Variable-reluctance resolver design guidelines

The design of a variable-reluctance resolver structure which can be integrated into brushless motors is considered. The resolver is designed to provide absolute position information for motor phase commutation and incremental position information for position control. Basic resolver operation is reviewed, and critical resolver signal characteristics which determine resolver position accuracy are identified. Using a magnetic circuit approach, the inductance of a variable-reluctance structure was computed as a function of position. From this information the tooth parameters which minimize the maximum resolver position error were determined. In addition, design guidelines were formulated and the difficulty in achieving high position accuracy was assessed