Nitrogen purging method, control module and device of water electrolysis hydrogen production system

The invention provides a nitrogen purging method, control module and device for a water electrolysis hydrogen production system, and the method comprises the steps: obtaining an oxygen concentration value of a hydrogen flow channel in the hydrogen production process of the system; if the oxygen concentration value is larger than a preset first oxygen concentration threshold value, the electrolytic cell is powered off; the first end and the second end of the first three-way valve are controlled to be communicated and isolated from the third end, so that nitrogen enters from the first hydrogen outlet and purges the cathode area of the electrolytic cell, and the hydrogen flow channel is communicated with the atmosphere so that mixed gas can be discharged to the atmosphere from the second hydrogen outlet; and after nitrogen purging for preset time, if the oxygen concentration value is smaller than or equal to the first oxygen concentration threshold value, the first end of the first three-way valve is controlled