Table of Contents
Pulse Width Modulation (PWM) is a technique used in embedded systems to control the power delivered to electronic devices, such as motors. It allows precise adjustment of motor speed and torque by varying the duty cycle of a digital signal. This guide provides an overview of PWM and how to implement it effectively in motor control applications.
What is PWM?
PWM involves switching a digital output on and off at a high frequency. The ratio of the “on” time to the total period is called the duty cycle. A higher duty cycle means more power is delivered to the motor, resulting in higher speed or torque. Conversely, a lower duty cycle reduces power and slows the motor.
Implementing PWM in Embedded Systems
Most microcontrollers provide hardware timers or dedicated PWM modules to generate PWM signals. These modules can be configured to produce signals with specific frequencies and duty cycles. Software-based PWM is also possible but less efficient and suitable for low-frequency applications.
Practical Considerations
When applying PWM to motor control, consider the following:
- Frequency: Choose a frequency high enough to prevent motor noise and vibrations.
- Duty Cycle Range: Use the full range (0% to 100%) for precise control.
- Filtering: Add filters if necessary to smooth the motor response.
- Protection: Implement current limiting and thermal protection to prevent damage.