A Statistical Solution to Efficiently Optimize the Design of an Inverter-Fed Permanent-Magnet Motor

This paper provides the fundamentals of integrated motor-drive system design knowledge that could be used as a basis to change the existing machine design approach from being a separate machine design tool to a more advanced engineering package in which the inverter performance can also be considered. Various users' preferences including motor performances in the transient, rated, and flux-weakening operations along with the inverter quality are studied by means of a detailed cosimulation process which utilizes finite element method, MATLAB, and SIMULINK packages to build the framework based on which magnetic, electric, and electronic devices and quantities are modeled, simulated, and postprocessed. A case study of an interior-permanent-magnet motor connected to a field-oriented controlled drive is investigated and the design process concepts are developed by means of a comprehensive statistical analysis. It is shown that incorporating the inverter quality into the design process changes the idea of optimum motor design, and hence, not only the design parameters but also the expectations from motor performances have to be revised. In fact, an integrated motor-drive system design process regarding the best motor operations in the transient, rated, and flux-weakening modes is targeted with the purpose of addressing design challenges of interior-permanent-magnet motors. To this end, the start-up torque, the rise time, the motor efficiency, the torque ripple, the constant power speed range, the characteristic current, the inverter efficiency, and the system cost, which cover a group of important objectives of different applications, are investigated. Finally, a design package will be able to address different designers' expectations more efficiently using the approach proposed herein.