Research And Implementation Of Digital Control Technique For Switching Power Supply Based On DSP

At present, the mainstream switching power supply applies analog IC circuits to control power energy, and there are problems such as harmonic pollution on the grid side and low power factor. In recent years, with the improvement and maturement of digital signal processing technology, and the rising of microprocessor cost performance, digital switching power supply has become a research hotspot of power supply field. Compared with analog control, digital control has more advanced and flexible control schemes, it can be easy to achieve programmable power supply and remote control. Research on digital switching power supply and achievement of power factor correction and intelligent control have important practical significance.This paper introduces DC/DC converter and power factor correction technology, and analyses the feasibility of developing digital switching power supply, then it deeply researches DC/DC converters with working principle, common topologies and control mode, and APFC with circuit topologies, control strategy, then it builds current control mode Buck DC/DC converter simulation model and Boost APFC simulation model with average current mode. After simulation verification of the two control schemes, it proves that choosed control schemes can be used in power factor correction switching power supply.Combined above simulation models and based on main performance indicators, this paper proposes a digital switching power supply centered on TMS320F28335 control circuit with main curcuit applied with Boost APFC curcuit and Buck DC/DC curcuit, then designes software and hardware. The hardware part is divided into main power circuit design with selection of device parameters, and control curcuit design with TMS320F28335 minimum system board's each control loop module. On the basis of the main program and the interrupt service program, the software part designes soft start module, sampling algorithm, voltage-fed algorithm, digital PI regulator and duty cycle generation strategy. At last, a experimental prototype is built and system debugging is completed, the experiment of power factor correction and voltage regulation shows that digital control scheme can meet theapplication requirements of switching power supply.