Submitted by marcuac on March 24, 2011
As you already know, when a regular AC motor is connected to the wheels via a fixed ratio link this configuration will not perform optimally at both low and high speeds. The ratio ends up being optimized for mid-range speed resulting in reduced low and high speed performance. One way around this problem is to have a variable gear ratio via a mechanical transmission, or achieve a similar result using a motor with variable number of poles.
I have been working on a design that can be electronically configured on-the-fly to operate in 4, 2 or 1 pole-pair mode, making it very suitable for fixed ratio application at both low and high speeds. I believe this design is very well suited for EV application and I thought you might want to have a look at it. Please provide a contact email and I will send you more information.