Semi-powershift dog clutch transmission

A power train system, comprising:

• a first electric machine;
• a second electric machine;
• a third electric machine;
• and
• a transmission system having:
• a first section, comprising a plurality of first section gearsets and at least a first non-friction clutch, where the first electric machine, the second electric machine, and the third electric machine are drivingly coupled to a first section gearsets;
• a second section, comprising a plurality of second section gearsets and a plurality of second non-friction clutches, and selectively coupleable to the first section gearsets via the second non-friction clutches;
• a third section, comprising a plurality of third section gearsets and a third clutch, and selectively couplable to the second section via the third clutch;
• and
• an output, where the output is selectively couplable to the third section gearsets via the third clutch.

A method of operating a transmission system, comprising:

• providing rotational energy to a transmission via a first electric machine through a first input during a first gear state;
• providing rotational energy to the transmission via a second electric machine through a second input;
• providing rotational energy to the transmission via a third electric machine through a third input;
• providing rotational energy from the first electric machine, the second electric machine, and third electric machine to an output of the transmission;
• during a gear shift to a second gear state:
• disconnecting a first powershifting clutch;
• providing rotational energy to the output from the first electric machine and the third electric machine while synchronizing the second electric machine and transitioning to a first intermediate gear state;
• providing rotational energy to the output from the first electric machine and the second electric machine and decoupling the third electric machine while transitioning to a second intermediate gear state;
• disconnecting a second powershifting clutch;
• and
• providing rotational energy from the second electric machine and the third electric machine to the output while synchronizing the first electric machine and transitioning to the second gear state.