Asynchronous machine DC injection DFAM Doubly feed asynchronoi machine Doubly-fed Doubly-feed asynchronoi machine Energy efficiency Energy efficient Energy efficient start-up Hydraulic turbines Hydroelectric pumped storage plant Pumped storage plants Pumped storage power plants Pumps Smooth starting Speed Start-up strategy Stators V/f start-up strategy Winding doubly-fed asynchronous machine energy efficient start-up hydroelectric pumped storage plant smooth starting