How does an electric bicycle controller work?
The common electric assisted bicycle adopts a handle control+central axis speed measurement control method. Among them, the handle control method is to send a handle signal to the controller of the power assisted bicycle by rotating the handle control, and the controller controls the motor output of the electric power assisted bicycle based on the handle signal.
The principle of central axis speed measurement control is to install a Hall element and a magnetic steel disc in the central axis part of the electric power assisted bicycle. After turning on the power of the electric power assisted bicycle, when the rider pedals the pedal of the electric power assisted bicycle, the central axis rotates, and the Hall element sends a fixed number of pulse signals once the central axis rotates. The controller measures the central axis speed by counting the pulses within a certain period of time, When a certain speed is reached (i.e. the central shaft rotates once and the Hall element outputs a pulse signal), the motor is started.
If the handle control is not used afterwards, the output of the motor will follow the central shaft speed in real time, that is, the speed of the motor will be proportional to the central shaft speed. If the cyclist stops pedaling and uses the handle control after the motor is started, the speed of the motor will be controlled by the handle afterwards.
After the motor is started, the cyclist continues to pedal while also activating the handle control. The controller will determine in real time which one has the highest current output for the handle control or the center axis speed measurement control, and the motor speed will be controlled by the one with the highest current output.
Of course, after turning on the power of the electric power assisted bicycle, it is also possible for the cyclist to directly control the motor through the handle without stepping on the foot pedal. However, this completely controlled method consumes more electricity and reduces the range of the electric power assisted bicycle.
However, when a cyclist pedals to start an electric power assisted bicycle, the motor cannot start the assistance until a certain speed is detected (i.e. the central axis rotates one cycle). During this period, the cyclist is more laborious, so the existing technology mentioned above cannot achieve precise 1:1 proportional assistance and cannot achieve precise assistance control of the electric power assisted bicycle.
There is an electric bicycle rear axle precise power signal acquisition and control system. The rear axle precise power signal acquisition and control system includes strain gauge, Hall sensor, power ratio adjustment button installed at the handlebar of the electric bicycle, and PCB circuit board installed on the DC brushless motor of the electric bicycle.
The strain gauge is pasted on the rear axle of the electric bicycle, that is, the axle of the DC brushless motor, the Hall sensor is pasted on the circumferential direction of the motor housing of the DC brushless motor, the PCB circuit board is pasted on the radial direction of the motor housing of the DC brushless motor, the PCB circuit board includes the signal controller, the DC brushless motor controller, the first socket and the second socket, and the signal controller includes the signal amplification circuit Pulse shaping circuit, voltage source, integration circuit and microcontroller, signal amplification circuit, pulse shaping circuit, voltage source, integration circuit are connected to microcontroller through corresponding pins;
The voltage source supplies power to the signal amplification circuit, pulse shaping circuit, integration circuit, and microcontroller; The strain gauge is connected to the first socket through a wire, the first socket is connected with the signal amplification circuit in the signal controller, and the deformation signal provided by the strain gauge is amplified and sent to the single chip microcomputer for processing;
The Hall sensor is connected to a second socket through a wire, which is connected to a pulse shaping circuit in the signal controller to shape the Hall signal provided by the Hall sensor and send it to the microcontroller for processing; The second socket is also connected to the power ratio adjustment button through a wire, which is used to change the amount of power provided by the system through the use of the power ratio adjustment button;
The microcontroller calculates the current speed V by calculating the Hall signal provided by the Hall sensor. By comparing the current speed V with the pre-set speed value, no assistance is provided when it is greater than the pre-set speed value; Convert the deformation signal provided by the strain gauge into the current voltage value U.
Compare the real-time voltage value with the preset maximum voltage value, if it is greater than the preset maximum voltage value, no assistance will be provided, and the corresponding calculation will be carried out for the voltage value and speed value not greater than the preset maximum voltage value, and the corresponding pulse width modulation P will be obtained as the control signal, and the integration will be carried out through the integration circuit, Obtain a stable control signal to control the DC brushless motor controller.
However, this new technology only discloses a precise assistance signal acquisition and control system for the rear axle of electric powered bicycles, and there is currently no control device for electric powered bicycles to achieve precise assistance control.
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