[IEEE 2019 IEEE International Electric Machines & Drives Conference (IEMDC) - San Diego, CA, USA (2019.5.12-2019.5.15)] 2019 IEEE International Electric Machines & Drives Conference (IEMDC) - Active Vibration Control of a Flexible Rotor in Magnetically Suspended High-Speed Motor to Pass the First Bending Critical Speed with Optimal Phase Compensation Control