AC or DC Drive for Electric Cars?

by Louis

Why does one select AC over DC drive for electric cars? I see both kinds of kits offered but I don't understand why one would choose one over the other.

Hi, Louis!
Ah, my favorite question!

Why choose a DC drive system? Drag racing, and low-budget conversions.

Why choose an AC drive system?

First: An AC electric car motor gets the most range for your battery buck. Think 80 miles instead of 30, yes, even with lead acid batteries.

Second: AC is better for highway driving, for a variety of reasons. That expensive controller really earns its keep on the freeway.

Third: AC will drive more like your regular ICE (internal combustion engine) machine, given adequate voltage, while DC has a distinctly different torque curve (more like a golf cart).

Fourth: If there are any hills in your driving range (sorry, small golf cart pun; ), you'll appreciate an AC drive system. DC motors don't excel under conditions of varying load - i.e. hills - and with your AC drive, that expensive controller again earns its keep recapturing the braking energy going downhill.

Fifth: The regenerative braking. With an AC drive system, regen braking is excellent and easy.

Sixth: If you want to convert a heavy vehicle, AC drive is the way to go.

And finally...The major automakers overwhelmingly choose AC drive systems when they build an electric car. I suppose they might have their reasons.


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