Power Balance of Cascaded H-Bridge Multilevel Converters for Large-Scale Photovoltaic Integration
Power Balance of Cascaded H-Bridge Multilevel Converters for Large-Scale Photovoltaic Integration
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DOI：
10.1109/tpel.2015.2406315
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发表时间：
2016
影响因子：
6.7
通讯作者：
Yifan Yu;G. Konstantinou;B. Hredzak;V. Agelidis
中科院分区：
文献类型：
--
作者：
Yifan Yu;G. Konstantinou;B. Hredzak;V. Agelidis
多电平级联H桥变换器是大规模光伏电站的理想选择。它们允许直接连接到中压配电网络，而无需笨重的工频电力变压器。由于辐照度水平、环境温度和其他因素的随机变量性质，预计三个阶段中的功率水平不相等。功率不平衡条件对这种拓扑产生了意想不到的问题，这种拓扑最初被设计为在平衡功率条件下工作。针对这一问题，本文提出了三种新的零序注入方法，作为对传统零序注入方法的扩展。仿真结果和一台430 V 8 kW三相七电平级联H桥样机验证了所提方法的有效性和可行性。
Multilevel cascaded H-bridge converters are promising candidates for large-scale photovoltaic power plants. They allow direct connection to medium-voltage distribution networks without the presence of bulky line frequency power transformers. Owing to the stochastically variable nature of irradiance level, ambient temperature, and other factors, power levels in the three phases are expected to be unequal. The power imbalance condition creates unexpected problems with this topology, which was initially designed to operate under balanced power conditions. To deal with this issue, the paper proposes three novel zero-sequence injection methods as an expansion to the conventional zero-sequence injection method. Results obtained from simulations and a 430-V 8-kW three-phase seven-level cascaded H-bridge prototype are presented to verify the effectiveness and feasibility of the proposed methods.