Mathematical Simulation of a PI Speed Controller for a Separately Excited DC Motor

The study is devoted to the mathematical simulation of a PI controller-based DC motor speed control system. DC motors are widely used in the industry to drive cyclic mechanisms requiring high response speed and starting torque, and linear control. The main methods to control the required separately excited DC motor speed characteristics comprise controlling the parameters of the armature and excitation windings powered from different sources. PI controllers are widely used in programmable logic controllers due to the simplicity and clarity of the mathematical tools. The PI controller mathematical model proposed is based on choosing optimal parameters to maintain the actual speed close to the set value. The optimal KP and KI coefficients of the PI controller have been determined, giving the best result for constant speed. The results of computer simulation in MatLab have been compared with that of the laboratory simulation. The data obtained based on the steady-state error and transient time using a PI controller look preferable to the voltage control simulation model. The developed mathematical model has shown the following key results: acceleration time <0.3 s; transient time <0.5 s; overshoot and steady-state error do not exceed 0.5 and 0.1 %, respectively.