A Novel High Step-Up Interleaved Boost Converter Research

As the traditional energy resources increasingly decreased, photovoltaic, fuel cells and other new energy resources has been widely used. However, due to the low forestage output voltage of photovoltaic, fuel cells and other new energy power generation system, which cannot supply to the electricity grid or directly to the load, therefore, a kind of high efficient high step up DC-DC converter are needed to rise the output voltage to the electricity grid level. Interleaved step up DC-DC converter’s input current ripple is small, voltage gain is high, which is very suitable for the new energy power generation system with low voltage and large current input, high voltage output. Therefore, to study a novel high step up high gain interleaved boost converter has great significance.Interleaving technology is widely used in the DC-DC converter because of its advantages. In this paper, the development status of isolated and non-isolated interleaved boost converters with interleaving technology is studied and a lot of problems in the development of novel high step-up interleaved Boost converter that need to solve are summarized. To solve these problems, a kind of non-isolated interleaved Boost converter with transformer and switch capacitor which suitable for new energy power generation system such as fuel cells is studied, the detailed analysis and Simulation of its working principle and steady-state performance is made, it was concluded that the converter has the advantages of less input and output ripple current, the leakage inductance energy without additional clamp circuits can be used, but its voltage gain is not high enough, the voltage stress of the switches and diodes is relatively high. Therefore, on the basis of the non-isolated interleaved Boost converter with transformer and switched capacitor, a novel high step-up interleaved Boost converter is proposed.This paper studied the operating principle of the novel high step-up interleaved boost converter in the duty cycle less than 0.5 and more than 0.5. Analyzed the steady state performance and deduced the voltage gain, voltage stress and current stress of switch and diode in detail, made a comparison and simulation about the analysis of the steady state performances between the proposed converter and traditional converter, the results show that the proposed converter has higher voltage gain, lower voltage stress of switches and diodes. In order to further research the proposed converter’s characteristic, the steady state space average method is adopted to build small signal model for that of operating in the duty cycle greater than 0.5. The transfer functions of input voltage to output voltage, duty ratio to output voltage are deduced, which contribute to the analysis of converter’s stability and the design of converter’s closed loop feedback compensation network, than the closed loop control system simulation model is built, the simulation results show that the closed loop system has good stability and dynamic performance.Finally, the proposed converter’s main circuit parameters, isolated circuit and driving circuit are designed in detail, a 200 W principle prototype is constructed according the design, the experimental results agree with the simulation results, which show the correctness of theoretical analysis of the proposed novel interleaved boost converter.