The Research On Control System Of Heavy-duty Electrical Wheels Autonomous Dump Truck Based On Frequency Control Technology

With the rapid development in economy,there is a growing demand for materials and energy in industry. Under this circumstances,the electric wheel dump truck, a very important transport used in mining environment, should also be developed in terms of it's stability, and controllability. The reality of the situation at home and abroad has proved that, because of it's excellent performance the dump truck equipped with the AC variable frequency drive devices will certainly replace those only with the traditional DC drive devices. In this paper, a new control scheme has been presented so as to overcome these main difficulties during the implementation of dump truck using AC variable frequency drive technology.First, it introduced the development trend and the development process of electric wheel dump truck, and the composition of its transmission system is also be described. Then, after analyzing the mathematical models of induction motor under different coordinates, the general law of vector control algorithm has been summarized. Considering the good performance electric wheel dump truck should show under harsh environment, the rotor flux-oriented control technology has been choosed as the essential technology for the AC drive system of electric wheel dump truck. Compared with the direct torque control, the rotor flux-oriented control can make inverter work with fixed switch frequency, and also let the wave range of torque to be the least. While compared with other flux-oriented control technology, it has the simpler structure,which is easy to be computed.It should be considered that the truck's power transmission system is supplied by diesel generators, which is different from those being supplied by power grid with good power performance.So this paper designed a system adopting space vector modulation algorithm in the full range, so that the inverter will achieve higher level of utilization of the bus voltage.Because of the harsh environment,the varied motor parameters should also be taken into account, which will cause the excitation current and torque current are not completely decoupled. According to this situation, a rotor flux angle modifier has been added using the fuzzy control algorithm, which will do a great help for the process of decoupling between excitation current and torque current and narrow the wave range of torque.Finally, the simulation system and the real experimental platform of electric transmission wheel dump truck based on rotor flux oriented control technology have been built, and then the experiments also have been finished on them.