Research On High Performance Control Strategy Of Synchronous Reluctance Motor

With the continuous increase in the price of rare earth permanent magnet materials in recent years and the destruction of the environment during the collection process,synchronous reluctance motors without permanent magnets in the rotor structure have become a new research focus.Common machines,such as fans,water pumps and injection molding machines,which are widely used in daily production and daily life,need low-cost and high-reliability synchronous reluctance motors to replace the traditional asynchronous motors because of their complex operating environment and large load torque changes.The focus of this subject is the high-performance control of synchronous reluctance motors under consideration of crosssaturation of magnetic circuits.First,the research background and significance of the topic are explained.The current research status is discussed and summarized from the aspects of motor control strategy and magnetic circuit saturation model.The rotor structure and working principle of the synchronous reluctance motor studied in this article are introduced.The mathematical model of the motor is established in the three-phase static coordinate system and the two-phase rotating coordinate system,and the commonly used additional control strategies are briefly analyzed,which lays the foundation for the subsequent design of high-performance control strategies.Secondly,the off-line measurement method is used to obtain the motor flux-current data,and the comparison with the finite element simulation results proves the correctness of the experimental results.To simplify the formula complexity of the traditional magnetic circuit cross-saturation model,this paper proposes a new type of magnetic circuit cross-saturation model,and substitutes the experimental data into the two models respectively.The comparison and fitting results show that the new model guarantees the accuracy of the model and simplifies the formula.Then,in view of the possible sudden load changes in industrial production,this paper proposes a direct torque control strategy based on MTPA.The synchronous reluctance motor is modeled in the MT reference frame.According to the motor model,a torque-flux double closedloop control system is established,and the MTPA control is improved according to the obtained magnetic circuit cross-saturation model.While improving the motor operating efficiency,the response speed of torque and flux linkage is improved.Next,to achieve wide-speed operation control of the synchronous reluctance motor,the operation range of the motor was studied by combining the voltage limit circle and the current limit circle.The modulation method of the inverter was changed to make full use of the DC bus voltage.At the same time,the flux reference calculation module and torque limit calculation module are improved to ensure that when the motor speeds up to above the base speed,the MTPA control and the field weakening control can be smoothly switched,and a complete highperformance control strategy for synchronous reluctance motors is obtained.Finally,MATLAB/Simulink is used to simulate and verify the proposed control strategy,and an experimental platform is built for synchronous reluctance motor based on TI hardware controller TMS320F28335.The effectiveness and reliability of the high-performance control strategy proposed in this paper is verified by the experimental results.