2.2 There is a problem
In the process of developing high-performance permanent magnet synchronous motor, at the same time, the above-mentioned results have been obtained, and some problems have been obtained, which need to be further studied and explored.
1) Irreversible demagnetization problem. If the design or use is improper, the permanent magnet synchronous motor is under too high (NdFeB permanent magnet) or too low (ferrite permanent magnet) temperature, under the armature reaction caused by the inrush current, or in the severe mechanical vibration When there is a possibility of irreversible demagnetization, or loss of magnetism, the performance of the motor is degraded or even impossible to use.
Therefore, it is necessary to research and develop methods and devices for checking the thermal stability of permanent magnet materials used in motor manufacturers, and to analyze the anti-demagnetization capabilities of various structural types, so as to ensure the use of corresponding measures for design and manufacture. The magnetic synchronous motor does not lose magnetism.
2) Cost issues. Ferrite permanent magnet synchronous motors have been widely used because of their simple structural process and reduced mass, and the total cost is generally lower than that of electric excitation motors. Since the current price of rare earth permanent magnets is relatively expensive, the cost of rare earth permanent magnet motors is generally higher than that of electric excitation motors, which needs to be compensated for by its high performance and operating cost savings. In the design, it is necessary to compare the performance and price according to the specific use occasions and requirements, and also carry out the structural process innovation and design optimization to reduce the cost.
3) Control problems. A permanent magnet synchronous motor maintains its magnetic field without external energy, but it also makes it extremely difficult to adjust and control its magnetic field from the outside. However, with the development of power electronic devices and control technologies such as MOSFETs and IGBTs, most permanent magnet synchronous motors can be used for armature control without magnetic field control. The design requires the combination of three new technologies: permanent magnet materials, power electronics and microcomputer control to make the permanent magnet synchronous motor operate under new conditions. In addition, the permanent magnet synchronous servo motor with permanent magnet synchronous motor as the actuator has a certain nonlinearity, strong coupling and time-varying system, and its servo object also has strong uncertainty. And non-linear, coupled with the system is susceptible to different degrees of interference, so the use of advanced control strategies, advanced control system implementation (such as DSP-based control), to improve the overall intelligent and digital level of the system, this should be the current A major breakthrough in the development of high-performance permanent magnet synchronous motor servo systems.
