Research On Intrinsic Safety Characteristics Of Single-ended Forward Converter

Electrical equipments used in coal mine must meet explosion-proof requirements. For the single-ended forward converter has many advantages such as simple peripheral circuits, high efficiency, large over-load capacity, isolated input and output and so on, it is very suitable to be applied in underground coal mine. Therefore, it is important to research on intrinsic safety characteristics of single-ended forward converter.Firstly, the working principle and energy transmission mode of single-end forward converter were studied. The formulas of output ripple voltage and peak inductance current were derived. Both in discontinuous and continuous mode, the variation laws between output ripple voltage and peak inductance current and load, input voltage and inductance were obtained. Secondly, the inductance breaking characteristics and output short-circuit discharging characteristics were analyzed. The formula of maximum output short-circuit energy among the entire dynamic range was derived. The intrinsic safety criterion was obtained. Thirdly, the design schemes both main circuit and control circuit of output intrinsic safety type single-end forward converter were proposed, and a design example was given. Lastly, the simulation calculations were carried out with Matlab software and Saber software respectively. The simulation results showed that the theoretical research achievements are correct and design schemes are feasible.