Patent ID: 7522435

Claim:
A power supply unit connected to a structure composed of at least one other power supply unit and forming a power supply system together with the structure, the power supply unit comprising: a pair of unit terminals connected in parallel with the other power supply unit; a power supply module to/from which power can be input/output; a voltage detection circuit for detecting a voltage across the power supply module; a current detection circuit for detecting current flowing in the power supply module; a voltage adjustment circuit that, when power is output from the power supply module, receives the voltage across the power supply module and increases the received voltage to thereby generate a first voltage larger than the voltage across the power supply module and then outputs the first voltage to the pair of unit terminals, and that, when power is input to the power supply module, receives a voltage between the pair of unit terminals and decreases the received voltage to thereby generate a second voltage smaller than the voltage between the pair of unit terminals and then outputs the second voltage across the power supply module; and a control circuit for controlling operation of the voltage adjustment circuit, wherein the voltage adjustment circuit is provided for two serial lines extending from both ends of the power supply module to the pair of unit terminals, the control circuit includes: a power calculation portion for calculating the magnitude of a power generated across the power supply module on the basis of a result of detection of the voltage detection circuit and a result of detection of the current detection circuit; an output portion for outputting a power calculation result of the power calculation portion to the structure; and a control portion for generating a control signal on the basis of a target output voltage of the voltage adjustment circuit, the power calculation result of the power calculation portion, and a power calculation result obtained from outside, and for outputting the control signal to the voltage adjustment circuit, and the power calculation result obtained from outside is received from the structure.