| Adjust-speed permanent magnet synchronous motors(PMSM)are widely used in new energy vehicles,aviation,marine,air-conditioning,petrochemical and other industrial fields due to their excellent characteristics such as high efficiency,high power density,high power factor,and good frequency control performance.Adjust-speed PMSM is highly coupled with its control system in actual use.The accurate calculation of Adjust-speed PMSM and its control system has a great influence on the dynamic response capability and steady-state operation performance of the motor control system.Therefore,this paper focuses on the design of Adjust-speed PMSM field-circuit coupled simulation design,motor loss calculation,and motor temperature field analysis.The main research contents are as follows:1.Discussed the Adjust-speed PMSM’s coordinate transformation,operating conditions,maximum torque per ampere(MTPA)control,current feedforward decoupling control and current lead angle field weakening control principles.2.Based on the finite element analysis software ANSYS/Maxwell,a 2D finite element simulation model of the electromagnetic field of the Adjust-speed PMSM was built,and the static characteristics were analyzed to obtain the parameters such as the motor’s dq axis inductance and permanent magnet flux.Adjust-speed PMSM field-circuit coupled simulation model was built based on the simulation platform ANSYS/Maxwell,ANSYS/Simplorer and MATLAB/Simulink.Adopt MTPA-based field weakening control strategy,conducted field-circuit coupling simulation of the motor under different loads.The magnetic flux density,torque,speed and current of the motor were obtained.3.Based on Bertotti’s three-phase iron loss separation model,the stator iron loss under the action of alternating magnetic field,considering the action of rotating magnetic field,and considering the combined action of rotating magnetic field and harmonic magnetic field are calculated.The stator iron loss,rotor iron loss,permanent magnet eddy current loss,and winding copper loss of the motor under different working conditions are calculated.4.Take the loss calculation result in 3 as the heat source.Build a prototype 3D temperature field finite element model in ANSYS/Steady-State Thermal and a prototype thermal network model in Motor-cad,the temperature field distribution of the motor under different working conditions described is calculated separately.Through the finite element simulation of the temperature field and the simulation of the thermal network,mutual verification of the simulation results shows that the simulation result is correct.The two-way coupling simulation of electromagnetic field and temperature field is simulated and compared with the simulation results of one-way coupling of electromagnetic field and temperature field.5.According to the demagnetization curve of the permanent magnet material,the direct axis demagnetization current of irreversible demagnetization of permanent magnets at 20 ℃ and 120 ℃ was calculated.Provide a theoretical basis for the rational design of the straight-axis demagnetization current of the Adjust-speed PMSM during weak field control and the increase of the speed expansion range of the motor... |
