Study Of Adaptive Digital PID Control Strategy For DC-DC Converter

As the core part of power supply,DC-DC switching converter has the advantages of high energy conversion efficiency,small size and good reliability.With the development of electronic information industry,DC-DC converter will show a broader market prospect and research value.The main content of this paper is to design a suitable digital control algorithm for DC-DC converter to improve the transient response capability of the converter system.Based on the traditional digital PID control algorithm,an adaptive digital proportional–integral–derivative(AD-PID)control algorithm is proposed.AD-PID algorithm is to adaptively adjust the proportional coefficient(K_p)and integral coefficient(K_i)according to the state of the output voltage.In this way,the system oscillation and multiple overshoot/undershoot are avoided,and the output voltage deviation and recovery time of the switching converter are reduced,so that the system can be stabilized quickly.The AD-PID control strategy only needs to detect the output voltage,as a feedback signal,simple and efficient.MATLAB/Simulink was used to establish the simulation model of Buck dc-dc converter under the traditional PID and AD-PID control algorithms.The simulation results show that the converter with adaptive PID control strategy has better transient response performance.On this basis,the hardware and software circuit design of Buck dc-dc converter is completed in this paper.The algorithm verification platform is built by FPGA.The number of LE used by the traditional PID algorithm is 2087,accounting for 33%of the total resources;the number of LE used by ad-pid algorithm is 4736,accounting for 76%of the total resources.All the commonly used FPGA can meet the experimental requirements.Experimental tests were conducted on the two control algorithms,and the experimental results showed that compared with the traditional digital PID control strategy,the dc-dc converter based on AD-PID control strategy can shorten the adjustment time of 30.4%and56.4%respectively when the load jumps and the input voltage jump,at the same time,the overshoot of the system is also smaller.Simulation and experimental results show that the dc-dc converter based on adaptive digital PID control strategy has better transient response performance.