| As electronic products are widely used in daily life,people’s demand for their power performance is getting higher and higher.DC/DC converters have become the most common switching power supplies because of their green,high-efficiency,and light-weight features.However,the converter itself is composed of power switching devices.Whenever the switch is turned on and off,the structure of the DC/DC converter will change greatly,so it has strong nonlinearity.At present,the modeling of converters often uses small-signal model analysis to linearize the model,which often ignores the influence of system uncertainty.This uncertainty can be divided into parameter uncertainty and model uncertainty.Deterministic,it is difficult to obtain excellent dynamic response.Therefore,this paper adopts the robust H∞ control algorithm to process the control of the converter,and combines it with the Linear Matrix Inequality(LMI)technology to apply it to the control system of the single-channel and dualchannel parallel Buck converters,which solves the problem of The problem of system error caused by parameter perturbation improves the dynamic response of the DC/DC converter.The main contents of this study can be divided into the following:(1)The robust H∞ control technology is introduced in detail,the uncertainty and robustness of the system are expounded,and the working principle of the DC/DC converter is analyzed.According to the parameter uncertainty,a linear Variable parameter(LPV)model.(2)The multi-cell model of the single-channel DC/DC converter and the parallel DC/DC converter based on the LPV system is described in detail,and the suboptimal control based on the H∞ norm,the minimum value of which is derived under the constraints of the regional poles The LMI expression form of Buck converter is obtained,and the state feedback H∞ controller is designed.In Matlab/Simulink,the simulation models of single-channel Buck converter and parallel Buck converter based on LPV polycellular representation are built,and the model of double closed-loop PI controller is also built,and the current sharing control is proposed for the parallel Buck circuit.The advantages and disadvantages of the two control algorithms are verified and compared in Matlab simulation.(3)The hardware circuit design of the DC/DC converter mainly includes the main circuit,the inductor current sampling circuit,the output voltage sampling circuit and the drive isolation circuit.Finally,the software part of the DSP controller is designed.(4)Through the construction of the experimental platform based on the DSP controller for the single-circuit Buck circuit and the parallel Buck circuit,it is concluded that the effect of the robust H∞ control is better than that of the double closed-loop PI control by comparing the experimental results,which further proves the robust H∞control algorithm has superiority. |
