Looking at the technological development of brushless motors in the world in recent years, the following development trends are presented:

　　1) Products are developing in the direction of specialization and diversification.

　　Almost all brushless DC motor products are manufactured, designed and manufactured for specific purposes. It is impossible to try to produce a universal series of brushless DC motors to adapt to the ever-changing application market demand. Various manufacturers design and manufacture various brushless DC motors with special structures and specific purposes, and constantly innovate in design, structure and new technology to meet the needs of different complete machine markets. E.g:

　　To adapt to different performance parameters of permanent magnet materials, new rotor magnetic circuit structures such as tile-shaped, ring-shaped surface bonding structures and various designs of embedded internal magnet structures have appeared. There are various external rotors, axial air gaps (planar motors), motors with slotless structures, linear brushless DC motors, etc.

　　Whether it is a permanent magnet brushless DC motor using ferrite permanent magnet or rare earth permanent magnet materials, the common permanent magnet rotor structure is a surface-mounted (hereinafter referred to as surface-mounted) permanent magnet structure. In recent years, well-known Japanese home appliance manufacturers have adopted their own patented rotor structures in the permanent magnet brushless DC motors of the new generation of inverter air conditioner compressors, and the embedded permanent magnet rotor structure has become the mainstream. The motor with the IPM rotor structure can obtain higher efficiency and enhance the rotor's ability to resist high-speed centrifugal force.

　　This article is taken from ------"Permanent Magnet Brushless DC Motor Technology