Comprehensive Research On Energy-saving Control Of Asynchronous Motor Under Periodic Load

Asynchronous motors have a wide range of applications in national production and life,and are the main power machinery for national electrification.At present,asynchronous motors used in China's industrial fields are often operated at no-load or light-load conditions,and there is a serious "big horse-drawn car" phenomenon,resulting in low efficiency and power factor of the motor,which will result in great energy waste.Therefore,this paper studies the control method of voltage regulation and energy saving according to the operating characteristics of the motor.The electric loss of the motor is studied according to the equivalent circuit of the asynchronous motor,and the principle of voltage regulation and energy saving of the asynchronous motor under periodic load is analyzed.The effects of load changes and voltage changes on the operating characteristics of the motor are then analyzed.It is explained that the running efficiency of the motor can be expressed by the freewheel angle to judge the energy saving effect of the motor.A two-dimensional T-S fuzzy controller with the freewheel angle deviation value and the freewheel angle change value as the input amount and the turn-off angle increment as the output is established.Aiming at the problem that the membership function and fuzzy rules in fuzzy control are difficult to establish and adjust,the fuzzy control and neural network are combined,and a four-layer BP neural network model is established according to the neural fuzzy control.The matlab simulation is performed according to the established neural fuzzy control model.The simulation results are calculated offline to obtain a fuzzy lookup table.The established neural fuzzy control model is simulated by matlab/simulink energy-saving simulation,and the harmonics generated during the voltage regulation process are analyzed.The main components of the active power and reactive power of the motor are the active power and reactive power of the fundamental voltage and current.Finally,based on theoretical analysis and simulation analysis,an asynchronous motor voltage regulation and energy saving device is designed.The hardware circuit includes STM32F103RCT6 minimum system,DC power supply circuit,power supply detection circuit,voltage synchronization signal detection circuit and thyristor tube voltage drop signal detection circuit,bidirectional thyristor drive circuit.Software design includes soft start,energy saving control and software protection.The designed device is tested on the pumping unit load,and the relevant data and waveform are recorded.It is proved that the voltage regulating energy-saving device can significantly reduce the phase current,reduce the active loss and reactive power loss of the motor,and improve the power factor of the motor.