Multiple input Fuzzy controlled DC-DC Converter for harvesting renewable energy

Several renewable energy sources are integrated to supply the load continuously with multi input converters (MIC). Instead of using several single input converters for each energy source for distributing power in micro and nano-grids it is advantageous to use multiple input converters which has simple structure, less devices and low cost. MIC is used for energy harvesting in hybrid system. In this paper a common switching function (CSF) with common duty ratio(CDR) can be generated by frequency division at high frequency for a MIC. The duty ratio of individual switch in the input source will be an integer multiple of CDR and independent of number of input sources. CDR is taken as control variable for regulating the output voltage of MIC. This switching strategy simplifies controller design and transforms the converter into a buck-boost converter with multiple inputs. The operating point of the converter is regulated by fuzzy controller. The results obtained from simulation and experiment shows the effectiveness of the switching strategy.