Research On Energy Efficiency Optimization Method Of Induction Motor Based On Maximum Torque Per Input Power

In modern society,resource waste has led to various resource shortages and environmental pollution.People have gradually paid attention to the research on optimization methods of energy efficiency levels of various production equipment.Induction motors are widely used as drive source in industrial production,and their operation consumes a lot of electric energy.In China,there are still a lot of old-fashioned induction motors still working,and these induction motors generally have low energy efficiency problems.There is still huge potential for induction motors in terms of energy saving,emission reduction and energy efficiency optimization,especially the research on energy efficiency optimization methods of induction motors.It is not necessary to replace or to upgrade and upgrade the original motor,just need change the control strategy of speed control drive system can achieve the improvement of energy efficiency of induction motor.Frist of all,on the basis of analyzing and summarizing the energy efficiency optimization methods of induction motors in the past,an energy efficiency optimization method called Maximum Torque Per Input Power is proposed.This method uses the mathematical model of the induction motor in the Loss Model Control method,the optimization goal of the Search Control method,and imitates the energy efficiency optimization idea of the Maximum Torque Per Ampere.The induction motor uses an iron loss resistor which parallel to the excitation branch to represent the iron loss of the motor,the mathematical equation that considering iron loss of the induction motor is listed,and also can built a simulation model of induction motor which considered iron loss,to compared with the simulation model not considering iron loss.Secondly,combining two widely used control methods in induction motor speed control system which is vector control and direct torque control,the realization method of energy efficiency optimization method based on Maximum Torque Per Input Power is studied.Select the rotor field orientation as the decoupling condition of the motor equation,and consider the condition of steady-state operation,the function formula of the ratio of output torque and input power which considering the effect of iron loss but only expressed by stator current of the induction motor is analyzed and obtained,when the ratio of torque and input power is maximum,an optimal proportional coefficient of the component of the stator current on the dq axis can be obtained.Because current component on the q axis represents the load torque current,therefore,the optimal value of the excitation current can be calculated according to the optimal proportional coefficient and the torque current.The optimal excitation current value calculated by the energy efficiency optimization method based on the Maximum Torque Per Input Power is used as the given value of the excitation current in the rotor field-oriented vector control system to realize the energy efficiency optimization of the induction motor,and on the basis of the optimal excitation current,it can also further calculation the optimal value of the stator flux,the optimal stator flux value can also be given of the direct torque control system,adjust the motor operation to achieve the optimization goal.Finally,the vector control system and direct torque control system of the energy efficiency optimization method of induction motor based on the Maximum Torque Per Input Power are studied,and the simulation model of the control system is built on the Matlab/Simulink simulation platform.Appropriate motor parameters and simulation conditions are selected.The analysis of the simulation results shows that the proposed method can not only enhance the performance of the original speed control system,but also the energy efficiency of the induction motor operation,the level has improved significantly especially in the medium and light load operation state.