Renewable energy is being rapidly developed and extensively utilized, which are commonly interfaced to the microgrids through the inverters. Therefore, the proper and fast extraction of the synchronous phases, frequency and amplitudes of the sequence voltages have brought major requirements under unbalanced and distorted microgrid voltage. In this regard, this paper presents a novel adaptive frequency method to improve the instantaneous sequence components detection method, which can significantly improve the accuracy of positive and negative sequence voltages. Based on the symmetric component method and the virtual vector construction module, the positive and negative sequence voltages with errors are calculated. The harmonic suppression module filters out the harmonics and random noise in the sequence voltages with errors. Then, the real-time difference frequency phase information of the sequence voltages is obtained by the difference frequency adjustment. With the closed-loop control of the difference frequency phase information, the microgrid frequency can be quickly and accurately obtained. The frequency information is fed back to the virtual vector construction module and the harmonic suppression module to obtain the frequency, amplitudes and synchronous phases of the positive and negative sequence voltages for inverter control in unbalanced and distorted microgrids. When the microgrid frequency changes greatly, the frequency detection module of this method can improve the accuracy of obtaining the positive and negative sequence voltages. Simulation results show that the proposed method can quickly and accurately capture the real-time sequence voltages in the three-phase asymmetric and distorted environment, and the validity and robustness of the proposed method are verified.

可再生能源正在迅速发展并得到广泛利用，通常通过逆变器将其连接到微电网。因此，在不平衡且畸变的微电网电压下，正确，快速地提取同步电压的同步相位，频率和幅度已经带来了主要要求。鉴于此，本文提出了一种新颖的自适应频率方法，以改进瞬时序列分量检测方法，可以显着提高正负序电压的精度。基于对称分量法和虚拟矢量构建模块，计算出带误差的正负序电压。谐波抑制模块滤除序列电压中的谐波和随机噪声，并带有误差。然后，通过差频调整得到时序电压的实时差频相位信息。通过差频相位信息的闭环控制，可以快速而准确地获得微电网频率。频率信息被反馈到虚拟矢量构建模块和谐波抑制模块，以获得正负序电压的频率，幅度和同步相位，以在不平衡和失真的微电网中进行逆变器控制。当微电网频率变化很大时，该方法的频率检测模块可以提高获得正负序电压的精度。