Summary: In this paper, the mathematical models of each part of the direct‐drive variable speed pumped storage unit are established, including the model of the pump turbine and its regulating system, the model of direct‐drive motor, and its excitation control system. Then we introduce two control methods of variable speed pumped storage unit, namely power priority control method, and speed priority control method. And then, the influence of the value of the internal parameters of the unit on the control characteristics of the unit is analyzed, and the control system of the unit is designed according to the value of the internal parameters of the unit, and the control parameters with the optimal control effect are obtained. Finally, the obtained optimal control parameters are verified using simulation software. [ABSTRACT FROM AUTHOR]