The battery voltage level indicates how the vehicle is moving:
acceleration leads to its reduction, in the opposite case, it
leads to its increase, and the regenerative braking happens. In
the later case the control system activates the Buck converter
to store part of the kinetic energy in the super capacitors bank.
During the acceleration phase T
1
is in switch mode allowing
energy transfer from the super capacitors to the battery. In the
regenerative phase (deceleration) T
2
is in switch mode
allowing an opposite energy flow. This last operation is only
possible when the cyclist stops pedaling. The brake lever
allows two different modes: electromagnetic and mechanical.
The above mentioned operations are managed by the
microcontroller and its function is the combination of two
main control levels: primary and secondary.