Design And Optimization Of TMS Power System

Transcranial magnetic stimulation(TMS)is a new technique that uses electromagnetic fields to stimulate the brain of patients to achieve therapeutic effects.It is one of the development directions in the field of bio-electrics because of its noninvasive,painless and strong penetrating ability.At present,TMS has become a common diagnosis and treatment method in neurosurgery,psychiatry and other clinical departments,and it has shown great potential in the field of brain function research.The power supply system of TMS is the basis of effective stimulation and one of the important factors that determine the intensity and effect of stimulation.The purpose of this paper is to design and optimize the power supply system of TMS.The power supply system of TMS consists of power factor correction device(PFC),high frequency resonant charging circuit and discharge circuit.First of all,this paper selects the totem pole PFC topology with excellent theoretical performance from many PFC topologies,and applies Ga N devices to this topology to make its theoretical efficiency reach the level that other topologies cannot reach.According to the actual demand,the conventional totem pole topology is optimized,the staggered parallel technology is applied,and the continuous diode is replaced,so that the totem pole PFC has higher reliability and efficiency.At the same time,the working mode of the totem pole PFC is analyzed,and the small signal model of the current loop and the voltage loop is established.Soft start technology is applied to reduce the distortion of zero crossing current.Secondly,in this paper,series and parallel resonance is selected as the resonant topology of high-frequency resonant charging circuit from four resonant topologies,and the characteristics of series and parallel resonance are utilized to increase the reliability of the system.In view of the shortcomings of two common charging strategies,a segmented constant-current charging strategy is proposed.At the same time,the electrical principle of transcranial magnetic stimulation is introduced,which leads to some details of the discharge circuit used in this paper.Finally,according to the actual needs of the circuit parameters are calculated,and the device selection.At the same time,the loss of totem column PFC is analyzed.According to the designed circuit and calculated parameters,the simulation is built and the prototype is made.The simulation and experimental results verify the feasibility of the design and optimization in this paper.