【正文】 驅(qū)動上，扭矩和速度控制在驅(qū)動系統(tǒng)的設(shè)計中也是很重要的因 素。但是，這種啟動方式不會產(chǎn)生穩(wěn)定的加速度，當(dāng)加速完成時，控制電機電壓的 SCR2 鎖定在全導(dǎo)通，為電機提供全壓。控制 DC 驅(qū)動技術(shù)一般應(yīng)用 SCR 裝置，它允許連續(xù)的變速操作。傳遞功率可達(dá)幾千千瓦。此種液力偶合器同樣由三個標(biāo)準(zhǔn)的液力偶合單元構(gòu)成，即葉輪、渦輪和一個包含工作環(huán)路的外殼。 VFC 驅(qū)動4 為傳送帶啟動提供了優(yōu)良的速度和轉(zhuǎn)矩控制，也能為多機驅(qū)動系統(tǒng)提供負(fù)載均分。 HVIGBT 模塊串聯(lián)可使用在 3. RV 和 4. 16kV的設(shè)備。 輸入端變流器 為通常使用 12 脈沖二極管整流器給直流環(huán)節(jié)電容器充電，在輸入端引入的諧波是很小的。它以一種優(yōu)化方式確定每一次開關(guān)時刻。 4 結(jié)論 近年來輸送機驅(qū)動控制技術(shù)的進(jìn)步已更為可靠，符合低成本效益和高效驅(qū)動的驅(qū)動系統(tǒng)為用戶提供了選擇。 therefore. they are limited to the lowpower, simpleprofile conveyor belt drives. Reducedvoltage starters. As conveyor power requirements increase,controlling the applied motor torque during the acceleration period bees increasingly important. Because motor torque is a function of voltage, motor voltage must be controlled. This can be achieved through reducedvoltage starters by employing a silicon controlled rectifier (SCR). A mon starting method with SCR reducedvoltage starters is to apply low voltage initially to take up conveyor belt slack. and then to apply a timed linear ramp up to full voltage and belt speed. However, this starting method will not produce constant conveyor belt acceleration. When acceleration is plete. the SCRs, which control the applied voltage to the electric motor. are locked in full conduction, providing fullline voltage to the motor. Motors with higher torque and pull vp torque, can provide better starting torque when bined with the SCR starters, which are available in sizes up to 750 KW. Wound rotor induction motors. Wound rotor induction motors are connected directly to the drive system reducer and are a modified configuration of a standard AC induction motor. By inserting resistance in series with the motor39。s rotating casing contains bleedoff orifices that continually allow fluid to exit the working circuit into a separate hydraulic reservoir. Oil from the reservoir is pumped through a heat exchanger to a solenoidoperated hydraulic valve that controls the filling of the fluid coupling. To control the starting torque of a singledrive conveyor system, the AC motor current must be monitored to provide feedback to the solenoid control valve. Variable fill drain couplings are used in medium to highkw conveyor systems and are available in sizes up to thousands of drives can be mechanically plex and depending on the control parameters. the system can be electronically intricate. The drive system cost is medium to high,depending upon size specified. Hydrokiic scoop control drive. The scoop control fluid coupling consists of the three standard fluid coupling cmponents: a driven impeller, a 11 driving runner and a casing that encloses the working circuit. The casing is fitted with fixed orifices that bleed a predetermined amount of fluid into a reservoir. When the scoop tube is fully extended into the reservoir, the coupling is 100 percent filled. The scoop tube, extending outside the fluid coupling, is positioned using an electric actuator to engage the tube from the fully retracted to the fully engaged position. This control provides reasonably smooth acceleration rates. to but the puterbased control system is very plex. Scoop control couplings are applied on conveyors requiring single or multiple drives from 150KWto 750KW. 1. 3 Variablefrequency control(VFC) Variable frequency control is also one of the direct drive methods. the emphasizing discussion about it here is because that it has so unique characteristic and so good performance pared with other driving methods for belt conveyor. VFC devices Provide variable frequency and voltage to the induction motor, resulting in an excellent starting torque and acceleration rate for belt conveyor drives. VFC drives. available from fractional to several thousand (kW)， are electronic controllers that rectify AC line power to DC and, through an inverter, convert DC back to AC with frequency and voltage control. VFC drives adopt vector control or direct torque control(DTC)technology, and can adopt different operating speeds according to different loads. VFC drives can make starting or stalling according to any given Scurves