Biomedical Engineering Reference
In-Depth Information
FIGURE 3-24
Controller for a
three-phase
brushless DC motor.
[Adapted from
(Yedamale 2003)].
FIGURE 3-25
Hall
sensor and drive
timing. (Brown
2002).
The Hall sensors have digital outputs that are high for 180
◦
of rotor rotation and then
low for the remainder. They are physically separated by 60
◦
so that an unambiguous digital
code is produced for every 60
◦
of rotation, as shown in Figure 3-25.
Note that each drive phase consists of one motor winding driven high, one driven
low, and the last one left floating. A necessary precaution with this kind of driver is that
both the high- and low-side drivers must never be actuated simultaneously. This is often
