SiC Three-Level Neutral-Point-Clamped Converter With Clamping Diode Volume Reduction Using Quasi-Two-Level Operation
SiC Three-Level Neutral-Point-Clamped Converter With Clamping Diode Volume Reduction Using Quasi-Two-Level Operation
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DOI：
10.1109/tpel.2023.3270370
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发表时间：
2023-08
影响因子：
6.7
通讯作者：
Xiang Lin;D. Dong
中科院分区：
文献类型：
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作者：
Xiang Lin;D. Dong
近年来，中压SiC MOSFET在高频固态变压器和多电平变流器等中压大功率领域得到了广泛的关注。虽然这些MOSFET的直接串联连接是更高电压电平的一种选择，但它需要复杂的电压平衡方法来在快速开关瞬态期间实现器件电压平衡。可替代地，可以使用诸如三电平（3L）中性点电位转换器的转换器级解决方案。本文提出了一种新的调制策略，结合3L和准两电平调制，通过严格控制二极管上的热应力来最小化箝位二极管的额定值和体积。该方法实现了更好的效率、更高的功率密度和更简单的转换器总线结构，以有效地串联堆叠两个SiC MOSFET。我们提出了一个实时钳位二极管损耗估计，以提高所提出的调制策略的有效性。为了验证所提出的转换器级方法和调制策略，我们测试了一个20 kV的额定相脚，两个10 kV的SiC MOSFET和3.3 kV的SiC二极管。
Medium voltage SiC mosfets have recently garnered considerable attention in the medium-voltage high-power areas like high-frequency solid-state transformers and multilevel converters. While direct series connection of these mosfets is an option for higher voltage levels, it requires complex voltage balancing approaches for device voltage balancing during fast switching transients. Alternatively, converter-level solutions such as the three-level (3L) neutral-point-potential converter can be used. This article proposes a new modulation strategy, combining 3L, and Quasi-two-level modulations, to minimize the rating and volume of clamping diodes by tightly controlling the thermal stress on the diodes. This approach achieves better efficiency, higher power density, and a simpler converter bus-structure to stack two SiC mosfets effectively in series. We present a real-time clamping diode loss estimation to improve the effectiveness of the proposed modulation strategy. To verify the proposed converter-level approach and modulation strategy, we test a 20 kV rated phase-leg with two 10 kV SiC mosfets and 3.3 kV SiC diodes.