Study On Planar Integrated Magnetics Of Switch Converter

The power magnetic component is the essential key component of all the power electronics devices. It takes on transfer and storage of magnetic energy, filtering and electric isolation. Normally its volume and weight only occupy 20%~30% of the entire circuit, while the loss occupies about 30% of the total loss. At the same time, various parameters of magnetic component influence greatly to the performance of the circuit. For example, leakage inductance of transformer affects the peak voltage; coupled capacitance of primary and secondary windings influences the isolation performance. Therefore, research on magnetic component has vital significance to reduce volume and weight of power electronics devices, as well as improve modulation performance of voltage. The drive towards higher power density and overall lower profile in switch mode power supplies has exposed a number of limitations in the use of conventional transformer structures. In order to achieve higher power density, it has to increase the converter switching frequency to achieve passive component size reduction. However, for conventional wire wound transformers this leads to problems of increased loss due to the skin and proximity effects in the round conductors particularly at frequencies above 100 kHz. In order to further efficiently reduce the volume and loss of magnetic component, achieve higher power density and work efficiency and improve output ripple, people did research on technique of magnetic integration, and applied it to design of power electronics of magnetic component. Using planar transformer and magnetic integration technique can realize switch mode power supplies with"short, small, light and thin".This paper mainly aims at research and design on magnetic component for LLC resonant converter which used for frond-end DC/DC converter. Using planar transformer and magnetic integration technique to integrate planar magnetic components such as planar transformer and planar inductance, then design planar integrated magnetics to reduce volume, weight, loss of magnetic component, and achieve higher power density of power converter. At the same time, use FEA and circuit simulation software to make integrated simulation analyze for distributing parasitic parameter of planar integrated magnetics, reduce its influence to final performance of converter and derive design disciplinarian of general planar integrated magnetics which apply for high-frequency switch mode power supplies. The main achievements as follows:â‘ Magnetic integration technique and planar transformer are studied; the concept of planar integrated magnetics technique is introduced; analyzing the integration method between inductor and inductor as well as that between inductor and transformer, and decoupled integration method; introducing the deriving method of circuit model of integrated magnetics.â‘¡A kind of LLC resonant converter which used for Frond-End DC/DC converter is studied, and integrated magnetics of LLC resonant converter is designed by using general model of integrated magnetics; a concrete design method for planar integrated magnetics is studied, and planar integrated magnetics for LLC resonant converter is designed.â‘¢A designed method for planar integrated magnetics is presented; electromagnetic simulation software Maxwell 3D is used to make analysis of eddy current field and electrostatic field for planar integrated magnetics. According to impedance matrix and capacitance matrix gotten from simulation, equation that extract parasitic parameters of planar integrated magnetics is deduced.â‘£The accurate equivalent circuit model is established by extracting parasitic parameters of planar integrated magnetics. Circuit simulation software Saber is used to make simulation of LLC resonant converter circuit which contains this equivalent circuit model of planar integrated magnetics. The final simulation analysis results verify the correctness of theory analysis.