The DC motors have staged a comeback with the advent of the silicon controlled
rectifiers used for power conversion, facilitating a wide range of speed control of these
motors. The permanent magnet DC motor with Proportional Integral (PI) controller is
widely used in industries where the load changes are very small. However, in certain
applications like rolling mill or machine tools where the system parameters vary substantially,
the conventional controllers like PI or Proportional Integral Derivative (PID) are not
preferable due to the fact that the drive operates under the wide range of changing load
characteristics. The modern automated industries introduces the variable speed drives, increase
the productivity and thereby increases the efficiency considerably by 15-27%. Since
the conventional controllers are delivering poor performance for the variable speed drive, it
is necessary to have an efficient controller which suits nonlinear operating condition.
The Artificial Neural Network (ANN), often called Neural
Network, is the most generic form of artificial intelligence for emulating the human thinking process
compared to the rule-based expert system and the fuzzy logic system. The proposed
scheme presents the ANN application in estimating and controlling the speed of the
PMDC drive to a set value.
The starting performance of the separately excited DC motor is affected by its
nonlinear behavior. The speed control DC motor is done with different control strategies. DC
motors are widely used in industrial and domestic equipment. The control of the position of
a motor with high accuracy is required. A desired speed may be tracked when a desired shaft position is also required. In
fact, a single controller may be required to control both the position and the speed. The
reference signal determines the desired position and/or speed. The controller is selected so that
the error between the system output and reference signal eventually tends to its
minimum value, ideally zero. There are various types of DC motor. Depending on the type, a
DC motor may be controlled by varying the input voltage, whilst another motor can be
controlled only by changing the current input. |