What is the current status of sensorless control technology for permanent magnet synchronous motors?
pmsm is widely used in aerospace, electric vehicles, industrial servo and other fields due to its inherent characteristics of high torque to inertia ratio, high energy density, and high efficiency. With the development of high-performance magnetic materials, power electronics technology, microelectronics technology and modern control theory, especially the introduction of high-performance control strategies such as vector control and direct torque control, the pmsm speed control system has developed rapidly. The pmsm vector control imitates the DC motor to obtain excellent dynamic and static performance through decoupling control of torque component and excitation component. It broke the dominance of the DC speed control system in the field of high-performance electric drive, and gradually entered the era of AC speed control system.
The high-performance pmsm control system relies on reliable sensor devices and precise detection technology. Traditional control systems mostly use mechanical sensors such as photoelectric encoders and resolvers to obtain rotor position information. However, it is difficult to install and maintain mechanical sensors, which not only increases the complexity of the mechanical structure of the system, but also affects the dynamic and static performance of the system, and reduces the robustness and reliability of the system. The performance of pmsm vector control system is often limited by the accuracy and response speed of mechanical sensors. High-precision, high-resolution mechanical sensors are expensive, which not only increases the cost of the drive control system, but also limits the application of the drive device under harsh conditions. The fundamental solution to the contradiction of mechanical sensors with low cost, high precision and high reliability is to remove the mechanical sensors and adopt sensorless technology. Therefore, the research of pmsm sensorless control technology has quickly become a hot spot.
Research status of pmsm at home and abroad
Research work on sensorless control technology was carried out abroad in the 1970s. In the following 20 years, scholars at home and abroad have conducted extensive research on the sensorless operation of AC motors and proposed many methods. These research results enable the motor drive system without sensor control to be applied in more industrial fields.
pmsm sensorless technology has two main development stages: the first generation of AC motors using sensorless vector control technology has appeared on the market after nearly 10 years of research and prototype tests. The speed regulation accuracy of the first generation sensorless motor is not high, and the speed range that can work normally is also limited. At low speed and zero speed, the mechanical characteristics are very soft and the error becomes very large, and the speed regulation cannot be carried out. The first generation of sensorless technology is still very imperfect, thus limiting its scope of use. What is being developed now is the second generation of sensorless technology, which is expected to have higher accuracy and complete torque control at zero speed, which is comparable to traditional vector control technology. The expected application fields of the second-generation sensorless technology are basically the same as the first-generation sensorless technology, but have better dynamic characteristics.
This article is from Allicdata Electronics Limited which offer electronic components, semiconductors, antennas, capacitors, connectors, diodes, transistors, IC,resistors. For more product information, please go to the website to get it.