Although I agree in theory:
Quote:
Originally Posted by Xringer
High current is a big problem. Wasted wattage is equal to the current squared x the resistance. P=I(squared)xR
If they could make a DC to AC(sinewave) converter that worked at 144vdc,
You could use much lower current.
. . .
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There are two practical problems:
- tapping the traction battery HV - although not insurmountable, there is a ground-fault circuit built into the battery controller. If the plug and/or electronics doesn't keep this high-frequency isolated, it could throw a false, ground fault code. Also, this is the sort of thing a skilled owner needs to do whereas most semi-technical types can deal with 12V and not 'let the smoke out' too badly.
- creating a 110 VAC sine-wave - pulse width modulation allows much smaller transformers that feeding into some 'starter caps' can generate a usable sine wave. But other than the photo-array vendors, such inverters are both rare and expensive compared to the 12V ones.
In the back of my mind is this approach:
- AC power tap/plug on MG2 - the main motor, this is already driven by a water cooled, high power inverter already in the car. So instead of driving the wheels, the tap provides AC, house power.
- spoof encoder signal - may also require spoofing the antilock brake sensors so the car thinks it running down the highway at 60 Hz.
This approach allows the existing power electronics already integrated into the car to provide external AC power. The car is put in 'AC power mode' and the parking brake set. Then the car 'drives' providing external AC power.
Another variation would simply 'spoof' the MG2 inverter signals so it begins 'driving' MG2 at 60 Hz. There is still the challenge of defeating the ground fault detector and making sure the HV ECU doesn't see an error.
The microcontroller and glue-logic should be fairly small as all of the power electronics are already in the car. We're looking at up to 18 kW, the amount of power MG1 can provide on its own.
Bob Wilson