy transmission system on the electromagnetic exposure conditions of each part of human bodies.It compares the maximum induction flux density and the maximum induction electric field density felt by the human body model with ICNIRP Guidelines For Electromagnetic Exposure Protection and the electromagnetic exposure protection limits stipulated in ‘Electromagnetic Environment Control Limit'(GB-8702-2014)formulated by China's Environmental Protection Department and the result shows that the designed pacemaker's wireless energy transmission system is in accordance with domestic and international requirements in electromagnetic exposure safety.