PWM generation in Simulink - Mini Project: Build & Apply

PWM Generation in Simulink

📖 Scenario: You are working on a simple control system that requires generating a Pulse Width Modulation (PWM) signal. PWM signals are used in many real-world applications like controlling motor speed or LED brightness by switching the signal on and off rapidly with varying duty cycles.

🎯 Goal: Build a Simulink model that generates a PWM signal with a fixed frequency and a configurable duty cycle.

📋 What You'll Learn

Create a sine wave or constant block as the reference signal

Add a PWM generator using a comparator block

Configure the PWM frequency and duty cycle using parameters

Display the PWM output waveform

💡 Why This Matters

🌍 Real World

PWM signals are widely used in electronics to control power delivery to devices like motors, LEDs, and heaters by adjusting the duty cycle.

💼 Career

Understanding PWM generation is essential for engineers working in embedded systems, robotics, and control systems design.

1

Create the Reference Signal

In your Simulink model, add a Sine Wave block. Set the Amplitude to 1 and the Frequency to 50 Hz. This will be the reference signal for PWM generation.

Simulink

# Add a Sine Wave block with Amplitude 1 and Frequency 50 Hz
# Your code here

Hint

Use the Simulink library to drag a Sine Wave block into your model. Double-click it to set the amplitude and frequency.

2

Add the PWM Carrier Signal

Add a Repeating Sequence block to your model to act as the carrier signal for PWM. Set its output to a sawtooth waveform that goes from 0 to 1 with a period of 0.02 seconds (which corresponds to 50 Hz frequency).

Simulink

% Step 1: Add Sine Wave block with Amplitude 1 and Frequency 50 Hz
% Step 2: Add Repeating Sequence block with sawtooth from 0 to 1 and period 0.02
# Your code here

Hint

The Repeating Sequence block can be configured to output a sawtooth by setting its time and output vectors accordingly.

3

Create the PWM Signal Using a Comparator

Add a Relational Operator block to compare the Sine Wave output and the Repeating Sequence output. Set the operator to <. This block will output 1 when the sine wave is greater than the carrier, generating the PWM signal.

Simulink

% Step 1: Add Sine Wave block with Amplitude 1 and Frequency 50 Hz
% Step 2: Add Repeating Sequence block with sawtooth from 0 to 1 and period 0.02
% Step 3: Add Relational Operator block with operator '<'
# Your code here

Hint

Use the Relational Operator block and set its operator to < to compare the two signals.

4

Display the PWM Output

Add a Scope block to your model and connect it to the output of the Relational Operator block. Run the simulation for 0.1 seconds and observe the PWM waveform on the scope.

Simulink

% Step 1: Add Sine Wave block with Amplitude 1 and Frequency 50 Hz
% Step 2: Add Repeating Sequence block with sawtooth from 0 to 1 and period 0.02
% Step 3: Add Relational Operator block with operator '<'
% Step 4: Add Scope block and connect to Relational Operator output
# Your code here

Hint

Use the Scope block to visualize the PWM output. Set the simulation stop time to 0.1 seconds.