串励电动机

Based on the working condition of the tractor, a new type of electric tractor drive system which combines a motor and a gear, and the evaluation index and the calculation method for dynamic performance of electric tractor are suggested; taking an electric tractor drive system as design object, the balance graph of drive-resistance force, climbable gradient under different shifts, and continuous working time are calculation analyzed.

根据电动拖拉机作业特点，提出了一种电动机和变速箱相结合的电动拖拉机传动系统结构方案，并给出了电动拖拉机动力性能和经济性能评价指标以及电驱动系统主要参数的设计计算方法，以基于串励直流电动机的某型号小四轮电动拖拉机电驱动系统为设计实例，计算分析了该电动拖拉机的驱动力-行驶阻力平衡图、不同挡位下的爬坡度以及连续作业时间。

Researches show that the drive force characteristics of the electric tractor drive system based on series DC motor is close the ideal characteristics, the curves are concave, low speed with constant power, and high speed with constant torque; the electric tractor has large working speed under different shifts, but the extensive coincidence speed shows that the variable ratio of the gear is unreasonable; the maximum climbable gradient of this electric tractor is more than 30%, and does not need frequent shift when working for its extensive climbable gradient; there are many influence factors of continuous working time, which the more obvious factors are working speed and working load, the working time increases with the increase of the working speed and working load.2. Simulation researches on the drive characteristic of the electric tractor.

研究结果表明：基于串励直流电动机(来源：ABC21论文网www.abclunwen.com)的电动拖拉机电驱动系统的驱动力特性场接近理想驱动力特性场，其各挡下的驱动力特性是一组下凹的曲线，低速恒转矩，高速恒功率；同一行驶速度下所对应高挡驱动力大于低挡驱动力，这是由电机的调速特性决定的；电动拖拉机各个挡位下具有较广的稳定作业速度范围，但是各个挡位之间速度重合的范围较多，说明所用变速箱变速比与电动机匹配不合理；电动拖拉机最大爬坡度达到30%以上，并且各挡爬坡度变化范围较广，作业过程中不需要频繁换挡；影响电动拖拉机连续作业时间的因素较多，其中作业行驶速度和作业负荷影响最为明显，作业负荷越大，连续作业时间就越短，作业速度越快，连续作业时间就越短。2、电动拖拉机驱动特性仿真研究。

First, the dissertation summarizes the properties, developing state and application fields of BLDCM, then its fundmental structure; operation principle and control strategy is also presented. On the base of roundly analyzing all kinds of the drive motor in electromotion type railway switch, BLDCM is proposed to replace the formerly traditional DC motor in railway switch. Second, the whole design scheme and key technology of control system is put forward based on analyse of the technical parameters and requirements.

首先，论文介绍了无刷直流电动机的特点、发展和应用概况，分析了稀土永磁无刷直流电机系统的基本构成、工作原理和控制方法；在对目前各种电动转辙机驱动电机分析的基础上，提出将稀土永磁无刷直流电机用于铁路转辙机，以替换原有的串励有刷直流电动机。

Then the model is applied to simulate the direct start-up process, the reduced voltage starting process and the starting process with series resistance in the armature circuit.

据此仿真模型进行了并励直流电动机的直接起动、降压起动、电枢回路串电阻起动的实例仿真实验，给出了有关仿真结果。

The engine main circuit have to be gurranteed drawing the torque of electric motor and rotation speed wholly to do regulateing of independence ,But also possess extensive setting range SS7's mould electric locomotive adopts Quan Kongqiao and semi bridge accuseeing series connection to make up the monophase bridge style commutation electric circuit ,The coil power supply is encouraged against the stringtrain by the electric motor the drawing armature to 3 parallels operation ,Still there is an excitation commutation bridge ,He encourages the coil power supply with 3 electric motors drawing together to the series connection ,Moreover has one another accuses the regulating action .

机车主电路必须保证牵引电动机的转矩和转速都可作独立的调节，而且要有宽广的调节范围。SS7型电力机车采用一个全控桥和一个半控桥串联组成单相桥式整流电路，向3台并联工作的牵引电动机电枢与串励绕组供电，还有一个励磁整流桥，向串联在一起的3台牵引电动机他励绕组供电，并具有相控调节作用。可以实现机车无级调速和无级削磁。SS7型电力机车采用再生制动方式，再生制动时，牵引电动机作直流发电机工作，并且将电能馈送回接触网，此时电力机车相当于一个移动的发电站。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。