31-05-2012, 12:21 PM
Switched Reluctance Motor Drives: Basics and Reseeach Trends
SRM.pdf (Size: 730.99 KB / Downloads: 69)
MOTOR DRIVES: IN GENERAL
The dc machine has been the primary choice for the
servo applications, because of their excellent drive
performance and low initial cost.
The advantages of the ac machine to the dc machine
are in the areas of torque-inertia ratio, peak torque
capability and power density. Also ac machines do not
need commutators and brushes.
The low cost, ruggedness and almost maintenance
free operation of the induction machines have made it
the workhorse of the industry.
BASIC CONSTRUCTION OF AN SRM
The SRM is a doubly-salient, singly-excited machine
with independent windings of the stator.
Its stator structure is same as PM motor, but the rotor
is simpler having no permanent magnet on it.
Stator windings on diametrically opposite poles are
connected in series or parallel to form one phase of the
motor.
Arc Widths
Constraints for rotor and stator pole
arcs:
Minimum size such that the motor can
produce torque in either direction for
any rotor position
ADVANTAGES
The rotor does not have any windings, commutators,
brushes or cages.
The torque-inertia ratio is high.
It provides high reliability, wide-speed range at
constant power, low manufacturing cost, fast dynamic
response, ruggedness and fault-tolerance.
No shoot-through and crossovers in the converter.