A Digital DC/DC Converter Based On BUCK Circuit

Digitalization is an important development direction for electronic technology. Itcould enhance the stability of electronic device, and is also one of vital step for therequirement of smart devices. However, the digital process of electronic electric devicesis not fast in the day which electronic technology is rapidly developing. Because of theperformance of traditional analog power easy to variation with temperature and badrepeatability, it is quite hard satisfied with the high performance demand of powerdevice. Gradually more and more attention begins to be put on the digital power.This paper takes the BUCK converter as the research target and focus on it’sdigitalization of feedback control loop. The major works are:1. Analyzes the two ways which the fundamental BCUK converter works on theContinuous Current Mode (CCM) and Discontinuous Current Mode (DCM), andsummarize the two feedback control models in usual application. Following the signalfeedback direction of the feedback control loop, paper gives the brief introduction to thebasic modules which is used into the loop digitalization.2. Discuss the limit cycle oscillation that digitalization brings into BUCK converterfeedback control loop. This oscillation is widespread in digital control system. Toenhance the output performance of BUCK converter, this problem couldn’t avoid. Thispaper analyzes the reasons which the oscillation generates, illustrate the threemathematic conditions to avoid the oscillation and it’s suppress technologies.3. Apply the Status Space Average Method (SSAM) to build the BUCK converter’smathematic models on the power level and feedback control loop, and use the bodediagram to analyze the models. To improve the dynamic performance of the system,designed a digital PID compensator under the foundation of models we build.4. Experiment validates the effectiveness of the PID compensator we design, and ahardware digital BUCK converter is made and tested the performance factors of this converter. This paper also validate the digital dither technique have a certain function tosuppress the limit cycle oscillation.