Research Of Power Supply With Digital Soft-switch

With the rapid development of urbanization and industrialization in our country, thedemand for electricity increases dramatically to form a broad market for electrical operatedpower equipment. Digital technology and soft-switching technology are hot spots of thecurrent power electronics technology and the combination of them can well meet therequirements for performance, weight, volume, efficiency and reliability of the large powersupply. In this paper, high-power high-frequency switching power supply which is appliedin power system is developed by adopting phase-shifted full bridge ZVZCS conversioncircuit and the key point is to use hardware and software to achieve the combination ofdigital and soft-switching technology.First, the background of digital and soft-switching power supply is elaborated simplyin this paper. Then against applications of high-power high-frequency switching powersupply in power system, a phase-shifted control method for soft-switching full-bridgeconverter topology of which the lagging leg has series diodes is selected on the basis ofanalysis and comparison and by taking current production cost and efficiency as well asflexibility and stability of the control into account. The working principle andimplementation conditions of this topology are analyzed in detail so that the main circuit,driver circuit, voltage and current acquisition circuit, protection circuit and so on aredesigned. At the same time, selections of parameters of the main components in circuits anddesignation of the magnetic components such as transformers are completed according toformula derivation and calculation as well as engineering experience. A digital controlsystem based on the small signal model of ZVZCS converter is designed, the executionprogram for this control system is introduced in detail and the corresponding digital PIDalgorithm is given. At the same time, the software design diagram is drawn according toexperimental requirements and the simulation analysis on the main circuit is conducted byusing Matlab/Simulink software.Finally, a digital soft-switching high-frequency switching power supply prototype isdesigned based on DSP2812. It can be seen from the simulation and experimental resultsthat the digital soft-switching power supply can meet the design requirements and digitalcontrol as well as soft-switching of ZVZCS can be achieved successfully. So the rationalityof the selected program and parameter design is verified.