An Improvement For The Secondary Coil Of Tesla Coil

Tesla coil is a kind of device which uses resonant method to produce high-voltage electricity,which has some applications in high energy physics research,insulation per-formance test and so on.In the Tesla coil,secondary coil is the most critical part for lifting voltage,and the focus of the design of Tesla coil.At present,in the design of Tesla coil,the popular height and diameter ratio is between 4 and 6,and few break through this range.For small and medium coils,such proportions may be acceptable,but for the large Tesla coil,it is not quite suitable,not only for the large material con-sumption,but also for the difficulty of the design and assembly,moreover,the actual circuit model and the widely used theoretical circuit model may produce inconsistent places.Therefore,in this paper,we propose to use the thin long coil which exceeds the proportional range as the secondary coil,analyze the advantages compared with the existing ratio,and verify the working effect of the slender secondary by experiment.The main contents of the paper are as follows:The coil which has the height and diameter ratio between 4 and 6 and the thin long coil exceeding this ratio is compared.It shows that the slender secondary coil not only has advantages in the design and fabrication of large Tesla coils,but also the distribution of current in the coil is more consistent and the actual circuit model is closer to the theoretical circuit model.The coupled circuit model of the Tesla coil is introduced.Through the analysis and calculation of the circuit model,the law of the resonant frequency splitting of the coupled circuit is obtained,and the conclusion that the lower resonant frequency should be used to motivate the primary resonant circuit is obtained through impedance analysis.Based on the analysis of the zero state response of the circuit,the relationship between the resonant voltage of the secondary circuit and the coupling coefficient as well as the resonant frequency difference between the primary and secondary circuits is obtained.The distributed capacitance model of electric spark and secondary coil is simulated by finite element simulation,which shows that the distribution parameters will cause the error between the actual circuit model and the ideal circuit model,and the corresponding improvement method is provided.The experiment platform of Tesla coil was designed and related experiments were conducted.Firstly,the correctness of the previous theoretical analysis and simulation results are verified,then,the primary coil is improved according to the characteristics of thin long secondary coil,and the reason of partial discharge on the surface of improved coil is found by simulation,finally the experiment is conducted with the secondary coil which has the diameter of 75mm and height of 1.5m(the height and diameter ratio is 20),in the case of 300V AC power supply,resonant frequency at 68kHz and 30 cycles excitation,the spark length reaches up to 3.6m,it shows that the slender coil has good working effect.Moreover,a new DRSSTC driving method is proposed at the end of the paper,this kind of driving method can utilize the energy of the resonant circuit more effectively,and is expected to improve the performance of the Tesla coil.