【正文】 意的特性。 4 結(jié)論 近年來輸送機驅(qū)動控制技術(shù)的進步已更為可靠，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。在這些選擇中，可變頻率控制 (VFC)的方法顯現(xiàn)出在將來長距離輸送中帶式輸送機扮 演了重要的角色。使用高壓工 GBT 的中點嵌位三電平逆變器本身可以提供電機終端所需的供電中高壓，使變頻控制的應(yīng)用更為簡單。通過成莊煤礦 2. 7km 長帶式輸送機中采用的中點嵌位三電平逆變器變頻調(diào)速 (VFC)控制系統(tǒng)的測試結(jié)果表明，采用 BVIGBT 的中點嵌位三電平逆變器以及使用轉(zhuǎn)子磁場矢量控制策略的感應(yīng)電機變頻傳動，使帶式輸送機驅(qū)動系統(tǒng)具有非常優(yōu)秀的性能，顯示出良好的應(yīng)用前景。 7 英文譯文 Belt Conveying Systems Development of driving system Among the methods of material conveying emploved, belt conveyors play a very imporient part in the reliable carrying of material over long distances at petitive cost. Conveyor systems have bee larger and more plex and drive systems have a l so been going through a process of evolution and will continue to do so. Nowadays, bigger belts require more power and have brought the need for larger individual drives as well as multiple drives such as 3 drives of 750 kW for one belt(this is the case for the conveyor drives in Chengzhuang Mine). The ability to control drive acceleration torque is critical to belt conveyors39。 performance. A efficient drive system should be able to provide smooth, soft starts while maintaining belt tensions within the specified safe limits. For load sharing on multiple drives. torque and speed control are also considerations in the drive system39。s design. Due to the advances in conveyor drive control technology, at present many more reliable. Costeffective and performance driven conveyor drive systems covering a wide range of power are available for customers39。 choices[1]. 1 Analysis on conveyor drive technologies 1. 1 Direct drives Fullvoltage starters. With a fullvoltage starter design, the conveyor head shaft is directcoupled to the motor through the gear drive. Direct fullvoltage starters are adequate for relatively lowpower, simple Profile conveyors. With direct fullvoltage starters. no control is provided for various conveyor loads and. depending on the ratio between full and noload power requirements, empty starting 8 times can be three or four times faster than full load. The maintenancefree starting system is simple, lowcost and very reliable. However, they cannot control starting torque and maximum stall torque。 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 rotor windings. the modified motor control System controls motor torque. For conveyor starting, resistance is placed in series with the rotor for low initial torque. As the conveyor accelerates,the resistance is reduced slowly to maintain a constant acceleration torque. On multipledrive systems. an external slip resistor may be left in series with the rotor windings to aid in load sharing .the motor systems have a relatively simple a ,the control systems for these can be highly plex, because they are 9 based on puter control of the resistance switching. Today, the majority of control systems are custom designed to mee