Electro-mechanical-thermal energy coupling characteristics analysis and EFMM-based energy modelling for machine tools considering dynamic thermal environment

Abstract

Machine tool is an isolated thermodynamic and inefficient energy-consuming system, whose energy consumption is increasingly influenced by its internal thermal environment. While the thermal environment changes dynamically due to the complex electro-mechanical-thermal (EMT) energy conversion characteristics. Therefore, it is urgent to expound the multi-energy coupling mechanism to establish an accurate energy model for machine tool. However, the existing studies merely emphasize the electro-mechanical conversion that related to the material-removal (MR) process and fail to reveal the dynamic characteristics of energy caused by EMT, which results in inaccurate energy models. In light of this, the energy flow matrix modelling (EFMM) method, which can model the multi-energy flows automatically and accurately, is introduced to construct a generic energy balance matrix equation for machine tool, where the coupling relationship between electrical, mechanical and thermal energy are taken into consideration. Subsequently, the dynamic mechanical and thermal energy are analyzed, respectively. Based on this, the total energy consumption and cutting energy efficiency models for machine tool in a dynamic thermal environment are established. The reliability and accuracy of the constructed models are demonstrated by the case study and comparative analysis. The results indicate that the average relative errors of the proposed energy models are mostly within 5 %. The presented approach is conducive to understanding the multi-energy coupling characteristics and providing a feasible way for energy-efficient machine tools.