Research On Capacitor Clamped High-Gain Non-Isolated DC-DC Converter And Its Non-Resonant Linear Soft-Switching Techniques

The crucial industrial applications of scientific exploration and national economy,such as the high-altitude airships,the satellites,the space probes,the electric vehicles and ships,require the miniaturized,lightweight,and efficient power conversion equipment.Research and design of the high-gain DC-DC converter with low cost,small size,high efficiency have very important scientific and application significance.Since the DC power generations or storage devices,such as photovoltaic cells,fuel cells,and storage batteries,have the characteristics of low voltage on the output side.In the power converter,the magnetic components with large volume and heavy weight can be reduced by increasing the switching frequency of the converter,while the volume and cost of the film capacitor for high frequency applications will be increased dramatically when the capacitance increases.However,up to now,there is not a satisfactory solution to decrease the capacitance of the film capacitor for reducing the volume and cost of the capacitor in the capacitor-type high-gain DC-DC converter.Consequently,in order to reduce the capacitance of the switched-capacitor-type high-gain DC-DC converter,this paper proposes the topological structures and non-resonant linear soft-switching techniques of the capacitor clamped high-gain non-isolated DC-DC converter.Firstly,the single-switch topology of the capacitor clamped high-gain non-isolated DC-DC converter is provided.Secondly,a series of interleaved parallel topologies of the capacitor clamped high-gain non-isolated DC-DC converter are analyzed.Then,the non-resonant linear soft-switching techniques of the capacitor clamped high-gain non-isolated DC-DC converter are proposed.Finally,the extension of the non-resonant linear soft-switching technique in the switched-capacitor high-gain non-isolated DC-DC converter are described in this paper.The detailed research contents and the innovation points are given as below.Firstly,to solve the problem that the conventional switched-capacitor high-gain non-isolated DC-DC converter requires a large capacitance to suppress the current spikes caused by the charging and discharging of the capacitors,the single-switch topology of the capacitor clamped high-gain non-isolated DC-DC converter is studied.The advantages of the lower current spike and the smaller capacitance in the capacitor clamped high-gain non-isolated DC-DC converter are verified by comparing with the conventional switched-capacitor high-gain non-isolated DC-DC converter,and the essential reason for reducing the capacitance is analyzed based on the topology structure.When the volume and cost of the capacitor are greatly reduced with the use of the smaller capacitance,the proposed topology can provide a cost-effective choice for the high-gain DC-DC converter in the power generation equipment with photovoltaic cells.Secondly,in order to meet the requirement of low current ripple and high voltage gain in the output DC-DC converter of the energy storage battery,a series of the interleaved parallel topologies and their general construction method for the capacitor clamped high-gain non-isolated DC-DC converter are proposed.The operation principles and performances of the proposed converter are analyzed in detail,and the advantages of the low current ripple,the high efficiency and the high voltage gain in the proposed converter are validated by the simulation and experimental results.The proposed interleaved parallel topology of the capacitor clamped high-gain non-isolated DC-DC converter has been applied for the power system of high-altitude airship,which provides a design method and topology selection.And the proposed general construction mothed of interleaved parallel topologies can provide a construction idea for the research and development of new converters.Thirdly,in order to achieve the soft-switching operation and eliminate the current spikes caused by the charging and discharging of the capacitors,based on the linear changing of inductor current and the Kirchhoff's current law,this paper proposes the non-resonant linear soft-switching technique of the proposed capacitor clamped high-gain non-isolated DC-DC converter.According to the proposed non-resonant linear soft-switching technique,a series of non-resonant linear soft-switching topologies of the capacitor clamped DC-DC converters are proposed.Moreover,the operation principle,simulation and experimental results of the proposed converters are analyzed and provided.The proposed soft-switching DC-DC converters can realize the zero-current-switching turn-on of all switches and the zero-current-switching turn-off of all diodes.Thanks to the linear current on the devices in the converter,the proposed soft-switching DC-DC converter can eliminate the current spikes caused by the charging and discharging of the capacitors.Finally,in order to detailed analyze the advantages of the proposed non-resonant linear soft-switching technique on reducing the capacitance and the current spikes caused by the charging and discharging of the capacitors,the expansion of non-resonant linear soft-switching technique in the switched-capacitor high-gain non-isolated DC-DC converter is provided.Compared with the conventional switched-capacitor hard-switching and the quasi-resonant soft-switching DC-DC converters,it is proved that the proposed non-resonant linear soft-switching topology of the switched-capacitor DC-DC converter can greatly reduce the current spikes caused by the charging and discharging of capacitors,and thus can greatly reduce the capacitance.A 1.3 kW simulation platform and experimental prototype are built to prove the results of theoretical analysis.To sum up,this paper on the problem that how to reduce the capacitance of the capacitor-type high-gain non-isolated DC-DC converter,presents the topological structure and the non-resonant linear soft-switching technique of the capacitor clamped high-gain non-isolated DC-DC converters.The proposed converters and the soft-switching techniques can effectively reduce the capacitance and then reduce the volume and the cost of the capacitors,and maintain the advantages of high voltage gain and high conversion efficiency.The research content of this paper provides a design method and a research idea for the application of high-gain non-isolated DC-DC converter in the crucial industry of scientific exploration and national economy.176 figures,28 tables,168 references.