One or more powertrains can include a motor-generator disposed therein that is electrically coupled to an energy storage device through an inverter gate. A regulation strategy can monitor operation of the powertrain to regulate the inverter gate to selectively discharge energy from the energy storage device to the motor-generator to assist the powertrain or to charge energy from the motor-generator to the energy storage device for future use. In an aspect, the regulation strategy may maintain a consistent speed of an internal combustion engine associated with the powertrain. In another aspect, the regulation strategy may regulate simultaneous operation of first and second powertrains disposed a parallel relation.