The Research On DC/DC Converter Control Scheme

In the latest years, with the rapid development of power electronic technology, the switching power supply which constructed by DC/DC converter has been applied in every field deeply. Some applications where exist the large signal disturbance demand a high quality of output waveform. In order to resist the large signal disturbance, the research of control scheme for the switching converter becoming a hotspot in the power electric technology field.Converter dynamic characteristics is relatively comple,,the traditional linear homogenization analysis methods have not directly application, it is required to use your new methods for modeling and analysis and the analytical method is more tend to simplify, accurate, comprehensive and perfect. Therefore, DC/DC converter control to obtain the new breakthrough, must establish a new, more accurate and practical big signal discrete model, and need to develop nonlinear control theoryBased on classical single or double feedback loop theory, the traditional analog controller is hard to guarantee the nonlinear DC/DC converter running with an ideal control performance in case of the large signal disturbance occurs. Comparing with the analog controller, digital controller can be easily realized the complicated nonlinear control strategy which could essentially improve the DC/DC converter controller performance. At present, the maturation of DSP hardware technology make it possible to realize digital controller for DC/DC converter, herewith, in power electronic study field, the study of nonlinear control strategy for DC/DC converter become very pop.Based on the Buck circuit as the research object, this paper carried on the small signal analysis, elaborated the basic principle and its own advantages and disadvantages of the three control strategies, a deep research on the three control strategy of robustness under the condition of the large signal disturbance, determine the sliding mode variable structure control strategy of good disturbance rejection of ability, has carried on the main circuit parameters and sliding mode controller design.In order to verify the correctness of the system design, the paper established the Matlab software main circuit, sliding model variable structure controller, and a simulation model of the three control strategy of system simulation. The simulation result showed that this design system is correct, control strategies feasible. With this proposed control method, sliding model variable structure control strategy in the voltage and the resistance mutation with good robustness and reference to the actual design had guiding significance.In order to verify the actual situation of system operation, this paper designed for TI company's TMS320F2812 models of DSP control chip of the Buck converter hardware system and software system, built an experimental platform, and conducted of the practical system commissioning, the experimental result had proved that this article elaborated by theory and system design is correct.