Homework 2 Solution
operation with a constant PWM signal of 50% duty cycle.
2. Recommend the suitable range of frequency for this PWM applied in
mictrocontrollers. Analyze the advantages and disadvantages of PWM
systems.
Solution:
1. Draw the PWM signal of 50% duty cycle for the motor current and voltage:
UMotor
50% On & 50% Off
UMotorMax
t
IMotor
2. Recommend: t
Recommend the suitable range of PWM frequency: Since the human hearing
range is from 20 Hz (cycles per second) to 20 kHz (20,000 Hz), the PWM for
the DC motor is used the frequency about 25-30 kHz (avoid noises/discomfort
to human).
Analyze the advantages and disadvantages of PWM systems:
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