A vehicle includes a traction motor coupled to a driveline. An engine and a generator are coupled to the driveline through a planetary gearset. A controller commands the traction motor torque based on a difference between a driver torque demand and an estimated powertrain torque. The estimated powertrain torque is based on an error between actual and estimated engine speed and an error between actual and estimated generator speed. The estimated powertrain torque may be further based on commanded or estimated engine torque and generator torque. The estimated powertrain torque may utilize a state estimator to calculate internal states based on the errors.