Research On The Linear Compressor For Regenerative Refrigeration Systems

An electromagnet resonance linear compressor is a new type of reciprocating piston compressor. It consists of a copper coil, permanent magnet, magnet iron, restoring spring, piston and the shell of compressor. Because of its mechanical-electrical integrative characteristics, this type linear compressor is sometimes indirectly called as a linear motor. This thesis deals with a linear compressor without valves for the regenerative refrigeration systems, which is compact in structure, high efficiency, larger driving power, and modulation convenient. With these advantages, a linear compressor can be used in some applications with need of linear driving.Through the analyses of operating characteristics and magnet loop structure, a linear compressor prototype is developed in this thesis for the regenerative refrigeration systems such as Stirling refrigerators. An engineering design procedure is obtained, and the measurement system and the experimental scheme are also designed in order to improve further the structure and performance of a linear compressor.A mathematical model is introduced for the mechanical vibration system and electromagnetic system of a linear compressor. The operating characteristics are obtained by simplifying and solving these model equations. The effects of these resonance parameters such as spring stiffness, moving mass, gas force, and damp force are analyzed on the performance of the linear compressor, and in resonance circumscription, the displacement of piston is largest, the efficiency of the system is highest.At the same time, the magnet fields in the motor are also analyzed using the magnet loop method and finite element method. In order to optimizing the structure and performance of the motor, the effects of the motor parameters and electrical source parameters on the magnet field distribution and the magnet intensity in the motor is gained by using software Ansoft. Through studying, the better changing relations with time have obtained for the electromagnet thrust force and piston position, the stroke of piston is enhanced with increasing voltage of the motor in limited domain.Based on the theoretical analyses on the resonant characteristics and magnet field, a moving-coil linear compressor prototype for a Stirling refrigerator system is developed and simulated. A general design method for a linear compressor is summarized. At the last of this thesis, an experimental system and a scheme are proposed for the further research on Stirling refrigerator.