不对称半桥零电压零电流PWM变换器的研究

发布时间：2018-07-02 14:35

本文选题：不对称半桥直流变换器 + 有源辅助无损边缘谐振电路　；参考：《东北大学》2014年硕士论文

【摘要】：直流变换就是通过电路控制开关管进行高速的开通与截止,将直流(交流)电转化为所需要的一组或多组电压的装置。随着电力电子技术的迅速发展,极大的推动了高效率、小体积、轻重量、高精度的开关电源的研究和应用。尤其在低压大电流输出和中小功率变换场合,降低开关管的电压应力以及减小电压和电流变化率对提高功率变换效率和减小EMI具有重要意义。不对称半桥直流变换器具有开关管电压应力低和拓扑结构简单的优点,因而得到广泛的研究。同时,为了提高开关频率和降低开关损耗,软开关技术应运而生。软开关技术可以改善功率开关器件的运行环境,提高系统运行的可靠性,降低变换器的功率损耗,抑制过高的电压电流变化率,有效防止电磁干扰,降低系统噪声等优点。因此,不对称半桥软开关直流变换器受到了国内外学者的广泛关注。通过对大量半桥型直流变换器拓扑的分析研究发现,半桥型直流变换器普遍存在轻载时难以实现软开关、副边整流电路损耗大的问题,这也是半桥型变换器在未来实际应用中必须解决的关键技术难题。针对上述问题,本文提出了一种不对称半桥(AHB)零电流准谐振变换器。本文提出一种不对称半桥(AHB)零电压零电流软开关PWM DC-DC变换器由PWM控制的带有边缘谐振无损缓冲单元的半桥逆变器和一个与高频变压器连接的倍流整流器组成。为了在高频逆变器的原侧获得较宽的零电流软开关变换范围,在半桥臂中采用的无损缓冲单元由一个开关管和一个无损电容组成,在PWM方式下实现宽范围的ZCS软开关转换,并且对输入电流等级不是十分依赖。此外,变换器能够零电压零电流关断。根据不同模式下的等效电路图,分析这种变换器的工作原理、软开关实现条件以及参数设计原则。最后,采用绝缘栅双极性晶体管IGBT (insulated gate bipolar transistor),通过仿真验证该变换器的有效性。
[Abstract]:DC conversion is a device that switches on and off at high speed through circuit control switches and converts DC (AC) electricity into one or more sets of voltages needed. With the rapid development of power electronics technology, the research and application of switching power supply with high efficiency, small volume, light weight and high precision has been greatly promoted. Especially in the case of low voltage and high current output and medium and small power conversion, it is very important to reduce the voltage stress and voltage and current change rate to improve the efficiency of power conversion and to reduce the EMI. Asymmetric half-bridge DC / DC converter has been widely studied for its advantages of low voltage stress and simple topology. At the same time, in order to increase the switching frequency and reduce the switching loss, soft switching technology emerged as the times require. Soft switching technology can improve the operating environment of power switch devices, improve the reliability of the system operation, reduce the power loss of the converter, restrain the excessive voltage and current change rate, effectively prevent electromagnetic interference, and reduce the system noise. Therefore, asymmetric half-bridge soft switching DC / DC converters have attracted wide attention from scholars at home and abroad. Through the analysis of a large number of half-bridge DC / DC converter topologies, it is found that the half-bridge DC / DC converter is difficult to realize soft switching when the load is light, and the secondary side rectifier circuit has a large loss. This is also the key technical problem which must be solved in the future application of semi-bridge converter. To solve these problems, an asymmetric half-bridge (AHB) zero-current quasi-resonant converter is proposed in this paper. In this paper, an asymmetrical half-bridge (AHB) zero-voltage zero-current soft-switching PWM DC-DC converter is proposed, which consists of a PWM controlled half-bridge inverter with edge resonant lossless buffer and a current-doubling rectifier connected with a high-frequency transformer. In order to obtain a wide range of zero-current soft-switching conversion at the original side of the high-frequency inverter, the lossless buffer cell used in the half-bridge arm consists of a switch tube and a lossless capacitor. The ZCS soft switching is realized in a wide range of PWM mode. And the level of input current is not very dependent. In addition, the converter can turn off zero voltage and zero current. According to the equivalent circuit diagram in different modes, the principle of the converter, the realization condition of soft switch and the principle of parameter design are analyzed. Finally, the effectiveness of IGBT (insulated gate bipolar transistor), is verified by simulation.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM46

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