CIRCUIT AND SYSTEM FOR DETECTING DC COMPONENT IN INVERTER DEVICE FOR GRID-CONNECTION

摘要

A DC component detecting circuit (18) detects a small DC component contained in the AC output power of a grid-connection inverter device (12), accurately within a short period of time, and has a simple, small-size, and lightweight configuration. The DC component detecting circuit (18) comprises separators (21, 22) for separating a voltage which is proportional to the output current of the inverter device into voltages in positive and negative half periods, integrators (23, 24) for integrating the separated voltages in the positive and negative half periods, and an adder (25) for adding integral signals in the positive and negative half periods from the integrators (23, 24).