AN1627 Freescale Semiconductor / Motorola, AN1627 Datasheet - Page 8

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

Let’s suppose that the motor is fed from a voltage source, the fundamental frequency created by the
power stage is constant. Figure 2-6. shows how the average motor torque (y-axis, relative amplitudes
only) depends on the switching angle (x-axis) at constant speed and applied voltage (PWM duty cycle
MOTOROLA
8
0
0
0
0
0
30
30
30
30
30
Freescale Semiconductor, Inc.
For More Information On This Product,
60
60
60
60
60
Figure 2-5.
90
90
90
90
90
Go to: www.freescale.com
120
120
120
120
120
150
150
150
150
150
180
180
180
180
180
15° switching angle
210
210
210
210
210
240
240
240
240
240
270
270
270
270
270
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