A Research On Efficiency Optimization Control For Speed Sensorless Induction Motors

Motor is widely used in industrial, commercial, agricultural and any other fields as an important drive equipment, and occupies important position. In China, about two thirds of power is consumed by the motors on various devices, and three quarters of these motors are induction motors. With the development of power electronic techniques, operating efficiency of motor can be improved by a variety of ways. As a major method in them, energy-saving control can greatly make motor efficiency be improved. Therefore, the research on efficiency optimization of induction motor is indispensable, and improving efficiency of motor has an important practical significance.In view of all kinds of drawbacks in the actual energy-saving system based on sensor measuring speed, the speed of induction motor is identified using BP neural network. Furthermore, minimum loss control algorithm is proposed based on speed sensorless technique.Firstly, by analysising energy control principle and existing methods of saving-energy control, the principle of minimum loss control is explored, and induction motor model with the iron loss is established. At the same time, based on the above model, the simulation model of control system is built, and the optimal flux is deduced. Meanwhile, induction motor model built considering iron loss is controlled by using the optimal flux; Secondly, by analyzing the operation mechanism of induction motor, a BP neural network model, whose inputs are stator voltages and the optimal flux, outputs are stator currents and speed, is established to estimate the speed of motor; Finally, the BP neural network model is injected into the minimum loss control system. Thus, a minimum loss control algorithm is achieved based on speed sensorless technique; and a simulation illustrates the effectiveness of the algorithm.