Using the Viable System Model to control a system of distributed DC/DC converters

Abstract

The complexity of control of the energy flow in automotive power nets has significantly increased in the last decades. Due to the introduction of a second voltage level with new degrees of freedom for an energy and power management, the complexity will further increase. The cybernetic approach of the Viable System Model (VSM) by Stafford Beer has successfully been used as a structural concept for the implementation of an energy management system for a single automotive power net and has significantly reduced the complexity of the control. This paper applies the VSM to the control problem of a group of DC/DC converters, distributed over the whole vehicle, coupling two automotive power nets. Initially it is shown how this new viable system of the converter group fits into the existing approach and how the viable systems of the two power nets form a new VSM. Subsequently, the application of the VSM in the converter group and how it forms a hierarchical control system is described. Additionally, a maximization efficiency point tracking (MEPT) algorithm is implemented in order to have each converter in its best operating point. Finally, the whole system is validated using a physical simulation.