Space Vector Flux Weakening in Permanent Magnet Synchronous Machines Considering Demagnetization Risks and its Performance Impacts

• Published in: 2023 15th IEEE International Conference on Industry Applications (INDUSCON) pp. 918 - 924
• Main Authors: Vecchia Gueter, Daniel Dalla, Chabu, Ivan Eduardo
• Format: Conference Proceeding
• Language: English
• Published: IEEE 22-11-2023
• Subjects: Demagnetization; electrical vehicles (EVs); flux weakening; hybrid electrical vehicles (HEVs); Magnetic flux; Mathematical models; Permanent magnet motors; Permanent magnets; permanent magnets (PMs); permanent magnets synchronous machines (PMSMs); Synchronous motors; Torque; Voltage
• ISSN: 2572-1445
• DOI: 10.1109/INDUSCON58041.2023.10374699

In many applications where torque is required in limited physical spaces, a permanent magnet synchronous machine (PMSM) is usually chosen because of its high power density characteristic. One example of this is in electrical propulsion, where high torque and speeds are needed. However, since PMSMs present difficulties in operating above their nominal speed, flux weakening methods are used to decrease the overall magnetic linkage flux, thus allowing the motor to accelerate. The most common method is called space vector flux weakening, and it can result in permanent magnets (PMs) demagnetization. In this paper, the equivalent circuit of a PMSM is explored, leading to the voltage equations used to explain the concept behind the space vector flux weakening method. Finite Element Method (FEM) simulations are executed to compare the demagnetization risk of two permanent magnet synchronous motors used in electrical vehicles (EVs) and hybrid electrical vehicles (HEVs), where flux weakening methods are applicable and relevant. Finally, torque analyses after demagnetization are also presented to understand performance impacts.