| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a DC current component detecting device for fully attenuating an AC component included in an AC output current of a system interconnecting inverter device as compared with a DC component, and accurately detecting a minute DC current component in a short time. <P>SOLUTION: The device includes a current detector, which outputs a current signal or a voltage signal proportional to the output current of the system interconnecting inverter device 12 as a detected signal. The detected signal of the current detector is input to an operational amplifier circuit 21 of a first stage. The DC component and the AC component are amplified by a predetermined amplification rate, respectively. The output signal of the operational amplifier circuit 21 of the first stage is input to an operational amplifier circuit 22 of a second stage. An AC component having an inverted phase and an equal amplitude is generated. The AC component is superimposed with the output signal of the operational amplifier circuit 21 of the first stage, to extract the DC component by canceling the AC component. The DC current component included in the output current of the system interconnecting inverter device 12 is detected from the extracted DC component. <P>COPYRIGHT: (C)2009,JPO&INPIT |
