Research Of Performance At Low Speed In Sensorless Control Based On Effective Flux Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)has been widely used in industry because of its high efficiency,large power density and small volume.In the permanent magnet synchronous motor control system,mechanical position sensors are used to obtain the rotor position.Because of its high cost and poor reliability in harsh environment,the sensorless control technology has gradually become a hot spot in related research fields.In this paper,the flux observer and the model reference adaptive method are combined to estimate the rotor position.By improving the basic structure of these two algorithms,a new sensorless control algorithm which can effectively improve the performance of low-speed operation is proposed.Firstly,the vector control strategy and sensorless control algorithm of PMSM are introduced.On this basis,the principle of flux observer algorithm is described,and the improved second-order generalized integrator structure is used to replace the pure integrator so as to solve the DC bias and integration saturation caused by the pure integration of the traditional voltage model.In order to improve the accuracy of rotor position estimation in low-speed section,the hybrid voltage/current model is selected for position estimation,and the effective flux is used to simplify the structure of the observer,which is convenient for the extraction of estimated position information.In view of the problem that the algorithm is susceptible to the change of stator resistance during operation,a new control algorithm combining model reference adaptive system(MRAS)and flux observer method is proposed.The voltage model and the current model are used as the reference model and the adjustable model of MRAS,and the rotor speed and the stator resistance can be identified in parallel.The control algorithm can improve the operational performance at low speeds and enhance the robustness of the system.The feasibility of the proposed control strategy is verified by simulation.Finally,the experiment platform is built based on the DSP chip TMS320F28379 D.In addition,the design process of hardware and software is described in detail.The experimental results show that the control strategy is effective and correct.