This paper presents a simplified speed controller for multiphase induction motors (MIM), designed to enhance performance across a wide range of speeds while minimizing computational complexity. The proposed controller, based on a Proportional-Integral (PI) approach, optimally adjusts motor speed by leveraging a perturbation-based estimation of control variables. A variable DC source supplies the motor, with Pulse Width Modulation (PWM) employed to generate a stable five-phase AC voltage. The controller's design is formulated as an optimization problem, where its parameters are tuned to minimize speed deviation errors. Simulation results demonstrate that the proposed controller significantly improves speed regulation. The system achieves a steady-state error reduction of 85%, with the actual speed closely tracking the reference speed under fluctuating DC supply conditions. Under variable load torque conditions, the controller minimizes speed deviation to less than 1%, ensuring robust performance. Compared to conventional PI controllers, the proposed approach reduces overshoot by 42% and improves settling time by 37%, making it a viable solution for industrial and high-performance applications requiring precise speed control.