If the components of the electric scooter are separated and evaluated one by one, the cost of the motor and control system is the highest. At the same time, they are also the "brain" of the electric scooter. The start, run, advance and retreat, speed, and stop of the electric scooter depend on Both are the motor control system in the scooter.
Electric scooters can run quickly and safely, and have high requirements for the performance of the motor control system, and also have greater requirements for the efficiency of the motor. At the same time, as a practical vehicle, the motor control system is required to withstand vibration, endure harsh environments, and have high reliability.
The hardware design scheme of the conventional scooter control system is shown in the figure below, which mainly includes the drive MCU, gate drive circuit, MOS drive circuit, motor, Hall sensor, current sensor, speed sensor and other modules.
The MCU works through the power supply, and communicates with the charging module, the power supply and the power module through the communication interface. The door drive module is electrically connected with the main control MCU, and drives the BLDC motor through the OptiMOSTM drive circuit. The Hall position sensor can sense the current position of the motor, and the current sensor and speed sensor can form a double closed-loop control system to control the motor.
After the motor starts running, the Hall sensor senses the current position of the motor, converts the rotor magnetic pole position signal into an electrical signal, and provides correct commutation information for the electronic commutation circuit to control the switching of the power switch tube in the electronic commutation circuit Status, and feedback the data to the MCU microcontroller.
The current sensor and the speed sensor form a double closed loop system, input the speed difference, the speed controller will output the corresponding current, and then the difference between the current and the actual current is used as the input of the current controller, and then output the corresponding PWM to drive the permanent magnet rotor Continuously rotate for reversing control and speed control. The use of the double closed loop system can enhance the anti-interference of the system. The double closed loop system increases the feedback control of the current, which can reduce the current overshoot and oversaturation, and obtain a better control effect, which is the key to the smooth movement of the electric scooter.
Some scooters are also equipped with electronic anti-lock braking systems. The system detects the wheel speed by sensing the wheel speed sensor. If it detects that the wheel is locked, it automatically controls the braking force of the locked wheel to make it roll while slipping (the side slip rate is about 20%) ), to ensure the safety of the owner of the electric scooter.