provides high degree flexibility
and being programmable easily adapted
to accommodate different drive applications.
The functions the control system are
grouped follows:
• sequential control
• closed-loop control
• communication and interfaces
• protection, supervision and diagnostics
MEGADRIVE-LCI: Control structure
Load
Sequential control
This part the control system generates the
signals the correct sequence for starting
up and shutting down the drive.
5
.Design and function
of the MEGADRIVE-LCI
control system
Structure
As can seen from the block diagram
below, the control system divided into three
parts for:
• interface modules
• programmable controller
• standard modules
The interface modules facilitate the exchange
of data with other drive components, remote
control from control room and communication
with higher level control system.
The standard modules includes the gate control
units for the thyristors and hard-wired protection
devices which duplicate and serve back-ups
for the protection functions performed the
digital control part. The functions
are performed several stages and include
intermediate checks for ensuring that start-up,
respectively shut-down proceeding normally
and also emergency shut-down routines which
are executed the event fault the drive.
The programmable controller part includes
the torque and speed controllers, complex
protection functions, the sequential control
for the starting and shutting down routines
as well the emergency trip, drive supervision
and general diagnostic functions. All these
tasks are performed high-speed
programmable controller which has been
specifically designed for large converter fed AC
drives
