Supervisory Hybrid Control of a Micro Grid System

This paper presents a systematic approach for the design and analysis of a supervisory hybrid control scheme for a micro grid system using hybrid control techniques. A generic micro grid configuration is assumed. The approach is elaborated with a specific micro grid configuration containing a self-excited induction machine based wind energy conversion system. By definition a micro grid operates in both grid-connected and in isolated modes. In each mode of operation there could be different combinations of the available energy sources in the system that are catering to the load demand. A hybrid control scheme which utilizes different control mechanisms for optimal control of a system under different operating conditions and in different operating states, presents an attractive paradigm for the control design of such a system. By partitioning a micro grid into different modules along suitable axis, the complexity of a Multiple Input Multiple Output (MIMO) control problem of the system can be significantly reduced. The control of the different modules of a micro grid system can then be tackled using the well established linear control theory which could then be combined using suitable transition, load and power management strategies to achieve optimal control of the micro grid system in all its desirable operating states. Supervisory hybrid control of a wind energy conversion and storage system is presented to illustrate the supervisory hybrid control design and analysis philosophy outlined in this paper.