AN1627 Freescale Semiconductor / Motorola, AN1627 Datasheet - Page 6

• Manufacturer Part Number: AN1627
• Description: Low Cost High Efficiency Sensorless Drive for Brushless dc Motor Using MC68HC (7)05MC4
• Manufacturer: Freescale Semiconductor / Motorola

2.3
The previously described model is used to obtain the typical waveforms at different switching angles.
See Figure 2-3., Figure 2-4. and Figure 2-5.
The x-axis represents electrical degrees of rotation. The y-axis represents relative amplitudes only. u
is voltage created by the power stage and applied to the motor. u
winding. A detailed look at waveforms u
MOTOROLA
6
Motor Behaviour at steady state condition
0
0
0
0
0
30
30
30
30
30
Freescale Semiconductor, Inc.
For More Information On This Product,
60
60
60
60
60
90
90
90
90
90
Figure 2-3.
Go to: www.freescale.com
120
120
120
120
120
VA
and u
150
150
150
150
150
180
180
180
180
180
A
0° switching angle
shows one interesting fact. These voltages can differ
210
210
210
210
210
240
240
240
240
240
270
270
270
270
270
A
is the voltage across the motor phase
300
300
300
300
300
330
330
330
330
330
uiA
PsiA
360
360
360
360
360
Torque
u0
id0
iA
uVA
uA
390
390
390
390
390
REV 0.2
AN1627
VA