In order to improve the output efficiency of a photovoltaic(PV) energy system,the real-time maximum power point(MPP) of the PV array should be tracked closely. The non-linear and time-variant characteristics of the photovoltaic array and the non-linear and non-minimum phase characteristics of a boost converter make it difficult to track the MPP as in traditional control strategies. A neural fuzzy controller(NFC) in conjunction with the reasoning capability of fuzzy logical systems and the learning capability of neural networks is proposed to track the MPP in this paper. A gradient estimator based on a radial basis function neural network is developed to provide the reference information to the NFC. With a derived learning algorithm,the parameters of the NFC are updated adaptively. Experimental results show that,compared with the fuzzy logic control algorithm,the proposed control algorithm provides much better tracking performance.
To extract the maximum power from a photovoltaic(PV) energy system,the real-time maximum power point(MPP) of the PV array must be tracked closely. The non-linear and time-variant characteristics of the PV array and the non-linear and non-minimum phase characteristics of a boost converter make it difficult to track the MPP for traditional control strategies. We propose a fuzzy neural network controller(FNNC),which combines the reasoning capability of fuzzy logical systems and the learning capability of neural networks,to track the MPP. With a derived learning algorithm,the parameters of the FNNC are updated adaptively. A gradient estimator based on a radial basis function neural network is developed to provide the reference information to the FNNC. Simulation results show that the proposed control algorithm provides much better tracking performance compared with the fuzzy logic control algorithm.
Chun-hua LIXin-jian ZHUGuang-yi CAOWan-qi HUSheng SUIMing-ruo HU
To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control (AIC) strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell (PEMFC) system in this paper. The PEMFC stack and the air supply system including a compressor and a supply manifold are modeled for the purpose of performance analysis and controller design. A recurrent fuzzy neural network (RFNN) is utilized to identify the inverse model of the controlled system and generates a suitable control input during the abrupt step change of external disturbances. Compared with the PI controller, numerical simulations are performed to validate the effiectiveness and advantages of the proposed AIC strategy.
