Control device for a vehicle power transmission system

There is provided a control apparatus for a vehicular power drive system that is configured to implement a torque reduction control during a shift operation of an automatic transmission and which permits a reduction in size of cost of an electric circuit including a smoothing capacitor. A torque reduction limitation control means 94 implements a torque reduction limit control for limiting a reduction of a second electric motor torque Tmg2 to within a range in which a smoothing capacitor voltage Vcon, the Tmg2 temporarily increases in relation to a reduction of the second electric motor torque in the above-described torque reduction control, a predetermined Umrichterdurchschlagsspannung Vmax not will exceed. Accordingly, the smoothing capacitor capacitance CCON need not be designed such that it overcomes an unlimited abrupt reduction of the second electric motor torque Tmg2 in the torque reduction control, so that the smoothing capacitor capacitance CCON can be designed relatively small. In this way it is possible to reduce the size and cost of a power source control circuit 60 including the inverter smoothing 60th