By including a differentiator from 10 Hz to 50 Hz, we increase the phase margin and the resulting
magnetic levitation system is stable even without the help of eddycurrent damping.
The new block diagram for the system is the following:
Here the eddycurrent damping component is removed and we add an additional differential
circuit with an operational amplifier OP27G.
In addition, we place the Hall sensor below the magnet to minimize the coupling between
the coil and the Hall sensor.
The resulting levitation system is shown by the figure below:
