| The 14th Five-year plan mentions the development of strategic emerging industries,and the role of switching power supply in all walks of life is very important,followed by higher requirements for switching power supply products.The research on the control system of switching power supply is of great significance to improve the performance of switching power supply.In this paper,the control system algorithm of Buck DC-DC converter is deeply studied.In this paper,the control system algorithm of a buck switching power supply with adjustable output is designed and implemented.Firstly,the working mode and modulation mode of switching power supply are analyzed in this paper,and the power parameters of the main circuit of buck switching power supply are determined.On this basis,the mathematical model of the system is established by using the state space average method.Then,the control system of switching power supply is focused on,and conventional digital PID controller,single neuron PID(SNA-PID)controller and fuzzy PID(Fuzzy-PID)controller are designed respectively.The system simulation model based on three control algorithms is built in MATLAB/Simulink.The simulation results show that when the input voltage is 100V and the switching frequency is 50kHz,The static performance of the system based on Fuzzy-PID control algorithm and SNA-PID control algorithm shows good results,and both are better than the static performance of the system under the conventional PID control algorithm.In terms of dynamic performance,the system based on Fuzzy-PID control algorithm has short start-up time and strong anti-interference ability,and shows better control effect than conventional PID algorithm and SNA-PID algorithm.Then,based on the digital power supply prototype of the research group,the hardware is improved in this paper,and the design and implementation of the system software is completed.Finally,the effectiveness of the control system algorithm studied in this paper is verified by experiments based on the digital power supply experimental prototype.The steady-state test results show that under the conditions of input voltage of 100V and output voltage of 80V,the output voltage ripple of the system based on Fuzzy-PID control algorithm is 0.57V,which is about 0.7%of the output voltage,which meets the design index requirements of the power supply,and is significantly reduced compared with the system controlled by conventional PID algorithm.The dynamic test results show that during the starting process of the output voltage rising from 0V to 50V,the starting time of the switching power supply system based on Fuzzy-PID control algorithm is 9.12ms,and the system has no overshoot;when the load jumps instantaneously,the system also shows strong robustness.Therefore,the control system algorithm studied in this paper can realize the stable and adjustable system output of 0～80V and meet the design index;at the same time,the research of this paper shows that the switching power supply system based on Fuzzy-PID algorithm has the advantages of short start-up time,small overshoot,strong anti-interference ability and good stability. |
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