An automotive air conditioning compressor electric motor drive

Abstract

The present thesis wishes to offer a possible solution for the automotive air conditioning compressor electric motor drive. The low cost, high efficiency, compact size and practical implementation constraints are considered for the two major research direction that arrise- motor design and control strategy.The thesis includes the design methodology for a 6 slots/ 8 poles 3 phase permanent magnet synchronous actuator with surface permanent magnets. Classic electromagnetic design is followed by the optimization design stage based on a modified Hooke-Jeeves method and FEM inspection. Furthermore, because the cogging torque and total torque ripples are not satisfactory, a FEM embedded hybrid design procedure is defined, that uses FEM calculated values and underrelaxation coefficients to go back and correct the geometrical/ electromagnetic variables that have major impact upon the aforementioned characteristics. A new sensorless control strategy, based on six-step commutation and trapezoidal current command is proposed. The necessary information is obtained by processing only the current and voltage measurements data from the d.c. link. The proposed method is conceived to comply with the air conditioning compressor drive requirements, but may be applied to other systems with similar characteristics.