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 and a combination of a fuel cell and a battery. 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 determining conductivity for a switch between poles of said first DC power source when a voltage command is lower than the electric potential output by said second DC power source; determining conductivity for a switch between the poles of said second DC source when the voltage command is higher than the electric potential output by said second DC source; and switching the pole to be connected to said load in accordance with the determinations.