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逆变器输出至变频电机端部的脉宽调制(PWM)电压为重复方波脉冲电压,但变频电机匝间绝缘实际承受持续时间为纳秒至微秒级的短脉冲电压。为研究两种电压下变频电机匝间绝缘性能的异同,测试分析了变频电机匝间绝缘在相同频率、电压峰峰值和上升时间的重复方波脉冲和短脉冲电压下的局部放电和耐电晕寿命。结果表明:重复方波脉冲电压在上升沿和下降沿的局部放电对称分布,而短脉冲电压在上升沿的局部放电特性与重复方波脉冲电压相似,在下降沿未检测到明显放电;重复方波脉冲电压下的频域能量主要分布在0.7~0.9 GHz,而短脉冲电压下的频域能量主要分布在0.9~1.1 GHz,且短脉冲电压下的局部放电持续时间比重复方波脉冲电压下短;短脉冲电压下漆包线的耐电晕寿命约为重复方波脉冲电压下的3倍。 相似文献
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高频脉冲下牵引电机绝缘的局部放电特性 总被引:1,自引:1,他引:0
变频牵引电机定子绝缘承受来自变流器的连续高压方波脉冲,可能导致绝缘过早失效,其老化机理与工频交流电压作用下差异很大。局部放电是导致变频调速牵引电机绝缘失效的主要原因之一。研究高频方波脉冲下的局部放电特性为牵引电机绝缘材料的改进和优化提供理论基础,试验分析了普通和聚酰亚胺纳米复合薄膜制成的电磁线寿命,结果发现纳米试样的寿命得到很大提高。针对普通和聚酰亚胺纳米复合薄膜研究了不同脉冲频率、上升时间和温度对放电起始电压、平均放电量和放电次数的影响。结果表明,频率的增加、上升时间的缩短和温度的增加加剧了局部放电活动,普通薄膜试样的局部放电活动更强,其原因是纳米粒子的添加导致纳米复合薄膜存在大量界面区和电导率增加,电荷的迁移速率增大,空间电荷累积效应减弱。 相似文献
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一种绝缘寿命测试用高压方波脉冲电源的研制 总被引:1,自引:0,他引:1
高压变频驱动绝缘寿命脉冲电应力加速试验需要对称双极性高压方波脉冲电源,当前的高压脉冲电源尚不能完全满足需要,而现有的高速功率电子器件难以直接产生所需波形高压脉冲电源。本文通过光纤传输脉冲同步控制信号,使多个隔离电压达20kV,幅值1kV的对称双极性脉冲逆变电路模块同步工作,将多个这种方波脉冲模块级联构成脉冲峰峰值8kV以上高压脉冲电源。该文分析并给出了多H桥级联方式下脉冲上升时间的估算方法以及各独立模块电源隔离电压和容量的确定方法。该高压脉冲电源构成方法可通过改变级联模块数量灵活改变脉冲幅值电压等级,经测试可较好满足绝缘寿命加速老化试验对脉冲波形的要求。 相似文献
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用介质损耗分析变频电机匝间绝缘老化特性 总被引:7,自引:3,他引:4
变频电机匝间绝缘承受来自逆变器的连续高压脉冲方波的作用,为探讨工频正弦电压作用下具有很大差异的老化机理,通过采用工频正弦和高压脉冲方波两种电压源对模拟变频电机匝间绝缘的绞线对试样进行了电热联合老化对比试验,测量损耗角正切tanδ随老化时间的变化趋势,并结合热刺激电流测量结果,分析了电压形式对匝间绝缘介质损耗产生和发展的作用机理。试验结果表明:绝缘内部有放电发生时,放电与空间电荷协同作用使绝缘缺陷迅速增多;无放电时空间电荷反复注入和抽出造成绝缘损伤。两者都导致高压方波脉冲老化下绝缘材料的tanδ高于工频正弦老化下的tanδ;高压方波脉冲下空间电荷可能是导致绝缘材料最后击穿的原因。 相似文献
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针对铁路机务部门,为了实现利用车载DC110 V电源对机车牵引电机进行快速、准确的检测,判断出故障源并及时的排除故障,保证机车车辆的通畅运营。通过对交流牵引电机的故障机理和诊断方法的研究,提出了一种通过单片机对牵引电机响应电流上升时间的测取来判断交流牵引电机绕组绝缘状态的检测方法。并通过对脉冲变压器的设计,来满足不同的牵引电机对检测电压的要求。从而达到减少铁路机务部门相关人员的工作强度。 相似文献
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将牵引电机应用于双流制窄轨电力机车时,由于窄轨机车轨距小,所以牵引电机安装空间异常狭小,比一般牵引电机在安装空间、电机结构、电磁负荷等方面的要求更加苛刻。针对窄轨双流制电力机车的运用特点和特殊要求进行了分析,提出了牵引电机的设计要求和关键技术难点,并对关键技术难点给出了相应的分析和解决措施。对该牵引电机的制造过程及电机试验测试情况进行了论述。试验结果表明,该牵引电机达到了设计预期,完全能满足设计要求。 相似文献
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On the main railways in Russia, two types of current in the contact wire are used: dc voltage of 3 kV and ac voltage of 25 kV with a frequency of 50 Hz. Therefore, prospective electric rolling stock should have double the power. Improving the capacity and structural speed of locomotives is based on the use of asynchronous traction motors (ATDs) with a squirrel-cage rotor allowing increasing the tractive force and the weight of the train and the capacity and speed of cargo delivery, increasing reliability and reducing life cycle costs, and increasing service life. Electrical equipment for such rolling stock should be used when working from either contact system, dc or ac. In this article, the scheme of power circuits is considered using the example of a module of a traction drive in one bogie of dual-system electric locomotives. It is proposed to use the secondary winding of the traction transformer as a choke of the input filter when powered from a dc contact system. Regulation of operation modes of asynchronous traction motors is carried out from static semiconductor converters with a two-tier structure. Input transducers provide the exchange of electric energy between the contact system and the intermediate link of dc voltage, and the output converters regulate the traction motors by changing the magnitude and frequency of voltage on the stator windings of ATD depending on the speed of the locomotive and its operating mode. 4QS input converters and output converters are autonomous voltage inverters of the intermediate ac: in the case of single-phase input and output, they are three-phase. The basic ratios are given to determine voltages and currents of 4QS converters, to determine the variable component of a rectified current 4QS converter, and to formulate requirements for a resonant L2C2 filter configured for a frequency of 100 Hz. Expressions are given for determining the ratio of the input power of the converter, as well as recommendations for determining the basic parameters of electrical equipment. 相似文献
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为了降低大功率机车牵引电机运行能耗,提出了一种基于牵引功率动态分配的机车牵引电机节能控制方法。首先,结合现场运行数据,建立牵引电机效率与其发挥牵引力及运行速度间的数学模型。然后,利用机车自动驾驶系统规划的区间速度及牵引力运行曲线,基于所建立的数学模型对不同牵引力分配策略下综合牵引电机能耗指标等进行计算,并选择最小化目标函数值的牵引力功率分配方案,控制机车各轴牵引力输出。最后,基于HX D 1型自动驾驶机车现场某条线路各区间运行数据,对所提方法进行仿真分析,验证了该方法的有效性。 相似文献
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为了避免器件温升对参数测量造成影响,"脉冲测试法"被广泛应用于功率IGBT模块的静态和动态参数测试中。该类设备内部单脉冲高压源脉冲宽度为50μs时脉冲的高压幅度可达7 k V以上,如何对该单脉冲高压源进行校准是一个技术难题。研制了脉冲高电压分压器,并使用数据采集单元搭建了脉冲高压参数校准装置,解决了功率IGBT模块测试设备的脉冲高压参数校准难题。通过测量不确定分析和实验验证,综合考虑各测量不确定度分量的影响,在包含因子k为2时,脉冲高压参数校准扩展测量不确定度为1.4%。 相似文献
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The peculiarities of the structure and regulation of an electric traction drive of the TEM9H prototype four-axle hybrid shunting locomotive, which has two-axle bogies and is connected in parallel asynchronous traction motors to one inverter, are considered. Using very dynamic algorithms for a discontinuous control of asynchronous motors in the regulation of the flux linkage of the stator and the electric battery with a large energy level and superconductors allows one to do without free diesel power for traction to adjust the force of traction required by law, applying the new algorithms of the maximum tractive and braking efforts. The pilot locomotive does not include inclined rods or special loaders to balance the vertical load of the axles of the locomotive, whereby the difference in vertical loads between the bogies of the locomotive is about 6 t at the nominal electromagnetic torque of the motor. Promising control algorithms of a traction electric drive of the TEM9H hybrid shunting locomotive with the joint regulation of asynchronous motors, allowing us to compensate for deficiencies in the design of the running gears and to ensure that the potential of adhesion is not less than 90% in a mode with maximum exertion, are analyzed on the basis of computer simulation. 相似文献
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