The next figure shows the Hall sensor signal alignment to BLDC motor Back-EMF signal. The Hall sensors detect the rotor
flux, so their actual state is not influenced by stator current. The Hall effect outputs in BLDC motors divide the electrical
revolution into three equal sections of 120°. In this so-called 120° configuration, the Hall states 111 and 000 never occur.
Figure 20. BLDC motor back-EMF and Hall sensor signal alignment
Based on the Hall sensor signal, the BLDC motor commutation table is developed. An example is shown in the next table.
The right-hand side of the table shows the Hall sensors signal, while the left side applied phase voltage.
Table 20. BLDC motor commutation example
Commutation Vector
Vector
Hall sensor pattern definition
Hall sensor
pattern result
Phase A
Phase B
Phase C
Hall Sensor C Hall Sensor B Hall Sensor A
NC
+V
DCB
-V
DCB
A
1
0
1
6
-V
DCB
+V
DCB
NC
B
1
0
0
5
-V
DCB
NC
+V
DCB
C
1
1
0
4
NC
-V
DCB
+V
DCB
D
0
1
0
3
+V
DCB
-V
DCB
NC
E
0
1
1
2
+V
DCB
NC
-V
DCB
F
0
0
1
1
3.10 Resolver Interface
The resolver interface is included to observe motor rotor position. The board is populated with the hardware interface to
measure motor position and speed. The resolver connector can be connected to J62.
For detailed description, see application note AN1942 or patent WO/2007/137625.
Design Considerations
S12ZVM12EVB Evaluation Board User Guide, Rev. 2, 03/2016
Freescale Semiconductor, Inc.
25
