中文摘要：

电力系统频率是衡量电能质量的一项重要指标，需要实时精确测量。利用三相电压信号固有特征，提出了一种基于αβ与dq坐标变换的频率检测算法，通过坐标变换，将三相电压变换到dq坐标系，滤除谐波，然后再变换到αβ坐标系获得基波频率。同时提出了采用双低通滤波器算法消除谐波对频率测量的影响，有效地解决了低通滤波器动态响应和稳态精度不能兼顾的矛盾。该算法所需采样数据量少，动态响应快，稳态精度高，计算量小。经过理论分析，该算法同样适用于单相系统频率检测。通过Matlab软件对算法进行了验证，分析了该算法的动态响应时间和稳态精度，仿真结果验证了该算法的正确性。该算法易于实现，具有很好的实用价值。

英文摘要：

Power frequency is an important indicator of power quality and requires precise and real-time measurements. A frequency detection algorithm based on αβ and dq coordinate transform is proposed using the inherent characteristics of three-phase voltage. Firstly, three-phase voltage is transformed into dq stationary coordinate system; then fundamental components are obtained through low pass digital filtering of d-axis and q-axis components; lastly, fundamental components are inversely transformed into αβ stationary coordinate system to obtain the frequency of power grid. Dual low-pass filters are adopted to eliminate the effect of harmonic on the frequency measurement, which resolves the contradiction between the dynamic response and steady state accuracy effectively. This algorithm requires less data and possesses better dynamic response with high steady state accuracy. Theoretical analysis proves that the proposed frequency detection algorithm can also be applied to single-phase system. Matlab simulation results prove that the proposed algorithm has good dynamic response and high steady state accuracy. It is easy to be implemented and has good practical value.