Parametric Analysis Of Multi-objective Model Based On IPM Synchronous Motor And Active-flux Control

The internal permanent magnet(IPM)synchronous motors has some special attributes,such as the high power density,the high power factor and the wide speed range,so it is widely used in new energy cars,textile machine,numerical control machines,wind turbine system and other fields.Based on the theory of electromagnetic field,two different multivariable parametrization models have been systematically established for IPM synchronous motors respectively.The parametric mathematical models have great significance for IPM synchronous motors optimal design.Detection precision of rotor position could directly affect the control accuracy of the motor system.Based on the active flux control algorithms,sensorless vector control model is used in wide speed range.The paper is carried out in the following aspects:Abandon the design concept of taking pole arc coefficient as the main variable.Model parameters such as pole arc coefficient,air gap flux density and cogging torque are significantly effected by magnet design parameters.Parametric analysis model of “V” type and Straight-Shape IPM synchronous motor have been established respectively.Revising magnetic flux leakage around the flux barrier,magnetic field intensity inside the rotor can be equivalent to the one on rotor surface.The variation tendency of pole arc coefficient and air gap flux density with design parameters could be analyzed.The surface tendency shows that pole arc coefficient and air gap flux density change nonlinearly with magnet and flux barrier design variables.The mathematical models of opening slots and half opening slots were established respectively.By means of relative permeance,flux density correction factor are derived by piecewise flux paths method to transform the flux density in slotless air gap model into the one in slotted model,then multivariate nonlinear function of cogging torque corresponding to magnet design parameters can be represented.After investigating curve tendency and gradually limiting the boundary condition,the precise solution to the most extend weakening cogging torque is obtained via implementing binary iteration search.The phenomenon of stator teeth root saturation is analyzed.Robust design structure is prone to add the flux area,and decrease the saturated extent of magnetic induction intensity.Appropriate grades silicon steel sheet material could weaken cogging torque effectively.Modular structure could maintain the relative increase of permeability.According to parametric analysis of auxiliary slots dimension,reasonable auxiliary slots shape and dimension could reduce saturation level and weaken cogging torque obviously.Precise measurement of initial position of motor rotor is curcial for sensorless control of permanent magnet synchronous motor.Based on the theory of active flux,IPM motor model can be converted to the pure non-salient rotor pole model.The active flux observer-based sensorless vector control system of permanent magnet synchronous motor is proposed.By using experiment results and Simulik simulation measures,the rotor position angle estimated by active flux obvisiver could better fit the practical rotor angle with characteristics of initial state,low speed as well as the medium and high speed light loads.