Research On Vector Control Strategy Of Synchronous Reluctance Motor

Synchronous Reluctance Motor(SynRM)is a synchronous motor which uses magnetic resistance to work.Compared with asynchronous motors,SynRM has no copper loss and high efficiency;compared with permanent magnet motors,SynRM has no permanent magnets,low cost,and no high temperature and Vibration demagnetization;compared with switched reluctance motor,torque ripple is small.SynRM has broad application prospects because of their excellent performance.The control strategy of the drive system is the core.The study of the SynRM control strategy in this paper has important theoretical significance and industrial application value.The mathematical model of SynRM in the stationary coordinate system and the rotating coordinate system is established,and the vector control strategy of SynRM d-axis constant flux linkage with speed sensor is deduced and studied,and the performance characteristics of each speed section under this control strategy are analyzed.The speedless sensor control scheme reduces the cost of hardware,enhances the adaptability of various industrial applications of the system,and this paper studies the speed sensorless vector control.Middle and high-speed zone:A speed sensorless contrSynRMol algorithm based on the back-EMF method is adopted,the rotor position is estimated using the back-EMF information,and the angle is observed with a phase-locked loop.Low-speed zone:Due to the small back-EMF of the motor at low speeds,the algorithm based on the fundamental wave equation of the motor has a large estimation error.Considering the high saliency ratio of SynRM,based on the analysis of the saturated saliency effect of SynRM,the speed estimation strategy of pulse high frequency voltage injection method suitable for low speed domain is adopted.Randidation Zone:Aiming at the smooth switching problem of the overlapping area between the low-speed zone and the high-speed zone of SynRM,the above two algorithms are combined to form a composite flux observer.The weighted average method is used to make the two algorithms smoothly transition in different speed zones,and the structure is constructed by The SynRM full-speed domain speed sensorless vector control system composed of back-EMF method and pulse high-frequency injection method.A SynRM speed sensorless control experiment platform with DSP as the controller is built,and the system software and hardware are designed.The hardware part includes the main power unit,sampling and conditioning circuit,optical coding and conditioning circuit,overcurrent protection and D/A circuits.,The software includes the main and interrupt programs.The experimental verification of vector control with speed sensor and speed sensorless vector control based on back electromotive force method,pulse high frequency injection method and the combination of the two has been completed on the prototype.The simulation and experimental results show that the back-EMF method realizes the stable operation of SynRM in the low-speed area without speed sensor,and the pulsed high-frequency injection method realizes the stable operation and start-up of SynRM in the low-speed area without speed sensor.The composite flux observer formed by the combination of the two algorithms realizes the stable operation of SynRM in the low-speed and medium-high-speed domains.