You can invert the power to let the motors produce extra torque against the current direction of travel, but this is
a) not regenerative
b) not healthy for any electric engine
c) also a pretty difficult job for a power controller.
a) True, but regenerative braking can be used down to very slow speeds after which active braking can be applied.
b) Squirrel cage induction motors have a real problem operating in the negative slip region because all power input into the motor (shaft power and power input to the stator) needs to be dissipated as heat in the rotor. For wound rotor induction motors or permanent magnet synchronous motors this is perfectly healthy. In the case of a wound rotor induction motor it is OK because the energy from the rotor can be extracted and fed back to the vehicle. In a permanent magnet synchronous motor there is no current in the rotor. The losses are reduced to the same as the normal operating losses - resistive loss in the motor windings and non-linear losses in the drive electronics. I'm not sure what type of motor the Lightning GT uses but when I was involved with the EV lab at Uni of Sydney permanent magnet synchronous motors were the favoured option.
c) Not too difficult for modern high speed PWM IGBT drive controllers.
Harking back to the lift example, they typically use permanent magnet synchronous motors and regen brake down to very low speeds and brake to a complete stop by applying negative slip to the stator. The mechanical brakes are only applied once the machine has come to a complete stop.
Also, on a number of occasions we have used this technique to slow down squirrel cage motors quickly so they can then be powered up in the opposite direction (typical application is a supply air fan that needs to be reversed to operate as a smoke exhaust fan). Because this only happens infrequently the heat in the rotor has not been an issue.
ISO standard for car battery modules? :lol:
That is not as silly as it first sounds.
Three phase is common in Australia? I mean in a domestic environment? Is this 110AC 3-phase into your own dwelling?
I can see the export potential for this car, I'm stuck with old fashioned single phase!
N.
"Not uncommon" is probably a better term. At a guess, only 5-10% of domestic premises would have existing three phase connections. For those that don't already have it, it is readily available because all the low network is run in three phase.
We operate on 240V single phase, 415V three phase here. Officially it changed to 230/400V in line with Europe a few years ago but the actual voltages have not changed, they just increased the tolerances from 240/415V +/- 6% to 230/400V +10% -6%.
I can't see any technical reason why three phase would be less available in the UK, it probably is just a question of demand. Because we have high cooling requirements that are typically met by air conditioning there is a reasonable demand for three phase power. In the UK (correct me if I am wrong) there would be less cooling demand and more heating demand, with the heating demands being met by other energy sources (natural gas, heating oil, etc).
