Research On Intrinsic Safety Characteristics Of Two-Phase Interleaved Magnetic Integrated Buck-Boost Converter

The power supply equipment which use in the coal mine, petrochemical inflammable, explosive environment need to take into account the problem of explosion-proof requirements. Intrinsic safety power supply arises at the historic moment. There is a contradiction of traditional mining intrinsic safety switching converter between large inductance, capacitance which is required by the electrical characteristics (such as low inductance current ripple, low output voltage ripple, high output power and efficiency) and small inductance, capacitance which is required by the intrinsic safety characteristics, as well as it is difficult to improve the output power for ordinary single channel Buck-Boost converter due to the restriction of the safety performance. This paper analysis intrinsic safety Buck-Boost converter which based on the theory of the staggered parallel magnetic integrated to solve the problems. According to the concept of equivalent electrical inductance and equivalent intrinsic safety inductance and utilizing the proper coupling coefficient, the switching converter can satisfy both the electrical characteristics and the intrinsic safety characteristics by enhancing the equivalent electrical inductance and reducing the equivalent intrinsic safety inductance, which destination is to enhance the out power. First of all, we analyses the working principle, the connection between coupling coefficient and duty ratio of the two-phase interleaved magnetic integrated Buck-Boost converter, gets the best coupling coefficient which can satisfy both the electrical characteristics and the intrinsic safety characteristics. Then this paper deduces the change law of the coupling inductance current and the output ripple voltage which base on the change of load, input voltage and coupling inductance. And we get the maximum of output ripple voltage and coupling inductance current in this paper, then we use the simulation software to check them. Secondly, we analyses the capacitance output short-circuit discharge energy and the inductor break discharge energy of two-phase interleaved magnetic integrated Buck-Boost converter, proposes the judgment standard of the non-explosive intrinsically safe, then making the optimization design of passive element (inductance, capacitance). Finally, comparing to the ordinary single-phase Buck-Boost converter, drawing two-phase interleaved magnetic integrated Buck-Boost converter can considerably enhances the electrical characteristics and the intrinsic safety characteristics. The theoretical analysis verified by simulation and experiment.