Research On Frequency Adaptive Algorithm For Harmonic Power Measurement

The widespread use of non-linear electrical equipment and distributed renewable energy has resulted in a large number of harmonics in the grid system.Power harmonics will not only pollute the power environment,damage to electrical equipment,but also seriously affect the accuracy of the fundamental energy measurement,and have effect on the benefits of the power plants,the power supply companies and the users.For this,the relevant research is carried out in this article.Firstly,the research background and significance of electric energy measurement are illustrated,and several main harmonic energy measurement methods are introduced with their advantages and disadvantages be analyzed.In the article,S Transform and Hilbert-Huang Transform are used to depict the characteristic of the measured electric spark signal.It showing that the change of amplitude and frequency of harmonic signals over time and the deficiency of the existing power metering algorithms for time-varying harmonic signals,it is necessary to propose new solutionsThen,the disadvantages of power measurement algorithm based on Discrete Fourier Transform are analyzed on dealing with distorted signals,and a power measurement algorithm based on frequency adaptive comb filter is presented.For the multi harmonic signals whose amplitude,frequency and phase are time-varing,the new algorithm and traditional Fourier Transform are compared in MATLAB.The amplitude,frequency of harmonics can be extract accurately by the new method,and then the harmonic powers are calculated.After that,the fundamental powers of electric signal and independent photovoltaic signal are computed though the new algorithm.It shows that the measurement results of the new algorithm can be more accurate.Based on TI's TMS320C6747 processor,the system power supply,clock and reset circuit,analog-to-digital and digital-to-analog conversion circuit,JTAG interface circuit and 485 communication interface circuit are designed,the harmonic generator program,signal acquisition and processing program and communication processing program are given,then the experimental platform is set up.The tracking curves of harmonic amplitude,harmonic frequency and harmonic active power are obtained in cooperation with the CCS Integrated Development Environment.According to the results of experiment,the estimation error is calculated,and by comparing with the simulation results,the validity of the algorithm is verified.At the end of the article,on the basis of summarizing the research done in this paper,the diretions of further research and improvement are put forward.