Abstract. In this paper, a review of Phase Locked Loop (PLL) algorithms and symmetrical component extraction methods intended for grid-connected power electronic converters are presented. Proposed classification is based on voltage representation in three coordinates: natural (abc), stationary (αβ) and rotating coordinates (dq). The three selected algorithms are described in details: Dual Second Order Generalized Integrator (DSOGI-PLL), Dual Virtual Flux -both in stationary coordinates. The third one, in rotating dq coordinates, is Dual Synchronous Reference Frame PLL (DSRF-PLL). A comparison of PLL algorithms is presented. Also, selected experimental results are given to verify practical application of discussed algorithms.

Abstract. This paper investigates control structure for grid connected three-phase two-level Voltage Source Converter (VSC) under distorted grid voltage conditions. Grid voltage is distorted by balanced and unbalanced voltage dips and higher harmonics. To address the problem, the control structure of converter is presented. The control system is a modification of Voltage Oriented Control (VOC) based on Dual Vector Current Controllers (DVCC). Grid synchronization under distorted voltage is achieved by employing Phase Locked Loop (PLL). Simulation and experimental results, which illustrate properties of proposed system, are presented.

The paper describes second order generalized integrator (sogi) which is specialized in band-pass filtering and orthogonalization of periodic signals. Modifications of the structure and the influence of parameters on the system performance is described. The article highlights the particular importance of model discretization method in the practical implementation, as well as reviews estimation methods of the: amplitude, frequency, offset and phase angle of the periodic signal. Examples of simulation and experimental results are presented

This paper presents model predictive control (MPC) with a finite control states set (FS) for three-level four-leg flying capacitor (FCC) converter. Principles of control method are presented and flying capacitor voltages control method is discussed. Experimental results of converter operating as a shunt active power filter (SAPF) and grid connected inverter (GCI) are shown.

This paper proposes a structure and two strategies for hybridization of a RAT (Ram Air Turbine) with supercapacitor storage. The structure consists in coupling a High Voltage DC (HVDC) source (RAT) with a low voltage storage device through a specific topology of bidirectional DC-DC static converter. The energy management strategies consists in entrusting the storage with the "high frequency" harmonics of the load power while the RAT only produces the average power: the RAT sizing and its mass can then be reduced. Lab test bench architecture, control strategy, topology of the converter and experimental results are presented in this paper.