The Research Of Parallel Active Power Filter

With the rapid development of modern power electronic technology,a largenumber of electronic devices are widely used in All walks of life. But they bring largeharmonics and reactive power for utility grid because of the impact and nonlinear ofdevice itself. So how to effectively suppress harmonics that is generated by thenonlinear load device is a hot problem faced by electric power industry.Active power filter is a new type of harmonic suppress device,it can realizereal-time detection, real-time compensation comparing with the traditional filteringdevice,so it is a very promising harmonic elimination device. At present the activepower filters have been walking in the forefront of suppress harmonic field. The mostimportant and core part is how to detect harmonic real-time accurately.This paper studied several detection methods of harmonic in electric powersystem,such as analog filter harmonic detection method，based on the three-phaseinstantaneous reactive power detection method，based on wavelet transform detectionmethod,based on neural network detection method,and based on simultaneousmethods.Through analyzing and contrasting the advantages and disadvantages ofseveral methods for detection harmonics, we determine a kind of method on harmonicthat harmonics can be detected for three-phase symmetry current and distortioncurrent.That is the instantaneous reactive power theory (i p iq), we can use this theoryto measure harmonic. We built active power filter modules based on this detectiontheory and active power filter structure in MATLAB,then we simulate active powerfilter system by chosing reasonable simulation parameters. And show the simulationresults, the simulation results show that the system can effectively suppress theharmonics and improve current waveform.On the base of simulation experiment,we designed each hardware circuit moduleof active power filter control system based on the digital processor chipTMS320F2812；we designed C language program preliminary,these program includesthe entire system initialization procedure, the AD sampling procedures, harmonicdetection procedures, PWM control procedures and related fault handler.We debugprogram preliminary in CCS. They laid the foundation for realize precise detectionabout harmonic current and further study on Active power filter.