变频调速技术及在下花园发电厂的应用

文章介绍了交流电动机的调速方法（变极调速、变转差率调速、变频调速）及其特点。重点介绍了交流电动机变频调速不仅可以做到从电动机同步转速向下调节，还可从电动机同步转速向上调节，调节范围宽，且可做到无级连续平滑调速，在调速过程中做到不改变电动机原工作性能，是一种理想的调速方法。     

电机绕组(十)

2·3 单相异步电动机的调速方法及其绕组和三相异步电动机一样,单相异步电动机在使用过程中也常遇到调速的要求,即希望电动机的转速能在一定的范围内进行调节。通常不外有二种调速要求,一种是要求速比成倍或较大的调速方式,此时可采用变极调速或串联电抗器调速以及可控硅调压调速等;另一种是要求转速的变化范围较小的调速方式,如风扇电动机,通常要求的调速范围约30％,即速比约为1:0.7。在以上各种调速方法     

永磁耦合调速装置节能性能试验

调速是国内外公认的电动机节能的最佳方式.目前实现电动机调速的方法主要有变频调速、液耦调速和串级调速等多种技术和方法,但国内还没有永磁耦合调速方而的研究和生产,这是国内首次进行永磁磁耦调速装置的调整试验.     

变频调速问答（九）：变频器的控制方式及应用（上）

问题1什么是控制方式?(1)控制方式的含义各种电动机在实现调速时,都必须采取一些辅助手段,以改善电动机的机械特性和调速特性。以直流电动机为例,在调速过程中,必须加入电流反馈环节(内环)和转速反馈环节(外环),才能使它的调速特性趋于完善。异步电动机的变频调速也不能例外。为了改善其在调速过程中的机械特性和调速特性,也必须采取一些必要的措施。不过,异步电动机在进行变频调速时,可采取的方法较多,比较灵活,可以通过功能预置方便地进行调整。变频器说明书中的所谓控制方式,就是在变频调速的情况下,改善异步电动机特性的方式。(2)电动机…     

三相异步电动机调速方式

问：三相异步电动机调速方式有哪几种？答：从调速的本质来看，不同的调速方式无非是改变交流电动机的同步转速或不改变同步转2种。在生产机械中广泛使用不改变同步转速的调速方法有绕线式电动机的转子串电阻调速、斩波调速、串级调速以及应用电磁转差离合器、液力耦合器、油膜离合器等调速。改变同步转速的有改变定子极对数的多速电动机，改变定子电压、频率的变频调速有能无换向电动机调速等。     

利用串级调速实现大功率异步电动机的调速

介绍一种未被广泛应用的异步电动机调速理论,即串级调速理论;详细论述了如何利用串级调速理论实现大功率异步电动机的调速,并通过工程实例证明了该方法的实用性和经济性.     

电液式交流电动机工频无级调速系统的研究

提出一种交流电动机定子绕组只接入工频电源的无级调速新方法,在这种方法中,交流电动机的定子是可以转动的,液压控制系统控制电动机定子的转向和转速,依照调速电动机的不同调速运行情况,液压泵电动机可以有停车,电动和异步发电三种不同的运行方式,而调速电动机在各种运行转速下电气参数和机械特性保持不变,文中介绍了样机的研制和初步试验结果。     

交流调速的应用

传动调速经过了机械调速、联轴节调速和电动机调速三个阶段。采用同步电动机变频调速代替直流电动机调速在传动调速史上展开了新的一页。     

利用串级调速实现大功率异步电动机的调速

介绍一种未被广泛应用的异步电动机调速理论,即串级调速理论;详细论述了如何利用串级调速理论实现大功率异步电动机的调速,并通过工程实例证明了该方法的实用性和经济性。     

笼型三相异步电动机调速和节能

正讲述笼型三相异步电动机变极调速和变频调速的特性,变频调速电动机的设计特点和节能优势。重点对变极调速电动机恒功率和恒转矩调速的接法和特性,变频调速电动机设计特点,基频以下和基频以上调速时对应的恒转矩和恒功率调速特性进行阐述和分析,从而指出两种调速电动机的特点和发展趋势。     

A new variable reluctance motor utilizing an auxiliary commutationwinding

A new concept for solving the current commutation and energy circulation problems in conventional variable reluctance motors (VRMs) is presented. The concept enables the energy stored in the magnetic field to be retained and utilized within the motor instead of being returned to the source. A new VRM and two companion converters are proposed and described in this paper. The operating principles of the motor and the converters are presented. Simulation results based on a linear model are presented to verify the operating principles. A prototype motor is built and tested to demonstrate the degree of improvement that can be realized with the new motor. The experimental results show that by eliminating these two problems, this new motor has important performance advantages over conventional VRMs     

Electrical field measurements on an EPRI two-pole, 20-hp WrittenPole motor

The recent introduction of the Electric Power Research Institute (EPRI) single-phase Written Pole soft-start motor may open new possibilities and marketing opportunities for rural electric cooperatives. The new single-phase high-efficiency AC motor technology promises soft-start capabilities that allow designs and application of up to 60 hp 240 V motors. This paper summarizes some of the technical aspects of the new single-phase motor technology. An actual field test and application of a Written Pole motor is also be used to compare motor starting currents and line flicker with manufacturer's literature and specifications     

New design for the high-performance drive system for DC brushless motor

The dc brushless motor, permanent magnet-type synchronous motor (PM motor), has been used widely in industrial robots, the machine tools for factory, and factory automations. Therefore, it is more desirable to improve the performance of the PM motor variable speed control system. Although only the torque component current is adjusted as the control method for the PM motor, so-called Vector Control, it is expected that the developed characteristics will be added to the PM motor. In this paper, new driving methods for the PM motor and a new design method for the variable speed control system are presented. The new motor driving methods which bring to the PM motor a new driving performance, e.g., a quick transient response or high-efficiency motor driving, can be implemented by controlling not only the torque component current, but also the magnetizing component current. A developed optimal control theory, i.e., the error system technique, is employed for designing the control system. The control law is endowed with a steady robustness against the variation of the system parameters and the ability of compensating the delay time due to the control processing. The effectiveness of the proposed method is confirmed by simulations and experiments.     

新型超声波电机原理与应用

超声波电机是一种运用压电陶瓷逆电效应原理研制出来的新型微特电机,与传统的电磁驱动的电机有着本质上的不同,具有十分广阔的应用前景。介绍了超声波电机的原理研究进展和应用前景。     

新型接法的三绕组单相电动机

在单相供电系统中,当电动机额定功率大于0.5 kW时,采用普通单相感应电动机是不经济的,为此提出一种新型连接方式的三绕组单相感应电动机,该接法对Y接法三相感应电动机的6个出线头进行改接,并与2个电容器相连接,改变了绕组中电流的相位,使三相电机在单相供电系统中实现接近对称运行。采用对称分量法研究该连接方式下电机对称运行需要满足的条件,讨论对称运行条件下电容的选择及其对电机性能的影响,推导了该电机性能计算的具体方法。针对该连接方式进行试验研究,并与三相对称运行进行比较。样机试验证明,新型接法三绕组电机的效率接近三相电动机在三相电源上对称运行的效率,且具有更高的功率因数,可替代普通单相感应电动机。     

Flux-Switching Motors for Automotive Applications

This paper presents a new class of brushless motor as an alternative to the permanent-magnet brushed motor used in the automotive industry. The new flux-switching motor is a very simple motor to manufacture, and, coupled with a powerelectronic controller requiring only two power semiconductor switches, it has the potential to be extremely low cost in high volume applications. The design of the motor and its simulation using coupled circuit and time-stepping finite-element analysis is presented. Tested performance has matched well with design targets and with simulation and is delivering performance comparable to a permanent-magnet brushed motor. The new motor and drive are very robust, requiring only two power MOSFETS and a simple microcontroller to create an extremely low-cost variable-speed drive for automotive applications.     

使用滑模控制的单相电动机新逆变驱动

针对单相感应电动机,提出了新的逆变驱动策略。与采用传统的逆变驱动控制相比,由于新的逆变驱动策略采用了LC滤波,因此可使单相感应电动机的控制输入是平滑的,控制精度更高。完整的控制系统由四级级联控制环组成,其内环实现感应电动机速度调节和电流控制,而外环实现电动机驱动,由此构成了新的电流模式定向控制,以替代磁场定向控制。逆变器开关驱动由滑模控制实现。由实验结果验证了该方案的有效性。     

高性能低谐波绕组感应电动机电磁性能的数值分析

针对普通感应电动机采用低谐波绕组后电磁场分析难度将会提高的问题,利用数值计算的方法,给出了适合低谐波绕组电机电磁性能的数值求解方法.以一台普通感应电动机为例,利用低谐波绕组理论,对定子绕组的线规和形式进行调整,设计具有高起动转矩的低谐波电机.通过对低谐波电机电磁性能的数值计算结果与实验结果的比较,验证了所推导的方法的准确性,提高了所设计的低谐波电机的起动性能.将低谐波电机与普通同型式的感应电动机的气隙磁场和转子齿部磁场进行比较,分析两种电机中磁密谐波成分的含量,结果表明低谐波绕组电机的各次谐波磁密大大降低.     

薄型超声电机两相及单相激励时的工作机理分析与实验研究

该文对环状超声电机定子中的行波的特征进行了分析，探讨了行波状态下电机定子端面质点椭圆运动轨迹与矩形板表面质点椭圆运动轨迹之间的差异。指出了圆环定子内圆周侧面中的部分区域具有对电机转子的推动作用。据此设计了一种可实现电机薄型化的新结构，并制作了样机，完成了电机定子性能测试和电机运行实验。运行实验结果表明，样机运转平稳，具有较大的输出转矩。实验中还发现，电机在只输入单相交变电压时仍能实现正常运转，分析了这一现象产生的机理。依据上述机理。可以设计一种新型驻波超声电机。     

A doubly salient doubly excited variable reluctance motor

A new variable reluctance motor is introduced to help solve the energy circulation problems which exist during commutation in conventional variable reluctance motors (VRM). The new motor design enables the energy stored in the magnetic field to be retained and utilized within the motor, instead of being returned to the source. The operating principles of the motor and associated power converters are presented. The analysis shows that by employing both short pitch and full pitch windings, this new motor can eliminate the two problems without extra conductors in the slots. As a result, the new motor has the following important performance advantages over conventional VRM: (1) it allows a significant improvement in the turn-off process and therefore allows higher speed capacity; (2) it has higher output with the same or higher efficiency with the same output because of the improvement on the turn-off performance and due to the utilization of the trapped energy; and (3) the machine can have a higher output with the same power converter because of the improvement of the energy conversion ratio