移相控制软开关PWM技术的研究

【作者】 孙松儿；

【导师】 范蟠果；

【作者基本信息】 西北工业大学 ， 电力电子与电力传动， 2001， 硕士

【摘要】 本文在对硬开关功率变换电路缺点分析的基础上，提出了软开关变换电路，并对软开关的定义、分类、发展及其控制策略做了归纳和总结。 同时对移相控制零电压（ZVS）软开关PWM（脉宽调制）功率变换器的工作原理、电路特性、以及一些常见的电路改进措施进行了分析，指出了它的优缺点。在这个基础上提出了一种新的零电压零电流（ZVZCS）全桥PWM功率变换电路。它克服了零电压全桥PWM变换器的高环流损耗、占空比丢失严重、滞后桥臂软开关受到负载范围限制的缺点。通过在变压器的原边加上隔直电容、饱和电感和在主通道上加上两个二极管，可以使初级电流的环流减少到零，滞后桥臂的开关管零电流开通，而超前桥臂仍然为零电压开通。本文对其电路拓扑结构、工作原理和电路特性做了较深入的阐述。 根据这种新的电路拓扑结构，采用IGBT作为滞后功率开关管的高电压、大功率DC-DC变换器实验得以进行。论文中完成了DC-DC变换器的主电路结构、参数的设计和控制保护电路的实现。其移相控制采用UC3879来实现，实验结果表明其电路拓扑结构是正确的。更多还原

【Abstract】 A soft-switching converter circuit is discussed on the basis of analysis of the hard-switching power converter circuit’s shortcoming in the paper. The definition, classification, development and the control strategy of the soft-switching have been summarized. The principle of operation, features of the general pulse-width modulated (PWM) power converter of zero-voltage-switching(ZVS) with phase-shift control are described.Its merits and shortcoming are pointed and some measures used to improve the circuit performance are given. Then a novel zero-voltage-zero-current full-bridge PWM soft-switching power converter is proposed. The new converter overcomes the limitations of the ZVS-FB-PWM converter ,such as the high circulating energy ,bad loss of the duty cycle, and limited the ZVS load range for the lagging-leg switches. By using the dc blocking capacitor and adding a saturable inductor and adding two diodes in the main channel., the primary current during the freewheeling period is reduced to zero. And allowing the lagging-leg switches to be operated with zero- current-switching ,meanwhile, the leading-leg switches are still operated with ZVS .The circuit topolQgy , principle of operation ,circuit features have been described detailedly. Based on the new circuit topology, an experiment of high-voltage,high-power DC-DC converter is presented where IGBTs are predominantly used as the lagging- leg switches. The design of structure and calculation methods of parameter in the DC- DC converter main circuit and the design of the control and protect circuit have been presented. The phase-shift control is implemented with UC3 879. The experiment results show the circuit topology is right.更多还原