Cor van de Water wrote:
It is rather simple to find out, since we had the same "feature" on the US Electricars. Does the charger draw a very significant amount of power (in the order of 500+ Watts) when delivering "no" power to the batteries? That is the loss in the motor inductor. mostly due to magnetization losses. On low powered (120V) chargers, this inefficiency is quite appalling.
Wow; I'm surprised the losses are that high. I've only used the motor-as-inductor trick with DC motors (using the field as the inductor for the charger). In that case, the losses seemed quite low. The motor stayed stone cold, and overall charger efficiency was on the order of 80% (DC output to the battery / AC line input).
How did US Electricar set theirs up? I think Alan Cocconi (AC Propulsion) used the AC induction motor's winding as the boost inductor of a PFC stage, to charge a 330+ volt pack from 240vac. It may be that using such a monsterous inductor for this would lead to higher losses if you weren't charging at high power.
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