Solcelleinverter

Photovoltaic power supplied to the utility grid is gaining more and more visibility, while the worlds power demand is increasing. Not many systems have so far been put into the grid due to their relatively high cost. The PV-modules was in the past the major contribution to the cost. A downward tendency is now located in the price for these modules and for the same reason the cost of the inverters are becoming more visibly in the total cost. The inverter is mainly needed for three reasons: - The low DC voltage generated by the PV-module (Typically 20 V to 40 V for a 72 cells PV-Module) must be amplified up to the higher AC level in the grid. On the other hand, it is not be necessary to include the amplification if more PV-modules are connected in series. This is however not the case for the AC-module inverter, where one inverter is interfacing one PV-module. - The power generated by the PV-module is very sensitive to its point of operation (current and voltage), and the inverter should therefore incorporate a function for tracking the Maximum Power Point (MPP). - As stated above, the PV-module is sensitive to its point of operation. The power delivered to the grid must follow a sinusoidal waveform, raised to the 2nd power, in order to inject a sinusoidal current. The power delivered by the PV-module must be a pure DC in order to operate the module at the MPP. The main objective for the project is to develop an inverter for AC-module applications. The target is to develop new and cost-effective solutions for injection of electrical power, generated by PV-modules, into the grid. There will be research activities in the fields of developing inverter-technologies. The research must result in an inverter for use with a single PV-module (app. 200 W). The inverter must be made for: low-cost, reliability, and mass-production. The project includes a State-of-the-Art (SOTA) analysis, a detailed statement about specifications and also modeling and simulations of entirely new topologies. One solution is picked out, on the basis of the previous mentioned research, for a final prototyping, which will be tested according to the specifications. The project will conclude with an inverter, which can be mass-produced. The project is sponsered by PSO (Elkraft System) (Søren Bækhøj Kjær, Frede Blaabjerg,Bo Holst; Danfoss A/S, Ivan Katic;Teknologisk Institut, Henrik Bindner Risø).