Power transmission system of hybrid electric vehicle

A power transmission system of a hybrid electric vehicle, comprising:

• an input shaft receiving engine torque;
• a first planetary gear set being a single pinion planetary gear set, and including:
• a first sun gear selectively connected to a transmission housing;
• a first ring gear;
• and
• a first planet carrier directly connected to the input shaft;
• a second planetary gear set being a double pinion planetary gear set, and including:
• a second sun gear;
• a second ring gear directly connected to the first ring gear and directly connected to an output gear;
• and
• a second planet carrier selectively connected to the first planet carrier and selectively connected to the transmission housing;
• a first motor/generator directly connected to the first sun gear;
• a second motor/generator directly connected to the second sun gear;
• a first clutch connected between the first planet carrier and the second planet carrier;
• a first brake connected between the second planet carrier and the transmission housing;
• and
• a second brake connected between the first sun gear and the transmission housing.