Patent attributes
In response to a decrease in observed battery voltage Vb to or below a preset threshold value Vs1, the control procedure of the invention closes the gates of an inverter for an air conditioner to stop a supply of electric power to the air conditioner (at a time point t1). In response to a further decrease in observed battery voltage Vb to or below a preset threshold value Vm1, the control procedure closes the gates of inverters for motors MG1 and MG2 to stop supplies of electric power to the motors MG1 and MG2 (at a time point t2). The threshold values Vs1 and Vm1 are set to keep the battery voltage Vb at or above a minimum required voltage for proper operations of an electric power steering (EPS). This arrangement guarantees the minimum required voltage for proper operations of the EPS and accordingly ensures the stable steering performance even in the event of a voltage decrease of the battery.