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current generation during regen braking 1
- Thread starter nbro
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GregLocock
Automotive
It depends on your vehicle but....
Regen is fairly unsuccessful as a braking mechanism, since your electrical system is usually sized around the traction requirements, which are low in an electric vehicle, yet the braking requirements are set by the surrounding traffic, ie a 1 g stop is necessary.
The short term high current spike is a pain to handle, frankly the best thing to do with it is stick it in a resistor.
Since this is complex and has the same net result as applying a mechanical brake, why not do that instead?
Cheers
Greg Locock
(I was the mechanical engineer responsible for the wheel motor on the WSC winning Aurora solar car)
Regen is fairly unsuccessful as a braking mechanism, since your electrical system is usually sized around the traction requirements, which are low in an electric vehicle, yet the braking requirements are set by the surrounding traffic, ie a 1 g stop is necessary.
The short term high current spike is a pain to handle, frankly the best thing to do with it is stick it in a resistor.
Since this is complex and has the same net result as applying a mechanical brake, why not do that instead?
Cheers
Greg Locock
(I was the mechanical engineer responsible for the wheel motor on the WSC winning Aurora solar car)
The auto industry is currently working on going to 42V (vs 12V) electrical systems. One related product that is coming out of this is a 42V starter / generator. It attaches between the engine and the transmission. It replaces the starter, alternator, and I believe the flywheel as well. Siemens automotive already has one on the market.
I believe there is a great potential to use this device for recovering break energy. The break pedal position could be sent to the control module, and activate the generator portion of the device proprotional to the break pedal position. The system would already be in place, so it would just be a matter of a sensor for break pedal position, some wire, and software to deal with it! A very low cost option if you already have the 42V starter / generator on your vehicle.
The only issue I would see is safety. Your would never have a brake-by-wire system without a backup system and safeties in place if for whatever reason the generator failed to brake the vehicle (ie. loss of power to the control module, etc.). I guess the mechanical brake system could remain, but be setup to only be applied when the break pedal was near the floor.
As usual, additional info may be found at I know there was a small artical on this system in SAE's "Automotive Engineering" monthly magazine within the past year. You might also try or other manufacturers that make a similar device. Good luck in your search!
I believe there is a great potential to use this device for recovering break energy. The break pedal position could be sent to the control module, and activate the generator portion of the device proprotional to the break pedal position. The system would already be in place, so it would just be a matter of a sensor for break pedal position, some wire, and software to deal with it! A very low cost option if you already have the 42V starter / generator on your vehicle.
The only issue I would see is safety. Your would never have a brake-by-wire system without a backup system and safeties in place if for whatever reason the generator failed to brake the vehicle (ie. loss of power to the control module, etc.). I guess the mechanical brake system could remain, but be setup to only be applied when the break pedal was near the floor.
As usual, additional info may be found at I know there was a small artical on this system in SAE's "Automotive Engineering" monthly magazine within the past year. You might also try or other manufacturers that make a similar device. Good luck in your search!
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