SUMMARYRecently, photovoltaic (PV) power systems have attracted considerable attention in attempts to mitigate global warming. In a PV power system, it is necessary to synchronize the grid voltage when a PV inverter is interconnected with a grid. This paper proposes a high-speed and high-precision phase-locked loop (PLL) using complexcoefficient filters for a single-phase grid-connected inverter. The proposed PLL can detect the phase of grid voltage that has superimposed harmonic components for grid fault. Moreover, numerical results show the effectiveness of the proposed method. C⃝ 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 189(4): 52-60, 2014; Published online in Wiley Online Library (wileyonlinelibrary.com).

No abstract

Ahstract-This paper proposes a novel approach for the controller design of a three-phase grid-tie inverter. First, the paper analyzes the input-output map of the system consisting of the cascade connection of a diagonal transfer function pre and post-multiplied by DQ (direct-quadrature) and inverse DQ transformations which are prevalently used as a controller for systems with a rotating axis. It shows that the input output map is time invariant when the angular velocity of DQ transformation is constant and derives the transfer function. It extends the result when the angular velocity is not constant, and derives an LPV state-space representation of the input-output map. Second, the paper analyzes the input-output map in terms of the positive and negative phase sequence components. Finally, the paper applies the analysis to the controller design for a grid tie inverter bypassing DQ transformation. The efficacy of the proposed method is verified by a simulation and an experiment.

No abstract

No abstract