A hybrid electric powertrain system includes a transmission, engine, e-accessory, primary and secondary electric machines, and controller. The e-accessory is powered by the secondary electric machine in response to an accessory torque demand. The engine and primary electric machine are connected to the transmission and configured, alone or in combination, to provide input drive torque to the transmission. The secondary electric machine is connected to the e-accessory and satisfies the accessory torque demand. A first clutch between the secondary electric machine and a transmission input member connects the secondary electric machine to the input member. The controller, in response to an output torque request, executes a power-sharing strategy using an objective cost function that allocates engine torque, primary motor torque, and secondary motor torque to the input member to satisfy the output torque request, while satisfying the accessory torque demand via the secondary electric machine.