Design comparisons of BLDC motors for electric water pump

Recently, many hydraulic automotive parts are being replaced by the electric parts using electric motor drive system because of high performance for the conventional car having engine and the growth of electric vehicles. In the many kinds of electrical motor drive systems, BLDC is generally applied for the power train motor, electric HVAC compressor, cooling fan and pump. It is due to high efficiency and high output power characteristics. In the BLDC motor design, the rare-earth magnet material e.g. Nd-Fe-B magnet is often used because of high flux density compared with any other magnet material. However, the material cost of Nd-Fe-B magnet is abnormally rising because of the shortage of supply. In this paper, the low cost design by the magnet material change is studied about the 20[W] BLDC motor design for electric water pump. The design results of conventional IPM (Interior Permanent Magnet) type BLDC motor using Nd-Fe-B magnet and SPM (Surface Permanent Magnet) type BLDC motor using Ferrite magnet is compared each other. As a result of this study, the design comparison results concerning about output performance and material cost are represented.