Study on the control strategy of VSG-based hydrogen production unit grid-connected for weak grid

The “3060” plan fully demonstrates the determination of China’s economic and social green and clean development. As an important secondary energy source, hydrogen has the advantages of high energy density, green and pollution-free, etc. As an ideal energy source in the future, green hydrogen is the final state of hydrogen energy prepared by electrical energy through electrolysis of water. The development of renewable energy hydrogen production will certainly help to achieve the goal of carbon peaking and carbon neutral. Therefore, the grid-connected control strategy of hydrogen production unit for weak grid is worthy of in-depth study. The research work in this paper is as follows: firstly, based on the analysis of the converter, a grid-connected control method of electric hydrogen production unit using virtual synchronization generator(VSG) control strategy is proposed. Secondly, a control method without phase-locked loop is adopted for the grid-connected phase synchronization part. Then, the stability of the proposed control strategy is demonstrated by using root locus plot. Finally, experimental verification is carried out. The experimental results show that the proposed control strategy makes the hydrogen production unit friendly to the weak grid with good adaptability, and at the same time, as a load, it can perform adaptive power regulation very well.