Abstract: Leakage current detection has always been one of the key issues of electric water heater controller and electric water heater manufacturer. Aiming at the problem of high false alarm rate and false alarm rate in the current built-in leakage current detection of electric water heater, based on the original built-in leakage current detection circuit, the DC bias circuit is added to improve the anti-interference ability of the circuit, and the leakage current alarm value adjustment circuit is added to calibrate the deviation of the alarm value of leakage current and improve the detection accuracy. Based on the above scheme, a new built-in leakage current detection circuit is built, and experimental research and demonstration are carried out on the controller of electric water heater. The experimental results show that the application of this circuit can improve the anti-interference ability and detection accuracy of built-in leakage current detection, so as to greatly reduce the missed alarm rate and false alarm rate of built-in leakage current detection of electric water heater.

Key words: Leakage current, DC bias, Test, Adjust