POWER CONVERSION DEVICE, AND ELECTRICITY STORAGE SYSTEM AND METHOD FOR CONTROLLING SAME

摘要

An electricity storage system comprises: a DC bus (1) disposed between a system power (40) and a DC load (5); an electricity storage device (3) for outputting a power supply voltage to the DC bus (1); a bidirectional DC/AC converter (42) for performing power conversion between the DC bus (1) and the system power (40); and a switch (7) for connecting and disconnecting between the DC bus (1) and the electricity storage device (3). A power supply disconnecting means for disconnecting the electricity storage device (3) from the DC bus (1) controls the power conversion operation of the bidirectional DC/AC converter (42) so that the charging and discharging currents of the electricity storage device (3) become zero and, when the charging and discharging currents of the electricity storage device (3) become zero by controlling of the power conversion operation, disconnects the electricity storage device (3) from the DC bus (1) by using the switch (7).