BLDC Motor Simulation with Sliding Mode Control Implementation

In this project, we develop a comprehensive simulation of a brushless DC (BLDC) motor controlled by a sliding mode controller (SMC). BLDC motors are synchronous machines powered by direct current, renowned for their high efficiency, minimal maintenance requirements, and compact design - making them ideal for electric vehicles, drone propulsion systems, and industrial automation applications. The sliding mode controller represents a robust nonlinear control strategy capable of effectively managing system uncertainties and external disturbances. Its core algorithm operates by forcing the system state to follow a predefined sliding surface trajectory toward the desired equilibrium point. This approach employs a switching control law that rapidly toggles between different system structures to maintain stability. In MATLAB implementation, this typically involves designing a sliding surface function and calculating equivalent control components using signum or saturation functions to mitigate chattering effects. Our simulation framework utilizes MATLAB/Simulink to model both the BLDC motor dynamics and the SMC architecture. The BLDC model incorporates three-phase inverter dynamics, Hall sensor positioning, and electromagnetic torque generation. The controller implementation includes: 1. Sliding surface design based on speed error and its derivative 2. Switching control logic with boundary layer implementation 3. Pulse-width modulation (PWM) signal generation for inverter control We conduct comprehensive performance analysis under various operational scenarios including: - Dynamic load torque variations - Speed reference tracking tests - External disturbance torque applications - Parameter uncertainty conditions The evaluation metrics focus on controller stability through Lyapunov stability analysis, robustness against parameter variations, and tracking performance using integral absolute error (IAE) calculations. The simulation includes real-time monitoring of phase currents, rotor speed, electromagnetic torque, and controller output signals. This BLDC motor simulation with sliding mode control serves as an effective engineering tool for understanding motor dynamics and advanced control techniques. The modular Simulink structure allows researchers to easily modify control parameters, test different sliding surfaces, and optimize system performance for specific applications such as precision motion control and fault-tolerant drives.