To enhance the voltage stabilization effect of the power line of a system which is equipped with a plurality of MG units that generate system voltage in the power line by boosting the voltage of a DC power source with a step-up converter and drive AC motors via inverters by this system voltage.

This controller executes the system voltage stabilization control to suppress the ripple of system voltage by operating the input voltage of a first MG unit 29 and a second MG unit 30, so that the deviation ΔVs between the target value Vs*and the detected value Vsf of system voltage may be smaller. At that time, it selects a MG unit which can materialize the target input power manipulated variable Pm*required for stabilization of system voltage by selecting one or both of the first and second MG units 29 and 30, using the information (the torque command or the rotational speed of each AC motor 13 and 14) of each MG unit 29 and 30, and executes the system voltage stabilization control with the selected MG unit.

COPYRIGHT: (C)2007,JPO&INPIT