A method is provided to control a hybrid powertrain comprising engaging gears corresponding to a first gear pair connected with a first planetary gear in a gearbox with a first coupling device connecting two rotatable components in the first planetary gear; activating a second electrical machine to generate a propulsion torque on the output shaft via a second gear pair connected with a second planetary gear and the output shaft; disconnecting the first gear pair from the countershaft, by controlling the first electrical machine and a combustion engine connected with the first planetary gear to achieve a substantially zero torque state between the first gear pair; connecting the first gear pair to the countershaft, by controlling the combustion engine to achieve a synchronous rotational speed between the first gear pair; and activating the combustion engine and/or the first electrical machine to generate a propulsion torque on the output shaft.

Provided are gearboxes including compound planet gear assemblies as well as methods of using such gearboxes. A gearbox includes at least a first ring gear and a second ring gear. Depending on the current gear selection, one of these ring gears may be engaged with a shifting mechanism or not engaged with any ring gears when in a neutral gear. The first ring gear may be constantly engaged with a first planet gear of a compound planet gear assembly, while the second ring gear may be constantly engaged with a second planet gear of the same compound planet gear assembly. The first planet gear may be also engaged with a sun gear coupled to a shaft. Another shaft is coupled to the shifting mechanism. Different gear selections of the gearbox engage different ring gears to the shifting mechanism thereby changing the rotational speed ratio of the two shafts.