Research On Real-time Predictive Control Strategy Based On FPGA And Application In Switch Power Supply

High power switching power supply model is complex and parameter is easy to change,the traditional proportion-integral-derivative(PID)control is difficult to acquire good control result.Adaptive predictive control,such as generalized predictive control,which is not sensitive to modeling parameters and external disturbances,can be well used in slow dynamic response systems such as diffusion furnaces,steam furnace and so on,with an excellent control result.But the control system flexibility and real-time performance is poor,and the cost is high.With the development of semiconductor manufacturing technology,Field Programmable gate Array(FPGA)adopts parallel processing mechanism,which has the advantages of fast operation speed and rich hardware resources,is gradually becoming an important digital platform of complex control algorithm to meet the high real-time requirements of fast response system such as switching power supply.This thesis introduces PID control algorithm,generalized predictive control algorithm and predictive control algorithm based on Laguerre model,and analyzes the advantages and disadvantages of traditional PID control algorithm and the two kind of predictive control algorithms.In order to combine the advantages of the PID control an predictive control,a kind of predictive control algorithm with PID structure is formed.By FPGA full hardware programming method,three kind of control algorithms are realized,and the validity of predictive control PID algorithm on switching power supply platform is validated by simulation and actual test.The main work of the thesis is as follows:1)the PID control algorithm,generalized predictive control algorithm and predictive control algorithm based on Laguerre(Laguerre)model are introduced in detail.Combining the advantages and disadvantages of predictive control and PID control,the predictive control with PID structure is formed.The two kind of control laws of predictive PID control are introduced in detail.2)Fulfill design of the whole switch power supply hardware platform.The components' parameter is calculatesd and the rational models are chosen according to the design goal;The influence of stray parameters and EMI on the normal operation of switching power supply are analyzed,and the peak absorption circuit,the Miller effect restraining circuit,FPGA minimum system,signal acquisition and communication module according to the function requirement of the control system are completed.3)According to the actual design parameters of switching power supply,the mathematic model of switching power supply platform is established by means of effective duty ratio method,and the dynamic characteristics of the model are analyzed.In addtion,the PID control and two predictive PID control algorithms are introduced,and the characteristics of switching power supply system based on the three kind of control algorithms are analyzed and compared by Matlab simulation.4)Using FPGA full hardware programming method to realize three kinds of control algorithm,and analysis algorithm calculation process of hardware resources and calculation time.In view of the complex problem of matrix inversion calculation,a special positive definite matrix inversion method is introduced.The Modelsim simulation of predictive control algorithm is completed,which has verifed the correctness of the program logic.After the switch power supply hardware test platform being built up,this thesis carries out a number of tests,and compares the three algorithms control result.The test results show that the switching power supply has achieved good stability and fast dynamic response based on the control of predictive control by FPGA full hardware programming method.