Research On Mine Hoist With Three-level Inventer's Speed-adjustable System Of Variable Frequency

With the rapid development of power electric & elctronic devices, microelectronic technique and modern control theories, AC drive has made great progress. Mine hoist AC speed-adjustable control which is one of an important application of AC drive has received wide attention.Mine hoist AC speed-adjustable system of high performance not only conserves energy, but also improves the running performace of high-power synchronous motor remarkably. At the same time, due to the multi-level inverter circuit's remarkable advantage (for example:less output harmonic & on-off frequency, etc.), it should be the preferred scheme which controls the main circuit of mine hoist speed-adjustable by using frequency conversion. Therefore, this paper which is based on mine hoist by using three-level & synchronous motor drive system, aimming at the studies of the diode-clamped three-level inverter system by using frequency conversion.In this paper, mine hoist electric dragging scheme, topology structure, control method for mine hoist inverter circuit and high-power devices have been summed up firstly. then, it has discussed the characteristics of mine hoist's journey control & craftwork requirement. The speed setting mode has been analysed and contrasted with the rotate speed-adjustable close-loop system. And, it has expounded the complex control theroy's practical meaning. Secondly, bacing on them, the SVPWM control strategy of three-level inverter has been studied stressfully. This section has analysed the production of seven segment vector method in reference voltage vector, its sectors, the judgement of small triangle area and other key taches surrounding by the space voltage vector figure. It has also analysed the three-level inverter's neutral-point voltage excursion producing mechanism simultaneously, giving a maths solving method.Since there existed some relationship between the diode-clamped three-level inverter's neutral-point voltage excursion and the output currents, it is necessary to build an universal model. This whole maths model was constructed inα-βtwo-phase stationary reference frame. On the basis of the space vector of fixed synthesizing vectors which the pre-researcher has brought forward, this paper has explored the three-level & synchronous motor DTC control strategy elementary and designed the system design figure as a whole, combining with two-level DTC control method. And, the corresponding simulative model has been established, which confirming the validity of academic production. Finally, it has also designed and studied the system's key taches such as inverter, excitation rectifying device and main control fibre-optical communication, combining with ACS6000 hoist drive. Through the debugging software DriveWindows, locate debugging has been carried through. Contrasted with locate debugging waveform shape, it also confirm the correctness of the given simulation scheme which this paper has done. It has also suggestted that the drive system worked reliably and satisfied with the manufacture craftwork's desire.