Integral VSC and preview control of efficiency and speed of a DC drive

This paper proposes a novel integral variable structure control (VSC) system and a preview control system to control the speed of a DC drive and obtain maximum efficiency over the whole control range. The reduced dynamic equation of the DC (RDE-DC) drive system is derived based on maximum efficiency. This is done to simplify the complexity of the control system and hence to reduce the execution time of the microprocessor. An integral action is introduced into the VSC to improve the transient response, minimize the steady state tracking error and reduce the rise and settling times of the drive system. An augmented system utilizing a pure integrator (filter) is introduced into the VSC system to mitigate the input chattering problem of the drive system. A preview controller is also synthesized and implemented with the RDE-DC drive system to maximize the efficiency and control the drive speed. This controller utilizes few future values of the desired signal and disturbance signal. The desired signal is the desired drive speed while the load torque is considered as a disturbance signal. The design procedures and comparisons between the different VSC control systems are made. Matlab simulation studies are carried-out to investigate the feasibility, tracking performance and robustness of the control system with changing the speed, torque and parameters of the RDE-DC drive system.