Reduced parameter variation sensitivity with a variable structure controller in brushless DC motor velocity control systems

A brushless DC (BLDC) motor velocity control system using a variable structure controller (VSC) has been investigated. Using the pole placement design method, with the state-space model of the BLDC motor, simplifies the design of the VSC controller. The controller is intentionally switched in its structure according to the sign of deviation of the system state from a switching surface where the system performance is prescribed. Chattering is reduced when the switching effort is made proportional to the magnitude of the system state deviation from the switching surface. With the application of a VSC, simulation results indicated that the system performance with respect to the sensitivity to parameter variations is greatly improved.<
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