POWER SUPPLY DEVICE, POWER SUPPLY SYSTEM AND CONTROL METHOD FOR POWER SUPPLY DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a power supply device, a power supply system or a control method of the power supply device for securing power supply in emergency without performing any special wiring work.SOLUTION: A power supply device 4 for supplying power to a power system 3 which receives the supply of power from a system power source 1 includes: a first power source; conversion means for converting power to be output from the first power source into an AC power; an outlet plug 46 connected to an outlet 34 of the power system 3 for outputting an AC power to the power system 3; and control means for controlling the conversion means. The control means includes: a connection detection part for detecting the connection of the outlet plug 46 to the outlet 34; a state detection part for detecting the state of the power system 3; and a determination part 405 for determining whether to output the AC power to the power system 3 on the basis of the detection result of the state detection part.