niu N-GT, Service Manual

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V1.0.0 67
FOC Controller
The controller for this model makes controlling in the way that it receives the signal from speed
regulation handle and controls operation of the brushless DC motor.
Main protective functions
1. Current limit protection
The maximum controller output current is limited to protect the motor, controller, battery and other
components from being damaged by a current greater than specified.
2. Rotation failure (overload) protection
The controller judges the motor status automatically in a certain period of time after the motor
rotation failure (over-current) occurs. It controls automatically the output current to protect safety of
the motor, controller and battery.
3. Under-voltage/over-voltage protection
The controller stops automatically the motor rotation when the input voltage to motor is lower or
higher than the set value, in order to protect safety of the motor and extend the battery lifetime.
4. Power cut-off protection in charging or braking
The controller stops the motor automatically to avoid unexpected injuries when the vehicle is being
braked or charged.
5. Control loss protection
The controller stops the motor automatically to avoid unexpected injuries when the Hall cable
sensor or its circuit fails and is out of control. The functions such as motor temperature protection,
controller temperature protection and motor winding short protection are also provided.