Adaptive Sliding Mode-based Observer and Current Controller for Torque Balance Control Strategy of Coaxial BLDC Motor

In underwater vehicle applications, coaxial brushless direct current (BLDC) motors, serving as thrust actuators, present significant challenges. These challenges encompass external disturbances induced by environmental factors and internal perturbations arising from rapid temperature and electrical parameter fluctuations. To address these issues, this study introduces an Adaptive Sliding Mode Control (ASMC) algorithm, employing field-oriented control techniques, and incorporates a Sliding Mode Observer (SMO) to mitigate the aforementioned disturbances. Additionally, a three-level inverter structure, accompanied by a Space Vector Pulse Width Modulation (SVPWM) algorithm tailored for high-power applications to minimize harmonic distortion, has been implemented. Subsequently, a torque balance control strategy is developed, based on the master-slave speed tracking method, incorporating all these control structures and algorithms. The reliability and effectiveness of the proposed controller are substantiated through comprehensive simulation analyses conducted using Matlab/Simulink.