EXERCISE: FUZZY LOGIC APPLIED TO ENERGY MANAGEMENT
Let’s consider a Hybrid Energy System (HES) composed of two different sources and storage systems: a wind generator (WTG), short and long term storage systems and a foreseeable generator (FDG) like micro gas turbine or diesel generator (figure 1). This HES is connected to a power grid.
The HES is managed with a fuzzy logic supervisor as shown in the following block diagram: (G1, G2, and G5 are normalization gains βref; wind generator pitch angle reference).
1) In your mind, what are the objectives of the supervisor?
2) What are the main constraints?
3) What are the means of action?
4) What are fuzzy supervisor inputs and outputs?
1) The objectives are: -To achieve a reference power determined by the network manager; -To provide a regular primary power reserve and to participate in primary frequency control; -To maximize wind power and to minimize the use of fossil fuel.
2) The main constraints are: The wind power fluctuation and the size of the storage units.
3) The control means are: The reference power of the storage systems, the reference power of the foreseeable unit and the reference of the wind generator pitch angle to reduce the generated wind power if necessary.
4) Inputs : -Short term storage level; – Long term storage level ; – Frequency error ∆f ; – Power error ∆p.
Outputs: – Short term storage power reference ; – Long term storage power reference; – FDG power reference ; – βref wind generator pitch angle reference.