Auxiliary power systems are widely used, and new, challenging problems in analysis, design and deployment of high performance power generation systems call for comprehensive analysis of the energy conversion, Our goal is to develop a complete mathematical model to perform nonlinear analysis of auxiliary power systems which integrate diesels and synchronous generators. This allows one to study the energy conversion needed to perform thorough analysis and to design energy management systems. In this paper, we study the full spectrum of the physical phenomena of interconnected energy conversion processes in diesels and synchronous generators. The fundamental research reported allows one to promote engineering enterprise in the development of high performance generation systems,