SR motor for EV?

[pamcinto]

I was hoping that I could get any information/comments that my colleagues at Eng-Tips may care to voice. I have been investigating SR motors (Switched Reluctance) and have been itching to play with one. I have many articles/papers/books on the control of these motors (as well as other electric motors) but nobody seems to be using SR motors for traction motor applications (Electric-Vehicles)? Is it because of any particular characteristics of this type of motor? I have read that they have torque-ripple but it seems that this would not be a big deal for an E-vehicle. I just thought that it would be nice to get away from brushes and permanent magnets...
Any informed comments are welcome.

Thanks friends,

Peter

 

[jbartos]

There are many postings in this forum covering reluctance motors and their properties, parameters, and controls. They can be found by using key word search. Essentially, the reluctance switched motors have more complicated controls, and tend to be heavier per their power ratings. They may even be less attractive than permanent magnet motors of certain types.

 

[ICEMAN]

I was involved in the application of switched reluctance drives from 1983 to 1992 using the first commerically available industrial SR drive system (5.5HP to 30HP).

In actual fact we designed, manufactured and installed the world's first SR digital drive system for cable windering machines.

In those days the noise and torque ripple was a problem when switching for angle mode (above 600 rpm) to chopping mode. The noise in the latter mode was like a bandsaw cutting wood. However, the response with excellent and often removed both ac and dc drives from arduous application and successfully used SR drives.

It is already used in some domestic applicances and will be used more in the future. It also, although nobody has really developed it yet, great potential is large power, high speed machines where the lack of inertia of the rotor is an great benefit.

The torque ripple could quite easily be rectified by using a larger number of polse (6 on the original motor) and using modern semicondutor technologies. Please bear in mind that the original TASC SR drive was developed in 1983 and used at that time (from these days perspective) slow devices.

SR drives have, I believe, great potential but is not being developed due to rush to mass produced AC PWM VFD which used 'supposed' standard AC motors. In reality the AC PWM VFD has infinite variable speed (as one Danish manufacturer used the claim) but without a motor connected. When you connect the motor that is when your problems start. I actually done an article for a Middle East journal to promote ac drives called "AC Drives - A Salesman Dream or a Users Nightmare".

Pamcinto - I am sure some people are using SR for traction. Why not email me at iancevans@vsdtechnicalservices.fsbusiness.co.uk for some co-operation in this field.