Figures-of-Merit (FOMs) are widely-used to compare power semiconductor materials and devices and to motivate research and development of new technology nodes. These material- and device-specific FOMs, however, fail to directly translate into quantifiable performance in a specific power electronics application. Here, we combine device performance with specific bridge-leg topologies to propose the extended FOM, or X-FOM, a Figure-of-Merit that quantifies bridge-leg performance in multi-level (ML) topologies and supports the quantitative comparison and optimization of topologies and power devices. To arrive at the proposed X-FOM, we revisit the fundamental scaling laws of the on-state resistance and output capacitance of power semiconductors to first propose a revised device-level semiconductor Figure-of-Merit (D-FOM). The D-FOM is then generalized to a multi-level topology with an arbitrary number of levels, output power, and input voltage, resulting in the X-FOM that quantitatively compares hard-switched semiconductor stage losses and filter stage requirements across different bridge-leg structures and numbers of levels, identifies the maximum achievable efficiency of the semiconductor stage, and determines the loss-optimal combination of semiconductor die area and switching frequency. To validate the new X-FOM and showcase its utility, we perform a case study on candidate bridge-leg structures for a three-phase 10 kW photovoltaic (PV) inverter, with the X-FOM showing that (a) the minimum hard-switching losses are an accurate approximation to predict the theoretically maximum achievable efficiency and relative performance between bridge-legs and (b) the 3-level bridge-leg outperforms the 2-level configuration, despite utilizing a SiC MOSFET with a lower D-FOM than in the 2-level case.

中文翻译：

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结合了半导体和多电平转换器特性的新品质因数

品质因数（FOM）被广泛用于比较功率半导体材料和器件并激发新技术节点的研究和开发。但是，这些特定于材料和设备的FOM无法直接转换为特定功率电子应用中可量化的性能。在这里，我们将设备性能与特定的桥臂拓扑相结合，以提出扩展的FOM或X-FOM，它是一种量化多级（ML）拓扑中桥臂性能并支持定量比较和优化的品质因数拓扑和电源设备。为了得出建议的X-FOM，我们重新审视了功率半导体的导通状态电阻和输出电容的基本定标定律，首先提出了修订后的器件级半导体品质因数（D-FOM）。然后，将D-FOM泛化为具有任意数量的电平，输出功率和输入电压的多级拓扑，从而产生X-FOM，该X-FOM定量比较了跨不同桥的硬开关半导体级损耗和滤波器级要求。支路结构和级数，确定半导体级可实现的最大效率，并确定半导体管芯面积和开关频率的损耗最佳组合。为了验证新的X-FOM并展示其实用性，我们对三相10 kW光伏（PV）逆变器的候选桥腿结构进行了案例研究，其中X-FOM显示了 产生X-FOM，该X-FOM定量比较了跨桥臂结构和电平数时的硬开关半导体级损耗和滤波器级要求，确定了半导体级可实现的最大效率，并确定了半导体管芯的损耗最佳组合面积和开关频率。为了验证新的X-FOM并展示其实用性，我们对三相10 kW光伏（PV）逆变器的候选桥腿结构进行了案例研究，其中X-FOM显示了 产生X-FOM，该X-FOM定量比较了跨桥臂结构和电平数时的硬开关半导体级损耗和滤波器级要求，确定了半导体级可实现的最大效率，并确定了半导体管芯的损耗最佳组合面积和开关频率。为了验证新的X-FOM并展示其实用性，我们对三相10 kW光伏（PV）逆变器的候选桥腿结构进行了案例研究，其中X-FOM显示了（一种） 最小的硬开关损耗是一种准确的近似值，可以预测理论上可达到的最大效率以及桥臂与桥臂之间的相对性能。 （b） 尽管采用了D-FOM低于2级情况的SiC MOSFET，但3级桥臂的性能却优于2级配置。