| Due to high efficiency,high power factor,and high-power density,permanent magnet synchronous motor(PMSM)is widely used in different occasions.In practical applications,the PMSM is highly coupled with its cooperating drive system.The accurate calculation of the control system and the PMSM has a great influence on the system performance,dynamic response capability and overload capability,and it is related to the efficiency of the entire motor control system.Therefore,the dissertation is focused on the strong coupled electromagnetic field of the motor and controller,the influence of driver master parameters and inverter fault and motor related physical quantity on the PMSM operating performance,and the thermal problem of the motor.The contents of the dissertation are arranged as follows:(1)For the problem that the calculation accuracy of the influence of controller on the motor is not accurate enough,a strong coupled two-dimensional electromagnetic field calculation model of the motor and the controller is established,then,the variation of electromagnetic field of PMSM under two typical driving modes is studied.By establishing a three-dimensional steady-state temperature field calculation model,the variation law of the temperature of the PMSM driven under square wave and sine wave drive is comparatively analyzed,which can lay the theoretical foundation for the driving mode selection of the motor control system and provide reference for the selection of PMSM applications.In this dissertation,taking the 12.5kW PMSM as the research object under inverter supply condition,the strong coupled two-dimensional electromagnetic field calculation model of the motor and controller can be established,the electromagnetic field changes of PMSM are studied under square wave and sine wave drive,respectively.The temperature variation of PMSM under two typical driving conditions is studied by three-dimensional steady-state temperature field calculation model.The results show that under the same cooling condition,compared with that under square wave drive mode,the maximum temperature of stator winding and permanent magnet is reduced by 7.1%and 9.1%under sine wave drive mode,respectively.Finally,an experimental platform for PMSM and controller driven by sine wave is established.Compared with the experimental measurements,the error of the calculated phase voltage,phase current,stator winding,and frame maximum temperature is 4.29%,3.05%,3.84%,3.63%,respectively,all within 5%,meeting the engineering calculation accuracy requirements,which can verify the accuracy of the strong coupled electromagnetic field calculation model of the motor and controller,and it can provide an effective theoretical tool for the electromagnetic field,temperature field,and operation of the PMSM under inverter supply condition.(2)Aiming at a series of complicated problems brought by the controller to the motor,the influence of time harmonic current,carrier ratio,modulation wave frequency and inverter fault on the electromagnetic field and temperature field of the motor is studied by numerical method under inverter supply condition,which can provide effective theoretical guidance for the controller optimization parameter.The concept of heat transfer capacity ratio is proposed,which can provide an effective way to analyze the heat transfer law of PMSM.In this dissertation,according to the influence research of the fundamental current on the electromagnetic field and temperature field for the PMSM with or without rotor sleeve,the concept of thermal conductivity ratio is proposed.And the heat conduction ratio of the motor is calculated under different working conditions,the relationship that the heat conduction ratio is proportional to harmonic current,sleeve size,sleeve conductivity,and axial length of the sleeve is further derived.The influence of carrier ratio and modulation wave frequency on the electromagnetic field and temperature field of PMSM is studied by using the established coupled magnetic field calculation model of the motor and controller driven under sine wave drive.In order to ensure the long-term safe operation of the motor and control system,the carrier ratio of the controller should be selected within the range of 5<Nzb?80.By establishing a strong coupled electromagnetic field calculation model of the motor and controller under typical three inverter faults,the variation law of the electromagnetic field of the PMSM is researched under the power tube open circuit fault on the first bridge arm,the two power tubes open fault of the same bridge arm at the same time,the short circuit fault of the upper power tube on the first bridge arm.In addition,the distribution law of motor temperature is studied under the first two faults.The results show that the rotor temperature is higher than the maximum working allowable temperature of the motor under the first two inverter faults,which can result that the motor was burned in a short time.Finally,the sine wave drive motor control test platform for inverter health and the first two inverter faults is built.The test results are in good agreement with the calculation results,which can verify the accuracy of the strongly coupled 2D electromagnetic calculation model between the motor and the controller under inverter faults.(3)Aiming at the stator-rotor structure design problem of PMSM,the relationship between the motor physical quantity and the eddy current loss in the rotor sleeve is established.The influence mechanism of the motor physical quantity on the motor temperature is studied under sine wave drive mode.The mathematical relationship between permanent magnet thickness,sleeve thickness,sleeve interval width,slot width,and rotor sleeve eddy current loss is derived.The influence of these physical quantities and the width and height of the bridge on the running performance,electromagnetic field,and temperature field of the PMSM is studied.The results show that the maximum temperature of the rotor has exceeded the maximum allowable temperature of the PMSM when the thickness of the permanent magnet is 1.5mm.As the thickness of the permanent magnet thickness increases,the rotor temperature of the PMSM decreases,when the thickness of the permanent magnet increases to 3mm,the reduction degree of the PMSM temperature has reached saturation.The sleeve thickness is nonlinear with the temperature of the rotor permanent magnet.When the interval width of the segmented sleeve is greater than 5mm,the loss and temperature of PMSM have reached saturation.The increase of the height and width of the slot directly affects the safe operation of the PMSM.(4)Aiming at the rotor high temperature problem of the PMSM,the influence of the rotor sleeve structure and material on the electromagnetic field and temperature field of the PMSM is studied under sine wave drive mode.The relationship between the eddy current loss in the sleeve and the axial section number of the sleeve,and the structural parameters of the sleeve is derived.The influence mechanism of the rotor sleeve structure and material on the rotor temperature is revealed.Based on the idea of cutting the eddy current path of the sleeve,a variety of sleeve structures such as linear and staggered mesh sleeve structure,axially uneven segmented sleeve structure,and squirrel cage sleeve structure are proposed.At the same time,the relationship between the axial segmented number of the sleeve,the structural parameters of the sleeve,and the eddy current loss in the sleeve is derived.And the influence of the sleeve structure and the number of sleeve segments on the electromagnetic field and temperature field of the PMSM is researched.Based on the principle of vacuum thermal barrier of vacuum flask,a new type of insulation sleeve structure is proposed.The influence of different sleeve structures on the eddy current loss and temperature of the PMSM is analyzed comparatively.Compared with the rotor maximum temperature of the prototype,the rotor maximum temperature of insulation sleeve structure,the squirrel-cage sleeve structure,and the axially uneven segmented sleeve structure is reduced by 11.6%,6.6%,and 2.1%,respectively.The linear square mesh sleeve and staggered square mesh sleeve is similar to the effect of the three-segment sleeve and six-segment sleeve,respectively,and the mesh-type sleeve is more saving material.In addition,the effects of various radial and axial composites material sleeve structures on the electromagnetic field and temperature field of PMSM are studied.The results show that,regardless of whether.the carbon fiber is located inside or outside the stainless steel,when the thickness ratio of carbon fiber to stainless steel is 9:1,the rotor losses and permanent magnet temperature reach the minimum value,and the maximum rotor temperature is reduced by 3.1% and 4% compared with the calculation result of the prototype temperature,respectively.After the method of suppressing the local maximum temperature of the permanent magnet is proposed,the maximum temperature of the permanent magnet is reduced by 8.6%,which is of great significance for preventing the thermal demagnetization of the PMSM. |
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