The piece-wise linearization research of interior permanent magnet synchronous motors field-weakening control

Based on the analysis of interior permanent magnet synchronous motors (IPMSM) mathematical model, the process of field-weakening control is studied in detail. A piece-wise linearization field-weakening control strategy is proposed in this paper. According to the characteristic of field-weakening control at different stages, the field-weakening control is divided into three areas, and all of the three areas are linearized respectively. The d-axis and q-axis current of working points, and control equation of the three field-weakening areas are got respectively. The linearized field-weakening control strategy saves the computation time of working point, improves the real-time performance of the system, and can realize maximum torque output. The test results prove that the IPMSM has better speed performance in wide speed regulating range by the use of the piece-wise linearization field-weakening control strategy. And the IPMSM is more controllable and has higher reliability. © 2015, The editorial office of Transaction of China Electrotechnical Society. All right reserved.