Research On Optimal Energy-Saving Control Method Of Variable Load Motor System

With the increasing depletion of global energy, people are in hard search of new alternative energy and meanwhile, more and more attentions have been paid to the energy conservation. The three-phase induction motor is the chief power consuming devices in the world, and its energy-saving research has been the focus of research in many countries. For the sake of achieving the principle of low-cost, highly reliable and realizable, a new optimal energy-saving method for variable-load motor system is demonstrated in this paper, which has been used in the application of thyristor technology and obtained a satisfaction result, after reading a lot of native and foreign literature and conducting survey.In this paper, the inefficient causes of three-phase induction motor in actual applications are analyzed at first, and then the research results and methods about motor energy-saving issues at home and abroad are introduced. After synthesizing the information above, it is pointed out that the thyristor has low-cost, high reliability and ease controlled features, and it is the ideal regulator device, which makes it more advantageous in motor control application than other devices. After that, the analysis of motor internal energy consumption and its relationship with external variables are completed based on the mathematical model of motor. Because of the features of multivariable, nonlinear, etc. the traditional motor energy-saving methods are no longer acceptable, thus a nonlinear optimal control algorithm-the search algorithm based on the optimal power factor angle is advanced, which has strong robustness, requires less parameters and can achieve the automatic optimization of the motor. Moreover, the designs of hardware modules of entire system are illustrated, such as the acquisition of RMS of the voltage and current, the detection of current and voltage zero-crossing points, the trigger circuit of thyristor, etc. The corresponding software design of search algorithm, power factor calculation and data filtering algorithms are also referred to. At last, according to the contrast of experimental data, it is proved that the motor which is controlled by the energy-saving search algorithm has a better energy-saving effect and the algorithm referred to in this paper is suitable in the applications of variable-load motor systems.