| Under the dual pressures of the current energy crisis and environmental pollution,replacing traditional fossil fuels with electricity,solar,wind and other clean energy is the fundamental way to solve the current problem.In practical application,as the output voltage of photovoltaic cells,fuel cells and other single power generation unit is relatively low and with a random volatility,the system needs a high-gain,and high efficiency DC/DC step-up converter to achieve the high DC voltage level to meet the need of post inverter input side.In addition,there are a wide range of needs of high-gain,high-efficiency DC/DC step-up converters in industrial applications such as powertrains for electric vehicles,uninterruptible power supplies and cathode ray tube display systems.The traditional Boost converter due to its own topology constraints,has difficulty in occasions such as the input and output difference of six times and above.Based on that,this paper studied the high gain DC/DC step-up converter of active switched-inductor networks.Firstly,the research status of non-isolated DC boost converter at home and abroad is reviewed in this paper.It is concluded that the DC boost converter with high voltage gain,low switching voltage stress,high energy conversion efficiency and good topological ductility will be an important research direction in the future.Then,the paper discussed the construction method and the way of boosting for the active switched-inductor network,combined the active switched-inductor networks with conventional Boost converters,came out a basic active switching inductor boost converter topology.The working principle of continuous current mode in inductance current is analyzed,and the circuit characteristics and simulation results are compared with traditional Boost converter.Theoretical analysis and circuit simulation results show that the voltage gain of the basic active switching inductor boost converter is slightly higher than that of the conventional Boost converter,however the output voltage of the output diode increases and the system loss increases.Secondly,for the basic problem that the active switched-inductor boost converter voltage step-up capacity is still limited and the output diode voltage stress is too large,this paper presents a high gain Boost converter based on active switched-inductor and switched-capacitor.The topology utilizes the dual boost of the active switched-inductor and the switched-capacitor unit to effectively increase the converter voltage gain and reduce the voltage stress of the switching device.The working principle and circuit characteristics of the proposed converter are analyzed in detail,and the theoretical analysis is verified.The result shows that the converter can work normally and have the above advantages.Based on the topology of the structure,this paper also proposed multi switched-capacitor unit series and parallel multi-stage boost converter,thereby further enhancing the voltage gain,expanding the converter application range.Finally,for the shortcomings that there is an excessive number of components in the topology of a multi-stage expansion in active switched-inductors and switched-capacitor boost converters presented in Chapter 3.Based on the preservation of its original advantages,this paper presents a high gain Boost converter topology of active switched-inductor and DCM(Diode-capacitor multipliers).The specific working principle and circuit characteristics are analyzed,and compared with the similar high gain Boost converter proposed by the researchers.The results show that the proposed topology has certain advantages.Similarly deduce multi-stage boost converter topology with multi DCM cells connected in series,and the state space average method modeling and single-voltage closed-loop controller design are used in proposed converter.An experimental prototype was built and the working principle and circuit characteristics of the topology were verified.The experimental results verify the correctness of the theoretical analysis. |
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