Research On Harmonic Detection And Control Strategy Of Active Power Filter

With the continuous development of industrial technology,a large number of power electronic devices are used in power equipment,which brings convenience to system control and user experience.At the same time,there are a large number of harmonics injected in the power system,causing serious distortion of grid current and voltage,which affects electrical equipment works normally.Active Power Filter(APF)is currently the most effective equipment for solving harmonic pollution,and it has been widely used in engineering applications.The traditional ip-iq harmonic current detection method based on instantaneous reactive power theory increases the system delay due to the existence of the low-pass filter,and the low-pass filter can’t have both response speed and filtering accuracy,and the harmonic detection accuracy is low.This article proposes an improved ip-iq harmonic current detection method that uses an integral average filter to replace the traditional low-pass filter to detect harmonic currents,effectively reduce the delay of harmonic current detection,and improve detection accuracy.The hysteresis comparison control method based on space voltage vector is adopted to realize current tracking control,so that the APF system can accurately track the harmonic current and generate compensation current.In MATLAB environment,an active power filter simulation model is built to carry out the compensation effect of APF system.The simulation results show that the grid-side current distortion rate after compensation is only 3.12%,and the power factor is approximately equal to 1.These data proves that the APF has suppressed harmonic currents and compensated reactive power better effect,using the hysteresis comparison control method based on the space voltage vector.Finally,APF was applied to a 110 k V substation in Shijiazhuang.The actual application data showed that the harmonic current distortion rate was reduced from 23.2% to 4.2%,and the power factor was increased from0.78 to 0.95,indicating that the application of APF can effectively suppress harmonics,compensate reactive power,and improve the power factor.