Voltage source inverter is a key element in an inverter-based distributed generation (DG) system for the integration of renewable energy resources with an existing power grid. Interconnection standards for the requirements of inverter output current quality are one of the foremost demands imposed by distribution system operators. The operation of a stabilised DG system with LCL -filter meeting current quality requirements is challenging due to variation in system parameters and non-ideal grid voltages. In this context, this study proposes a robust controller design and modified control structure to improve current quality in the presence of distorted grid voltages. The controller is designed based on general mixed sensitivity problem formulation to achieve robustness against system parameters variation and ensure high-quality injected current under normal grid voltage. The control performance of the designed robust controller with a feed-forward loop is investigated under distorted grid voltage. Furthermore, an inverter current compensation is proposed, employed by an additional inverter current feedback loop through the high-pass compensator. The current quality investigation with variation in different parameters and low power operation shows enhanced control performance of the proposed solution under distorted as well as normal grid voltages. The main features of the proposed scheme are the simplicity in design, easy implementation, and better harmonics rejection capability without limiting the control loop stability. The simulation and experimental results validate the effectiveness of the proposed method .

中文翻译：

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H基于逆变器的分布式发电系统的_∞鲁棒控制和改进的谐波抑制

电压源逆变器是基于逆变器的分布式发电（DG）系统中的关键元素，用于将可再生能源与现有电网集成在一起。逆变器输出电流质量要求的互连标准是配电系统运营商提出的最重要要求之一。具有以下功能的稳定DG系统的运行拼箱 由于系统参数的变化和不理想的电网电压，满足当前质量要求的过滤器具有挑战性。在这种情况下，这项研究提出了一个稳健的控制器设计和改进的控制结构，以在电网电压失真的情况下提高电流质量。的控制器是根据一般混合灵敏度问题公式设计的，旨在针对系统参数变化实现鲁棒性，并确保在正常电网电压下获得高质量注入电流。在电网电压失真的情况下，研究了具有前馈环路的鲁棒控制器的控制性能。此外，提出了逆变器电流补偿，该逆变器电流补偿由通过高通补偿器的附加逆变器电流反馈环路采用。当前在不同参数变化和低功率运行情况下的质量研究表明，在失真以及正常电网电压下，所提出解决方案的控制性能得到了增强。该方案的主要特点是设计简单，易于实施，以及更好的谐波抑制能力，而不会限制控制回路的稳定性。仿真和实验结果验证了该方法的有效性。 。