Efficiency Optimization Of Variable Frequency Speed Control System

Asynchronous motor is the main power equipment in industry,transportation and other fields.With the rapid development of society,energy and environmental issues are concerned.Because the frequency control technology has a significant contribution to the motor energy saving,it widely used in recent years.The motor is usually operating of a rated constant excitation mode,when the motor light load constant rated flux control can make asynchronous motor efficiency reduction.Therefore,it is of great theoretical and practical application to study the efficiency of asynchronous motor speed control system.In this paper,the vector control system of asynchronous motor variable frequency speed control is studied.Rely on this object to study,we can see that the control method can improve operational efficiency.The work has been done as follows:By studying the mathematical model of asynchronous motor,the dynamic mathematical model of asynchronous motor considering stator iron loss is established and the corresponding vector control system is simulated.This paper studies the following ability and immunity of variable frequency speed control vector control system.These properties are characteristic of steady-state performance and dynamic performance.In this paper,by analyzing the principle of asynchronous motor efficiency optimization,we discuss several efficiency optimization strategies which are often used as follows: the control strategy of optimization efficiency based on the loss model method,the control strategy of optimization efficiency based on the minimum stator current efficiency and the control strategy of optimization efficiency based on minimum input power online search efficiency.Among them,a detailed simulation experiment is carried out on the control strategy of optimization efficiency based on the loss model method.The loss model is established,and then,the rotor flux with the best efficiency can be deduced.The simulation results show that the system has a good effect on the optimization efficiency of the system when the rotor flux is optimal.The control strategy of optimization efficiency based on fuzzy search method is studied.That is,the input power of the motor is minimized and the efficiency is optimized when we use the fuzzy control technique to search the optimal rotor flux set point.The fuzzy controlleris designed,and the control system is simulated.The experimental results show that the fuzzy search method can find the optimal rotor flux linkage accurately.The optimal rotor flux linkage can significantly reduce the input power,improve the system operational efficiency and realize the energy saving operation of the motor.This paper proposes a hybrid control strategy of optimization efficiency for loss model method and fuzzy search method.Advantages and the disadvantages of the loss model method and the fuzzy search method can be complementary to each other.And the simulation experiment is carried out.The experimental results show that the new control strategy makes the search result more accurate and the optimization time shorter.Because DSP can facilitate the rapid implementation of complex control algorithms,a complex control algorithm vector control system commonly used DSP design and implementation.For this problem,this paper presents an implementation method,which uses the RTW tool to transform the Simulink simulation model of the efficient optimization algorithm into C code.This method allows that the efficient optimization algorithm can be applied to the DSP vector control system.