Research And Implementation On Electric Energy Measurement Algorithm Under Wide-range Frequency Deviations

With wide application of abundant non-linear loads, a large number of harmonics are generated and inject into the power grid. Frequency deviation and severe aberrance of current and voltage wave caused by non-linear loads lead to the increase of electric energy measurement error.Aiming at the electric energy measurement problem under wide-range frequency deviations, this dissertation detailedly analyzes a new electric energy measurement algorithm. The algorithm integrates CIC filter, Prony algorithm and MLM algorithm, and consists two parts:signal filtering and power and frequency measurement. The CIC filters are constructed to filter the DC、 fundamental and higher harmonics components in the voltage and current. And then, the DC、 fundamental and higher harmonics active power are calculated, their apparent power are calculated and fundamental frequency is measured with Prony-based algorithm, and the precision of both the active and apparent power are improved with MLM algorithm. To verificate this algorithm, this dissertation do a lot of simulation with Matlab. The simulation results indicate that, compared with existent algorithm, the measurement with this algorithm has a higher precision over a wide range of frequency deviations.After algorithm simulation, this dissertation implements the electric energy measurement algorithm on DSP. First, the hardware platform for the algorithm implementation is designed, which mainly includes voltage/current sampling circuit, signal regulation circuit and DSP-based data processing circuit. And then the algorithm is implemented on the DSP-based hardware platform. The software implementation of algorithm is divided into three parts:filter design, power calculation, and frequency measurement. The current DC、fundamental and higher harmonics CIC filters are designed with the fundamental frequency measured at the last moment. In power calculation part, DC、fundamental and higher harmonics active power are firstly calculated, then the precision of power measurement are improved with MLM algorithm. In frequency measurement part, the fundamental frequency is measured with Prony algorithm.Finally, this dissertation tests and analyzes the electric energy measurement algorithm implemented on the DSP-based hardware platform. By comparing the national standard of electric energy parameters, the experimental results validate the algorithm’s efficiency on electric energy measurement under wide-range frequency deviations.