Optimal Control Of DC-DC Converter Based On Servo Compensation

Modern electronic equipment is becoming stricter to the requirement of power supply.High efficiency,light and stable application of switching power supply is becoming more and more widely.DC-DC converter is one kind of important in switching power supply,its role is that will not be stable direct voltage transform to stable and controllable direct voltage.In recent years,many algorithms have been proposed for DC-DC converter.Most of the control algorithm aim for the disturbances of power supply load change and the input voltage fluctuation and design controller,ensure the rapid response of the system and to keep the output voltage stable.About the disturbances of DC-DC converter,in this thesis,a new control algorithm is designed.The main work is as follows:Firstly,introduce the background of the DC-DC converter background,development and research status at home and abroad.And introduce some of the basic theory used in this study,important theorem and the solving method,etc.Secondly,this thesis takes a Buck converter as an example.Use state space average modeling method to establish the state space average model.Model linearization method was used to get the Buck converter linear state space average model.On the basis of the linear model introduces servo compensator,with the controlled by servo compensator series is augmented controlled object,so as to realize the zero static error of system tracking.Design dynamic output feedback guaranteed cost controller based on LQR,use the pole placement of the linear matrix inequality(LMI)constraints system,convergence speed and other parameters.Using the MATLAB toolbox to solve the linear matrix inequality(LMI)controller parameters are obtained.Finally,the controller is developed for the simulation of the closed loop system.In the input voltage is the sin function disturbance,voltage jump and the high frequency pulse response of system.At the same time for system operation in the process of load change and circuit parameters perturbation are simulated.According to the results of simulation analyze anti-interference ability and robustness of the system.Adjusting the QR matrix for deviation signal and control the duty ratio constraints,constraints on the system of control signals by duty ratio is optimized,and guarantee the duty ratio in the range of feasible.The simulation results show that the control system can realize zero static error tracking,and quick response and good stability.