<p>In the majority of the isolated areas, the diesel generator is the principal source of electric power. For these areas, the price of extension of the electrical supply network is prohibitory and the price of fuel increases radically with insulation. The continuous fall in the prices of the generators based on renewable energy and the increasing reliability of these systems led to a greater use of the sources of renewable energy for the generation of electric power in the isolated areas. The diesel generators can incorporate in a network with other sources in base of renewable energies in order to create a new network known as distributed network. More recently intermittent renewable resources such as the wind power were considered as a distributed generation which is seen as being deployed to reduce the total emissions. The distributed generation equipment sets causing electric disturbances result in destabilizing the global network as well as pollutant, for these reason, system D-FACTS comes to answer all the concern of the customers, manufacturers, suppliers and the managers of the distributed network<em>.</em></p>

This paper proposes a strategy de controlling a static AC/DC converter based on direct power control (DPC). The instantaneous active and reactive power   is controlled in such a way to ensure the PWM rectifier with a sinusoidal current absorption. This control has proven effective in terms of reduction of total harmonic distortion (THD) of current absorbed. Offers a good control of active and reactive power with an operation   at unitary power factor. The test of robustness carried out and the results have proven DPC good performance with strong possibility of  de integrate it into the field of high voltage and high power as electric traction.

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In this paper, an analysis of the potentialities of the 6, 12 and 24 pulse cascade rectifiers in eliminating harmonics injected in the electric network is treated. Given the dimension, the number of the required transformers and the high cost of the cascade rectifiers, an alternative consisting in multilevel rectifiers with PWM control are proposed as an alternative. These can generate quasi-sinusoidal currents leading to a reduction of the harmonic distortion thanks to the high number of voltage levels. The obtained results are very promising.

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