DC motor modeling in Simulink - Mini Project: Build & Apply

DC motor modeling in Simulink

📖 Scenario: You want to understand how a DC motor works by building a simple model in Simulink. This will help you see how voltage input affects motor speed and current.

🎯 Goal: Build a basic DC motor model in Simulink using blocks for voltage input, motor parameters, and output displays for speed and current.

📋 What You'll Learn

Create a Simulink model with a DC voltage source

Add blocks to represent motor electrical and mechanical parts

Configure motor parameters like resistance and inertia

Connect blocks to simulate motor speed and current

Display motor speed and current using scopes

💡 Why This Matters

🌍 Real World

Modeling DC motors helps engineers design and test motor control systems before building physical prototypes.

💼 Career

Understanding motor modeling is useful for roles in automation, robotics, and control systems engineering.

1

Set up the DC motor parameters

Create variables in the MATLAB workspace for the DC motor parameters: R = 2 (resistance in ohms), L = 0.5 (inductance in henrys), Kb = 0.01 (back EMF constant), Kt = 0.01 (torque constant), J = 0.01 (moment of inertia), and b = 0.1 (friction coefficient).

Simulink

# Define motor parameters in MATLAB workspace
# Your code here

Hint

Use simple assignment statements like R = 2; to set each parameter.

2

Create the Simulink model and add blocks

Open a new Simulink model and add these blocks: DC Voltage Source, Sum, Gain, Integrator, and Scope. Arrange them to start building the motor's electrical circuit.

Simulink

R = 2;
L = 0.5;
Kb = 0.01;
Kt = 0.01;
J = 0.01;
b = 0.1;
% Add Simulink blocks: DC Voltage Source, Sum, Gain, Integrator, Scope
% Your code here

Hint

Use the Simulink Library Browser to drag and drop these blocks into your model.

3

Connect blocks and set motor equations

Connect the blocks to model the motor equations. Use the Gain blocks to represent resistance R and inductance L. Use the Sum block to calculate voltage difference. Add integrators for current and speed. Set gains for torque constant Kt and back EMF constant Kb.

Simulink

R = 2;
L = 0.5;
Kb = 0.01;
Kt = 0.01;
J = 0.01;
b = 0.1;
% Connect blocks to model motor equations
% Set gains for R, L, Kt, Kb
% Use integrators for current and speed
% Your code here

Hint

Think of the motor as two parts: electrical (voltage, current) and mechanical (torque, speed). Use gains and integrators to connect them.

4

Run simulation and display motor speed and current

Run the Simulink simulation for 5 seconds. Use Scope blocks to display the motor speed and current outputs. Make sure the scopes show the changing values over time.

Simulink

R = 2;
L = 0.5;
Kb = 0.01;
Kt = 0.01;
J = 0.01;
b = 0.1;
% Run simulation for 5 seconds
% Connect Scope blocks to motor speed and current
% Your code here

Hint

Use the sim command with your model name and time. Open the scopes to see the results.