Optimal Control Of Dsp-based Vector Control Of Induction Motor Efficiency

As Is well known, induction motor plays an important role in modern industry, and is a kind of electric equipments which have the most power consumption. When induction motor operates underload, especially lower than 20% the rated load, its efficiency and the power factor will drop obviously. So the induction motors carrying lightly for the long time have the very big economy energy space. With the development of the technology of Variable Frequency Speed Regulation, the performance of induction motor is improved, but it still exists that problem. Therefore it is important to improve the efficiency of induction motor under partial load not only from the viewpoint of energy saving, but also from the broad perspective of environmental.Firstly, A simulation model for induction motor taking core loss into account by using the build-in modules of SIMULINK based on induction motor mathematic model in rotate coordinate is introduced. In this model, There are not only normal physical quantity such as three-phase current and speed, but also interior quantity such as voltage and current at different system. So this model is very suit to simulate high performance motor even control system.Secondly, based on the analysis of the loss of induction motor in detail, the thesis further investigates the efficiency optimal problem of induction motor with vector control under partial load and stable state. The thesis has discussed the question deeply and done a large number of simulation experiments using Loss Minimization Controller(LMC) based on model, Search controller(SC) based on golden sections and Hybrid ControIler(HC) combining the advantages of LMC and SC. The simulation results show that LMC can reduce the motor loss widely and have good dynamic performance, but easy to influence by the fact that the parameters of the motor change; Though SC can overcome this shortcoming, but have low convergence speed; HC can not only shorten the convergence time, but also overcome the problem of parameters variation. Simulation results prove that HC is a kind of good control strategy that optimizes efficiency.Thirdly, the article summarizes the development of DSP and its application in the motor control domain. Based on the already hardware, the vector control efficiency optimization system based on TMS320LF2407A is perfected. A some hardware circuits such as 3.3V power supply, current measuring, speed measuring and system procedure flow chart are given. Some key subprograms are introduced in detail and a great deal ofexperiment results are get. The results indicate induction motor of vector control has heavy energy-conserving space while it operates far from the rated values, and the efficiency can promote more than 30%. The results not only verify the theory results above, also provide the way of thinking for the improvement of general vector control system.Finally, the directions and measures to be improved and studied further are pointed out.