1. Introduction

The BLDC Motor RPM Control System is designed to regulate motor speed using two control techniques: Proportional–Integral–Derivative (PID) control and Sliding Mode Control (SMC). The system measures the motor's rotational speed and adjusts the control signal to maintain the desired RPM under varying load conditions. By comparing both methods, the project evaluates speed accuracy, response time, and stability.

2. Objectives

• Control BLDC motor speed accurately.

• Implement PID and Sliding Mode Controllers.

• Maintain the desired RPM under changing loads.

• Compare speed response and control performance.

• Reduce speed error and improve stability.

• Explore advanced motor control techniques.

3. Methodology

• Connect a BLDC motor to a suitable electronic speed controller (ESC).

• Measure motor speed using a Hall-effect sensor or encoder.

• Use a microcontroller to collect RPM feedback.

• Implement PID and Sliding Mode Control algorithms.

• Adjust the motor control signal according to the selected controller.

• Record RPM, settling time, overshoot, and steady-state error.

• Compare both controllers under different speed commands and load conditions.

4. Instrument List

• BLDC Motor

• Electronic Speed Controller (ESC)

• Arduino Due or STM32 Controller

• Hall-Effect Sensor or Rotary Encoder

• PID Controller Algorithm

• Sliding Mode Controller Algorithm

• Motor Driver Circuit

• LCD Display

• Battery or DC Power Supply

• Tachometer

• Computer for Data Analysis

5. Working Principle

• The BLDC motor rotates according to the control signal supplied by the ESC.

• The speed sensor measures the actual RPM and sends feedback to the controller.

• The desired RPM is compared with the measured RPM to calculate speed error.

• The PID controller adjusts the control signal using proportional, integral, and derivative actions.

• The Sliding Mode Controller uses a defined sliding surface and switching control law to reduce speed error and improve robustness against disturbances.

• Both controllers are tested under similar operating conditions to compare speed tracking, response time, overshoot, and disturbance rejection.

6. Advantages

• Accurate RPM regulation

• Improved speed stability

• PID and SMC performance comparison

• Better load disturbance handling

• Reduced steady-state error

• Practical motor control research

7. Conclusion

The BLDC Motor RPM Control System demonstrates the application of PID and Sliding Mode Control techniques for accurate motor speed regulation. By evaluating both controllers under different operating conditions, the project helps identify their strengths in speed tracking, stability, and disturbance rejection. The results can support the selection of suitable control methods for electric vehicles, robotics, industrial automation, and other BLDC motor applications.