P. Sarvghadi; M. Monfared
Abstract
Parallel connection of two or even more single-phase inverter modules is a successful solution to increase the reliability and the efficiency of an inverter at moderate power levels. Stable operation and proper current sharing among parallel inverter modules is a key issue, especially when they are connected ...
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Parallel connection of two or even more single-phase inverter modules is a successful solution to increase the reliability and the efficiency of an inverter at moderate power levels. Stable operation and proper current sharing among parallel inverter modules is a key issue, especially when they are connected to a common load through unequal output filter impedances. In this paper, a new formulation and consequently a proper current sharing control algorithm for parallel connected inverter modules with the possibility of unequal filter impedances is proposed. Also a dual-loop voltage control with the filter current as the inner loop feedback signal, considering the effect of digital control delay, is adopted. The controller parameters are designed according to a frequency domain analysis. Finally, theoretical achievements are confirmed by experimental test results on a test rig with two 250 W parallel connected single phase inverters.
Power Electronic
M. Heidari; M. A. Shams Nejad; M. Monfared
Abstract
Because of installation for local consumers and since it is free of all contaminations, connecting photovoltaic cells to the grid via single-phase inverter is significantly on the rise. In this paper, a new simple current control is proposed for a single-phase grid-connected voltage source inverter. ...
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Because of installation for local consumers and since it is free of all contaminations, connecting photovoltaic cells to the grid via single-phase inverter is significantly on the rise. In this paper, a new simple current control is proposed for a single-phase grid-connected voltage source inverter. Using the PQ theory and modelling a single-phase system as an unbalanced three-phase system, a method is provided for reference current generation. In the proposed method, it is not necessary to generate a fictitious phase for the current signal. Also, the removal of adjusting filter parameters which were used to generate fictitious current signal increases the simplicity of the control system and reduces computational efforts, especially in the presence of distortion in the current. The simulation results confirm that the proposed method provides a precise and fast current control with minimum harmonic distortions.