Research On DCDC Converter Based On Secondary Side Snubber Circuit Of Transformer

In the age of information technology,all fields have higher requirements for the stability and quality of power supply.With the advancement of a series of scientific research projects in unmanned environment,such as aerospace and deep sea,power source of high stability and efficiency has become the key unit of research.A novel full-bridge isolated DC/DC converter topology based on secondary side snubber circuit of transformer is proposed.First,according to the basic principles of the circuit,a working period of the topology is decomposed into four working modes and the working state anaylsis of the switches and circuit energy flow under each mode is made.The equivalent circuit diagram of the switching process circuit is obtained and the functional expression of circuit parameters based on kirchhoffs law is listed and the value range of relevant circuit elements is obtained according to the boundary conditions.Then,the calculation formula of transformer is derived to calculate the iron core,winding turns and leakage inductance parameters of the transformer used in the experiment.Electromagnetic field simulation software ANSYS Maxwell is used to verify the calculated parameters of high-frequency transformer windings.Through software modeling,the effects of different winding modes,air gap size and air gap position on the electromagnetic parameters of the transformer are compared,and the appropriate core model and winding mode are selected to wind the experimental transformer that meets the requirements.The inductance and leakage inductance parameters of the winding transformer are measured and compared with the simulation results.Next,the topological circuit model is established by Matlab Simulink to simulate the above calculation results.The soft-switching characteristics of the circuit are verified by comparing the simulation results of the switching of auxiliary branches.The non-ideal transformer is modeled by Saber to solve the problem that the transformer model leakage inductance is not equivalent in Simulink.Finally,the control circuit,drive circuit,sampling circuit schematic diagram and PCB diagram are drawn,the physical platform is built,the topology hardware circuit is established and the optimization of switch action characteristics of isolated full-bridge DC/DC converter by secondary side absorption circuit is verified.