Project background:
As we all know, electro-excited synchronous motors can easily adjust DC excitation and have a small DC excitation capacity, so they have advantages in field adjustment that permanent magnet synchronous motors cannot achieve. Permanent magnet motors also have a series of unique advantages due to the elimination of brushes and slip rings, such as high efficiency, large torque/mass ratio, simple structure, small size, etc., and are used in electric traction (roads and railways), textile drives, Aviation navigation, variable-speed power generation (automobiles, aircraft, wind power generation) and other fields. However, the air-gap magnetic field of permanent magnet motors is determined by magnetic steel and magnetic circuit permeance, which remains almost constant during operation, and excitation adjustment is difficult, which largely limits the development and application of permanent magnet motors.
Hybrid excitation motors not only inherit many characteristics of permanent magnet motors, but also have adjustable excitation. When used as generators, they can provide constant voltage power supply; when used as motors, they have the advantages of large starting torque and wide speed regulation range. It has broad application prospects in many industrial fields and military fields such as aerospace and ships.

Main research content and innovation points:
(1) Key research was carried out around the parallel-structure hybrid excitation synchronous generator, and the design method of the parallel-rotor hybrid excitation synchronous generator was studied. With the help of the armature reaction theory, the respective working states of the permanent magnet part and the electric excitation part were revealed, and the operation mechanism of the motor under different configurations of excitation current and load current was studied; the combination of the permanent magnet part and the electric excitation part was discussed.
(2) A new type of series magnetic circuit hybrid excited claw-pole generator is proposed. The magnetic circuit calculation method and 3D finite element analysis are used to study the magnetic density of each part of the new motor, and the appropriate pole pairs and reasonable magnetic steel thickness are determined. The no-load characteristics, external characteristics and regulation characteristics of this new motor are discussed.
(3) A magnetic shunt radial structure hybrid excitation synchronous generator is designed. By adjusting the excitation current, the magnetic shunt structure can be used to easily adjust the air-gap magnetic field of the motor. The structure and working principle of the motor are described, the concepts of magnetic shunt point, magnetic non-dividing calculation square flow point and load balance point are discussed, the magnitude of air-gap flux at magnetic shunt point and magnetic non-dividing point is qualitatively analyzed, and the positions of magnetic shunt point, magnetic non-dividing point and load balance point are calculated using two-dimensional finite element method.
(4) According to the development trend of "permanent magnet driving for spindle", taking the mixed-excited machine tool spindle motor as the research direction, a structure of a mixed-excited machine tool spindle motor is proposed, the overall plan is designed, and the technical route is formulated. Based on in-depth motor multi-physical field simulation research, various parameters of the motor are calculated and determined. A principle prototype was trial-produced and verified by test that it met the design requirements.

The hybrid excited synchronous motor studied in this research has the advantages of permanent magnet synchronous motors and electrically excited synchronous motors, with small excitation power and high efficiency. It has been applied and promoted in Shanghai Jufeng Motor Automation Co., Ltd. and Shanghai Dasu Motor Co., Ltd. respectively. The new output value in the past three years has been 37.27 million yuan.

This achievement has published 17 papers in domestic and foreign journals and international conferences, was cited 168 times by him, authorized 2 national invention patents and 13 utility model patents; published a monograph "The Structure and Principles of Hybrid Excitation Motors" in Science Press. Department; trained more than 800 graduate students; The application and promotion of this achievement has achieved good economic, social and environmental benefits, effectively promoted the development of efficient and energy-saving motor products, and promoted talent training and scientific and technological progress in the new motor industry.