Abstract: (6532 Views)
The switched reluctance motor is a singly excited, doubly salient machine which
can be used in generation mode by selecting the proper firing angles of the phases. Due to
its robustness, it has the potential and the ability to become one the generators to be used in
harsh environment. This paper presents an energy conversion by a Switched Reluctance
Generator (SRG) when bifilar converter circuit and discrete position sensors are employed.
As the generator’s speed increases by a prime mover the shape of current waveform
changes in such a way that limits the production of generating voltage. At high speeds, it is
possible for the phase current never reaches the desired value to produce enough back-emf
for sufficient voltage generation, therefore, the output power falls off. In order to remedy
this problem, the phase turn on angle is advanced in a way that the phase commutation
begins sooner. Since one of the advantages of this type of generator is its variable speed
then, the amount of advancing for the turn on angle should be accomplished automatically
to obtain the desired output voltage according to the speed of the generator, meaning, as the
generator speed increases so should the turn on angle and vice versa. In this respect, this
paper introduces an electronic circuit in conjunction with the position sensors and the drive
converter to achieve this task for a desired output voltage when a SRG feeding a resistive
load. To evaluate the generator performance, two types of analysis, namely numerical
technique and experimental studies have been utilized on a 6 by 4, 30 V, SRG. In the
numerical analysis, due to highly non-linear nature of the motor, a three dimensional finite
element analysis is employed, whereas in the experimental study, a proto-type generator
and its circuitries have been built and tested using bifilar converter. A linear analysis of the
current waveform for the generator under different advancements of the turn on angle has
been performed numerically and experimentally and the results are presented.
Type of Study:
Research Paper |
Subject:
Electrical Machines Design Received: 2011/08/01 | Revised: 2013/05/25 | Accepted: 2013/05/25