Anode gas purification control method for proton exchange membrane fuel cell

The invention discloses an anode gas purification control method for a proton exchange membrane fuel cell. The method comprises the steps of constructing an anode water management structure, and controlling the anode water management structure to work by utilizing an anode nitrogen concentration observer; controlling the hydrogen flow through a hydrogen circulating pump to take away liquid water contained in gas in a fuel cell stack and remove the liquid water through a second water-vapor separator, and removing the liquid water condensed and separated from gas through a first water-vapor separator; adopting an anode nitrogen concentration observer to process to obtain a nitrogen concentration observation value, using a purification duration process model to obtain purification duration time, when the nitrogen concentration observation value reaches a nitrogen concentration threshold value, opening a purification valve, and discharging nitrogen; and closing the purification valve afterthe purification duratio