【作者】 沈萍；

【导师】 龚春英；

【作者基本信息】 南京航空航天大学 ， 电力电子与电力传动， 2008， 硕士

【摘要】 本文以中功率航空静止变流器直流环节对主要研究对象,分析了常用的DC/DC变换器拓扑结构,优选电路结构简单、容易控制且较适合于中小容量的半桥电路作为直直变换拓扑。在分析了变压器副边加无源无损缓冲吸收电路的脉宽调制对称半桥变换器工作原理及电路特性后,研制了270V直流输入,360V直流输出,输出功率为550W的样机一台,副边整流管两端电压尖峰得到有效抑制。随着高性能、高效率、轻量化和小型化越来越成为直直变换器所追求的目标,本文引入通过固定死区的互补调频控制LLC型串并联谐振变换器,充分地利用电路本身的特点,由串联谐振电感、谐振电容和变压器的激磁电感发生谐振,实现了原边开关管的零电压开关和整流管的零电流开关。详尽分析了LLC型串并联谐振变换器在不同频率范围内的工作过程,并以其直流电压增益特性、谐振网络的归一化输入阻抗和零电压开关的条件为变换器主要特性进行了探讨,给出了参数设计方法和参数间及对变换器的影响,在上述理论基础上以同样的指标设计并研制了LLC谐振变换器样机一台,并给出实验结果和分析,验证了理论分析和工程设计的正确性。最后借助数学工具Mathcad对两种变换器主要器件的损耗进行了分析计算,包括MOS管、整流管、磁性元件等,给出了损耗分布和效率曲线图,为进一步优化设计具有一定的指导意义。更多还原

【Abstract】 Aeronautical Static Inverter (ASI) used in medium power is being researched in this thesis, after reviewing and analyzing the common DC/DC converters, the DC/DC stage of ASI employs half-bridge converter, which is simple and easy to control in this power range situation.The operation principles and characteristics of symmetry half-bridge converter which is controlled by pulse-width modulation mode and appending with passive and lossless snubber circuit were first presented. Then a 550W DC/DC converter of 270V DC input and 360V DC output PWM symmetry half-bridge converter is designed and the converter designed above had effective impact on restraining the high voltage stress of rectifying diodes at the side of secondary coil. Nowadays, high performance、high efficiency and light weight are the most important performance figure of all kinds of DC/DC converter. Adding a inductance and capacitance into the PWM symmetry half-bridge converter above, the LLC series-parallel resonant converter was gained. Using variable frequency control mode with a refined small times together, achieves the effect of Zero Voltage Switching (ZVS) with the MOSFET and the effect of Zero Current Switching (ZCS) by the resonance of resonant inductor, resonant capacitance and the magnetic inductor of the transformer.The thesis discusses the operation principles within different frequency rang, especially focusing on DC gain characteristics、normalized input impedance and ZVS constraints. By concluding the influence brought on the converter by the main parameters, the method of designing parameters of converter is outspreaded. The LLC resonant converter is produced with the same converter specification. At last the loss of these two converters is discussed including MOSFET, rectifier diode, magnetic components and etc., by means of Mathcad, also the loss distribution and theoretical efficiency are obtained. All of these are helpful to optimize further.更多还原