Research On Active Reset Circuit In Pulse Power Systems

Pulse transformer plays an important role in the field of pulsed power technology.It not only can transform the amplitude and polarity of pulse,but also can be used as power synthesis and transformation element.But in pulsed power systems,the volume of the core cannot be too large.On the one hand,the cost of magnetic core material is high,and on the other hand,it will affect the output performance of the device.In order to improve the utilization efficiency of magnetic cores,the most effective way is reset.Development so far,the most widely used methods are pulse reset and DC reset,the pulse reset demagnetize the core by use of the discharge current of storage capacity,the DC reset demagnetize the core by use of the DC current through the additional third winding of the core.But they are need extra huge amount of energy,in addition,the residual energy in the magnetic core after the pulse need to be dissipated through the absorption circuit,thus reduced the energy utilization efficiency of the system.The active reset circuit cannot only realize the reset of the core,but also can recover the residual energy in the core after the pulse,thus improve the energy efficiency of the system and facilitate the compact design of the system.First of all,this thesis introduces the current research status of core reset technology in pulse power systems,and analyzes the key problems.In the transformer-coupled boost circuit,the front response characteristics of pulse transformer,the hysteresis effect and the operation of magnetic core reset were introduced.Secondly,the operation of the active reset circuit was analyzed in detail,and the analytical equations for each interval of a cycle are deduced.The topology circuit was built in the simulation software and completed the simulation of several cycles,the influences of different parameters on the simulation results were analyzed.Thereafter,an experimental circuit with an output pulse of 80V/1.6A was designed.The test of the drive circuit and the pulse discharge experiment with/without reset circuit were completed.The active reset circuit was verified by comparing the changes of the saturation time of the magnetic core.Finally,the operation of the linear transformer driver(LTD)and the key problems of the traditional reset methods were introduced.The LTD topology circuit based on the active reset circuit was established and the operations of each interval were analyzed by equivalent circuits.The feasibility of the theory was verified by simulation of the circuit in several cycles.Thereafter,the experiment of LTD circuit was completed,and it is confirmed that the reset circuit can realize the reset of magnetic cores in different modules.In addition,the effects of pulse width,pulse voltage and reset time on magnetic core reset were analyzed.