Nonlinear speed control of large industrial DC motor drives with an energy efficiency enhancement loop

The paper presents a novel dynamic speed reference trajectory tracking controller using an error driven self-adjustable, self-regulating nonlinear control block. The speed controller has two time-decoupled control/regulation loops namely: (i) the speed reference trajectory tracking loop; and (ii) a supplementary minimum power input dynamic tracking-search loop to ensure higher utilization efficiency for inrush type, cyclical and dynamic loads. The paper presents Matlab digital simulation results of a DC motor drive system with the switching inherent delay and other drive/control nonlinearities taken into consideration. The self adjusting hyper error driven nonlinear control block ensures good speed reference tracking, minimum inrush current and excursions as well as online energy conservation and electrical power energy savings for large industrial DC motor drives in the range (100 kW-1000 kW).