PLL制御を利用した磁気浮上 [in Japanese] Application of Phase-Locked Loops to Magnetic Suspension Systems [in Japanese]
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This paper demonstrates that phase-locked loop techniques can be applied to stabilize an active magnetic suspension system with displacement sensors of frequency type. Feeding back the difference of frequency in addition to PLL control is proposed to speed up the process of phase-locking. It is also pointed out that the self-sensing magnetic suspension is realized with a hysteresis amplifier, which is a switching power amplifier whose switching frequency varies with the position of the suspended object. In the experiments, a PLL control feeding back the switching signal of a hysteresis amplifier is successfully implemented in a magnetic suspension system with a conventional PD controller. The measured responses to step and sinusoidal disturbances show that an integral feedback arises automatically in the magnetic suspension system because the control input is produced from the difference in phase between the reference and feedback signals in the PLLs.
- IEEJ Transactions on Sensors and Micromachines
IEEJ Transactions on Sensors and Micromachines 115(3), 287-293, 1995-03
The Institute of Electrical Engineers of Japan