A control method for a power converter capable of reducing overall volume of a system and energy loss by using a plurality of power sources and distributing loads to them without a DCDC converter. The power converter has DC power sources and poles formed by connecting various poles of the DC sources. Voltage is applied to a load by switching between poles. The method includes operating a switch between poles of the first DC power source when a voltage command is lower than the electric potential of the second DC power source; and operating a switch between the poles of the second DC source when the voltage command is higher than the electric potential of the second DC source.