Research On High Gain DC/DC Converter Topologies With Coupled Inductor

In new energy generation system,the output voltage of renewable energy such as solar and fuel cells is much lower than the input voltage of the grid-connected inverters.Therefore,DC/DC converters with high voltage gain are needed to convert their low voltage into high DC voltage to meet the grid and the load requirements.The traditional Boost converter has lower voltage gain and its input side has current ripple,which cannot meet its boosting requirements.High gain DC/DC converters with coupled-inductor can achieve high voltage gain at low duty cycle by introducing the coupled inductor technology and has low cost and high reliability.In this paper,three new high gain DC/DC converters are proposed from the perspective of topology innovation.Firstly,this paper summarizes the research background and significance of high gain DC/DC converters,and introduces its research status.Secondly,combined with the structural advantages of quadratic Boost converter and the voltage doubler cell,and introducing the coupled inductor into the quadratic Boost converter,high gain DC/DC converter with coupled inductor voltage doubler cell is designed.In this paper,the operation principle and steady-state performance of the converter are analyzed in detail,since the voltage across switch is less than the output voltage,the voltage stress is effectively reduced.The leakage energy in coupled inductor can be recycled and finally transferred to the output side,which improves energy efficiency.Finally,the correctness of the converter is proved by simulation and experiment.Then,the resonant ripple absorption circuit can eliminate the characteristics of input current ripple,combined with the advantage of the coupled inductor and voltage doubler cell,high gain reduced input current ripple Boost converter with coupled inductor voltage doubler cell is proposed.The operation principle and steady-state performance of the converter are analyzed in detail from two modes of continuous conduction mode and discontinuous conduction mode,and the implementation condition of zero input current ripple is deduced in this paper.The coupled inductor and the voltage doubler cell are introduced in the converter to reduce the voltage stress of the switch.Therefore,the low on-resistance MOSFET for reduction of the conduction loss and cost can be employed.Finally,the experimental results show that the proposed converter can achieve high voltage gain and zero input current ripple.Finally,based on high gain reduced input current ripple Boost converter proposed above,further improvements are made.By optimizing the combination and reducing the number of components,high gain reduced input current ripple DC/DC converter with coupled inductor is proposed.The working principle of the converter is introduced,and the steady-state characteristics of the converter are analyzed,and the performance comparison analysis is carried out with other converters.It is shown that in the case of the same number of components,this paper proposed converter can achieve high voltage gain and reduced input current ripple.The reduction in the number of components further simplifies the circuit topology and increases the power density.Finally,the correctness of the theoretical analysis is verified by simulation and experiment.