Investigating the Effects of Non-Linear Loads on Generator Sets

Non-linear loads have become more prevalent due to the increasing use of power electronics for power conditioning and regulation. The current harmonics generated from non-linear loads can cause long-term effects on generator sets, such as the degradation of their lifetime due to higher operating temperatures and component failures due to high current transients. A testbed was developed to run a 3-kW military tactical generator set under non-linear loads. The 3-kW generator set includes a permanent magnet alternator (PMA) and a power electronic converter to deliver a 120VAC/240VAC output at 60 Hz. A range of non-linear loads was developed to create several load profiles for the generator set. The generator set was tested in four-hour and two-hour intervals for several weeks under different load profiles to stress its alternator and internal power electronics. In addition, several measurements were taken during testing, such as the output power, output voltage and current, and stator winding temperature. The collected data and testing suggest that the power electronics converter is more susceptible to the current harmonics than the PMA. These issues can result in premature failures and overall degradation of the lifetime of the generator set.