Working principle of 48V brushless DC motor

The 48V brushless DC motor interacts with the magnetic field generated by the armature winding and the permanent magnet to ensure that the magnetic field remains vertical when the motor is running, thereby generating maximum torque. Its working principle is based on the constant magnetic flux density distribution under the magnetic pole. When the motor is running, the current entering the armature winding is constant, thereby continuously generating constant torque. In other words, the magnitude of the torque is only determined by the magnitude of the armature current and is not affected by other factors.

When the motor is running, the rotor position sensor is responsible for detecting the rotor position signal in real time. This signal is used to control the switching state of the commutation drive circuit and adjust the connection state between the armature winding and the power supply. The drive circuit controls the stator winding through the power switch. When the winding is energized, a rotating magnetic field is generated on the stator, driving the rotor to rotate accordingly. As the rotor rotates, the position sensor continuously detects its angle and adjusts the current direction through commutation to ensure that the current direction in the conductor remains unchanged, thereby generating continuous torque and ensuring smooth operation of the motor.

The composition of the 48V brushless DC motor includes the motor body, the electronic switching circuit and the rotor position sensor. These three parts constitute a closed-loop control system. In the motor body, the stator winding is often connected in star or delta, and the inverter of the electronic switching circuit can use a half-bridge circuit or a full-bridge circuit. These choices directly affect the performance and manufacturing cost of the motor.

Winding utilization

Unlike traditional DC motors, the windings of 48V brushless DC motors are intermittently energized. By improving the utilization of the windings, the number of energized conductors can be increased, the winding resistance can be reduced, and the overall efficiency can be improved. For example, the utilization of three-phase stator windings is higher than that of four-phase, and four-phase windings are better than five-phase. In terms of electronic switching circuits, inverters with full-bridge control can improve motor efficiency and are more effective than half-bridge control.

Torque ripple

In brushless DC motors, the output torque usually produces a certain amount of pulsation, which may affect the smooth operation of the motor in some applications. Therefore, reducing torque ripple is the key to improving motor performance. Generally speaking, the more phases a motor has, the smaller the torque ripple. For example, the torque ripple of a five-phase motor is smaller than that of a four-phase motor, while the ripple of a three-phase motor is relatively large. In addition, the full-bridge control drive circuit can better reduce torque fluctuations and is more stable than the half-bridge control.

Circuit cost

The more phases the motor has, the more switches the drive circuit requires, and the manufacturing cost increases accordingly. Taking the full-bridge drive as an example, the number of switches required is twice that of the half-bridge drive, resulting in higher costs. In addition, the structural complexity of the multi-phase motor also increases its production cost, so when selecting a motor, it is necessary to weigh the balance between performance and cost.

Advantages of 48V brushless DC motor

Compared with traditional brushed motors, the 48V brushless DC motor has the following significant advantages:

1. Long life: Due to the brushless structure, there are no mechanical wear parts, which reduces maintenance requirements and replacement frequency.

2. High efficiency: The brushless design reduces energy loss and improves energy utilization, especially in applications that require precise control and frequent speed regulation.

3. Low noise: The brushless design eliminates the friction noise of the carbon brush, making the motor run quieter.

4. Strong reliability: The electronic control system of the brushless DC motor makes it more advantageous in overload and overvoltage protection, and is suitable for long-term stable operation.

This type of motor is widely used in scenarios that require flexible starting and speed regulation, such as power tools, industrial equipment, fans, electric vehicles, etc. If you are looking for an efficient and reliable 48V brushless DC motor, welcome to visit the official website of Cimuc Motor for more information on high-quality products.