Parameters and Volt-Ampere Ratings of a Synchronous Motor Drive for Flux-Weakening Applications

This paper deals with the selection of the motor parameters and the inverter power ratings for a permanent magnet (PM) synchronous motor drive in order to meet a given flux-weakening torque versus speed characteristic. Appropriate combinations of stator PM flux linkage, d- and q-axis inductances, and inverter current rating at a given voltage are derived, in normalized values, as functions of the specified flux-weakening speed range and torque limits. By means of these sets of data, the drive designer can easily individuate and compare all the suitable synchronous motors (defined by the d- and q-axis inductances and flux linkage) and the related inverter volt-ampere ratings, for the desired flux-weakening performance. Therefore, this paper can be considered a synthesis work rather than an analysis one and can profitably be used for an optimal design of a synchronous motor drive.