Research On Position Sensorless Control Strategy Of Double Salient Electro-magnetic Motor

There are no windings and permanent magnets on the rotor of the double salient electromagnetic motor,which can withstand larger centrifugal force and higher ambient temperature,and is suitable for high-speed and high-temperature operation,but rotor position information is needed to realize correct commutation of the double salient electro-magnetic motor,and the installation of the position sensor weaks the advantages of the simple rotor and reduces the reliability of the system.In order to overcome this defect,the sensorless control method of the double salient electro-magnetic motor is studied in this paper.First,the structure and mathematical model of the double salient electro-magnetic motor are briefly introduced.Combining the ideal inductance model and mathematical equations,the electromagnetic torque is analyzed in detail.On this basis,the basic control method of the double salient electro-magnetic motor is analyzed.The finite element software ANSYS/Maxwell was used to build a physical model of the double salient electro-magnetic motor,and its basic electromagnetic characteristics were calculated and analyzed.In order to improve the efficiency of the simulation,a simulation model of the double salient electro-magnetic motor was built in Matlab/Simulink using the motor parameters calculated by the finite element model.Secondly,introduced the method of obtaining the interval of the rotor from the relationship of the phase winding response current by injecting the detection pulse into the armature winding,it mainly uses the characteristics of the armature self-inductance that changes with the rotor position.Through comparative research,a method based on the corresponding relationship between phase winding-field winding mutual inductance and rotor position is proposed,by injecting sinusoidal current into the field winding,and using the magnitude relationship of the three-phase armature winding induced potential to determine the initial position of the rotor,and using ANSYS /Maxwell has carried on the simulation verification to this method.After obtaining the initial position of the rotor,in order to achieve no-reverse start under no-load or light-load conditions,a no-reverse start strategy was developed through the analysis of cogging torque,self-inductance torque and mutual inductance torque.Then,based on the method of detecting the initial position of the rotor,the armature winding detection pulse injection method and the excitation winding sinusoidal current injection method are respectively applied to the low speed section.The former uses the armature winding to alternately inject detection pulses and acceleration pulses,and uses the magnitude of the response current of the phase windings when the detection pulses are injected to determine whether the commutation point has been reached;The latter superimposes a fixed-frequency,fixed-amplitude sinusoidal current in the DC excitation current,filters the non-conducting phase voltage,and uses the obtained sinusoidal response voltage as the commutation criterion.In the middle and high speed range,the excitation current is kept constant,and the non-conducting phase voltage is used as the commutation criterion,and it is judged whether the rotor reaches the commutation point by comparing with the threshold voltage at the commutation point.Finally,according to the parameters of the experimental prototype,the hardware circuit of the double salient electro-magnetic motor control system is designed,an experimental platform is built,and some of the aforementioned methods are experimentally verified.