The Research And Design Of Digital Switching Power Supply

As an important component of power electronic equipments,switching power supplyplays a vital role in various fields of daily life. In recent years, due to the rapid evolution ofdigital processing chips, the digital control switching power supply has become a primarydirection for power supply development. Compared with the traditional analog power supply,switching power supply have a lot of advantages in miniaturization, intelligent and highfrequency. On the other hand, the green energy supply based on power factor correctiontechnique is a significant developing trend.This paper introduces the evolution history and current situations of switch power supplyand digital control switching power supply development prospect firstly. Analyzes thetopologies, the operating principles, control strategies of power factor correction techniqueand Phase-Shift Control Full-Bridge soft switching converter. Based on these theories, designsa digital switching power supply based on DSP control. This power supply adopts two levelstructure, the former is the active power factor correction circuit for power factorcompensation, the after is Phase-Shift Control Full-Bridge soft switching DC/DC converter,two circuit using two pieces of DSP to realize two stage discrete control.Hardware circuitdesign methods are introduced in detail, mainly include component parameters calculationmethods and selection principles of power conversion circuit; digital control circuit designconsists of sampling circuit, drive circuit, communication circuit, etc. Software designincludes the flow charts of primary programs and the process to produce phase shift PWM.This paper introduces a kind of F-PI compound controller, which uses the classical PI controlmethod to compensate the blind spot near the equilibrium point of fuzzy control, thiscontroller has the advantages of the two control methods. Finally, on the use of F-PIcompound controller of the APFC circuit is simulated in the MATLAB/Simulink platform.The simulation results prove the F-PI composite controller has good control effect and thedesign scheme of PFC circuit is correct.