Abstract
Direct current (DC) motors are widely utilized for industrial applications in due their excellent and wide range of speed and torque regulation, reliability, low-cost and ease of maintenance. However, for proper and reliable operation of DC motors, a robust motion control aimed at providing desired motor dynamic behavior is necessary. In this paper, speed control of a Separately Excited DC (SEDC) motor is presented. The control is carried out by comparing the SEDC output speed with a predefined reference thereby establishing an error signal. A Model Predictive Controller (MPC) optimized using Bat Inspired Algorithm (BIA) manipulate the error and generates an optimal control signal for the Hysteresis Current Controller (HCC). The HCC compares the reference current and actual armature current of the motor. Based on the comparison, it generates the gate signal for DC-DC chopper drive which in turn controls the SEDC input voltage. To ascertain the effectiveness of the proposed control scheme, the SEDC is subjected to a varying speed at constant load and varying load at constant speed. The performance of the proposed BIA-based MPC is compared to that of conventional PI controller based on integral squared error (ISE), settling time (ST) and maximum speed deviation (MSD) as performance metrics. It is established that the MPC-based speed control has outperformed the PI controller by roughly 43.55%, 32.46% and 40.94% with regard to the ISE, ST and MSD of the speed deviation respectively.

Key words: Bat inspired algorithm; MPC controller; PI controller; Separately excited DC motor, Speed control