高升压比移相全桥直流变换器的研究

发布时间：2018-06-14 06:24

本文选题：移相全桥 + 高升压比　；参考：《浙江大学》2014年硕士论文

【摘要】：移相全桥直流变换器作为最为经典的拓扑之一,在中大功率应用方面一直广受欢迎。主要是由于拓扑本身存在软开关易实现,结构简单等优点,同时由其演变而得到了很多零电压、零电流拓扑结构,但是该拓扑是由Buck变换器演变而来,所以其主要使用于降压型应用场合,对于升压型场合,则要依靠变压器来实现升压作用。移相全桥变换器自身具有的软开关特性还是吸引了广大的工程师将其应用于升压场合,而应用于升压场合必然会暴露诸多缺陷和问题。本文主要设计了双变压器原边绕组并联副边整流串联结构将移相全桥推广至高升压应用场合,并对使用中的关键问题进行分析,同时给出相应的解决方案。首先,本文针对高升压应用场合,专门设计了双变压器原边绕组并联,副边整流串联的结构,有效减小了变压器的匝比,降低二极管电压应力,分析了应用移相全桥变换器谐振电感带箝位二极管的拓扑结构的工作原理,详尽介绍了加入箝位二极管后变换器工作的各个模态,为二极管的箝位机制提供了理论分析,同时给出了仿真研究结果。其次,本文重点对于移相全桥应用于高升压比场合中的诸多难点问题进行了分析研究,主要包括针对高升压场合专门设计的双变压器原边绕组并联,副边整流串联结构相对于传统电路结构优势,如在变压器设计、温升,二极管电压应力,占空比丢失等方面的突出贡献；滞后臂的软开关如何实现、隔直电容的大小对于变换器工作状态的影响、箝位二极管不同的箝位位置对于变换器工作状态的影响以及整流二极管的吸收电路分析设计等等问题,验证了双变压器结构在高升压场合应用中的优势,同时对难点问题提出了相对应的解决方案。最后,为了验证分析及设计的合理性,制作了1.5kW的移相全桥直流升压变换器的样机。通过实验验证了双变压器原边绕组并联副边串联结构能够有效降低功率变压器温升,提升变换器效率,方便整流二极管选型,实现移相全桥高升压场合应用。移相全桥变换器作为DC/DC变换器领域里广受推崇的拓扑结构之一,是中大功率场合最常用的拓扑结构,本文设计的双变压器原边绕组并联,副边串联结构能够将其推广至高升压比的场合,因而具有相当重要的意义。对其应用中的各个难点问题均给出了详尽的分析与解决方案,具有重要的工程实践意义,希望对于各位工程师能有参考价值。
[Abstract]:Phase-shifted full-bridge DC / DC converter, as one of the most classical topologies, has been widely used in medium and large power applications. The main reason is that the topology itself is easy to realize and the structure is simple. At the same time, a lot of zero-voltage and zero-current topologies are obtained by its evolution, but the topology is evolved from the Buck converter. Therefore, it is mainly used in the application of voltage-down, for the boost-up, it depends on the transformer to achieve the boost-up effect. The soft-switching characteristic of phase-shifted full-bridge converter has attracted many engineers to apply it to booster field, but it will inevitably expose many defects and problems. In this paper, a series structure of parallel auxiliary side rectifier with primary winding of double transformer is designed to extend the phase shift full bridge to the application of high boost voltage. The key problems in use are analyzed, and the corresponding solutions are given. First of all, for the application of high boost voltage, this paper specially designed the structure of double transformer's primary side winding in parallel and secondary side rectifier in series, which can effectively reduce the turn ratio of transformer and the voltage stress of diode. The working principle of the resonant inductance band clamped diode using phase-shifted full-bridge converter is analyzed. The modes of the converter with clamping diode are introduced in detail, which provides a theoretical analysis for the clamping mechanism of the diode. At the same time, the simulation results are given. Secondly, this paper focuses on the analysis and study of many difficult problems in the application of phase-shifted full-bridge in high booster ratio, mainly including the parallel connection of dual transformer primary side windings specially designed for high boost occasions. The secondary side rectifier series structure is superior to the traditional circuit structure, such as the outstanding contribution in transformer design, temperature rise, diode voltage stress, duty cycle loss, and how to realize the soft switch of the lagging arm. The influence of the capacitance on the working state of the converter, the influence of different clamping position of clamping diode on the working state of the converter, and the analysis and design of the absorption circuit of rectifier diode, etc. The advantages of the dual transformer structure in high voltage booster applications are verified, and the corresponding solutions to the difficult problems are put forward. Finally, in order to verify the rationality of the analysis and design, a 1.5 kW phase-shifted full-bridge DC boost converter prototype is made. It is proved by experiments that the series structure of parallel auxiliary edges of the primary side windings of double transformers can effectively reduce the temperature rise of power transformers, improve the efficiency of the converter, facilitate the selection of rectifier diodes, and realize the application of the phase-shifting full-bridge high boost voltage situation. As one of the most popular topologies in DC / DC converters, phase-shifted full-bridge converters are the most commonly used topologies in medium and high power situations. The secondary side series structure can be extended to high boost voltage ratio, so it is of great significance. The detailed analysis and solution of each difficult problem in its application are given, which have important engineering practical significance, and hope to be of reference value to the engineers.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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