A high performance rectifier for electrical power generation from marine currents

A new circuit topology is introduced, to build up a power electronic rectifier for applications foreseeing electrical power generation from marine currents. The new power converter seems able to guarantee both DC-side voltages with very low ripple and sinusoidal generator currents. The proposed circuit topology is intended for applications in which, for each power generation unit, two turbines (and electrical generators) are contextually used. Firstly, six conventional single-phase rectifiers are connected in series at their DC-side terminals, so achieving a DC-voltage with high mean value and very low ripple. Then, the power factor of each single-phase rectifier is corrected by means of an effective passive technique, recently introduced and discussed. After correction, AC-side generator currents practically become sinusoidal, so avoiding troublesome oscillating torques on generator and turbine boards. In order to improve the efficiency of the proposed rectifier, an electronic resistance emulator circuit is also introduced to emulate the wasting behavior of resistors needed for correction of circuit power factor. The results of numerical simulations, referred to both conventional and the proposed rectifier and performed by using Pspice on a case-study of about 1.5 MW of active power, are reported and discussed.