This paper deals with the control of a H2 production system supplied by wind power and assisted by the grid. The system architecture consists of a pitch-controlled wind turbine coupled through a diode rectifier to an alkaline electrolyzer, which in turn is connected to the electric grid through a fully-controlled bidirectional electronic converter. A control strategy for the electronic converter is proposed to regulate the electrolyzer current at its rated value. Thus, H2 production efficiency is optimized despite wind power and temperature variability. Control design is based on sliding mode techniques, which are particularly appropriate to control fast switching devices and exhibit strong robustness properties. Additionally, in high wind speeds, a pitch control loop is activated to limit the wind power capture below admissible values.