Power factor correction techniques for Non linear loads - Forum

Power factor correction techniques for Non linear loads

Modern electronic equipment does not represent a completely passive load to the AC mains or power line. Historically, loads have been fairly benign, having either resistive characteristics (light bulbs) or input currents that are sinusoidal but phase-shifted (AC motors). Most electronic systems now use one or more switch mode power converters that will tend to draw current from the power line in a non-sinusoidal fashion. This input current characteristic results in current and possibly voltage distortions that can create problems with other equipment connected to the power line and degrade the capability of the mains. These problems have led to the creation of design standards for the purpose of limiting the allowable harmonic distortion on the power line. Fortunately, solutions are available for meeting these standards. These solutions are referred to as Power Factor Correction (PFC) techniques.


bharath on 26th Sep 2015, 10:47 AM

Harmonics generated by nonlinear loads are one of the major causes of a poor power quality. So, harmonic elimination, in the source or with active filtering, is needed to achieve a better power quality. In modern single phase low power equipment's they should have a pre-regulator stage, achieving an almost sinusoidal input current. In medium/high power single or three phase networks when it is not possible to eliminate the harmonic currents in the input stage in some connection point, the active power filter is the solution to be implemented. The active filter operation in the harmonic elimination mode allows an increasing in the power quality due to the achieved sinusoidal current flowing in the network.

satish on 26th Sep 2015, 11:00 AM

By installing suitable sized switched capacitors into the power distribution circuit, the power factor is improved and the value becomes nearer to 1 thus minimizing wasted energy.

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