A switched mode rectifier for improved interface with alternators

Summary form only given, as follows. Electromechanical generators that feed a DC bus through a diode bridge rectifier are commonly applied. Among other examples, synchronous generators (alternators) are used in vehicles to generate the electrical power. The resulting phase currents are nonsinusoidal, which together with the relatively high output impedance of these machines cause significant phase voltage distortions. In addition, the current harmonics induced in the machine windings detrimentally affect the generator in terms of excessive heating (due to both: conduction losses and core losses mechanisms), pulsating electromechanical torques and more. In this work a novel approach is presented for rectification of alternators output; a switched mode topology is continuously controlled so as to draw nearly sinusoidal current at it´s input and yet supply a DC output. This way, current harmonics in the alternator´s winding are practically eliminated. Calculations indicate that the power throughput of some alternators can be increased by 40% due to this newly proposed rectification method, i.e. increase power packaging by 40%! The conceptual approach was validated by experimental results, which showed an increase of 34% of a particular alternator´s power throughput.