IEEE International Electric Vehicle Conference

[randyd]

It's less than 1 month away!

It's the very first EV conference from the IEEE!

It's being held in Beautiful Greenville, South Carolina!

Selected topics include:

• "Design of a Wheel-hub Motor with Airgap Winding and Simultaneous Utilization of all Magnetic Poles"
• "Using Clonal Selection Algorithm for Optimal Power Train Component Sizing and Design of Electric Vehicle"
• "A Computationally Intelligent Maximum Torque per Ampere Control Strategy for Switched Reluctance Machines"

And much, much more!

Here's the main link: http://electricvehicle.ieee.org

[smilingcat]

since switched reluctance motor is brought up:

I think the future of electric motor is going to be switched reluctance motor. for those not familiar with it, it has no permanent magnet and no coils for the rotor. Magnet is only in the stator.

So how does it work? Think of solenoid. It has a coil and an iron rod. iron rod sits in axial alignment with the coil and partially/fully out of the coil. You energize the coil and the resultant magnetic force will pull the iron rod into the center of the energized core. Switched reluctance motor works with same principle. It is also one of the oldest motor design.

Why isn't it used? The torque generated by the switched reluctance motor is not uniform as the rotor rotates. In fact it is very "jerkey". Enough so that it can damage the motor itself or surrounding equipment.

So why the interest now? Computer controlled, and advanced electronic switches IGBT and development in switching regulators make it possible to have constant torque as the rotor rotates.

And because of motor is extremely simple in design, its very rugged. Permanent magnets such as SmCo and NdFeB magnets are expensive and when broken/shattered the powder is toxic.

And even though the magnet exists only in the stator, it can be used in regenerative braking. Yes! It can generate electricity. But it needs finesse in electronics to do so.

To give you an idea of switched reluctance motor, GE has a 12" diameter by 12" long switched reluctance motor with over 300HP.

And yes, this is the type of motor I will be designing.

[smilingcat]

One warning. If you search on switched reluctance motor, you will come across lot of garbage. Mostly things called free energy. They have no understanding of 1st and 2nd law of thermodynamics. If fact, most things you find will be this (free energy) nonsense.

[PatQ562]

The switched reluctance motor does have some legitimate literature and support, but it's hard to find actual specs for EV-sized units. It would be interesting to see a direct comparison for the same sustained and peak power ratings, for AC induction, PM synchronous motor (using hard to get neo) and the switched reluctance motor, regarding weight and efficiency.

And wasn't there something about staggered poles to alleviate the jerky torque?

Pat Q

[smilingcat]

staggerd poles reduces the peaks and troughs of the torque as a function of rotor angle. It does this by making more peaks and troughs, so instead of having lets say 6 peaks and 6 troughs over 360 degrees. You make 18 peaks and 18 troughs. You are trying to average it out. But this complicates the rotor and stator geometry. And if you were to use more stator poles, more magnetic coils, then you have to deal with more high power switching circuits. More cables for each unique coils.

Part of the reason why you can't find too many technical detail is that, the research topic is "hot" with lot of patent activity. Of all the motor patents being generated right now, it sounds like switched reluctance motor related patents are the bulk of motor patents being applied.

And I'm stupid enough to jump into the frey.

[PatQ562]

You go guy!
You are smart to minimize the number of coils and costly high power electronic driver stages, and use ever-cheaper computer power to smooth out the torque. I can advise FWIW that digital programming for closed-loop power supply control is not for the faint of heart.
That said, power switching transistors come in certain popular sizes, and you may find that more banks of a commercially popular device is cheaper than fewer banks of some ultra-powerful device. Also it seems logical to build the motor and controller in a common package for common cooling and to minimize the cost of cable runs.
Pat Q