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电气专业 英文原文、中文翻译

The Development of Frequency Variation Speed Control

1. The Popularity and Prospect of Frequency Variation Speed Control

The electrical machinery exchange frequency conversion velocity modulation technology is the electricity saving, the improvement technical process improves the product quality and the improvement environment, the impetus technology advancement one main method now The frequency conversion velocity modulation by its outstanding velocity modulation and the braking quality, the high efficiency, the high power factor and the electricity saving effect, the widespread applicable scope and other many merits by the domestic grandfather was thought most has the development future velocity modulation way. The electrical transmission control system usually by the electric motor, the control device and the information installs 3 parts to be composed, the electrical transmission relates uses the electric motor by to save the electrical energy and to control the machinery reasonably the operating condition, the realization electrical energy - mechanical energy transformation, achieves, the high production, the low consumption goal high quality. The electrical transmission divides into does not modulate velocity and modulates velocity two big kinds, the velocity modulation is divided the exchange to modulate velocity and to direct current modulates velocity two ways. The variable speed motor directly does not supply power by the electrical network But the machinery which does not modulate velocity along with electric power electronic technology development this kind of original manuscript more and more many changes to the velocity modulation transmission by to save the electrical energy The improvement product quality, enhances the output Therefore the velocity modulation transmission is an important profession, already obtained the country to take, at present had certain scale.

In recent years exchanged in the velocity modulation most to be active, to develop quickest is the frequency conversion velocity modulation technology, the frequency conversion velocity modulation is exchanges the velocity modulation foundation and the branch content. The last century transformer appearance causes the change voltage to become very much easy, thus has accomplished a huge electric power profession. Since long ago, the alternating current frequency always is fixed, the frequency conversion velocity modulation technology appearance causes the frequency to become may the full use resources.

In this recent 10 years, the frequency conversion technology application has the very big development in our country, and obtained the good effect to be possible to say, the frequency conversion technology has accepted for the majority users, but had no alternative but to point out, our country in frequency conversion technology application aspect, with developed country level Shang You very big disparity. At present, the AC motors we are using now use frequency variation speed control only

about 6%, but the developed country is 60%~70%, Japan on air blower, water pump frequency conversion velocity modulation use rate is 10%, but our country is less than 0.01%, In Japan air-conditioner using frequency variation technique rate is 70%, but our country's only then just started Embarks from this reality, frequency conversion technology remain have the very big development space, we should complete the promoted application work doggedly.

And with the constant development of control technique and control avenue, frequency variation speed controlled has developed the vector controlled frequency variation velocity modulation, by controlling the AC motor inside act for shunt DC motor field coper’s flux, to enhance the permanent torqu e output scope and static and dynamic character, make the AC motor frequency variation speed controlled system superior to DC motor voltage variation speed controlled system. For simplifying the control system, reducing the fault rate, there has developed a vector controlled frequency variation speed control without speed sensor which based on the vector controlled frequency variation speed control. In some application which have low require , vector controlled frequency variation speed control without speed sensor could completely compare with the vector controlled frequency variation speed control that have speed sensor. The vector control has the epoch-making significance to the AC current motor velocity modulation.

Frequency variation speed control is the best way in the motor speed modulation, it is the perfect gear in the company’s technical reform and product renewal, it is the essential composition in the industrial automatic system, it is the assumption of realizing the automatic of product proceed and management, it is also the precondition in the development of informationization. In our country’s traditional estate, using the DC motor speed control actuation account about 85%~90% in the speed controlled system, but the AC speed controlled system account about 10%~15%. Low efficiency, bad quality, large cost, high fault rate have already been the bottleneck that restrain the development of the company. So, we must promote the advanced AC frequency variation speed technique positively, arms the traditional industry with the advanced equipment, promote a further development in the automation, the industrialization and the informationization.

2. Our Country’s Development Condition in Speed Controlled Technique

Our country is a developing country, so many product’s research ability has behind the developed countries. From now on, the product of frequency variation speed controlled that ourselves made only act for last century 90s in the international. With the reform and opening, rapid development of economic, forms a large market, it opens to the country companies, also the foreign companies. Many products are exported from the developed countries, and runs well in our country, satisfied our need in fabrication and living. Many co-partership companies in our country make the

international advanced products. The domestic complete department independently is designing the manufacture in the complete set installment to use the foreign import company and the joint venture supposes advanced each, own develop the application software, can provide the first-class electrical transmission control system for the domestic and foreign important engineering project. Although obtains very many result, but should see because domestic develops, the production product ability voluntarily is weak, is serious to the overseas company's dependence.

As early as in the country "85" technical attack plan, the alternating velocity modulation technique was listed as the key technical attack project, but because our country’s electric power and electronic device aggregate level is very low, although the production of IGBT、GTO component has introduced the overseas technique, it has not formed the economies of scale benefit, almost does not have the independent development ability of new frequency converter production, this has affected the domestic frequency conversion velocity modulation technique development in the certain degree. In the high efficiency AC-AC frequency convert technique、the motors without commutator technique and so on, the domestic product also has the suitable disparity in the digitization and the system reliable aspect compares with the overseas level, in the medium efficiency frequency convert technique, nearly all productions use ordinary V/F control inland, few adopt the vector control technique, and can not satisfied the market requirement in the variety and quality. But in overseas, the frequency conversion technique obtains the full development, and has obtained the remarkable achievement in each aspect. In power component aspect, high voltage、the appearance of SCR、GTO、IGBT、IGCT with high current capacity and the using in series and parallel, the high-pressured and high efficiency frequency converter production obtains the production and the promoted application. In microelectronic technique aspect, 16bit and 32bit high speed microprocessors as well as the fast development of DSP and ASIC technique, provided the hardware method in realizing the frequency converter which with high accuracy multi-purpose. In theory aspect, the vector control, the magnetic flux control, the torque control, the intelligent control, the new control theory and so on have provided the related rationale for the high performance frequency converter development, we may see that, in the overall, the alternating frequency conversion velocity modulation technique in our country has big disparity compares with international level.

Therefore, the AC frequency variation speed control technique has the following sides:

(1) The basic research of control strategy in frequency converter has a large gap compares with the foreign level.

(2) The technical level of the whole machine is low in the frequency converter,

although we had input certainly people, material resources, but because of the disperse power, did not form a certainly technique and production scale.

(3) All the semiconductor power device product in the frequency converter is blank.

(4) Correlative Industries and relative Industries drop behind.

(5) Few production and sale, low reliable and technological standards.

With the development and improvement in the power electronic technique, power divert based on power electronic circuit technique and various control technique, the AC frequency variation speed controlled technique is mature day by day, and sure to be the main way in the future. With the constant development of power electronic technique, reliable character, well adoption, cheap price that the frequency converter have will become true. This technique will gain widely, popularity appl ication .At present, foreign developed countries’ frequency convert technique towards to the miniaturization, high reliability, defend with harm, more function, high character, and our country is coming on now.

3. Frequency Variation Speed Controlled Mode

The alternating frequency conversion velocity modulation technique obtained the rapid development in 20th century. This is related with some crucial technical which gain unprecedented progress, they are Motor vector control technique, Direct torque control technique, PWM technique, Entire numerical control technique and self-setting technique which based on microcomputer and large scale integrated circuit, and so on.

(1) Vector Control Technique

Vector transformation control technique is a one kind of new control thought and control theory which posed by SIEMENS CO. in 1971. It is realizing the stator current excitation component and the torque component solution lotus root by rotor magnetic field direction detection, and vector transformation, achieved the goal that separately control the motor flux linkage and the electric current, as a result, obtain finely static, dynamic performance. Until now, the vector control technique has obtained the considerable development, and also obtained the widespread application.

(2) Vector Control Without Velocity Generator Technique

Vector control without velocity generator technique abolish the problems that the environment compatibility、install and maintenance bring on, reduce the cost, enhance the system reliability, at the same time, union vector control, has the fine performance of vector control. The speed estimate method in vector control technique without velocity generator, besides basis mathematical model computation electric motor rotational speed, at present the more applied are the model to refer auto-adapted method and expands the Kalman filtering law. In addition, entire Uygur rotor magnetic flux sight, tooth overtone electric potential, such as this theory and so on,

also appearance in the vector control without velocity generator technique. Since 1983 proposed the vector control without velocity generator technique control strategy, receives the academic circles and the industrial field continuously highly focused all the time. Hitachi company and Sichuan electrical machinery and so on had published the research results separately in 1987, and had promoted the product one after another. At present, vector control without velocity generator technique in frequency converter controlling in the velocity modulation scope is about 1:50, some individual merchant has 1:75 or even higher product.

(3) Direct Torque Control Technique

In1985, Germany's M. Depen-block proposes the direct torque control technique (DTC)for the first time,The direct torque control technique analyzes the motor mathematical model directly under the stator coordinate system. Uses the stator magnetic field direction detection but not to need the solution lotus root electric current,directly control the electric motor flux linkage and torque, enable the torque to obtain the fast response, in order to obtain the highly effective control performance.

Direct torque control technique is another kind of new、high performance alternating frequency conversion velocity modulation technique after vector control technique in the nearly 10 years, this kind of control technique is insensitive to the electrical machinery parameter, not influence by the rotor parameter, easy and feasible, it has the broad development and the application prospect.

(4) PWM (pulse width modulation) Control Technique

In1964, Germany's A. Schonung and some people took the lead to propose the pulse-duration modulation (PWM -pulse width modulation) frequency conversion thought, opened the recent development domain for the modern alternating velocity modulation system. The PWM control technique controls the inversion output alternating fundamental wave voltage peak-to-peak value by changing the rectangle pulse width, controls its output frequency through changing the modulation cycle, in order to carry on the output voltage peak-to-peak value and the frequency control on the inversion at the same time. The PWM technique simplified the inversion structure, can distinctly change the output wave shape of the frequency converter, reduces the overtone loss of electric motor, and reduces the torque pulsation, at the same time enhances the performance of dynamic response system. The PWM technique also may use in the rectifier controlling, can realize the input current which approaches the sine extremely. And may cause the electrical network power factor is 1. The PWM rectifier thus is called “the green converter”. At present, PWM technique has become the most widespread control technique applied in the frequency converter. The unceasingly velocity modulation performance of alternating current motor is as a result of the PWM technique unceasing progress enhancement in the very great degree. At present the widely applies is the optimizes PWM law which developing

based on the regular sampling PWM foundation, that is Thrice Harmonic Superpose theory and voltage space vector PWM theory.

(5) Numerical Control Technique

The digitalize in control technique is the key technique of static frequency conversion installment, also will be the next development tendency, at present in the market frequency conversion installment nearly comprehensively has realized the numerical control. Has realized the fast operation and the high accuracy control by using the DSP and the ASIC technique, and could gain a fine current wave, reduce the noise of the frequency converter in a large scale, and the scanning time also be reduced in a large scale, at present the electric current response is 0.1~0.7ms, the speed response is 2~4 ms, could satisfy the control request sufficiently in the transmission domain. At the same time, on account of the application of the micro electron and ASIC technique, the installment primary device quantity can be reduced in a large scale, thus, could make the frequency conversion equipment volume to be reduced, the reliability obtains the large scale enhancement. The entire numerical control way can make the information-handling capacity of frequency converter enhance greatly. The complex control has been realized in nowadays which could not be realized by simulation control mode, so that, the RAS which mean Reliability, Availability, Serviceability could be realized.

(6) Self-setting Technique

The self-setting technique is widespread used in the frequency conversion velocity modulation system day by day, it may accord to the speed and the load to auto adjust the parameter of the control system, enable the system with rapid dynamic response. The self-setting technique divides into off-line and the on-line. The research results in the kind of off-line has been applied in the most production, before the system program operate, it operate a block self-setting program, recognize the correlation data, and amend the parameter of the system program that related, in order to gain a approved system control performance. Moreover, improve the control technique, enhance the robustness of the system, also have close relatives with self-setting technique.

中文译文

变频技术的发展

1.变频技术的普及前景

电机交流变频调速技术是当今节电、改善工艺流程以提高产品质量和改善环境、推动技术进步的一种主要手段。变频调速以其优异的调速和起动制动性能,高效率、高功率因数和节电效果,广泛的适用范围及其它许多优点而被国内外公认为最有发展前途的调速方式。电气传动控制系统通常由电动机、控制装置和信息装置三部分组成,电气传动关系到合理地使用电动机以节约电能和控制机械的运转状态,实现电能-机械能的转换,达到优质、高产、低耗的目的。电气传动分成不调速和调速两大类,调速又分交流调速和直流调速两种方式。不调速电动机直接由电网供电,但随着电力电子技术的发展这类原本不调速的机械越来越多地改用调速传动以节约电能(节约15%~20%或更多),改善产品质量,提高产量。在我国60%的发电量是通过电动机消耗的,因此调速传动是一个重要行业,已经得到国家重视,目前已有一定规模。

近年来交流调速中最活跃、发展最快的就是变频调速技术,变频调速是交流调速的基础和主干内容。上个世纪变压器的出现使改变电压变得很容易,从而造就了一个庞大的电力行业。长期以来,交流电的频率一直是固定的,变频调速技术的出现使频率变为可以充分利用的资源。

这十年来,变频技术的应用在我国有很大的发展,并取得了良好的效果可以说,变频技术已为大多数用户所接受,但是不能不指出,我国在变频技术的应用方面,与发达国家的水平尚有很大差距,目前,我国在用的交流电动机使用变频调速运行的仅6%左右,而下业发达国家已达(60%~70%),日本在风机、水泵上变频调速的采用率已达10% ,而我国还不足0.01%.在日本,空调器的70%采用了变频调速,而我国才刚刚起步。从这个现实出发,变频技术尚有很大的发展空间,应该锲而不舍地做好推广应用工作。

而且随着控制技术和控制手段的不断提高,变频调速又由变压变频控制的变频调速发展到了矢量控制变频调速,通过控制交流电动机里相当于并励直流电动机励磁绕组的磁通变化,提高变频器的恒转矩输出范围和动静态特性,使得交流电动机变频调速系统的性能超过了直流电动机调压调速系统的性能。为了简化控制系统,减少设备故障率,在矢量控制变频调速的基础上又发展了无速度传感器的矢量控制变频调速。在一些对动静态特性要求不太高的应用中,无速度传感器的矢量控制变频调速己完全可以和有速度传感器的矢量控制变频调速相媲美。矢量控制对交流电机调速具有划时代的意义。

变频调速是电机调速的最佳方式,是企业技术改造和产品更新换代的理想设

备,是工业自动化系统必不可少的组成部分,是实现生产过程和管理自动化的前提,也是信息化发展的先决条件。在我国传统产业中,采用直流电机拖动的调速系统约占调速系统总量的85%~90%,而交流调速系统仅占10%~15%。效率低、质量差、消耗大、故障率高己成为制约企业发展的瓶颈。因此,必须积极推广先进的交流变频调速技术,用先进的设备武装传统产业,促进自动化、工业化和信息化的进一步发展。

2. 变频调速发展趋势

如果说以第一个晶闸管的出现作为交流电动机变频调速的起点,可以认为它的发展历史己40多年了。而变频调速技术真正高速发展时期,应该是在PWM 调制技术的出现和微机控制技术发展之后。特别是最近20年来,随着交流调速技术的应用普及,交流变频调速在化工、火电厂、矿山、油田、机械制造、城市建设、水处理、甚至家电等行业己经全面推广使用,一般主要用于节能及控制。随着变频技术的普及和深入,以及国际、国内电器设备使用的有关标准意识的强化,电力系统行业和用户对变频技术的质量要求也越来越高。变频调速的发展趋势主要围绕下面几个方而展开。

(1)高性能的智能控制变频器

380V系统的低压变频器是国内的主要研究对象,应用交流调速的基本理论,结合神经网络控制、鲁棒控制、模糊控制,或其他智能控制等手段,实现电机运行参数的自动辨识,以期达到自适应、自调整的最优控制。这方面己有一定的研究成果。

(2)速度传感器研究

从前面所述的各种变频调速的理论可知,一般系统都要用到转速传感器。在实际使用中,由于变频设备和被控电动机有一定的距离,而高精度的转速传感器都要使用专门的电源,被控电动机有的是在户外,运行工况非常恶劣,要保证速度反馈的准确性,有时不得不采取特别措施,因此也会增加额外费用,运行的可靠性和控制精度也会因此受到影响。无速度传感器的变频调速系统,是通过现场采集的电流电压量,以及控制的实施策略,综合出被控电机的实际转速。这种控制方案要求计算机的控制速度较高,并有足够的精度。

(3)针对功率因数提高和谐波污染的研究

低压变频调速系统的控制虽然己经是非常成熟了,但目前国际、国内的产品,一般都是矢量控制和直接转矩控制,重点放在电机变频控制理论的实现和完善上,而对变频器的输出波形、功率因数,以及谐波污染等问题还没有引起足够的重视。最近10多年来,国外在这一领域己有较深入的研究。有的针对功率因数,有的强调输出波形。多重化技术就是为了解决输出波形问题。最近几年的研究表明,

利用PWM输出控制解决谐波输出问题,是比较理想的方法,它可以省去多重化中的变压器,或过多的开关元器件,使变频器的体积和重量减少,但这种方法不能解决所有谐波的消除问题,只能部分消除特定谐波。这方面的研究论文还不多,也还没有成熟的类似低压变频器的产品出现。

(4)高压变频器的研究

变频器的主要作用之一是节能。而高压电动机的节能效果是比较明显的,大功率的风机和水泵用电动机一般都是高压电动机。国内,高压变频调速和它的节能控制还是一个比较薄弱的环节.它主要是针对6~10kV的交流电动机进行变频调速控制。这种高压电动机广泛应用于火力发电厂的送风机和引风机上。同样也可用于其他如石油化工、矿山、冶炼、机械制造等行业的变频节能控制。从某种意义上讲,由于目前国内还不能完全生产高质量的合格电力电子器件,而且,国外低压变频器的性能价格比也比国内自己研究的变频器高得多。因此,在这方面还有许多研究工作要做。

随着电力电子技术最近20多年的飞速发展,功率半导体器件的成本逐年下降,技术工艺和性能也得到不断改善.电力电子器件的应用己从传统的直流调速、直流屏、斩波器等领域延伸到交流调速和电力系统的质量控制领域.并正朝着高电压、大功率的方向发展.这也是千年之交和世纪之交我国电力电子技术应用的发展趋势。

(5)无换向器同步电机的变频调速

无换向器电动机也是在20世纪70年代发展起来的新型调速系统。它是一种变频调速同步电动机.也可以认为是一种用半导体电子开关线路代替换向器和电刷作用的直流电动机。根据采用的控制方式不同.可分为直流无换向器电动机和交流无换向器电动机。直流无换向器电动机采用交-直-交或直-交变频控制系统;交流无换向器电动机采用交-交变频控制系统。近10年来.国内外杂志上有许多相关的研究论文。而且,也有一定的成果出现。

3. 变频调速控制方式

交流变频调速技术在20世纪得到了迅速发展。这与一些关键性技术的突破性进展有关,它们是交流电动机的矢量控制技术、直接转矩控制技术、PWM技术以及微型计算机和大规模集成电路为基础的全数字化控制技术、自整定技术等。

(1)矢量控制技术

矢量变换控制技术是西门子公司于1971年提出的一种新的控制思想和控制理论。它是以转子磁场定向,采用矢量变换的方法实现定子电流励磁分量和转矩分量之间的解藕,达到对交流电动机的磁链和电流分别控制的目的,从而获得了优良的静、动态性能。迄今为止,矢量控制技术己经获得了长足的发展,并得到

了广泛应用。

(2)无速度传感器矢量控制技术

无速度传感器控制技术免去了传感器带来的环境适应性、安装维护等问题,降低了成本,提高了系统的可靠性,同时结合矢量控制,具有矢量控制的优良性能。无速度传感器技术中速度估算的方法,除了根据数学模型计算电动机转速外,目前应用较多的有模型参考自适应法和扩展卡尔曼滤波法。此外全维转子磁通观测器,齿谐波电势(RSH)等理论也出现在无速度传感器技术中。从1983年提出无速度传感器矢量控制策略以来,一直受到学术界和产业界的高度重视,日立、安川电机等公司在1987年分别发表了研究成果,并相继推出了产品。目前,无速度传感器矢量控制变频器的调速范围为1:50左右,个别厂商有1:75甚至更高的产品。

(3)直接转矩控制技术

1985年.德国的M . Depen-block首次提出直接转矩控制技术(DTC)。DTC控制直接在定子坐标系下分析交流电动机的数学模型。采用定子磁场定向而无需解藕电流,直接控制电动机的磁链和转矩,以使转矩得到快速响应,从而获得高效的控制性能。

直接转矩控制技术是近10年继矢量控制技术之后发展起来的又一种新型的高性能交流变频调速技术,这种控制技术与矢量控制技术相比,对电机参数不敏感,不受转子参数的影响,简单易行,具有广阔的发展和应用前景。

(4)PWM控制技术

1964年,德国的A. Schonung等率先提出了脉宽调制(PWM -pulse width modulation)变频的思想,为近代交流调速系统开辟了新的发展领域。PWM控制技术通过改变矩形脉冲的宽度来控制逆变器输出交流基波电压的幅值,通过改变调制周期来控制其输出频率,从而在逆变器上同时进行输出电压幅值和频率的控制。PWM技术简化了逆变器的结构,能够明显的改善变频器的输出波形,降低电动机的谐波损耗,并减小转矩脉动,同时提高了系统的动态响应性能。PWM 技术还可用于整流器的控制,能够实现输入电流非常接近正弦.。并可使电网功率因数为1。PWM整流器因而被称为“绿色”变流器。目前,PWM技术己成为变频器中应用最为广泛的控制技术。交流电机调速性能的不断提高在很大程度上是由于PWM技术的不断进步。目前广泛应用的是在规则采样PWM的基础上发展起来的准优化PWM法,即三次谐波叠加法和电压空间矢量PWM法。

(5)数字化控制技术

控制技术的数字化是静止变频装置的核心技术,也是今后的发展趋势。目前市场上的变频装置几乎全面实现了数字化控制。采用DSP和ASIC技术实现了

快速运算和高精度控制,可以得到良好的电流波形,使变频器的噪音大幅度降低,并且扫描时间大幅度缩短,目前电流响应为0.1~0.7ms,速度响应为2~4 ms,足以满足传动领域的控制要求。同时由于应用微电子技术和ASIC技术,装置的元器件数量得以大幅度减少,从而使变频装置的体积减小,可靠性得到大幅度提高。全数字控制方式使变频器的信息处理能力大为增强。采用模拟控制方式无法实现的复杂控制在今天都己成为现实,从而所谓的RAS概念即可靠性(Reliability)、可操作性(Availability)、可维修性(Serviceability)得以充实。

(6)自整定技术

自整定技术在变频调速系统中的应用日益广泛,它可以根据速度和负载的变化自动调整控制系统的参数,使得系统具有快速的动态响应。自整定技术分为离线式和在线式两种。离线式的研究成果己经在相当多的产品中应用,它是在运行系统程序之前通过运行一段自整定程序,辨识相关数据,并修改系统程序的相关参数,以期获得良好的系统控制性能。另外,改进控制技术,提高系统鲁棒性也和自整定技术紧密相联系。

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