基于混合控制LLC谐振变换器的航空二次电源研究
发布时间：2018-07-16 09:12
【摘要】：航空高压直流电源系统具有电网重量轻、易实现不中断供电等特点,是飞机电源系统未来的发展方向之一。本文以航空高压直流电源系统中的二次电源DC/DC变换器为研究对象,讨论了适用于二次电源直流母线变换器的功率拓扑,其中全桥LLC谐振变换器可在宽负载范围内实现原边开关管的零电压开通和副边整流管的零电流关断,有助于提高变换器效率和功率密度,是二次电源直流母线变换器的理想拓扑。本文首先介绍了传统变频控制全桥LLC谐振变换器的工作原理,分析了寄生参数造成的轻载增益特性失效现象,及其给变换器带来的不利影响,提出以变频和移相相结合的混合控制方式作为解决对策。基于时域分析法对混合控制全桥LLC谐振变换器的工作原理和基本特性进行了分析,推导了变换器增益特性与占空比和频率之间的关系。本文以频率作为电压增益特性的基本控制量,在此基础上进一步分析了另一变量占空比的最优值,通过构建变换器轻载损耗与占空比、频率、负载三者之间的数学模型,分析轻载运行时各负载点的最优占空比,以此作为控制依据,使变换器运行损耗最小化。针对低压大电流输出应用,为了进一步提高变换器的效率,本文讨论了适用于混合控制方式的同步整流方案,实验对比了励磁电感外置方案和同步整流管导通压降检测方案的同步整流效果,最终采用导通压降检测方案来实现同步整流,并采用电感补偿的方法优化了导通压降检测方案的驱动信号。最后完成一台270V/28V 1000W的原理样机的设计与实验验证,实验结果验证了理论分析和工程设计的正确性。
[Abstract]:The high voltage DC power system has the characteristics of light weight and uninterruptible power supply. It is one of the future development directions of the aircraft power supply system. In this paper, the two power DC/DC converter in the high voltage DC power supply system is used as the research object, and the power topology of the two DC bus converter is discussed. The bridge LLC resonant converter can realize zero voltage opening of the original side switch and the zero current turn off in the secondary rectifier in a wide load range. It is helpful to improve the efficiency and power density of the converter. It is the ideal topology of the two power DC bus converter. This paper first introduces the working principle of the traditional variable frequency control full bridge LLC resonant converter. This paper analyzes the failure phenomenon of light load gain characteristics caused by parasitic parameters and its adverse effects on the converter. A hybrid control mode combining frequency conversion and phase shift is proposed as a solution. Based on the time domain analysis method, the working principle and basic characteristics of the hybrid control full bridge LLC resonant converter are analyzed, and the converter is derived. The relationship between the gain characteristics and the duty ratio and frequency. Based on the frequency as the basic control of the voltage gain characteristics, this paper further analyzes the optimal value of the duty ratio of another variable. By constructing the mathematical model between the light load loss and the duty ratio, the frequency and the load three, the load points are analyzed in the light load operation. The optimal duty cycle is used as the control basis to minimize the loss of the converter. In order to further improve the efficiency of the converter, in order to further improve the efficiency of the converter, this paper discusses the synchronous rectification scheme which is suitable for the hybrid control mode. The experiment compares the excitation inductor external scheme and the synchronous rectifying tube conduction pressure drop detection scheme. In the end, the synchronous rectification is adopted to realize the synchronous rectification, and the driving signal of the pressure drop detection scheme is optimized by the inductance compensation method. Finally, the design and experimental verification of a 270V/28V 1000W prototype are completed, and the experimental results verify the correctness of the theoretical analysis and the engineering design.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V242.2;TM46
[Abstract]:The high voltage DC power system has the characteristics of light weight and uninterruptible power supply. It is one of the future development directions of the aircraft power supply system. In this paper, the two power DC/DC converter in the high voltage DC power supply system is used as the research object, and the power topology of the two DC bus converter is discussed. The bridge LLC resonant converter can realize zero voltage opening of the original side switch and the zero current turn off in the secondary rectifier in a wide load range. It is helpful to improve the efficiency and power density of the converter. It is the ideal topology of the two power DC bus converter. This paper first introduces the working principle of the traditional variable frequency control full bridge LLC resonant converter. This paper analyzes the failure phenomenon of light load gain characteristics caused by parasitic parameters and its adverse effects on the converter. A hybrid control mode combining frequency conversion and phase shift is proposed as a solution. Based on the time domain analysis method, the working principle and basic characteristics of the hybrid control full bridge LLC resonant converter are analyzed, and the converter is derived. The relationship between the gain characteristics and the duty ratio and frequency. Based on the frequency as the basic control of the voltage gain characteristics, this paper further analyzes the optimal value of the duty ratio of another variable. By constructing the mathematical model between the light load loss and the duty ratio, the frequency and the load three, the load points are analyzed in the light load operation. The optimal duty cycle is used as the control basis to minimize the loss of the converter. In order to further improve the efficiency of the converter, in order to further improve the efficiency of the converter, this paper discusses the synchronous rectification scheme which is suitable for the hybrid control mode. The experiment compares the excitation inductor external scheme and the synchronous rectifying tube conduction pressure drop detection scheme. In the end, the synchronous rectification is adopted to realize the synchronous rectification, and the driving signal of the pressure drop detection scheme is optimized by the inductance compensation method. Finally, the design and experimental verification of a 270V/28V 1000W prototype are completed, and the experimental results verify the correctness of the theoretical analysis and the engineering design.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V242.2;TM46
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