Controlling a drive system having a planetary gear set

A method of controlling a drive system (14) includes receiving a machine travel speed request, and determining an output speed of a variator (28), associated with the drive system (14), required to satisfy the travel speed request at a current power source speed. The method also includes determining that a storage device (68) operably connected to the variator (28) has an amount of stored energy sufficient to operate the variator (28) at the variator output speed, and providing torque to a machine transmission (16) with a machine power source (12) and the variator (28). The variator (28) is operated at the variator output speed using stored energy from the storage device (68) to provide torque to the transmission (16). The torque provided to the transmission (16) with the power source (12) and the variator (28) is sufficient to satisfy the travel speed request at the current power source speed.