Study on a BLDC motor having higher winding inductance: A key to field weakening

The study covers the design, analysis and experimental study of a 1 kW motor which is designed for a special in-wheel motor driven light electric vehicle. The main concern is to design a BLDC motor having a higher value direct-axis phase inductance which is providing high performance field weakening operation. A sub-fractional slot concentrated winding structure with unequal tooth widths is chosen. The design phase is including the motivation and the computer aided design works. A software package based on configurator approach is used to determine the motor parameters in a broad sense. Then the motor is modeled in a Finite Element Analysis (FEA) package for detailed analysis and, particularly the 2D and 3D field analyses are obtained to verify winding inductance value. The designed motor is manufactured precisely and an experimental study is held to verify the design work including the precise measurement efforts for the motor inductance. Also the field weakening operation of the motor is managed by using phase current advance method.