Drive system including a transmission having a plurality of different operating modes

A drive system including a transmission having a plurality of different operating modes, the system comprising:

• a transmission output shaft;
• a stationary member;
• a gear set including first, second, and third elements, the first element connecting with the transmission output shaft, an output shaft of a non-electric power plant connecting with the first element through the second element for driving the first element and a drive shaft of an electric power plant connecting with the first element through the third element for driving the first element;
• a non-friction, controllable, first coupling assembly having a first coupling state for grounding the second element to the stationary member, a second coupling state for grounding the third element to the stationary member and an uncoupling state to allow the second and third elements to drive the first element, the first coupling assembly being non-hydraulically controlled to change state;
• a group of gears including fourth, fifth, six and seventh elements connecting with the transmission output shaft;
• a non-friction, controllable, second coupling assembly having a first coupling state for coupling the fourth element to the transmission output shaft, a second coupling state for coupling the fifth element to the transmission output shaft, and an uncoupling state for uncoupling the transmission output shaft from the fourth and fifth elements, the second coupling assembly being non-hydraulically controlled to change state;
• and
• a non-friction, controllable, third coupling assembly having a first coupling state for coupling the sixth element to the transmission output shaft, a second coupling state for coupling the seventh element to the transmission output shaft, and an uncoupling state for uncoupling the transmission output shaft from the sixth and seventh elements, the third coupling assembly being non-hydraulically controlled to change state.