非隔离型LLC谐振变换器分析设计

LLC谐振网络变换器是一种软开关变换器,能够降低损耗、实现高频化、提高效率,在通信电源、电池充电器等方面有着广泛的应用。传统LLC变换器为隔离型的谐振变换器,其中包含一个高频隔离变压器。在功率较大的场合中,隔离变压器设计困难,且漏感较大,导致损耗高,影响变换器性能;另一方面,隔离变压器由两个绕组组成,导致谐振变换器的体积较大,从而影响变换器的功率密度,若直接将其用于高频、高效的非隔离应用场合,不利于其效率和成本优势的发挥。提出一种具有输入输出共地结构的非隔离型LLC谐振变换器,适用于光伏逆变器、LED恒流驱动等非隔离场合。最后搭建了实验平台,实验验证了理论的正确性。

Analysis and Design of Non-isolated LLC Resonant Converter

The LLC resonant network converter is a soft-switching technology which can reduce losses,achieve higher frequencies,and improve efficiency.It has a wide range of applications in communication power supply,battery charger,etc.The traditional LLC converter is an isolated resonant converter,which contains a high frequency isolation transformer.In the case of high power,the isolation transformer design is difficult,and the leakage inductance is large,resulting in high loss and affecting the performance of the converter.On the other hand,the isolation transformer is composed of two windings,which leads to the large volume of the resonant converter,and thereby affects the power density of the converter.If the converter is directly used in high-frequency and highefficiency non-isolated applications,it is not conducive to its efficiency and cost advantages.A non-isolated LLC resonant converter with input-output common-ground structure was proposed,which is suitable for non-isolated applications such as photovoltaic inverter and LED constant-current drive.Finally,an experimental platform was built to verify the correctness of the theory.