Abstract: A hybrid alternator includes a stator and a rotor, with the rotor having longitudinally separate wound field and permanent magnet rotor portions. A rotor excitation circuit applies a forward polarity to the wound field rotor portion to increase output in a boosting mode at low RPMs and a reverse polarity to decrease output at high RPMs in a bucking mode to maintain a constant voltage output. Alternative embodiments combine a magnetic flux concentrating design for efficient low speed operation with integral strength for high speed capability. Dual voltage output is provided either through dual stator windings or through a voltage converter circuit. Single voltage output is provided using only one stator winding. A three state voltage regulator allows voltage regulation without inducing reverse currents onto the power bus in the lightly loaded or no battery conditions.