Abstract The high penetration of distributed energy resources (DERs) consisting of photovoltaic and fuel cell and wind power plants into the modern power grid results in several challenges such as stability and reliability. In this regard, this paper proposes proportional complex integral (PCI)-based control scheme of distributed energy inverter (DEI) connected to the utility grid to overcome limitations of synchronous rotating coordinate systems based control schemes. The dynamic performance, power quality and stability of the grid connected DEI are enhanced in contrast to proportional integral (PI)-based control scheme during unbalanced and distorted grid voltages. A noteworthy contribution of this paper is that the third-order (3rd) current harmonic stemmed from the DC-link voltage (DC-LV) oscillations is eliminated at the grid side. Elimination of the DC-LV oscillations contributes to reducing the size of the DC capacitance and increasing the lifetime of the power conversion system. Active power reference is calculated in a closed-loop control system based on the DC-LV controller or based on maximum allowable active power injection according to the control objectives. Another contribution to previous studies is to eliminate the need for a phase locked loop (PLL). The complexities and additional hardware requirement for phase estimation are reduced. The performance comparison for two control schemes has been evaluated in terms of dynamic response, removing active power oscillations (APOs) for the DC-side voltage stability, removing reactive power oscillations (RPOs) for the AC side voltage stability, reducing the DC-LV oscillations for the elimination of third-order current harmonic and protection of the inverter from overcurrent. The effectiveness and availability of the proposed control scheme are confirmed through a set of case studies.

中文翻译：

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基于比例复积分的分布式能量转换器连接到不平衡电网系统的控制

摘要 由光伏、燃料电池和风力发电厂组成的分布式能源（DER）在现代电网中的高渗透率导致了稳定性和可靠性等多项挑战。在这方面，本文提出了基于比例复积分 (PCI) 的分布式能源逆变器 (DEI) 连接到公用电网的控制方案，以克服基于同步旋转坐标系的控制方案的局限性。在不平衡和失真的电网电压期间，与基于比例积分 (PI) 的控制方案相比，并网 DEI 的动态性能、电能质量和稳定性得到了增强。本文的一个值得注意的贡献是在电网侧消除了源自直流母线电压 (DC-LV) 振荡的三阶 (3rd) 电流谐波。消除 DC-LV 振荡有助于减小 DC 电容的尺寸并延长电源转换系统的使用寿命。有功功率参考是在基于 DC-LV 控制器或基于最大允许有功功率注入的闭环控制系统中根据控制目标计算的。对先前研究的另一个贡献是消除了对锁相环 (PLL) 的需要。降低了相位估计的复杂性和额外的硬件需求。已在动态响应方面评估了两种控制方案的性能比较，消除了直流侧电压稳定性的有功功率振荡 (APO)，消除了交流侧电压稳定性的无功功率振荡 (RPO)，减少 DC-LV 振荡，以消除三阶电流谐波并保护逆变器免受过流影响。所提议的控制方案的有效性和可用性通过一组案例研究得到证实。