Design and Development of Linear Drive for Compressor

Abstract

Linear actuator device for gas compression has significant importance in a cryo-cooler system. The compressor provides acoustic power to drive the cooling phenomenon in the pulse tube cryo-cooler. In general, the compressor is designed based on electromagnetic effect. But such compressors have limiting factors, such as heating due to eddy current, large size, and exhibit Electromagnetic Interference (EMI), which is undesired for space applications. A novel linear drive compressor actuated using a Piezoelectric actuator is presented here. Piezoelectric actuators have an inherent limitation of extremely small elongation as compared to their length. A Mechanical amplification system along with resonance amplification is proposed. Motion transfer is done using flexures and housing assembly. This study includes theoretical formulation and numerical study of the amplification system. An equivalent analytical spring-mass-damper model is formulated to determine resonance frequency. CAD model of the same is prepared and simulations are done using CREO and Hyperworks™. Amplitudes of the piezoelectric actuator elongation and piston displacement are Presented. Design is aimed to achieve an operating frequency of 100 Hz. Partial Numerical Agreement were found between actual compressor experimental result and both analytical and CAD model.