Torque-maximizing field-weakening control: design, analysis, and parameter selection

The torque-maximizing field-weakening control scheme proposed by Kim and Sul is developed further. The performance under imperfect field orientation conditions is investigated, and it is shown that an overestimated-rather than an underestimated-model leakage inductance should be used. A slightly modified algorithm, which offers better robustness and reduced computational complexity, is presented. The importance, for good performance, of combining the scheme with current and speed controllers featuring antiwindup and improved disturbance rejection is emphasized. The dynamics of the resulting closed-loop system are analyzed. Obtained in the process, are rules for selection of all controller parameters, allowing tuning without trial-and error steps. Good performance of the resulting system is verified experimentally.