POWER SYSTEM AND POWER SUPPLY DEVICE

A power supply device (10) includes a storage battery (12), a capacitor unit (16) connected to the storage battery (12), a power converter (18) including three phases connected to the storage battery (12) in parallel, a control device (60) configured to control a switching on and off of switching elements (SW1 to SW4, SU1 to SU4, SV1 to SV4) included in the three phases respectively, a first connection terminal (PW1; PU1; PV1) connected to a P terminal (32P) of a DC charger (30) and located between first and second switching elements (SW1; SU1; SV1 and SW2; SU2; SV2) in any one of the three phases, and a second connection terminal (PW2; PU2; PV2) connected to an N terminal (32N) of the DC charger (30) and located between third and fourth switching elements (SW3; SU3; SV3 and SW4; SU4; SV4) in another one of the three phases.