Modern Methods for Analysis and Reduction of Current and Voltage Harmonics

More than 60% from the electricity in the developed countries is driven through the static power converters. Among the known advantages, these introduce a series of disadvantages concerning the waveform of the current and of the alternative voltage of the power distribution network, which is equivalent to the presence, besides the fundamental harmonic, of the higher harmonics in the electric networks.Non-linear loads deform the current from the network, even if the supply voltage is sinusoidal. The electric scheme of such a load can be presented as a linear load corresponding to the fundamental harmonic of the current and a multitude of current sources corresponding to each high rank harmonics. The latter produces supplementary loss through Joule effect and also lead to an incorrect functioning of the protections and, due to the power failures on the short-circuit impedances, distorts the voltage on the terminals of the capacitor and pollute the environment with electromagnetic emissions of high frequency.Therefore it is necessary to develop solutions in order to compensate the current and voltage harmonics.