The Applications Of Adaptive Sliding Mode Control In Buck-Boost Converter

In recent decades,the power electronics technology has being continuously developed,and especially switched DC-DC converters have been widely used.A DC-DC converter is a DC voltage that converts a certain value of DC voltage to another value.At present,all kinds of DC-DC converters are used in large quantities for theoretical research and industrial and agricultural applications.Among them,the industrial applications of DC-DC converter are mainly major power source systems,including power supplying for automobiles,ships,airplanes,and computers.With the increasing demand of the converter market,optimal control algorithm of the converter has become increasingly important.The object of this thesis is Buck-Boost converter.The goal is to design the controller to the converter to achieve the output control of the converter to ensure that the output voltage of the converter can be maintained within the desired output range.In this thesis,the influence of the two kinds of conditions are addressed of the control law design.The first one is that the inductor and capacitor is time-varying parameters and the another is that the input voltage and the load resistance are uncertain parameters,respectively.The corresponding adaptive sliding mode control algorithms are designed.The specific research contents are:First of all,it introduces in detail the circuit structure,working principle and modeling of the Buck-Boost converter.Secondly,the effect of parameter uncertainty on the output voltage characteristics is analyzed,and an adaptive sliding mode controller is designed to eliminate the effects of time-varying parameters on the output of the converter and to ensure that the output voltage remains within the desired range.Finally,through the simulation results,the effectiveness of the controller is verified.Thirdly,since sliding mode algorithm,PID algorithm cannot compensate unknown parameters in system,an adaptive sliding mode control algorithm based on Luenberger observer is proposed to deal with such uncertainties.Considering that when the input voltage of the converter or the external load impedance are unknown or all of them are unknown,the output voltage of the closed-loop system can be maintained within the desired range through the design of the controller.Finally,a Buck-Boost converter experimental platform was built.The experimental platform consists of a total of six parts.Experiments have been performed by writing LabVIEW programs and FPGA programs to realize the control law.The experimental results further verify the effectiveness of the designed controller.