This paper presents a novel structure to inject the electric energy from photovoltaic modules to the grid based on a 27-level asymmetric multilevel inverter. This work proposes mixing existing approaches based on string and central inverters to implement a hybrid structure that generates highly sinusoidal waveforms. Indeed, the presented structure allows for a staircase AC voltage waveform with a low level of harmonic distortion, which is a key feature for photovoltaic energy conversion. The proposal is supported with theoretical analyses that include system modeling and a suitable control strategy to track both the active and reactive power. A low power proof-of-concept prototype was built to validate the properness of the proposal. Several dynamic tests were performed, such as severe load impacts, partial shading and fault ride-through capability.

中文翻译：

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用于光伏能量转换的27电平非对称多电平逆变器

本文提出了一种基于 27 电平非对称多电平逆变器的新型结构，将光伏组件的电能注入电网。这项工作建议混合现有的基于串式逆变器和中央逆变器的方法，以实现一种生成高度正弦波形的混合结构。事实上，所提出的结构允许具有低水平谐波失真的阶梯式交流电压波形，这是光伏能量转换的一个关键特征。该提议得到了理论分析的支持，包括系统建模和合适的控制策略来跟踪有功功率和无功功率。构建了一个低功耗的概念验证原型来验证提案的正确性。进行了多项动态测试，例如严重的负载冲击，