1 Subjects: “...doubly-fed variable speed pumped storage power station...”

2 Subjects: “...variable speed machines...”

3 Subjects: “...variable speed condition...”

4 Subjects: “...variable speed operation...”

5 Subjects: “...variable speed WECS...”

6 Subjects: “...variable speed dual-rotor wind turbine...”

7 Subjects: “...variable speed limits...”

8 Subjects: “...variable speed pumped storage system...”

9 Subjects: “...variable speed...”

10 Subjects: “...variable speed...”

11 Subjects: “...variable speed...”

12 Subjects: “...variable speed pumped storage system...”

13 “...; increasing performance in variable speed electrical drives and direct online induction motors; applying...”