A Research Of DC-DC Converter By Fuzzy Variable Structure Common Model Adaptive Control Methods

Recently, DC-DC converter as the key of switching power supply has gradually been an efficient substitute for linear power supply with its advantages of reduced volume, weight and high efficiency. And combining with the huge market potential, the research of DC-DC converter is popular both at home and abroad. The control method, as one of the key areas in DC-DC converter research, has also significantly changed. On one hand, as a time-varying, strong non-linear system, DC-DC converter's control effects can not meet the needs of application on many special occasions because of using classical control theory to design the controller. On the other hand, with the development of modern control theories, some advanced control theory can obtain good control results in a number of specific occasions. This paper introduces some modern control methods to the DC-DC converter design. By combining these advanced control methods and learning from each other, it can be able to significantly improve the DC-DC converter control performance. The work of this paper is as followed:Firstly, on the base of introducing the DC-DC converter working principal and modeling methods, it designs the controller by sliding mode variable structure control, uses the equal control concept to fix the switching frequency, uses the reaching law concept and combines the fuzzy control to less the chattering problem and enhances the control performance.Secondly, it introduces the generalized common model control, this method transforms the DC-DC converter to the standard third-order linear system, and it not only enhances the control performance but also clarifies the physical meaning of the control system parameters.Finally, it resolves the problem that the control performance would turn to worse if the system parameters mismatch. Two improved methods are discussed in this paper. The first introduces the strong tracking filter to estimate the system parameters, and adjusts the controller parameters online according to the estimated parameters. The second method introduces the sliding mode variable structure control into the generalized common model control, it enhances the control performance of the system by double-loop control.