Research On Control System Of Mine Electric Traction Locomotive

Mining traction electrical locomotive is one kind of important transport toolswidely used in mines, with the complex working environment, low reliability ofpower supply, poor working condition and overload phenomenon making the controlof the electrical locomotive very difficult. So the mining traction locomotive need tohave big starting torque, speed smoothly, reliable operation, anti-jamming capabilityand outstanding overload ability to meet the requirements of mine traction.Most of mine traction electrical locomotive in China use DC series motor asthe traction motor. With the development of the power electronics, micro-electronics,control theory, and information technology, all kinds of electric drive system havebeen researched by more and more domestic and foreign scholars and engineers. ACdriving technology has matured, with superior speed regulation performance. ACmine locomotives are gradually replacing DC mine locomotives.The control method of induction motors can be divided into two kinds, based onsteady-state model and based on dynamic model. VVVF control method with speedopen-looped is a popular control method based on steady-state model, with simplesystem structure, low cost and poor speed regulation performance. Vector controland direct torque control method are two main control methods based on dynamicmodel, with complicated system structure and remarkable speed regulationperformance, which meet the requirement of high performance control. The maincontributions of this dissertation summarized as following:1. In rotating coordinate system, this dissertation analyzes the constraints ofvoltage and current under different frequency to obtain the maximum output torque.By comparing the characteristics of asynchronous motor and traction electriclocomotive, the induction motor used as traction motor has the similar characteristicswith the traction electric locomotive.2. According to the traction force of the electric locomotive, the different loadsof traction locomotive and loading vehicles converted into the comprehensive load.All influence factors of the traction locomotive, gearbox wheel convert to the side ofmotor, based on this the integration model of traction system established 3. The direct torque control and vector control schemes are compared against thereal condition. Based on vector control strategy as the control scheme of the motor,and combined of speed closed-loop control, the hybrid of speed mode and torquemode for the mining traction control method is proposed.4. Based on analysis the negative factors of the DC bus voltage fluctuation forthe traction control system, the dissertation proposes the feed-forward controlmethod to suppress the DC bus voltage fluctuations and the control scheme isvalidated.5. Research and analyze the schemes of speed sensor-less control, synchronousspeed estimation method using differential of the torque current is proposed, as wellas the core algorithm of the speed estimation. The algorithm is proved correctlythrough the simulation. The dynamic and static performances are good and it meetsthe requirements traction electric locomotive.6. The hardware and software system of the control part for the mining tractionelectrical locomotive is designed. Based on dsPIC30F6010A, the low powerexperiment platform and high power product prototype designed for the tractionlocomotive. Introduce performance Indicators of two different power control system,the related test results of the product prototype and test at mine site are given at last.Experiment results show that the system is able to start with heavy load, andhas good steady speed performance, rapid dynamic response, wide speed regulationranging from low speed to constant power area and ability of smooth switch betweenspeed and torque mode, which meets the requirement of mine locomotive.