Design And Thermal Calculation Of A New Linear Generator For Thermoacoustic System

Thermoacoustic power generation technology is a new way of energy application. The low-quality heat source can be used in this technology with good suitability, high efficiency, simple structure, long life. As long as the temperature difference of the thermoacoustic engine's hot end and cold end reaches a critical temperature, it will produce sound wave oscillating. The transformation of sound to electricity is completed by the linear generator. This major work is to design a linear generator to match characteristics of the high frequency and small amplitude, and to calculate parameters of the linear generator.First, the paper introduces the research status of the thermoacoustic power generation technology and halbach array. According to some certain rules, the halbach permanent magnet array is composed of permanent magnets with different magnetization directions. The halbach array can make one side of the magnetic field strengthen, and make the other side of the magnetic field weaken. It not only helps increase the air-gap flux density and improve the flux density sinusoidal waveform, but also reduces the loss of the mover yoke. The halbach array can help the linear generator improve efficiency.Second, the paper analysis the composition and the principle of thermoacoustic power generation system. Several commonly used linear generators are analyzed and compared. According to the requirements of thermoacoustic power generation system, the cylindrical permanent magnet linear generator is used.Then, the stator of permanent magnet linear generator uses cylindrical structure. The magnet on the mover of permanent magnet linear generator uses the structure of halbach array. This paper completes the electromagnetic design of the permanent magnet linear generator. According to the calculation results, the main dimensions of the permanent magnet linear generator are determined. It also elaborates the choice of electromagnetism load, permanent magnet, coil winding.Again, the magnetic field distribution of the linear generator is analyzed. Under the no-load condition, EMF waveform and the RMS are calculated. Under the load condition, the copper loss, iron loss , efficiency and power density are calculated.Finally, the three-dimensional mathematical model and the finite element model of the temperature field is established. Under the rated operating condition, temperature distribution of the permanent magnet generator is analyzed. It sums up the principle of the generator temperature distribution to guide the design of permanent magnet generator.