High-Performance Control Strategy for Low-Speed Torque of IPMSM in Electric Construction Machinery

Electric construction machinery with zero emission and high efficiency is considered to be a main development trend. An electric motor (EM) in electric construction machinery often needs to work at low speed or even in stalling conditions with large torque value and high work efficiency. In this paper, based on vector control of the maximum torque per ampere (MTPA) of an internal permanent magnet synchronous motor (IPMSM), a voltage and current composite observation algorithm was studied to improve IPMSM control performance at low speed. By establishing the observer model, the amplitude limited compensation for the voltage flux observation method was used to observe the EM stator flux. After being combined with the current observation method and the stator current obtained by coordinate transformation, the EM parameters in real-time can be identified for MTPA. Experimental research was carried out. The results show that the algorithm improved the speed control characteristic and output torque per unit current of the EM under low-speed working conditions.