Joshi Jyoti, Jately Vibhu, Kala Peeyush, Sharma Abhishek, Lim Wei Hong, Azzopardi Brian
Department of Computer Science and Engineering, Graphic Era Hill University, Dehra Dun, 248002, India.
Department of Electrical & Electronics Engineering, School of Engineering, University of Petroleum and Energy Studies, Dehra Dun, 248007, India.
Sci Rep. 2024 May 2;14(1):10118. doi: 10.1038/s41598-024-60244-x.
Under grid voltage sags, over current protection and exploiting the maximum capacity of the inverter are the two main goals of grid-connected PV inverters. To facilitate low-voltage ride-through (LVRT), it is imperative to ensure that inverter currents are sinusoidal and remain within permissible limits throughout the inverter operation. An improved LVRT control strategy for a two-stage three-phase grid-connected PV system is presented here to address these challenges. To provide over current limitation as well as to ensure maximum exploitation of the inverter capacity, a control strategy is proposed, and performance the strategy is evaluated based on the three generation scenarios on a 2-kW grid connected PV system. An active power curtailment (APC) loop is activated only in high power generation scenario to limit the current's amplitude below the inverter's rated current. The superior performance of the proposed strategy is established by comparison with two recent LVRT control strategies. The proposed method not only injects necessary active and reactive power but also minimizes overcurrent with increased exploitation of the inverter's capacity under unbalanced grid voltage sag.
在电网电压骤降情况下，过流保护和充分利用逆变器的最大容量是并网光伏逆变器的两个主要目标。为了促进低电压穿越（LVRT），必须确保逆变器电流为正弦波，并在逆变器运行的整个过程中保持在允许范围内。本文提出了一种针对两级三相并网光伏系统的改进型LVRT控制策略，以应对这些挑战。为了提供过流限制并确保充分利用逆变器容量，提出了一种控制策略，并基于一个2千瓦并网光伏系统的三种发电场景对该策略的性能进行了评估。仅在高发电场景下激活有功功率削减（APC）回路，以将电流幅度限制在逆变器额定电流以下。通过与两种近期的LVRT控制策略进行比较，验证了所提策略的优越性能。所提方法不仅能注入必要的有功和无功功率，还能在不平衡电网电压骤降情况下，通过更多地利用逆变器容量来使过电流最小化。
