【正文】 可靠的低成本和高效驅(qū)動的驅(qū)動系統(tǒng)可供顧客選擇 [1] 1 帶式輸送機(jī)驅(qū)動 1. 1 帶式輸送機(jī)驅(qū)動方式 全電壓啟動 在全電壓啟動設(shè)計(jì)中，帶式輸送機(jī)驅(qū)動軸通過齒輪傳動直接連接到電機(jī)。因此，這種方式只用于低功率，結(jié)構(gòu)簡單的傳送驅(qū)動中。此種控制方式功率可達(dá)到 750kW。該方式的電機(jī)系統(tǒng)設(shè)計(jì)相對簡單，但控制系統(tǒng)可能很復(fù)雜，因?yàn)樗鼈兪腔谟?jì)算機(jī)控制的電阻切換。DC 驅(qū)動系統(tǒng)在機(jī)械上是簡單的，但設(shè)計(jì)的電子電路，監(jiān)測 和控制整個(gè)系統(tǒng)，相比于其他軟啟動系統(tǒng)的選擇是昂貴的，但在轉(zhuǎn)矩、負(fù)載均分和變速為主要考慮的場合，它又是一個(gè)可靠的，節(jié)約成本的方式。由于循環(huán)流體產(chǎn)生扭矩和速度，在驅(qū)動軸和從動軸之間不需要任何機(jī)械連接。 固定充液液力偶合器 固定充液液力偶合器是在結(jié)構(gòu)較簡單和僅3 具有有限的彎曲部分的輸送裝置中最常用的軟啟動裝置，其結(jié)構(gòu)相對比較簡單，成本又低，對現(xiàn)在使用的大多數(shù)輸送機(jī)能提供優(yōu)良的軟啟動效果。為了控制單機(jī)傳動系統(tǒng)的啟動轉(zhuǎn)矩，必須監(jiān)測 AC電機(jī)電流給電磁閥的控制提供反饋 。此種液力偶合器需要在工作腔以外設(shè)置導(dǎo)管 (也稱勺管 )和導(dǎo)管腔，依靠調(diào)節(jié)裝置改變勺管開度 (勺管頂端與旋轉(zhuǎn)外 殼間距 )人為的改變工作腔的充液量，從而實(shí)現(xiàn)對輸出轉(zhuǎn)速的調(diào)節(jié)。 VFC裝置為感應(yīng)電機(jī)提供變化的頻率和電壓，產(chǎn)生優(yōu)良的啟動轉(zhuǎn)矩和加速度。 VFC 控制器可以容易地裝在小功率輸送機(jī)驅(qū)動上。 2 使用 IGBT 的中性點(diǎn)箱位三電平逆變器 由于串聯(lián)器件電壓均分容易，器件每次開關(guān)的 dv/dt 低以及輸出端出色的諧波品質(zhì)，三電平電壓型逆變器在大功率傳動應(yīng)用中變得越來越流行。 2. AV 逆變器每個(gè)開關(guān)只需要一個(gè) HVIGBT[2,3]。例如，當(dāng)開關(guān) S1u 和S2u 閉合時(shí)， U 相處于狀態(tài) P(正母線電壓 )，反之，當(dāng)開關(guān) S3u 和 S4U 閉合時(shí)， U 相處于狀態(tài) n(負(fù)母線電壓 )。若對輸入諧波有 更高的要求，可以使用 24 脈沖二極管整流器作為輸入變流器。對相加結(jié)果的頻率信號積分，然后產(chǎn)生單位矢量 (cosθ e 和 sinOθ e )，最后通過矢量旋轉(zhuǎn)器產(chǎn)生電壓 V’角θ控制 PWM 調(diào)制器。 產(chǎn)生的諧波盡可能的小，使用盡可能低的開關(guān)頻率以最小化開關(guān)損耗 。圖 3 為測試結(jié)果波形。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(jī)扮 演了重要的角色。 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 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 meet a conveyor system39。 the driving hydraulic turbine known as the runner and a casing that encloses the two power ponents. Hydraulic fluid is pumped from the driven impeller to the driving runner, producing torque at the driven shaft. Because circulating hydraulic fluid produces the torque and speed, no mechanical connection is required between the driving and driver power produced by this coupling is based on the circulated fluid39。 P N and 0 are the do bus points. The phase U, for example, is in state P (positive bus voltage)when the switches S1uand S2u are closed, whereas it is in state N (negative bus voltage) when the switches S3u and S4u, are closed. At neutral point clamping, the phase is in 0 state when either S3u, conducts depending on positive or negative phase current polarity, respectively. For neutral point voltage balancing, the average current injected at 0 should be zero. 2. 2 Line side converter For standard applications. a 12pulse diode rectifier feeds the divided DClink capacitor. This topology introduces low harmonics on. the line side. For even higher requirements a 24pulse diode rectifier can be used as an input converter. For more advanced applications where regeneration. capability is necessary, an active front. end converter can replace the diode rectifier, using the same structure as the inverter. 2. 3 Inverter control Motor Control. Motor control of induction machines is realized by using a rotor flux. oriented vector controller. Fig. 2 shows the block diagram of indirect vector controlled drive that incorporates both constant torque and high speed fieldweakening regions where the PW M modulator was used. In this figure, the mand generated as function of speed. The feedback speed is added with the feed forward slip mand signalψ,the resulting frequency signal is integrated and then the unit vector signals(cosθe and sinθ e)are generated. The vector rotator generates the voltage Vs and Angle θe mands for the 14 PW M as shown. PWM Modulator. The demanded voltage vector is generated using an elaborate PWM modulator. The modulator extends the concepts of spacevector mod