Controllers - EGG-electric-unicycle/documentation GitHub Wiki
The generic EUC controller electronic board is mainly composed of:
- Microcontroller STM32F103 - is "the brain" of the system
- BLDC controller - include 6 power mosfets and all the circuitry to control them; hall sensors circuit; BEMF circuit; current measurement
- IMU MPU6050 - the accelerometer and gyroscope
- Buzzer
- LEDs - for indicating the battery status
Picture of a EUC controller electronic board:
See also information about other generic EUC controller boards:
Pictures of electrical signals
Seems there are 2 different ways to control the motor - one for low speed up to medium speed and other for higher speed. The 1st way seems specific to this application were a motor may work at very low speeds and even stopped. The 2nd way seems to be the standard 6 steps trapezoidal control.
1st way, low to medium speed: yellow: phase 1, blue: hall sensor signal.
2nd way, high speed: yellow: phase 1, blue: hall sensor signal.
On the 1st way, when the wheel is stopped, there is a square (duty-cycle is 50%) on all the 3 phases (the signals are in phase) and the frequency is 15.625khz.
Yellow: phase 1, blue: phase 2. Motor stopped:
When the motor rotates, one phase keeps the duty-cycle at 50% and the other 2 phases have duty-cycle higher and lower than 50%. That 2 phases have inverted duty-cycle value, like if one have 25% duty-cycle, the other have 75%. The PWM signals seems to be center aligned. This signals seems to change, maybe using 6 steps by following the hall sensors signals.
Yellow: phase 1 signal with 10% duty-cycle, blue: phase 2 with 50% duty-cycle.
Yellow: phase 1 signal with 10% duty-cycle, blue: phase 2 with 90% duty-cycle.
Yellow: phase 1 signal with 25% duty-cycle, blue: phase 2 with 75% duty-cycle.
The change from 1st to 2nd way to control the motor seems to happen when the transition of hall sensors signal are about 10ms period (2 transitions at each 10ms - at about 17.4km/h speed):
Please see MicroWorks 18m/h controller board page were we are documenting the technical details.
See more picture here: https://github.com/generic-electric-unicycle/documentation/tree/master/images/controller