Frequency Tracking Based On Recursive Damped Least Square Algorithm And FPGA Implementation

The frequency of Power system is a very important indicator of overall quality of the network.The high and low frequencies will result in a greater impact on the grid, it may even make the system crash.lt has a very significant significance to track the frequency of Power system.Least squares fitting is treated from the perspective of measurement error model system identification or parameter estimation, parameter estimation, system identification and prediction and other fields have a very wide range. After the traditional method of least squares algorithm is a set of sample data processing to find the best values to describe the characteristics of the sample data, and other data sampling interval is obtained by a certain length, try to find a best fit curve. But there are limitations in the system when the online identification parameter for offline identification. Based on the traditional method of least squares on a forgetting factor and added damping Damping Recursive least squares algorithm can be applied to real-time requirements are relatively high parameter identification systems.The main work are as follows:(1) The theory of recursive damped least square method is studied,and the recursive least squares method is applied to track the instantaneous frequency of power system.Recursive formula and the adaptive damping factor is proposed.(2) Signal for the power system model for the ideal signal, instantly hopping model model and the power system frequency signal containing harmonic and noise components occurred were to do a more detailed the simulation,the tracking error of frequency is analysed under different window lengths.And harmonic analysis is taken as an example to demonstrate the effectiveness of the algorithm.(3) FPGA hardware platform is used to track the frequency of power system, as with decimals and inverse cosine functions such as processing algorithms, so the use of nuclear convenient way algorithm embedded computing will eventually the results of the chip through the LCD800* 600 color screen is displayed, and the design of an 8-bit memory chip to store the results, and the results are sent to the logic analyzer captures signals SignalTap.Due to the damping factor, the case of harmonic and noise and frequency of mutations in the signal contained in the power, the algorithm can quickly track changes in the power system,results show the effectiveness of the algorithm,damping factor played a very important role.Hardware implementation results further validate the robustness,speed and accuracy of this algorithm.