Systems and methods for generating a high voltage direct current using electric-field generators are disclosed. The electric field generator can comprise a rotor member, rotor poles coupled to the rotor member, stator poles corresponding to the rotor poles, and a dielectric medium positioned between the corresponding stator and rotor poles. The method can comprise applying an electric field between corresponding stator and rotor poles, receiving a mechanical energy input causing the rotor member to rotate, changing an alignment of the corresponding stator and rotor poles as a result of the rotation of the rotor member, increasing the voltage of the electric field between the corresponding stator and rotor poles as a result of the alignment change of the corresponding stator and rotor poles, and discharging the electric field to place a charge on a DC bus when the voltage of the electric field reaches a predetermined level.