With the improvement of global awareness of environmental protection and the transformation of energy structure, new energy vehicles, as an important representative of green travel, are ushering in unprecedented development opportunities. As the core component of the power system of new energy vehicles, the design and optimization of the motor is directly related to the energy efficiency, driving range and driving experience of the vehicle. Among them, the design of new motors and the application of weak magnetic control technology have become one of the key technologies to improve the performance of new energy vehicles. This paper will deeply discuss the design points of the new motor of new energy vehicles and the realization principle of weak magnetic control technology, in order to provide reference for the innovative development of new energy vehicle industry.

New motor design: the pursuit of high efficiency and lightweight

The key of new energy vehicle motor design lies in high efficiency, lightweight and reliability. Traditional motors have been difficult to meet the high requirements of new energy vehicles in terms of energy efficiency and power density, so the design of new motors has become a hot spot of industry research.

1. Rotor structure design

The built-in permanent magnet synchronous motor (IPMSM) has become the first choice for new energy vehicle drive motors due to its high torque/power density and good weak magnetic capacity. Among them, the tangential built-in rotor structure of Spoke improves the air gap magnetic density through flux aggregation, which has a higher torque/power density. However, this kind of structure has the problems of large inner flux leakage and insufficient utilization of potential reluctance torque. To this end, the researchers proposed a new modular high salient pole ratio polymagnetic rotor structure, by optimizing the magnetic circuit design, effectively solve the above problems, improve the motor torque output and weak magnetic expansion ability.

2. Material and process innovation

In terms of material selection, the new motor uses high-performance permanent magnet materials and lightweight high-strength materials, such as carbon fiber composites, to reduce the weight of the motor and improve the power density. At the same time, advanced manufacturing processes such as precision casting, laser welding and 3D printing technology ensure the compactness and reliability of the motor structure.

3. Electromagnetic design optimization

Electromagnetic design is the key to motor performance. Through accurate electromagnetic field analysis and simulation, motor parameters such as pole number, slot number, winding structure and magnetic circuit design are optimized to achieve efficient motor operation and low loss. In addition, the fractional slot short-distance winding technology can further reduce the harmonic loss and improve the motor efficiency.

Weak magnetic control technology: improve energy efficiency and broaden the speed range

Weak magnetic control technology is an important technology in the motor control of new energy vehicles, which can improve the energy efficiency and broaden the speed regulation range of the motor by adjusting the magnetic field strength of the motor.

1. How it works

The core idea of weak magnetic control is to reduce the energy loss in the process of magnetic flux change. When the motor is running at high speed, the excitation component in the stator current is reduced to reduce the magnetic field intensity, so as to keep the output voltage within the allowable range and avoid overvoltage protection. This process needs to ensure that the output torque of the motor meets the needs of the premise, to achieve the improvement of the motor speed.

2. Control strategy

The weak field control strategy includes control based on voltage limit ellipse, control based on current distribution and direct torque control. Among them, the control method based on voltage limit ellipse can make the motor run in voltage limit ellipse by adjusting the component of current vector on dq axis, and achieve maximum torque output. The control method based on current distribution achieves the optimal balance of motor efficiency and torque by precisely controlling the current of D-axis and Q-axis. The direct torque control method can directly adjust the voltage vector by monitoring the motor torque and flux in real time to achieve fast response and efficient control.

3. Control system design

The realization of weak magnetic control technology needs a complete control system, including hardware design and algorithm design. In terms of hardware design, advanced power semiconductor devices and high-precision sensors are used to ensure the stability and accuracy of the control system. In the aspect of algorithm design, through in-depth analysis and modeling of the magnetic field variation characteristics of the motor, the best control strategy and parameter setting are determined to achieve efficient and stable operation of the motor.

Conclusion and prospect

The design of new motors for new energy vehicles and the application of weak magnetic control technology are key technologies to improve the performance of new energy vehicles and achieve green travel. By optimizing rotor structure, using high-performance materials and advanced manufacturing processes, as well as precise electromagnetic design and control strategies, the energy efficiency and power density of motors can be significantly improved. At the same time, the application of weak magnetic control technology further broadens the speed regulation range of the motor and improves the energy efficiency of the vehicle at high speed. In the future, with the continuous progress of material science, manufacturing process and control technology, the design and control technology of new energy vehicle motors will be more intelligent and efficient, providing strong support for the sustainable development of the new energy vehicle industry.