点击图片查看大图
TSC06401C TSC06401C TSC06401C
2007-03-20 23:03 伺服电机原理和应用-1 伺服电机原理和应用
PWM伺服放大器 东元伺服电机张生 182-019-88-309 东元Q/-8788-56-087 东元电机 东元驱动器
PWM Servo Amplifier
PWM伺服放大器被用作小尺寸的伺服场合,如使用直流有刷伺服电机.图11-89展示这一类型放大器的图.从左下图中可以看到单相交流电源供电给放大器. 右上图中交流电经整流后,被送到驱动的输出单元,驱动输出单元用四个IGBT来产生脉宽调制波形.IGBT连接后以便他们提供30-120V直流电压,高达的电流到直流有刷伺服电机.电机的极性由图中显示.
The PWM servo amplifier is used on small-size servo applications that use DC brush-type servomotors. Figure 11-89 shows a diagram for this type of amplifier. From the diagram you can see that single-phase AC power is provided to the amplifier as the supply at the lower left part of the diagram. The AC voltage is rectified and sent to the output section of the drive that is shown in the top right comer of the diagram. The output section of the drive uses four IGBTs to create the pulse-width modulation waveform. The IGBTs are con-nected so that they provide 30-120 volts DC and up to to the brush-type DC servo-motor. The polarity of the motor is indicated in the diagram.
在这张图的中间的保留电路显示一些从故障逻辑板上的故障电路,在图的下方提供一路输出信号.可以看到故障输出信号包括过压,过温及过电流.第四个信号作为SSO(系统状态输出).它显示当故障发生时的系统状态.一个跳线用来设置SSO信号
The remaining circuits show a variety of fault circuits in the middle of the diagram that originate from the fault logic board and provide an output signal at the bottom of the diagram. You should notice that the fault output signals include overvoltage, overtempera-ture, and overcurrent. A fourth signal is identified as SSO (system status output), which in-dicates the status of the system as faulted anytime a fault has occurred. A jumper is used to set the SSO signal as an open collector output with a logic level "1" indicating the drive is ready, or as a normally closed relay indicating the drive is ready. 在这张图的右下角的输入脚用来显示驱动的的使能控制或抑止,选择是前过放大控制还是向后放大控制.抑制信号作为控制信号.当放大器过高的时抑制输出过程.FAC和RAC信号限制电流到放大或缩小5%
The input terminals at the bottom right part of the diagram are used to enable or inhibit the drive, and to select forward amplifier clamp (FAC) or reverse amplifier clamp (RAC). The inhibit signal is used as a control signal, since it inhibits the output stage of the amplifier if it is high. The FAC and RAC signals limit the current in the opposite direction to 5%.
左上方显示的是输入信号.VCS(速度控制信号)要求一个+VCS和一个-VCS信号来提供不同的信号
The input signals are shown in the diagram at the upper left side. The VCS (velocity command signal) requires a +VCS and a -VCS signal to provide the differential signal.
伺服放大器和电机的应用场合
Applications for Servo Amplifiers and Motors
可以从伺服电机和放大器一些典型的应用场合延升到其它更好的使用场合.图11-90显示的是一台伺服电机被用作控制一个压力喂食器.在这个应用表中,薄片材料被送入一个卷压器中,在那儿它被用一把刀刃切长一定长度.薄片材料可以是一个带有切断点标记的商标或是广告纸.带有切断点标记的.在这个场合中,薄片材料的速度和位置司切断点保持同步.反馈传感器可以是一个编码器或是解码器,它同一个光电传感器连接在一起,用来判断标记的位置.所提供的操作面板用来使操作者能减慢系统动作,以维护刀刃或是换一卷新的材料.面板上可以进行参数调整以适应每一种原料.系统也可以同一个可编程的控制器或其它类型的控制器连接,以便操作面板上可以用来选择每一种材料或产品在运行时的正确的切断点.
You will get a better idea of how servomotors and amplifiers operate if you see some typical applications. Figure 11-90 shows an example of a servomotor used to control a press feed. In this application sheet material is fed into a press where it is cut off to length with a knife blade or sheer. The sheet material may have a logo or other advertisement that must line up registration marks with the cut-off point. In this application the speed and po-sition of the sheet material must be synchronized with the correct cut-off point. The feed-back sensor could be an encoder or resolver that is coupled with a photoelectric sensor to determine the location of the registration mark. An operator panel is provided so that the operator can jog the system for maintenance to the blades, or when loading a new roll of material. The operator panel could also be used to call up parameters for the drive that correspond to each type of material that is used. The system could also be integrated with a programmable controller or other type of controller and the operator panel could be used to select the correct cutoff points for each type of material or product that is run.
伺服电机原理和应用(一)
伺服电机可以应用于交流电机或直流电机,由于早期的大电流的控制只能通过SCR完成,所以以前的伺服电机主要是直流电机,随着晶体管可以控制大电流以及高频开关大电流,交流伺服电动机也广泛使用.早期的伺服电机主要是用于伺服放大器,现在这类电机应有于伺服放大或变频控制,这就意味着一台同样的伺服电机可以应用于伺服系统,也可以变频驱动.一些公司在伺服系统上使用闭环控制而不在使用步进电机,这样一台连接到一只高速控制器上的简单交流电动机也可以作为一台伺服电机
Servomotors are available as AC or DC motors. Early servomotors were generally DC motors because the only type of control for large currents was through SCRs for many years. As transistors became capable of controlling larger currents and switching the large currents at higher frequencies, the AC servomotor became used more often. Early servomotors were specifically designed for servo amplifiers. Today a class of motors is designed for applica-tions that may use a servo amplifier or a variable-frequency controller, which means that a motor may be used in a servo system in one application, and used in a variable-frequency drive in another application. Some companies also call any closed-loop system that does not use a stepper motor a servo system, so it is possible for a simple AC induction motor that is connected to a velocity controller to be called a servomotor.
当普通电机被设计成伺服电机时,需要做些改进,包括在不过热条件下,一定速度范围内运转,在速度为零时,维持某一转矩使负载停在某一位置,在不过热条件下,低速长时间运转.老的电机有一个散热风扇直接装在转轴上,当电机在低速运转时,风扇不能产生足够的风来降低电机温度,新的电机配一独立风扇,,它能产生最适宜的冷却风.这种风扇由一恒压电流供电,无论伺服电机以何种转运转,都能以最高转速运转.在伺服系统中常用的一种电机就是永磁电机,永磁电机的绕组电压可以是交流也可以是直流.这类永磁电机同以前的PM电机类似.
Some changes that must be made to any motor that is designed as a servomotor in-cludes the ability to operate at a range of speeds without overheating, the ability to operate at zero speed and retain sufficient torque to hold a load in position, and the ability to operate at very low speeds for long periods of time without overheating. Older-type motors have cooling fans that are connected directly to the motor shaft. When the motor runs at slow speed, the fan does not move enough air to cool the motor. Newer motors have a separate fan mounted so it will provide optimum cooling air. This fan is powered by a con-stant voltage source so that it will turn at maximum RPM at all times regardless of the speed of the servomotor. One of the most usable types of motors in servo systems is the permanent magnet (PM) type motor. The voltage for the field winding of the permanent magnet type motor can be AC voltage or DC voltage. The permanent magnet-type motor is similar to other PM type motors presented previously. Figure 11-83 图11-83显示的是一台普通永磁电机的剖示图.图11-84展示的是伺服永磁电机的剖示图.从图中可以看出,新的电机在轴承室,转子,定子上同以前的电机类似.主要的区别只在于这种新类型的电机可以较大的负载从静止状态动作,这类永磁电机同样有一个编码器或resolver被放置在电机内部.这个可能确保设备能更精确的显示电机轴的位置或速度.shows a cutaway picture of a PM motor and Fig. 11-84 shows a cutaway diagram of a PM motor. From the picture and diagram you can see the housing, rotor and stator all look very similar to the previous type PM motors. The major difference with this type of motor is that it may have gear reduction to be able to move larger loads quickly from a stand still position. This type of PM motor also has an encoder or resolver built into the motor housing. This ensures that the device will accurately indicate the position or velocity of the motor shaft.
FIGURE 11-83 Typical PM servomotors
FIGURE 11-84 Cutaway picture of a permanent magnet servomotor.
.
