Research On Parameter Synthesis Optimization And Magnetic Integration Method Of High Power Interleaved Buck Converter

Due to the rapid progress of distributed generation,electrified transportation and aerospace applications,higher requirements are put forward for the weight,efficiency,volume and control performance of high-power DC-DC converter.Based on the synchronous rectifier interleaved parallel buck converter,this paper focuses on its miniaturization,lightweight,high efficiency and fast control.The specific work of this paper is as follows:In order to solve the design difficulty between efficiency and volume of converter,a parameter comprehensive optimization design method is proposed in this paper.Based on different duty cycle,the voltage and current ripple of interleaved parallel converter are analyzed.Follow the equation of ripple analysis,the expressions of the design inductance and capacitance of the converter are solved.In the parameter design process,the efficiency of the converter is taken as the boundary condition of program execution,and the results of passive component volume modeling of the converter are taken as the objective function to find the optimal solution in the boundary adjustment.According to the optimal solution,the inductance and capacitance of the converter are designed to ensure that the designed converter meets the requirements of high efficiency and realizes the design goal of miniaturization.In order to solve the problems that the independent inductor cannot reduce the current ripple while maintaining the constant transient response speed and the large volume and mass of the independent inductor,the coupled inductor technology is applied to the interleaved parallel converter.Firstly,the two coupling modes are analyzed from the perspective of loss and magnetic saturation.Based on two staggered parallel buck converters,the circuit mode conversion law is analyzed in detail,and the expressions of equivalent steady-state inductance and equivalent transient inductance are obtained.The steady-state ripple and transient response speed of the converter with coupled inductor and independent inductor are compared.Compared with the parameters of independent inductor and taking the steady-state response and transient response as constraints,the first formula required for the design of coupled inductor is obtained.The core reluctance modeling of the coupled inductor is completed,and the expressions of self-inductance and mutual inductance are obtained according to the duality principle.The volume and weight modeling of the inductor core are carried out,and the expressions of self-inductance and coupling coefficient are obtained as the objective function of the coupling inductor design.Taking the steady-state current ripple and transient response speed of the converter as constraints and the expressions of volume modeling and weight modeling as objective functions,the self-inductance and coupling coefficients are solved.According to the solution results,the coupling inductance with specific coupling coefficient is designed.Based on Si C MOSFET,an experimental prototype with rated power of 40 k W is built,and the experimental research based on independent inductance and coupled inductance is completed in the full voltage range,which verifies the correctness,effectiveness and feasibility of the theoretical analysis.