【作者】 王宏佳；

【导师】 孙铁成；

【作者基本信息】 哈尔滨工业大学 ， 电气工程， 2007， 硕士

【摘要】 环境和能源等问题给电力电子学科提出了高效率发电、高效率电力变换和控制的要求。在这种高效率、高性能电力变换要求下,软开关多电平变换技术成为了目前电力电子学科的一个研究热点。三电平变换器的开关管电压应力仅为直流电源输入电压的一半,结合软开关技术,非常适用于高电压、中大功率的应用场合。针对这一情况,从减小开关损耗、改善IGBT电流拖尾和提高变换器效率的角度出发,本文提出了一种新型的具有无源钳位电路的ZVZCS三电平DC-DC变换器拓扑结构。深入分析了这种新型变换器拓扑的工作原理、参数设计以及控制方案。在分析Buck变换器小信号模型的基础上,根据变换器的工作特点和谐振机理,采用三端开关器件模型法,建立了ZVZCS三电平DC-DC变换器的小信号模型,推导出变换器的传递函数和频率特性,对系统的控制器进行了设计,使其具有良好的动态和稳态性能。使用PSpice软件对三电平变换器的工作情况进行了计算机仿真分析,通过调节仿真参数,电路性能得到优化,证明了所提出三电平变换器拓扑的正确性。为验证设计的可行性,结合DSP数字控制,设计了一台输出功率144W、开关频率60kHz的具有无源钳位电路的ZVZCS三电平DC-DC变换器实验样机。对变换器的主电路,驱动和保护电路进行了设计,采用TMS320F2812芯片构成控制电路。对实验样机进行实验调试,结果证明变换器软开关负载范围较大,开关管电压应力低,整流二极管上电压过冲减小,整机效率较高,达到了设计指标要求,验证了理论分析的正确性。更多还原

【Abstract】 Environment and energy problems issues power electronics discipline for the efficient power generation, conversion and control requirements. In such a high-efficiency, high-performance power conversion request, soft-switching multi-level conversion technology has been attracting more and more attentions. Three-level converter has the advantage that the switch voltage stress is only half of the input voltage. Associated with soft-switching technology, it is very suitable for high input voltage, middle or large power applications. In view of the situation, for reducing switching loss, improving current trails of IGBT and improving the converter efficiency, a novel ZVZCS three-level DC-DC converter using passive clamp circuit is proposed. The operation principle of the converter is analyzed as well as parameter design and control characteristics.Based on the analysis of small-signal model of the Buck converter, the small-signal model of the ZVZCS three-level DC-DC converter is built according to operating characteristics and the resonant mechanism by using the method of PWM switch equivalent model. Transfer function and frequency characteristics of the system are analyzed. The design of compensator enhances the system with good dynamic and static performance.PSpice is used to simulate the operation of the three-level converter. By adjusting the parameters of simulation, the performance of circuit is optimized. The correctness of the proposed three-level converter is proved.To verify the feasibility of the design, combining DSP digital control, a 144 W, 60 kHz ZVZCS three-level experimental prototype is built. The power circuit, driving and protection circuit of the converter are designed. TMS320F2812 is used to constitute control circuit.Experiments of the prototype are carried out. From the experiment result, it can be indicated that the ZVZCS three-level converter using passive clamp circuit has wider soft-switching load range, lower voltage stress on switch, lower overshoot voltage on the rectifier diode and high efficiency. The performance requirements of the converter are achieved, and the correctness of the theoretical analysis is verified.更多还原