Module platform for PV inverters

The overall goal in the project is to develop a module-platform for single-phase PV-inverters with advanced control and prototyping of 1.5 kW units. At Aalborg University most efforts have been put into the design and software implementation of the control featuring: • Robust current controller with harmonic compensation • On-line grid-impedance measurement using harmonic injection • Phase locked loop for grid synchronization Proportional-resonant controller technique has been used in order to get a good control of the current with zero stationary-error and good perturbance rejection. Additionally, selective harmonic compensation has been achieved using resonant controllers. Grid impedance on-line measurement has been achieved by injection a non-characteristic frequency voltage signal and measuring the response in current. Using DFT, this harmonic has been estimated from the measured current and voltage. The method has been successfully tested on a 3kW PV module prototype and used to detect islanding situation. The project is sponsored by the PSO-programme in collaboration with PowerLynx A/S. (Remus Teodorescu, Frede Blaabjerg, Lucian Asiminoaie; Uffe Borup, Christian Dorofte, Powerlynx A/S)