Research On Loss And Temperature Of PMSM With Different Carrier Modes Based On The Field Circuit Coupling Method

With the development of electric electronics technology,the permanent magnet synchronous motor(PMSM)is widely used in production and life with a small size,light weight,high efficiency and high power factor.In addition,with the popularity of the inverter power supply,voltage space vector pulse width modulation(SVPWM)is widely used because of its superior steady-state and dynamic response capabilities.The traditional SVPWM technology uses triangular wave as a carrier wave.The higher current harmonic content and the motor low-frequency vibration caused by triangular carrier wave have puzzled the relevant scholars at home and abroad.In recent years,the application of sawtooth wave in pulse width modulation technology has been paid more and more attention by scholars at home and abroad.In order to explore the influence of different carrier forms on motor performance,this paper studies the motor output performance,loss and temperature under SVPWM triangle carrier and sawtooth carrier.Firstly,in order to systematically consider the influence of carrier form on motor output performance,a SVPWM co-simulation model of PMSM is built,based on ANSYS Maxwell,ANSYS Simplorer and MATLAB Simulink software,to more accurately simulate the motor running state.The simulation results show that: compared with a triangular carrier,the amplitude of sideband harmonics of sawtooth carrier phase current is significantly reduced,and the amplitude of sideband harmonics is reduced by 47% when the rated speed is 3000 rpm,this has a good suppression effect on the low frequency vibration of the motor.At the same time,the amplitude of high frequency harmonics at the integral multiple of switching frequency increases obviously.For example,the speed of 600 rpm has increased by 210%.Because the amplitude of high-frequency harmonics is small,and the amplitude difference of low-frequency harmonics of motor phase current under SVPWM triangle carrier and sawtooth carrier is obvious,it is necessary to analyze the motor loss and temperature under the two carrier modes.Secondly,the motor output torque fluctuation and loss distribution of the motor output torque in two carrier modes of SVPWM triangular carrier and sawtooth carrier are analyzed by coupling-simulation platform.The simulation results show that: compared with the SVPWM control method using triangle carrier,the SVPWM control method using sawtooth carrier will aggravate the motor torque ripple.Besides,compared with the SVPWM control method using triangle carrier,the motor loss of SVPWM control method using sawtooth carrier increases about1% at 600 rpm,1800 rpm and 3000 rpm,and decreases about 0.5% at 1200 rpm and 2400 rpm.Thirdly,the temperature distribution of the SVPWM triangle carrier and sawtooth carrier at different speeds is analyzed and the results show that when the speed is 600 rpm,the temperature difference is obvious.And the motor temperature rise is higher than the triangular carrier,the temperature difference is about 1℃,and the remaining speed of the two carrier mode motor temperature rise is small.The main reason for this phenomenon is that compared with SVPWM control technology using triangle carrier,when the SVPWM control technology using a sawtooth carrier,the eddy current loss of motor rotor is increased by about 25%,core loss increases by 8%and copper consumption gap is less than 1% when the motor speed is 600 rpm.With the increase of speed,the total loss of motor increases,and the difference of motor loss in two carrier modes account for a smaller proportion of the total loss of the motor,and the difference of temperature rise becomes smaller.Finally,to clarify the specific effects of different carrier forms in the SVPWM control method,the motor experiment platform is built,and the motor experiments under the two carrier modes of SVPWM triangular carrier and SVPWM sawtooth carrier were completed.The experimental results show that compared with the SVPWM control method using triangle carrier,the torque ripple and copper consumption of the SVPWM control method using sawtooth carrier are increased by 36% and 4% respectively.In the SVPWM control method,it is not suitable to change triangle carrier into sawtooth carrier directly.Although the sawtooth carrier can significantly reduce the harmonic amplitude of the phase current sideband,the high-frequency vibration caused by the sawtooth carrier needs special attention.