Design Of Digital PID Controller For DC-DC Converter Based On DSP

Switching power supply technology uses switch power converter for electric power transformation to meet the requirements of all kinds of electricity, which is an important field of power electronic technology, and has a good application prospect. With the prosperous development of science and industrial technology, the demand of power quality for some new electronic equipment is becoming higher and higher. Therefore, research on high performance switching power converter has become the main direction in the study of modern power technology. In this paper, on the basis of introduction on the mathematical model of several basic DC-DC converter, expounded digital control technique based on DSP and the digital PID control theory with fixed frequency Pulse Width Modulation technology, and designed the digital PID compensator for DC-DC converter based on DSP, the main work and research results were as follows:Firstly, introduced the topology structure features and mathematical modeling method of several Basic DC-DC converter in detail, and did the simulation with Matlab, which established the theoretical basis for the design of digital PID controlled DC-DC converter based on DSP in the following.Secondly, analyzed the conventional PID control theory, illustrated the implementa-tion procedure of PID compensator combined with the system function, and realized the digital conversion of conventional PID from S domain. At last, given the specific strategies of completing digital PID controller based on DSP.Thirdly, combined with analysis of digital PID control theory, took the Buck converter as an example, completed the actual circuit and control program design of the main power loop circuit and the digital PID controller circuit, and made the experimental prototype.Finally, experimental prototype test and the result analysis.The experimental results show that the converter used digital PID control method based on fixed frequency PWM technology has higher reliability and flexibility, its output characteristic is greatly improved:the steady-state output error is small, lower noise sensitivity, faster dynamic response and excellent transient characteristics of load.