| By applying the concept of memory machine into the multi-tooth switched flux permanent magnet machine,the equivalent magnetic circuit model is designed by using the topology of a new multi-tooth switched flux permanent magnet memory machine.Based on the topology of this machine,the following parts are mainly studied according to the equivalent magnetic circuit model:1、The topology of multi-tooth switched flux permanent magnet machine is discussed and the formula for solving the combination of the stator/rotor teeth is derived.A magnetic circuit models at different rotor positions are established with/without considering the coupling.Then,the equivalent magnetic circuit of the machine,the equation between the flux linkage and the open circuit back-EMF,the electromagnetic torque equation and the inductance equation are derived.2、The magnetic field on-line regulation of the machine is introduced.The on-line demagnetization and magnetization can be realized by applying current pulse.In the study of this part,the circuit to protrude the current pulse is developed.In this circuit,a second-order linear homogeneous differential equation with constant coefficient can be obtained.The amplitude of current pulse for the memory machine is analyzed.3、In order to improve the calculation accuracy and reduce the calculation time in the previous linear model,the piecewise linear hysteresis model is developed.The application of low coercive force permanent magnets in memory machine is expressed.Then the Jiles-Atherton hysteresis model,Frohlich hysteresis model and parallelogram hysteresis model are given.Based on the hysteresis models,a new piecewise linear hysteresis model is proposed.According to the proposed piecewise linear hysteresis model,the flux-linkage and open circuit back-EMF can be easily calculated.4、Based on the equivalent magnetic circuit model of the machine,the iterative process is completed in MATLAB.Before the iterative calculation,magneto-resistance of each part of machine and permanent magnet magnetism are obtained by the equivalent magnetic circuit model.The magnetic flux formula of the machine under the magnetization,nonmagnetization and demagnetization are derived.Then,the optimal size of permanent magnets of the machine is decided by the magnetic field regulation coefficient.Finally,the magnetic circuit model,which is used to electromagnetic torque calculation,is studied.The relationship between the average torque and the q-axis current,the average torque and current angle is obtained.5、A prototype machine was made to verify the piecewise linear hysteresis model. |
