A bidirectional buck-boost power converter 13 including a pair of inverter modules 14, 15 disposed at an output of a machine, and an inductor L.sub.o connected between the pair of inverter modules 14, 15. A method for controlling a voltage output of a machine starter generator having an inverter rectifier and bidirectional buck-boost converter, includes outputting a dc voltage controlled by bidirectional buck-boost pulse width modulation (PWM) switching control, when the starter generator is in a generator mode.