Patent ID: 8766661

Claim:
A malfunction detecting device for a solar cell panel for detecting a malfunction in the solar cell panel, the solar cell panel comprising a solar cell panel body and a bypass diode having a cathode electrically connected to a positive terminal of the solar cell panel body and an anode electrically connected to a negative terminal of the solar cell panel body, the device comprising: an AC source that is provided on one of positive and negative sides of the solar cell panel body and can apply AC voltage superimposed on DC voltage to the solar cell panel; a measuring means provided on another of the positive and negative sides of the solar cell panel body to measure voltage or current output from the solar cell panel; and a control unit comprising a malfunction determination portion that controls the AC source to control input voltage or input current to be input to the solar cell panel and determines malfunction in the solar cell panel by comparing the input voltage or the input current to output voltage or output current measured by the measuring means, wherein the malfunction determination portion comprises: a panel body malfunction determination portion controlling the AC source to reverse-bias the bypass diode and determining malfunction in the solar cell panel body on the basis of input voltage or input current at that time and output voltage or output current measured by the measuring means; and a bypass diode malfunction determination portion controlling the AC source to forward-bias the bypass diode and determining malfunction in the bypass diode on the basis of input voltage or input current at that time and output voltage or output current measured by the measuring means.