A power plant for an aircraft such as an unmanned aero vehicle in which a gas turbine engine drives an electric generator to produce electrical power for a system load of the aircraft. An engine control unit monitors engine performance and regulates engine power output through fuel flow control to a combustor. A power control module regulates power output of the generator to the system load and to a battery through a bus. A pulse width modulation is used between the power control module and the bus to optimize performance of the gas turbine engine instead of adjusting fuel flow to the combustor.