Research On High Step-up DC/DC Conversion Technology With Low Voltage Input

In the design of small and medium power solar street lamps,parallel single lithium batteries can be used as LED Street lamp load supply.However,the natural low-voltage output characteristics of single lithium battery can not meet the voltage demand of street lamp load.In this paper,aiming at the characteristics of single lithium battery,a topology with high gain,high efficiency and suitable for single battery boost is selected,and a variety of boost modes are compared and analyzed.Finally,clamp coupled inductor converter and coupled inductor and switched capacitor converter are selected for theoretical analysis The design process of the converter is analyzed,and the high gain converter is applied to the actual project.The main research contents and achievements of this paper are as follows:(1)Single lithium battery and high gain are introduced in detail DC/DC The research status of high gain conversion technology is summarized and classified,and several classic high gain conversion technologies are selected for detailed analysis.(2)Two kinds of high gain converters based on coupled inductor are analyzed in detail and verified by simulation.The input-output relationship of the two converters,the voltage and current stress of the switch and the current stress of the output diode are derived.(3)In order to further compare the performance of the converter and select the appropriate boost circuit topology for the solar street lamp system,two kinds of coupled inductor high gain converters are designed and tested.According to the experimental results,the two kinds of high gain converters are analyzed in detail from the aspects of voltage gain,switching device voltage stress and converter efficiency.Finally,it is concluded that the performance of coupling inductor and switching capacitor converter is better than that of clamp coupling inductor converter.(4)The coupled inductor and switched capacitor high gain converter is applied to the project of "solar street lamp system based on single lithium battery parallel connection",the design of the prototype charge and discharge circuit is completed,and the control strategy and software function realization of the system are analyzed in detail.Finally,it is proved that the coupling inductor and switched capacitor converter can realize the step-up transformation of single lithium battery LED The load provides stable energy.