Performance evaluation of controllers applied to power generator set operating with wastewater biogas

The improvement of renewable energy resource-based power plants is a real and modern global challenge, and therefore, biogas applied in reciprocating Internal Combustion Engines is an excellent alternative to this challenging task. Biogas can be obtained from various sources and its composition varies according to the biomass type used in its production, but the majority of this fuel is composed of methane ( CH_4 ) and carbon dioxide ( CO_2 ). However, there is no reliable control to hold the power quality following Brazilian Electricity Regulatory Agency (ANEEL) requirements. In such a context, this paper presents four control schemes to assure the power quality by a generator set operating with biogas from wastewater treatment. In order to accomplish it, a mathematical model was developed to represent the mechanical and electrical phenomena involved in the generation process. These control systems were evaluated in load and biogas composition variation scenario at same time in an environment developed in MATLAB/Simulink. The performed tests showed that the scheme composed by two Proportional Integral Derivative in parallel operation switched by fuzzy logic controller with particle swarm optimization tuning is better than all schemes proposed in this work and this layout enables the power plant to remain connected to the grid in all simulation scenario, because power frequency and voltage remained within limits imposed by national standards.