Optimized DC-AC boost converters for modular photovoltaic grid-connected generators

The market for photovoltaic systems has considerably developed during the last few years, be it for grid-connected power generation or along the sun applications. However, the cost of solar modules remains a sensitive issue which entails the need for a better use of available power. In this paper, we present an architecture allowing the operation of each separate photovoltaic module at his optimum, independently of other modules. For this purpose, we consider the use of large number of small converters, each of them being associated to one photovoltaic module, instead of only one converter. To be economically feasible, we propose a structure which allows simultaneously to galvanically isolate the module from the grid, to increase the voltage, to convert DC current to AC current. The whole structure ensures that the power conversion is done with reduced losses. The converter structure is also designed for parallel operation with as many modules as necessary in order to obtain the desired power. It ensues that the dynamic response of a module must be carefully studied to avoid any unforeseen oscillation between two or more different converters or between a module and others loads distributed along the network.