Solutions to reduce harmonics from power converters and grid at equipment and distribution level

The increase of electrical applications inevitably brings more non-linear loads installed on the power system consequently responsible for drawing the non-sinusoidal currents from the power supply. A typical example of a non-linear load is an AC-DC converter, where the energy is usually converted by a standard diode rectifier due to the simplicity, reliability, lower cost and no need of bi-directional power flow; which make this topology commonly met in many of the actual Adjustable Speed Drives (ASDs).
The drawback of this topology is the generation of the harmonic currents in the power supply, which is of a major concern as the harmonic currents are responsible for the increase of the electrical losses, unpredicted electrical resonances, equipment failures and malfunctions of instrumentation.
Numerous solutions have been proposed in literature to reduce the harmonics currents, sustained by theoretical analysis, by simulation studies and, by physical implementations. As these studies showed, the harmonic mitigation is not possible without costs and engineering and it has not yet been found a complete solution, that may be inexpensive, reliable, very efficient and readily for any installation.