The role of neodymium magnets in electric bicycle control systems

In addition to the commonly used permanent magnet motors, electric bicycle control systems also use neodymium magnets. It is worth mentioning that the core components of these control systems are usually integrated into a handlebar that can rotate within a range of 0-30 degrees, making the design compact and efficient. Although there are many styles of handlebars on the market, the working principle is the same.

Components of the electric bicycle control systems

The control system is mainly composed of neodymium magnets, return springs, Hall elements, and controllers.

Neodymium magnets, also known as neodymium-iron-boron magnets, are the third generation of rare earth permanent magnets with the strongest performance and the most widespread use. They can generate a permanent and stable magnetic field within the handle without requiring additional electrical energy.

The role of neodymium magnets in electric bicycle control systems

The function of the return spring is to return the rotatable handlebar to its initial position after the user releases their grip, ensuring the safety of vehicle operation. When the user rotates the handlebar to increase speed, the return spring is compressed. When the user releases their grip, the return spring extends, returning the handlebar to its initial position.

The Hall element is a magnetic sensor based on the Hall effect, which can detect changes in the magnetic field and convert them into electrical signals that are transmitted to the controller. The Hall element has three wires connected to the controller, namely the power line, ground line, and signal output line. The Hall element and the neodymium magnet work together to form a sensor that senses the rotation angle of the handlebar.

The commonly used linear Hall components for electric bicycle handlebars include YS3503, YS49E, and YS495A.

image 1
Controller

The controller is a core control device used to control the starting, running, speed, stopping, and other electronic components of electric bicycles. It is like the brain of electric bicycles and is an important component of electric bicycles.

Principle of electric bicycle control systems

The role of neodymium magnets in electric bicycle control systems 9

When we turn on the electric bicycle switch, the power cord of the Hall element will receive a 5V working power supply provided by the controller. When we turn the handlebar, the position of the magnet fixed inside will change, and the magnetic field strength will also change accordingly.

Hall elements can accurately capture this magnetic field change and convert it into corresponding electrical signals. Hall elements also output a varying voltage of 1-4.2V to the controller based on the magnetic field strength.

After receiving the electrical signal from the Hall element, the controller will analyze and process it. By interpreting this electrical signal, the controller can accurately understand the rotation angle of the handlebar. Based on this information, the controller will further adjust the motor to control the speed and torque of the motor, and ultimately achieve control of the vehicle speed. The greater the voltage received, the faster the motor speed will be.

After receiving the electrical signal from the Hall element, the controller will analyze and process it. By interpreting this electrical signal, the controller can accurately understand the rotation angle

Type of magnets on the handlebar of electric bicycles

Although the performance standards for the control system are far less stringent than those for permanent magnet motors, a magnet with a high energy product is still required to improve control sensitivity and reduce usage space. Among the various performance levels, manufacturers most commonly use N35 grade neodymium-iron-boron magnets. It has high magnetic properties and can work stably for a long time below 80°C, which is sufficient for daily use in electric bicycles.

image 2
The role of neodymium magnets in electric bicycle control systems 10

There are mainly two types of magnets in the handlebar:

One is to embed a single curved magnet in the handlebar, and the magnetic induction intensity on different parts of the magnet surface will vary slightly. When the magnet rotates, the magnetic induction surface of the Hall element can capture this subtle change and thus change the output voltage.

Another structure is to install a plastic ring inside the handlebar, and install a magnet on each side of a certain arc of the ring, so that the Hall element is located between the two magnets.

When the handlebar of an electric vehicle is rotated, the magnetic induction intensity on both sides of the Hall element changes accordingly. This design is similar to the principle of using an arc-shaped magnet, but not exactly the same. Specifically, the magnetic induction intensity between two small magnets is susceptible to interference from multiple factors such as installation location and material deformation, resulting in less control and sensitivity than the first type. However, the advantage of this design is that it can save neodymium magnet materials and reduce costs.

Contact us: Contact | HQ Magnet (hq-magnet.com)

Our YouTube channel: HQ Magnet – Neodymium Magnets Factory Wholesale – YouTube