Research On Control Parameter Design Technology Of DC-DC Converters

In the industrial,household electronics,Marine and aerospace fields,DC-DC converters have a wide range of applications.With the expansion of the applied field,the requirements of adaptability and response quickness are becoming more and more strict.So using reasonable control methods to guarantee the accuracy of the converter output and good dynamic performance attracted the attention of people.Nowadays,the widely used PI control strategy can make the system have good steady-state performance,the algorithm is simple and easy to implement,but can not meet its fast and accurate requirements under load mutation and input voltage fluctuation.Based on converter energy balance angle as the breakthrough point,this paper design a new kind of self-tuning PI controller.At first,this paper designed the circuit topology of DC-DC converter,and the voltage single closed-loop PI control system of the Buck converter using incremental PI controller were designed,and make simulation to verificate it.Then this paper analyzed the energy flows process of DC-DC converter between input energy,energy storage element to absorb and release,and load energy consumption.On the basis of the energy theroy,self-tuning PI controller using difference between the actual energy and the expectation energy was proposed.Using the energy theroy can simplifiy the parameters of the fuzzy self-tuning controller,which reduced the numbers of control rules to make fuzzy control strategy implement easier.In addition using the section function to simplify the single input fuzzy self-tuning strategy.At the same time,aimed at the shortest adjust time of output response,this paper completed function curve fitting for the controller parameters and the adjust time,through this function one better group of K_P and K_I was found.In the simulation environment,the model of self-tuning control strategy based on energy balance was created,the experiment simulations verified the feasibility and superiority of the parameter setting method,and then compared with the incremental PI controller from the two aspects of startup performance and dynamic performance.Finally,this paper set up the DC-DC converter control system based on DSP28335 hardware experiment platform,and write the experiments required DSP program,completed the incremental PI control and parameter self-tuning control based on energy balance system startup,load mutation and under a given voltage mutation experiment.these experiment proves the correctness and the feasibility of the energy balance setting method,and this method can make the controler have superiority of dynamic performance by comparison with experimental data.