Research On Position Detection Technology Of Consequent Pole Permanent Magnet Synchronous Machine Based On Hall Sensor

Permanent magnet synchronous motors are widely used in electric vehicles,household appliances,power tools and other fields because of the advantages of simple structure,high power density and high efficiency.Consequent pole permanent magnet synchronous machine(CPSM)replace some of the permanent magnet poles with iron core poles on the rotor to improve the utilization rate of permanent magnets and reduce the cost of the motor.Therefore,it has a good application prospect in the low cost field.This work is conducted based on the application of CPSM.Aiming at the problem of asymmetric Hall signals in CPSM,the position estimation strategy of asymmetric Hall signals is studied in depth.Firstly,this paper briefly explains the theory of CPSM,and then introduces the current development of control strategies for permanent magnet synchronous motor and the position detection technology of switching Hall.At the same time,the main research content of this paper is proposed.Secondly,the mathematical model of the CPSM is constructed,and the theories of field-oriented control and space vector pulse width modulation are introduced.The Hall signal of the CPSM is analyzed,and a method of re-dividing the Hall signal by the PM-arc ratio is proposed.Moreover,the traditional position estimation method based on Taylor series expansion is improved.The error source of this strategy is analyzed,and a compensation strategy is proposed.A simulation model is built in MATLAB/Simulink to verify the feasibility of this algorithm by simulation.Thirdly,in order to further improve the accuracy of position detection,a vector tracking observer based on the mechanical equation of motion is proposed for position observation.And a method to select the coefficient matrix by variable bandwidth gain is proposed.By further studying the asymmetric Hall position signal,the position signal is described as a position vector,and then the asymmetric Hall signal harmonic model is proposed.At the same time,the harmonic model is introduced into the vector tracking observer to achieve higher precision rotor position detection.The correctness and performance of this algorithm is verified by simulation.Finally,a set of experimental platform based on Micro Lab Box and CPSM is established.A series of experiments are conducted with this experimental platform.The experimental results show that both the improved Taylor series expansion algorithm and the vector tracking observer based on the asymmetric Hall signal harmonic model are feasible,and have great position estimation accuracy in both dynamic and steady state situations.