Field Weakening Design for a High Speed Nine-phase Permanent Magnet Synchronous Machine in More Electric Aircraft

High speed multi-phase permanent magnet synchronous machine (PMSM) offers increased power density and fault-tolerant ability, which qualifies it a promising solution for the ever-increasing power and reliability demands of more electric aircraft (MEA). Pushed by the high-speed design, high performance field weakening control of the machine necessarily demanded. Under the concept of field oriented control (FOC), field weakening methods can be designed considering different priority between d and q axis control. This paper aims comparing those differences and proposing the suitable solution for the high speed PMSM drive in MEA. The equivalent circuit of the field weakening loop is derived, which demonstrates the tuning of the field weakening controller in terms of stability and performance without considering the anti-windup and saturations. Recommendations on the design of anti-windup and saturations considering d and q-axis prioritizations are provided.