Research On Active Clamp Forward Converter Based On The Integrated Magnetic Technology

Light weight, small size, high efficiency switching power supply is thefuture direction of the electronic market. In order to meet the needs of thedevelopment of the switching power supply, R&D personnel can not rigidlyadhere to the circuit topology, control strategy and optimal switching devices.Due to the volume of magnetic devices accounted for almost30%of theconverter's total volume, so going on the research of magnetic devices is verymeaningful.Put forward three integrated schemes of transformer and inductor in forwardconverter, and elaborate the principles of reducing current ripple with theintegrated magnetics. Analyze the working principle of the active clamp forwardconverter with integrated magnetics and the conditions of zero current ripple indetail. Moreover, through simulation, analyze the influence of magneticreluctance on current ripple.Establish simulation model of integrated magnetics based on thegyrator-capacitor model, the simulation model adds the nonlinear characteristicsof iron core, and the simulation results show the effectiveness of the model. Thispaper establishes the simulation model of active clamp forward converter withintegrated magnetics, the simulation results show that the integrated magneticscan reduce the current ripple. And through simulation, compare the effects ofintegrated magnetics with different reluctances on the output current ripple.Establish the small-signal model of the closed-loop voltage controlledconverter with integrated magnetics, the simulation results of MATLAB showthat the integrated magnetics can improve steady-state performance of theconverter. And derive the dynamic equivalent inductor of the converter withintegrated magnetics, theoretical analysis shows that if the output changes inmore intense conditions, the introduction of integrated magnetics can improvethe dynamic performance of the converter. Meanwhile, the simulation resultsshow that the compensation parameters can make the closed-loop system stable.Finally, two50W active clamp converters with integrated magnetics andwithout, are built to verify the operation principle. Test and analyze thewaveforms of the main topology, the output current ripple, the output voltageripple, and the efficiency curve. Experimental results show that the introductionof integrated magnetics can reduce the volume of the magnetics and the outputcurrent ripple.