Research On Magnetization Model And Rotor Flux Observation Of Combined-magnetic-pole Memory Motor

With the traditional permanent magnet synchronous motor widely used in various fields,its speed range is narrow,the low efficiency of high speed area is attracting more and more attention.But the emergence of memory motor provides an effective way to solve the problem.On the one hand,in these topologies,the combined magnetic pole type memory motor with the advantages of wider speed range,smaller power consumption,and lower cost gradually becomes the prototype research hotspot in the field of magnetic adjustment.On the other hand,the lack of systematic formulation of the control strategy limits its utilization due to the failure of ensuring the real-time and reliable detection of rotor flux in control strategy.A rotor flux observer is applied,which enables the real-time identification of the rotor flux in this paper.The focus are the research of(1)the basic structure and working principles of the combined magnetic pole memory motor,(2)the control strategy of this motor,(3)and design and analysis of the rotor flux observer.The first chapter systematically discusses the basic structure and working principles of the combined magnetic pole memory motor.The V-type combined magnetic pole type memory motor is selected as an instantiated template at first.After analyzing its basic structure,the motor air gap magnetic density waveforms in the situations of magnetization and demagnetization are studied through its working principles.Then,this chapter thoroughly analyzes the magnetic properties of AlNiCo permanent magnet and later establishes a magnetization model of AlNiCo permanent magnet under conditions of magnetization and demagnetization.For the purpose of improving the accuracy of this magnetic model,the model is designed with the help of hysteresis tester.After establishing the conceptual model of the motor,the focus is then switched to its specific control strategy.To control the motor,the constant torque control strategy is adopted in the low-speed region while piecewise constant torque control strategy is utilized in the high-speed region because of the variable working point of the permanent magnet.According to the motor's output characteristics at adjustable magnetic points,the constant no-load EMF method is adopted to adjust the magnetic state.Simulation results show that this control strategy can ensure that(1)the motor output torque is large enough in the low-speed region,(2)the motor has a high efficient working condition in the high-speed region,(3)and control system has excellent dynamic as well as static characteristics in a wide range of speed regulation process.The design and the analysis of the rotor flux observer are discussed after the determination of control strategy.The rotor flux adaptive observer traditionally is sensitive to the motor parameter disturbance.To solve this problem,this chapter uses the feedback gain optimization to eliminate the influence of q axis inductance that seriously impacts the identification accuracy of the disturbance process.The simulation result shows that:(1)when the parameters of the motor are of no disturbance,the rotor flux observer can accurately identify the real-time rotor flux;(2)when the motor parameters are of perturbation,the rotor flux observer can weaken the perturbation of parameters to ensure the precision of the observer.Last but not least,experiments designed for the rotor flux adaptive observer are performed.The procedures are conducted as follows: accurately measuring the stator resistance and the d-axis and q-axis inductance of the motor by the static measurement method;building the experimental platform,designing the flow chart of the observer system,and writing the experimental program.The experimental result shows that the rotor flux observer can resist the parameter disturbance,and real-time feedback of the rotor flux information coincides with the simulation result.All the evidence verifies the plausibility of the designed observer system.