A modified flux-weakening control method of PMSM based on the d-q current cross-coupling effect

Single current regulator flux-weakening control based on the d-q current cross-coupling effect is a novel strategy for PMSM (permanent magnet synchronous motor). This flux-weakening strategy can solve the problem that two current regulators of traditional algorithms conflict with each other in high speed operation region and lead to poor system performance. Q-axis voltage given scheme is a key issue of this method, which influences PMSM´s voltage utilization ratio, efficiency and load capability. Based on voltage equation of PMSM, this paper described the basic principle of flux-weakening control based on the d-q current cross-coupling effect and presented a modified control method. The disadvantages of existing control methods and the expected results of the proposed control method were analyzed by using stator current trajectory in i_d-i_q coordinate plane. Dynamic control process was analyzed in the range of small signal. The modified control method can adjust q-axis voltage to motor operating condition. It does not depend on motor parameters or look-up table, and is easy to achieve. This method is verified by the results of simulation and experiment.