Research On High Power Density Magnetic Integrated Digital Power Supply

Recently,the demand for high power density switching power supplies is increasing in aerospace field,and the power density and reliability of switching power supply determine the overall performance and mission efficiency of spacecraft.In practical application,the input current of various converter topologies is in intermittent mode,which leads to pulse variation of input power.Since such pulse power fluctuations will adversely affect the reliable and stable operation of the converter and the power supply stability of the input power supply,it is necessary to insert additional filters in use,which will lead to the increase of the overall volume and weight of the power supply system.In this paper,aiming at the two key points of low current ripple and high power density,a new type of magnetically integrated isolated / unisolated DC/DC converter is designed.The digital control method is adopted and the nonlinear control of high power density switching power supply is realized with the combination of topology characteristics.Aiming at the switching power supply topology with input current discontinuous characteristics,a new type of magnetically integrated non-isolated and isolated converters are designed by using magnetic integration technology without increasing the volume and weight of the main power device.Both kinds of converters have the characteristics of low current ripple and high power density.The output inductor in this topology is replaced by multi-circuit magnetic integrated element to achieve low current ripple and high power density.The magnetic integrated element includes three inductors: input inductor,output inductor and auxiliary inductor.The coupling of input inductor and output inductor helps to realize the continuous characteristic of input current of converter,while saving core element and increasing system power density.The additional auxiliary inductors and capacitors can significantly reduce the ripple effect of input current ripple caused by the input / output inductance coupling without increasing the switching stress of the main power device.The converter adopts digital control and nonlinear control strategy.Compared with the traditional analog control,the converter has high flexibility,good control effect,easy to realize over-voltage and over-current protection,and accomplishes real-time monitoring and other auxiliary functions.After establishing the small signal model of the proposed magnetic integration topology,the parameters of the magnetic integration component areoptimized,the physical model is built in Saber software,and the simulation analysis is carried out in time domain,and the hardware circuit is built.The nonlinear digital control is implemented on the UCD3138 platform.The design of low current ripple and high power density switching power supply with low current ripple and high power density is verified by experiments.