An improved rotor speed estimation method of IPMSM drives with cyclic fluctuating load

In order to estimate the speed fluctuation band of interior permanent magnet synchronous motor (IPMSM) under speed sensorless control with cyclic fluctuating load accurately, an improved rotor speed estimation method is proposed. A rotor flux oriented vector control with conventional model reference adaptive system (MRAS) based rotor position/speed estimation is employed as the basic control strategy for IPMSM drive. The finite element method (FEM)-based model of IPMSM is built by magnetic field analysis in JMAG software to obtain motor parameter variations caused by different phase currents and rotor position. These motor parameter variations are used in MRAS for precise speed fluctuation band estimation. Furthermore several motor output torque patterns matching the cyclic fluctuating load with feed-forward compensation strategy are developed to lower the speed ripple. Simulation and experimental results demonstrate the feasibility and effectiveness of the proposed control methods, which shows that the error between actual speed fluctuation band and estimated speed fluctuation band is limited within a very low level.