The motor controller unit is one of the main parts of an electric bike, it is the brain of the e-bike, controlling the motor’s speed, start, and stop. It is connected to all the other electronic parts such as the battery, motor, and the throttle(accelerator), instrument cluster(speedometer), PAS or other speed sensors if exist. A controller is composed of main chips (microcontrollers) and peripheral components (resistors, Transistors, Diodes, MOSFET, sensors, etc). Generally, there are PWM generator circuit, AD circuit, power circuit, and power driver circuit, signal acquisition, conditioning and processing circuit, over-current and under-voltage protection circuit inside the controller.