Stop command:
• Stop(): stop motor with a deceleration phase
• HardStop(): stop motor immediately
Regarding the rotor position feedback, the 60-degree
resolution provided by the 3 pairs of Hall sensors used in many
BLDC motors is frequently not enough. Since many gimbal
BLDC motors have 6-pole pairs above, each mechanical
revolution is equivalent to six rounds of electrical resolution.
A 12-bit position encoder/sensor (absolute encoder and/or
incremental encoder) is desirable. A simplified control scheme
is illustrated in (Figure 6).
Conclusion
Over the last few years, BLDC motors have received increasing
attention in industrial and consumer application domains
due to their fast response to speed and torque commands,
quiet spinning, smooth rotation with low torque ripple, and
superior power efficiency. Adding to these advantages, recent
advancements in integrated motor control ICs have allowed
designers to significantly reduce the size, weight, and cost
of the power electronic controller circuits used in BLDC
applications.
Figure 6. Gimbal axis BLDC motor position control.
(Source: STMicroelectronics)
Figure 7. Gimbal axis motor control system block diagram
(Source: STMicroelectronics)
A block diagram illustrating an axis control system
design is shown in (Figure 7).
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