A conventional synchronous (rotating) reference frame control requires small-signal models and introduces cross-coupling terms. In this study, a virtual charge-based scheme for grid synchronisation with only current measurements has been proposed for a three-phase grid-connected inverter with a first-order filter. The methodology described in this study curbs the dependency of the inverter on the information of the grid voltage to generate unit vectors from the phase-locked loop. This kind of estimation is especially important during grid voltage sensor failures or a distant point common coupling or weak grid conditions. In the proposed estimation scheme, no noisy differentiation is involved and only the nominal values of the interfacing filter parameters are utilised, making the implementation easier in digital microcontrollers. Also, a current control architecture based on feedback linearisation concept has been explored and embedded with the proposed grid voltage estimation technique, and the corresponding performance has been evaluated via simulation and experimental studies.

中文翻译：

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无电网电压传感器的三相并网逆变器的基于虚拟电荷的同步和基于反馈线性化的电流控制

传统的同步（旋转）参考帧控制需要小信号模型，并引入了交叉耦合项。在这项研究中，针对带有一阶滤波器的三相并网逆变器，提出了一种仅基于电流测量的基于虚拟电荷的电网同步方案。本研究中描述的方法可抑制逆变器对电网电压信息的依赖性，从而从锁相环生成单位矢量。在电网电压传感器故障或遥远点公共耦合或弱电网条件下，这种估计尤为重要。在所提出的估计方案中，不涉及噪声微分，并且仅使用接口滤波器参数的标称值，这使得在数字微控制器中的实现更加容易。也，