American Journal of Applied Sciences

Methodical Tuning of Proportional Plus Integral Controllers for Cascade Control of Separately Excited DC Motors

Ibrahim Al-Abbas

DOI : 10.3844/ajassp.2012.1891.1898

American Journal of Applied Sciences

Volume 9, Issue 11

Pages 1891-1898


The cascade control of DC motors by PI controllers was extensively used in industry. Approximation rules based on plotting the output of the system or on computer simulation were used to determine the parameters of these controllers. This study was done to develop mathematical expressions to calculate the parameters of these controllers. Output time functions of the system and there derivatives were used to obtain mathematical relationships relating directly the motor parameters and the controller parameters. These relationships were used in tuning process of the cascade system. The dynamic performances of the system were examined in single loop form and in closed loop form for a step change in control variable (the input voltage) as well as for step change in disturbance (mechanical load). The performances of current closed loop system and the speed closed loop were acceptable. The steady state error was zero and the maximum overshoot was less than 20%. The developed relationships can be used in design and analysis of cascade DC drive systems and cascade AC drive systems.


© 2012 Ibrahim Al-Abbas. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.