Research On Wide Voltage DC Converter Based On Tidal Current Power Generation Technology

Tidal current energy is a kind of clean and renewable new energy.Compared with wind and solar energy,tidal current energy has high energy density,is easy to predict,and is easier to use.Therefore,it is of great significance to develop technology based on tidal current energy generation to alleviate energy crisis and realize energy diversity.However,the voltage generated by power generation based on tidal current energy needs to be converted by DC/DC converter,but in this process,there may be drawbacks such as excessive overshoot and long regulation time,which will cause voltage mutation and efficiency reduction,etc.Therefore,it is necessary to focus on the study of DC/DC converter under the technology of power generation based on tidal current energy,so as to reduce the overshoot of the system,and shorten the adjustment time.First of all,based on the power flow technology and the theoretical framework of DC/DC converter,the overall design of power flow system is carried out in this paper.The structural principle and working characteristics of Buck type DC/DC converter are studied in depth.Meanwhile,the small signal model of Buck converter is established by using the state space average method,and the transfer function from output voltage to duty ratio is derived.Secondly,the fuzzy PID controller is designed,the main contents include membership function selection,rule base design,fuzzification,fuzzy logic reasoning and control variable defuzzification,and the fuzzy PID controller simulation model is established.The results show that the control system of Buck type DC/DC converter under fuzzy PID control has some shortcomings,such as high overshoot and long adjusting time.Then,the working principle,algorithm model and key parameters of the basic particle swarm optimization algorithm are analyzed,and it is found that the basic particle swarm optimization algorithm is prone to slow convergence speed and low precision in the later iteration.Based on this,the learning factor of the basic particle swarm optimization algorithm is improved,and the function analysis and convergence research are carried out.At the same time,the function of linear change,inverse cosine change and inverse tangent change is constructed for the convergence experiment of learning factors,and the test function is used for the fixed value experiment of learning factors,and an improved particle swarm optimization algorithm for the value of random learning factors is established.The simulation results show that the improved particle swarm optimization algorithm has the advantages of fast convergence speed and high optimization accuracy.At the same time,the simulation model of the improved particle swarm optimization fuzzy PID is established in MATLAB,and the parameters P,I and D of the fuzzy PID are optimized.The results show that the Buck type DC/DC converter control system with the improved particle swarm optimization has the advantages of short adjustment time,low overshoot and strong stability.Finally,the hardware experiment platform is built based on FPGA chip,and the start-up response test,steady state performance test and dynamic performance test are carried out.The experimental results verify the superiority of the improved particle swarm optimization algorithm.