Research On Induction Motor Drive System Based On Efficiency Optimization Control

Induction motor has been widely applied in industry, agriculture and other fields, because of its simple structure, low prices and high reliability. The number of induction motor accounts for a sizeable proportion in drive system applications. In practical applications, the majority of induction motor drive system often operates in light or no-load conditions, which leads to the power factor and efficiency low, and energy wasted. So it is a generally concerned topic how to improve the operating efficiency of induction motor drive system in motor industry.In this paper, the research aim is to improve the system efficiency of the induction motor drive within wide load. Through theoretical analysis, the relationship is studied that between the energy consumption of induction motor drive system and the operation principle of energy saving in light load. Based on the steady induction motor mathematical model we set, the relations of the efficiency and power factor is derived with the rotor frequency and slip frequency, it also gain the change regularity between efficiency and power factor. Then, the optimal efficiency analysis is made according to different load and speed under the principle of optimum efficiency.The constant power factor control methods is analyzed and studied in this paper. From the principle, the method is simple and easy to realize. However, the study results show that the constant power factor control cannot maintain optimum efficiency. Because the power factor is not constant within the whole speed of change when motor run at maximum efficiency. Therefore constant power factor control is only an approximate optimal control. In order to solve this problem, this paper presents an method to gain the optimal power factor curve of induction motor drive, and adjust voltage energy-saving control strategy is raised with optimum power factor.Based on this control strategy, the paper presents models for all aspects of the system with MATLAB / Simulink tools, makes simulation analysis according to different speed and load. The simulation results are consistent with theoretical analysis. On the basis of simulation analysis, devising the system function module rationally, setting a platform of induction motors efficiency optimization control system based on DSP and intelligent power module (IPM). It compiles practical program. Finally, the whole system is tested and the results have been given.