Electronic DC transformer with high power density
Electronic DC transformer with high power density
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高功率密度电子直流变压器
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
M. Pavlovsky
中科院分区：
文献类型：
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作者：
M. Pavlovsky
本论文主要研究采用电流隔离技术来提高大功率DC-DC转换器功率密度的可能性。实现高功率密度的三个基石是：减小无源元件的尺寸，减少损耗，特别是有源元件的损耗和热管理。除了基础之外，转换器组件的空间集成也是高功率密度的重要因素。无源器件的尺寸减小是通过提高工作频率来实现的。另一方面，工作频率的增加也会增加无源元件本身的损耗。因此，本文对磁性元件绕组中的功率损耗进行了研究，特别是对变压器绕组进行了研究。将多个无源组件集成到一个组件中也被认为是提高功率密度的手段。主要的挑战是在公认的高功率水平上集成组件。较高的工作频率会导致有源元件中的开关损耗显著增加。较高的损耗会降低效率，并且需要较大的散热器，从而降低较高的工作频率对总功率密度的影响。本文采用零电压开关准零电流开关拓扑结构来降低有源元件的功率损耗。必须移走转炉部件内部产生的热量，以防止其过热。由于体积越小，功率消耗越大，功率密度越大，执行这项任务就越困难。本文从元件级、变流器级和系统级三个方面对功率变流器的热管理进行了研究。每一级都是单独讨论的，并提出了适当的散热方法和概念。转换器组件的空间集成对于获得高功率密度也很重要。成功集成组件的关键是做出设计选择，以产生尺寸和形状兼容的组件。本文讨论了在设计高功率密度大功率变流器时应遵循的基本准则。运行条件和要求随功率转换器处理的功率水平而变化。因此，设计概念和方法的可扩展性对于它们在所考虑的广泛应用中的实际实施是重要的。本文简要讨论了在功率密度和转换器组件性能方面的放大问题。在一台50kW的变流器样机上验证了在高功率下实现高功率密度的能力。达到的功率密度在水冷却时为11.2kW/升，强制风冷时为6.6kW/升。研究还表明，通过设计高功率密度，效率可能不会受到影响。最终的变流器样机在较宽的负载范围内测得的效率高达97.5%。
This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components and thermal management. In addition to the cornerstones, the spatial integration of converter components is considered as it is also important for high power density. The size reduction in passives is obtained by increasing the operating frequency. On the other hand, an increase of operating frequency yields also higher losses in passive components themselves. Therefore, the thesis addresses the power loss in windings of magnetic components with special attention to the transformer windings. Integration of several passive components into a single component is also considered as the means to increase the power density. The main challenge is the integration of components at the considered high power levels. A high operating frequency results in a substantial increase of switching losses in active components. The higher losses yield reduced efficiency and require larger heatsinks which consequently reduce the effect of the higher operating frequency on the overall power density. In this thesis, the power loss in active components is reduced by applying so called Zero-Voltage-Switching Quasi-Zero-Current-Switching topology. The heat generated inside converter components must be removed to prevent them from overheating. Performing this task becomes more difficult as the power density increases because of higher power dissipated in a smaller volume. The thesis considers thermal management of a power converter on component, converter and system level. Each of the levels is addressed separately and adequate heat removal methods and concepts are proposed. Spatial integration of converter components is important to obtain a high power density as well. The key to the successful integration of components is to make design choices which result in components of compatible dimensions and shapes. Basic guidelines that should serve as an aid in the design of high power density high-power converters are discussed in this thesis. The operating conditions and requirements vary with the power level processed by a power converter. Therefore, the scalability of the design concepts and approaches is important for their practical implementation in the wide range of considered applications. This thesis briefly discusses scaling up with respect to power density and performance of the converter components. The ability of achieving high power densities in high power is demonstrated on a 50 kW converter prototype. The reached power density is in order of 11.2 kW/litre with water cooling and 6.6 kW/litre with forced air cooling. It is also shown that by designing for high power density, the efficiency might not need to suffer. The measured efficiency of the final converter prototype is as high as 97.5 % in a broad load range.