Application Research On Three-level Frequency Converter Of The Shaft Hoist In Yangchangwan Coal Mine

Mine hoist is one of the most complex power transmission equipments in mine.Its working reliability,operation efficiency and speed regulation performance are the key factors for efficient production of mine,and are the basis for realizing intelligent mine and unmanned mining.In this dissertation,Yangchangwan mine shaft hoist speed control system is taken as the research object,aiming at high efficiency,high reliability and low power grid pollution,the principle and parameter design of shaft hoist speed control,low switching frequency predictive control of three-level converter and speed control strategy of shaft hoist are studied in depth,and the design scheme of Yangchangwan mine shaft hoist is given.In this dissertation,a low-speed direct-connected excitation synchronous motor drive system based on three-level converter is selected as the speed control system of vertical hoist.The operation conditions of vertical hoist are analyzed,the speed control principle of vertical hoist is studied,and the main circuit parameters of three-level AC-DC-AC converter are designed according to the operation conditions of Yangchangwan coal mine vertical hoist.This dissertation establishes a mathematical model of three-level rectifier.Aiming at the problems of incommensurability of multiple control objectives,complex adjustment of weighting coefficients and inability to take into account multiple control objectives in traditional multi-objective predictive control based on weighting method,a predictive control of three-level rectifier based on multi-objective hierarchical optimization is studied.The multi-objective optimization of three-level rectifier is divided into operation constraint layer.The compatible optimization layer and the optimal optimization layer is introduced into the compatible optimization layer to achieve multi-objective compatible control.A method of measuring switching frequency of three-level rectifier based on multi-step extension method is studied,which effectively realizes multi-objective satisfactory control at low switching frequency.This dissertation studies the air gap flux orientation control strategy of double-winding electric excitation synchronous motor.By designing winding switching device and fault-tolerant control scheme,the half-speed full-load operation of vertical hoist can be realized in single frequency converter fault,which effectively increases the reliability of the system.A new zero-speed hover controller based on auto-disturbance rejection control(ADRC)is proposed to solve the problem of largeovershoot and poor anti-external disturbance ability of speed regulator based on PI controller.The non-linear control law effectively suppresses the position jitter of cage caused by speed overshoot,and observes the load rotation of motor through extended state observer.Moment disturbance can effectively overcome the external disturbance caused by elastic deformation of wire rope.Combining with the actual situation of Yangchangwan mine shaft hoist,the hardware design scheme of three-level converter is given.The design method of three-level converter cascade bus and the design of main control circuit are emphatically studied.The simulation results show that the control strategy studied in this paper is correct and effective.There are 58 figures,11 tables and 113 references in this dissertation.