Study On The Vibration And Generation Control Strategy Of A Thermoacoustic Linear Motor

Thermoacoustic electric generator technology can convert low-quality thermal energy such as solar energy,kitchen hearth waste heat and nuclear reactor waste heat into electrical energy.It is a new power generation technology with great potential for development.It has many advantages,such as no pollution of working quality,high reliability of work,low cost,long service life and strong adaptability of heat source.The thermoacoustic power generation technology is the core of thermoacoustic electric generator system(TAEGS)and TAEGS is composed of heat source collection device,traveling wave thermoacoustic engine,single-phase cylindrical permanent magnet linear motor and subsequent energy storage device.Although thermoacoustic electric generator system has the above advantages,its energy conversion efficiency is still very low,especially,the power capacity of the system is weak.There are also shortcomings such as the difficulty of the starting of the traveling wave thermoacoustic engine.Therefore it can be solved by the appropriate control technology to solve the problem of difficult vibration of the thermoacoustic machine and the weak output power of the system.In this paper,the output characteristics of thermoacoustic power generation system are studied in the following aspects:Firstly,the basic structure of the traveling wave thermoacoustic engine and the single-phase cylindrical permanent magnet linear motor are introduced and their working principles are analyzed.Based on the understanding of the two subsystems,the electro-mechanical-acoustic interconnect model of the thermoacoustic power generation system is built according to physical model of the two subsystems,and the resonance characteristics of the system are analyzed.Besides,the thermoacoustic power system studied in this paper is introduced to provide a theoretical basis for the study of thermoacoustic power system control strategy.Secondly,the control strategy of the vibration stage of the thermoacoustic electric generator system is studied.Control strategy of route and current control is used for single-phase cylindrical permanent magnet linear motor at the starting stage of a thermoacoustic linear motor.The sinusoidal current control,square wave current control and current starting control scheme based on back electromotive force detection are compared and analyzed.The feasibility of the control scheme is further verified by the analysis of Matlab/Simulink simulation.Finally,the control strategy of the generation phase of the thermoacoustic electric generator system is studied.Instantaneous direct current control scheme is used to control single-phase voltage bridge PWM rectifier circuit.The parameters of the external voltage loop and current inner loop of the PI controller are also designed.The unit power factor is acquired,in other words,the phase of the AC side voltage and the current is the same.The output characteristic and conversion efficiency of thermoacoustic electric generator system are improved.At the same time,the change of the system operating state when the external load resistance is suddenly changed is studied.The correctness of theoretical research and simulation analysis are verified by the analysis of Matlab/Simulink simulation.