Principle and design of high frequency planar transformer

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Principle and design of high frequency planar transformer [Copy link]

Abstract: Conventional transformers operating at high frequencies have problems such as large leakage inductance, large turn-to-turn capacitance, severe skin effect and proximity effect, and local hot spots in the magnetic core. A new type of transformer, a high-frequency flat transformer, has been developed. It can reduce leakage inductance and turn-to-turn capacitance, eliminate local hot spots in the magnetic core of conventional transformers, and improve problems such as skin effect and proximity effect. It has the advantages of high power density, high efficiency, low electromagnetic interference, simplicity and low price.

Keywords: Planar transformer, primary inductance, leakage inductance, skin effect, proximity effect,
transformer has always been a stumbling block for power supply equipment and devices to reduce size, increase power density, and achieve modularization. Although the high-frequency conversion technology can get rid of the bulky power frequency transformer after the introduction of power supply, a high-frequency transformer with a ferrite core is still needed. Although the volume of the ferrite core high-frequency transformer is smaller than that of the power frequency transformer, it is still far from the requirements of modularization. Not only is it too large in size, but its heat generation and leakage inductance are not small. Therefore, in recent years, many experts, scholars, and engineers have been studying ways to solve this problem. The successful development of high-frequency planar transformers has made a leap in transformer technology. It can not only reduce the size of the transformer a lot, but also make the temperature rise inside the transformer very low, the leakage inductance very small, the efficiency can reach 99.6%, and the cost is half of that of ordinary transformers of the same power. It can be used as AC/DC and DC/DC converters in single-ended forward, flyback, half-bridge, full-bridge and push-pull converters. It is particularly suitable for low-voltage and high-current converters. Therefore, it is particularly suitable to use it as a power supply for modern computers.

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