Power Factor Optimization Method for Induction Motor High-Speed Drives

The induction motor (1M) voltage closed-loop field-weakening method can achieve the maximum torque output capability. However, the active power that supplies the load and the reactive power that forms the magnetic field are confined by the voltage boundary, leading to power factor deterioration. To address this problem, the principle of optimal power distribution is derived for 1M high-speed drives. It is quantitatively proved that to maximize the power factor, the dq-axis stator currents should maintain a certain proportion. On this basis, the power factor optimization control is achieved by regulating the flux current through a closed-loop structure and a limit block. Compared with the conventional method, the power factor with the investigated method is effectively improved in the field-weakening region. The effectiveness of the proposed algorithm is demonstrated on a 3.7kW IM drive system.