新能源电动汽车英文翻译

1、湖 北 文 理 学 院毕业设计(论文)英文翻译题 目在采用PWM逆变器下的变速感应电机驱动器中的传导性排放轴承电 流的减少和鉴定专 业机械设计制造及其自动化班 级机制0911姓 名杨成杰学 号2009116140指导教师职 称周立文（学校） 冯南（企业）2013年 5月 10日Minimization and identification of conducted emission bearing current in variable speed induction motor drives using PWM inverterAbstract. The recent increase in

2、 the use of speed control of ac induction motor for variable speed drive using pulse width modulation (PWM) inverter is due to the advent of modern power electronic devices and introduction of microprocessors. There are many advantages of using ac induction motor for speed control applications in pr

3、ocess and aerospace industries, but due to fast switching of the modem power electronic devices，the parasitic coupling produces undesirable effects. The undesirable effects include radiated and conducted electromagnetic interference (EMI) which adversely affect nearby computers, electronic/electrica

4、l instruments and give rise to the flow of bearing current in the induction motor. Due to the flow of bearing current in the induction motor，electrical discharge machining takes place in the inner race of the bearing which reduces the life of the bearing. In high power converters and inverters, the

5、conducted and radiated emissions become a major concern. In this paper, identification of bearing current due to conducted emission, the measurement of bearing current in a modified induction motor and to minimize the bearing current are discussed. The standard current probe, the standard line imped

6、ance stabilization network (LISN), the electronics interface circuits are used to measure high frequency common mode current，bearing current and to minimize the conducted noise from the system. The LISN will prevent the EMI noise entering the system from the supply source by conductive methods, at t

7、he same time prevents the EMI generated if any due to PWM, fast switching in the system, will not be allowed to enter the supply line. For comparing the results with Federal Communications Commission (FCC) and Special Committee on Radio Interference (CISPR) standards, the graphs are plotted with fre

8、quency Vs，line voltage in dB V，common mode voltage in dB V and the bearing current in dBA without and with minimizing circuits.Keywords. EMI;a.c.drives; bearing current.1. IntroductionWith the development of power electronic devices like the insulated gate bi-polar transistor (IGBT), the power MOSFE

9、T and the advances in microprocessors, the ac induction motor is becoming popular in variable speed drives with PWM inverter circuits. Since the rise time and fall time of the IGBT are less than 200 nanoseconds, the dissipation loss across the device becomes very less and there by increases the perf

10、ormance of the circuit. However, due to the fast switching action of the device the dw/dt of the inverter output becomes large. This high dw/dX voltage transition coupled with parasitic stray capacitance in the system causes high frequency line to ground current or common mode current and hence bear

11、ing current; introducing large EMI in the system.In figure 1，Ilg (the magnitude of ground current) depends on the cable capacitance, machine capacitance，parasitic capacitance of the devices, the output voltage rise time (tr ise) and the system voltage, Voltage gets induced in the rotor shaft of the

12、induction motor due to fast switching. This induced voltage generates circulating current and flows to the ground through the bearing resulting in an electrical discharge machining (EDM) action at the inner race of the bearing.Due to the EDM, the life of the bearing reduces. The common mode voltage

13、Vng (figure 1) can be measured from the star point of the stator winding of the induction motor (IM) or connected node of three 1MO resistors to the ground in case of the IM connected in delta. The reasons for common mode voltage generation are already discussed.It is noted that the sum of sinusoida

14、l balanced phase voltages in a 3-phase IM at the star point is equal to zero. Therefore,Vng=(Van+Vbn+Vcn)/3 Common mode current=Cd/dt Where C is the total capacitance of the system and Van,Vbn and Vcn are the voltages between the respective phases and the star point in the stator winding2.Existing c

15、onducted emission, bearing current identification and measurement methodsVarious methods have been proposed to reduce the conducted emission common mode voltage and the measurement of bearing current. An output reactor connected to the inverter out put reduces the dv/dt of the inverter output voltag

16、e, which in turn reduces the common mode voltage at the star point of the IM and the flow of bearing current. Wious configurations of L-C filter have been reported. The inductance L，and capacitance C are designed according to the permitted insertion loss for the given power rating of the inverter. T

17、he draw back of the filter method is the voltage drop across the filter.In the passive filter method, the transformer secondary should be isolated for its successful operation and this is not possible in many process/engineering industries. An active common noise canceller has been tried to eliminat

18、e the conducted emission common mode voltage produced by the PWM inverter. The active common noise canceller superimposes a compensating voltage applied at the star point. This has the same amplitude as the common mode voltage produced by the PWM inverter but has opposite polarity; hence the common

19、mode voltage applied to the load is cancelled completely. However, this method is suitable only for low voltage/power applications due to the resistive current sensor. Julian proposed a filter circuit for reducing the common mode voltage.This filter circuit is based on current sensing and it operate

20、s a fast transistor amplifier for the current compensation. Significant attenuation of the common mode voltage occurs.The method presented in this paper is different from earlier methods. Here,the phase current is sensed by the individual current transformer (CT) and is suitable for any voltage leve

21、l. Since the CT is used for sensing the phase current there is no voltage drop in the sensor there by there is no reduction of terminal voltage applied to the IM.In tiidr circuit, the primary winding of the transformer is connected in series in each of the phases. Since the circuit uses the transfor

22、mer, there is voltage drop due to the phase current of the IM, hence the terminal voltage applied to the IM gets reduced. The circuit is also used to reduce the common mode voltage and the common mode current at the star point of the IM. But this circuit is useful for the low voltage and low power a

23、pplications.In the present work,the standard LISN,the standard current probes are used and the results are compared without and with the common mode voltage reduction circuits for the PWM inverter used for variable speed ac IM drives.Julian proposed a filter circuit for reducing the common mode volt

24、age.This filter circuit is based on current sensing and it operates a fast transistor amplifier for the current compensation. Significant attenuation of the common mode voltage occurs.The method presented in this paper is different from earlier methods. Here， the phase current is sensed by the indiv

25、idual current transformer (CT) and is suitable for any voltage level. Since the CT is used for sensing the phase current there is no voltage drop in the sensor there by there is no reduction of terminal voltage applied to the IM.In tiidr circuit，the primary winding of the transformer is connected in

26、 series in each of the phases. Since the circuit uses the transformer, there is voltage drop due to the phase current of the IM, hence the terminal voltage applied to the IM gets reduced. The circuit is also used to reduce the common mode voltage and the common mode current at the star point of the

27、IM. But this circuit is useful for the low voltage and low power applications.In the present work,the standard LISN,the standard current probes are used and the results are compared without and with the common mode voltage reduction circuits for the PWM inverter used for variable speed ac IM drives.

28、在采用PWM逆变器下的变速感应电机驱动器中的传导性排放轴承电 流的减少和鉴定摘要由于现代电力电子器件的出现和微处理器的采用，交流异步电机的速度控制被广泛应用了,这种使用用于使用PWM逆变器的变速驱动器中。使用交流感应电机，将速度 控制运用在工艺和航空航天工业上有很多优点，但由于现代电力电子器件具有快速开关 性，寄生耦合产生了不良影响，这些不良影响包括辐射性的和传导性的电磁干扰，这些电磁干扰对附近的计算机，电力、电仪器产生不利影响，还是感应电机里的轴承电流发 生流动。由于感应电机里的轴承电流发生流动，在轴承的内圈会发生放电现象，这样会 降低轴承的内圈寿命。在高功率转换器和逆变器中，辐射性的和传导

29、性的排放成为主要 的关注。在这篇文章里，由于传导性的排放，讨论了轴承电流的鉴定，在修改后的感应 电机的轴承电流的测量，轴承电流的减少，标准电流探测仪，标准线阻抗稳定网络，电子接口电路，这些被用于测量高频共模电流，轴承电流和减少来自系统的传导性的噪声。标准线阻抗稳定网络通过传导方式将减少从供给源进入系统的电磁干扰噪声，如果人意与PWM系统中的快速开关性有关的，将不被允许进入供应线，那么就同时阻止电磁干扰的产生。在与联邦通讯委员会和特别电台干扰标准委员会标准比较后，在有最小化电路和无最小化电路的两种情况下，改图以频率比绘制，以dBV作为线电压，dBV作 为共模电压，dBA作为轴承电流。关键词：电磁

30、干扰，交流驱动器，轴承电流1.介绍在电力电子器件的发展下，如绝缘栅双极晶体管，电力MOS场效应晶体管和在微处 理器的进步下，交流感应电机在使用PWM逆变电路的变速驱动器中变得受欢迎了。由 于绝缘栅双极晶体管的上升时间和下降时间不比200纳秒少，整个设备的散热损失变得 小了，从而提高了电路的性能。然而由于设备的快速开关动作，逆变器输出的dv/dt变大 了，这种高dv/dt的电压转换与系统中的寄生杂散电容耦合高频率的接地线电流或者共模 电流，因此成为轴承电流，在系统中引入大量的电磁干扰。在图1中，I/g(接地电流的大小)取决于电缆电容，机器电容设备的寄生电容，输出电压的上升时间和系统电压，由于感应电机的快速开关性，在感应电机的转子轴上产生了电压，这种感应电压引起了循环电流，通过轴承入大地，