The "High Performance Control Method of Permanent Magnet Motor" invented by Prof. Xiao Xi’s team, Department of Electrical Engineering, won a the Gold Medal AFJ Award (Gold Medal) at the 46th Geneva International Exhibition of Inventions held from 11 to 15 April, and was recommended by the Avec les Felicitations du Jury.

The AC permanent magnet motor control system is widely used. Because of the high-order non-linearity of the system model and the strong coupling of electric, magnetic, thermal multi-field and multi-physical factors in various complex working conditions, how to achieve high performance and high reliability of the system becomes an important and difficult problem, and also an important technical bottleneck restricting the development of many industries. In view of the actual needs of industrial automation equipment such as industrial robots and CNC machine tools, the team has carried out a research on the high dynamic response, high-reliability and high- precision control technology of AC motors. The main achievements of the project include: putting forward a set of incremental predictive control methods and strategies for AC permanent magnet motors, and giving the theoretical analysis and optimal design method of the control system, which can upgrade the torque dynamic response speed and system stability; proposing a set of low-delay sampling, filtering algorithm and interpolation prediction method for position and speed control in very low speed region, which can effectively reduce speed and position measurement delay and improve speed and position control accuracy; to solve the problem of permanent magnet motor’s loss of excitation, proposing an dynamic observation method based on extended Kalman filter from the perspective of motor control, which can realize the dynamic on-line monitoring, analysis and optimal control of permanent magnet magnetic field of permanent magnet motor.

Results: Through the cooperation between Tsinghua University and related enterprises, the high performance motor control system developed by Tsinghua University has been widely used in robots, processing centers and various industrial automation equipments. User units include more than 20 power transmission equipment enterprises at home and abroad. Typical application cases include: Localization of the key technology of multi-axis servo control in multi-joint robots, which occupies a significant market share; and the motor-driven high-voltage circuit breaker based on high dynamic response algorithm, which fills the gap in the domestic industry, and realizes the successful operation of the first set in China.