Grid-connected inverter system with seamless transfer function

摘要

Various embodiments of the present invention relate to a grid-connected inverter system. A technical problem to be solved by the present invention is to provide the grid-connected inverter system having a seamless switchover function, which comprises: an inverter unit which converts output of DC power into AC power; a disconnection unit which is connected among the inverter unit, a system, and a load to perform switchover between system connection operation and independent operation; a filter unit which is to perform sinusoidal output of the inverter unit; and a control unit which operates the inverter unit in current control mode or in voltage control mode. In addition, the control unit operates the inverter unit in the current control mode for a period of time longer than extinction time of the disconnection unit when detecting an abnormal condition in the system. On the other hand, the control unit operates the inverter unit in the voltage control mode when the disconnection unit is turned off to disconnect the system and the load.