A Multilevel DC to Three-Phase AC Architecture for Photovoltaic Power Plants
A Multilevel DC to Three-Phase AC Architecture for Photovoltaic Power Plants
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DOI：
10.1109/tec.2018.2877151
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发表时间：
2019-03
影响因子：
4.9
通讯作者：
Prasanta K. Achanta;Brian B. Johnson;Gab-Su Seo;D. Maksimović
中科院分区：
文献类型：
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作者：
Prasanta K. Achanta;Brian B. Johnson;Gab-Su Seo;D. Maksimović
本文提出了一种光伏（PV）逆变器架构组成的堆叠直流到三相交流转换器块。几个这样的块，每个包含一个转换器功率级和控制，串联连接在其交流侧，以获得光伏发电厂的无变压器中压交流接口。串联连接结构通过四重有源桥式DC-DC转换器实现，该转换器在PV输入和每个模块内的三个交流侧相位中的每一个之间提供隔离。此外，由于输入的PV功率作为恒定平衡的三相交流功率传输，因此瞬时输入-输出功率平衡绕过了对大容量能量存储的需求。为了简化实施并最大限度地提高系统的可扩展性和弹性，分散的块级控制器无需集中手段即可实现直流链路电压调节、最大功率点跟踪和交流侧功率共享。所提出的架构进行了验证模拟的PV串到中压交流系统由六个块和一个概念验证的硬件原型，由三个级联的转换器块。
This paper presents a photovoltaic (PV) inverter architecture composed of stackable dc to three-phase ac converter blocks. Several such blocks, each containing a converter power stage and controls, are connected in series on their ac sides to obtain transformerless medium-voltage ac interfaces for PV power plants. The series-connected structure is made possible by a quadruple active bridge dc–dc converter that provides isolation between the PV input and each of the three ac-side phases within each block. Furthermore, since incoming PV power is transferred as constant balanced three-phase ac power, instantaneous input–output power balance bypasses the need for bulk energy storage. To streamline implementation and maximize system scalability and resilience, decentralized block-level controllers accomplish dc-link voltage regulation, maximum power point tracking, and ac-side power sharing without centralized means. The proposed architecture is validated by simulations of a PV string to medium-voltage ac system consisting of six blocks and on a proof-of-concept hardware prototype that consists of three cascaded converter blocks.