Wireless Power Transfer System For Implantable Device Based On Signal Channel Feedback

With the development of medical technology,implantable electronic medical device can replace the functions of body organs,which has gradually become an important medical treatment,there are urgent clinical demands.But the power supply method for implantable device is always a clinical problem to be overcome.Especially for the large power dissipation device as artificial heart,the implanted batteries often can only provide power for a short period.And the method that it sends power from outside to the implantable device through a wire will cause infection which leads to other lesion.Fortunately,the wireless power transfer(WPT)technology can get rid of wire to provide power for equipment in non-contact way,which can solve the problem of power supply method for implantable medical device.However,it has shown that the WPT technology is sensitive to change the system parameters in some stud ies.When the distance of transmission,the load or the input changed will affect the characteristic of the system,leading to fluctuation for output of system and running unstable,or out of work and even collapse.In addition,different electrical equipment will have a variety of needs on the power quality.For example,it is Not only to meet stable output when the load or transmission distance change,but also to achieve communication at the same time for the artificial heart.And it is expected that the volume of the implanted part can be small,the loss can be little and the temperature of the implanted part can be controlled below the human body temperature without affecting human health.Therefore,it is necessary to design a suitable control strategy for WPT technology in order to meet the needs of implantable medical device and also to ensure the stability and reliability of system.In order to complete this design,the present research situation of implanted medical equipment is studied,and the realization scheme of the two key goals of regulator output and data transfer is summarized.By analyzing the advantages and limitations of various previous schemes,a control strategy to meet the requirements of the system design is proposed.In order to meet the demand of volume and loss of implantable part,the circuit of implantable part consists of the resonance network and uncontrollable rectifier filter.Then the output parameters of system is sent to control part by synchronous communication technology,the control strategy to achieve regulator output is designed with the energy input control method in the control part.In addition,in order to reduce the use of high-frequency communication on human radiation hazards,low-frequency directional signal channel is chosen to complete the data transfer,because of the higher the frequency of electromagnetic wave is,the higher of the radiation risk to the human body.The system parameters design to match energy input control method is presented after analyzing the system model.Then the design and construction of the hardware test platform is carried out to verify the proposed control scheme.The experimental results show the feasibility of the proposed control scheme.When the system load or mutual inductance changes within the specified range,the system can keep the output voltage stable.