I’m intrigued by the possibility to use the embedded engine alternator used in motorbikes as a “motor” other than a generator.
It is in fact some sort of a three phase motor, there are already mild hybrid vehicles using this approach to provide electric assistance to the petrol engine.
I would like to use the existing alternator, it wont have the advantages of a proper motor, however it could be useful in some ways:
Idle stabilisation on some types of engines: there are some types of engine which have odd firing sequences, V twins which much irregularity, engines with cam profiles hard to be fed properly by the engine ecu at idle.
Being able to drive the alternator as a motor and having an high resolution feedback of its speed can lead to a non mechanically constrained way to “help” the regularity of the petrol engine.
Assisted gear changes: on some vehicles gear changes are clutchless, there are electronic devices which temporarily disable ignition to the petrol engine to provide a repentine deceleration of the engine side of the gearbox, to have the two sides (engine and wheel) not forcing on each other, this allows for a “on the fly” gear upshift. (This process is called quickshift)
The same happens in downshifting, when the vehicle is decelerating and the wheel is rotating the engine, the engine is powered for a brief moment to “equalise” the speed of the two sides of the gearbox, with the same target as before: free the gearbox, this allows for a fast downshift. (This process is called autoblipper)
Here the smart alternator can be used as a brake, generator, in the upshifting phase and as a motor in the downshift phase.
Luckily the motorbike alternators have no electronics in it, the three phases are thrown out and theres an external regulator which charges the vehicle battery.
To start playing in this field i think ill require to install hall sensors between the windings and find some sort of driver board compatible with this application. The alternator I’ve got is rated 60v 500w. It can reach 11000 rpm.
It would be necessary to measure its speed with a sufficient resolution to detect and react to the imbalance at low speeds, but not too high to flood the mcu at high speeds, dont know if the halls itself are enough for this or i need some encoder to assist this process.
The driver board should have the capability to collect the energy generated by the alternator to recharge the battery of the system.
I have very little experience on electric motors, I would be happy if you can point me to the best hardware approach to start exploring this topic.