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In this article, a grid-connected photovoltaic system with functionality of power quality enhancement is studied. The integration of the photovoltaic generator into the grid takes place in one stage, using a three-phase voltage source inverter. A direct power control algorithm strategy with a new switching table has been proposed to decrease power losses into the voltage source inverter, to enhance power quality, to optimize the control of instantaneous active and reactive powers, and to perform as a multi-function device by incorporating shunt active power filter functionality. In addition to this control strategy, a maximum power point tracking perturb and observe algorithm is applied to the inverter to extract optimal available power from the photovoltaic array. The proposed system can provide the power factor correction, harmonic elimination, reactive power compensation, and simultaneously inject the maximum power available from the photovoltaic array to the load and/or grid. The multifunctional features of the proposed control algorithm are demonstrated using extensive simulation studies and are validated through experimental results. [ABSTRACT FROM AUTHOR]

This article deals with shunt active power filtering for power quality improvement with hysteresis current controllers by two methods of implementation assessed under unfavorable non-linear load and source conditions. Fully digital and simple hybrid hysteresis control strategies are tested based on a numerical integrator proportional DC bus controller combined with phase-locked loop outputs to generate current references. In two cases, reference mains currents are generated to ensure three-phase sinusoidal synchronized waveforms of the mains currents. The experimental evaluation of the robustness control in these two implementation methods is verified using a 10-kVA shunt active power filter in steady state for transitional conditions (step load, switch-on of shunt active power filter) and in the worst case of unbalanced loads (break phase) and source voltages. Several experimental results are presented and discussed to prove the robustness and excellent performance of the proposed simple hybrid technique. [ABSTRACT FROM AUTHOR]

The aim of this work is to design a static feedback gain used to force a three-phase shunt active power filter to act as a current source capable of delivering the appropriate harmonics demanded by non-linear loads. This filter is connected in parallel to a three-phase power distribution system in order to keep the current supplied by the latter almost sinusoidal. The control design is performed using the H∞ suboptimal control theory based on linear matrix inequalities (LMIs), with both partial and full state feedback. Numerical simulations will be presented in order to investigate the advantages of the full state feedback structure over the partial state feedback one, and to compare the performances of the corresponding H∞ static control laws. [ABSTRACT FROM AUTHOR]

The simulation and experimental study of proportional integrator (PI) controlled DC bus voltage of three phase shunt active power filter (APF) to improve power quality by compensating harmonics and reactive power required by nonlinear load is proposed. The compensation process is based on sensing mains currents only, an approach different from conventional methods, which usually require harmonics or reactive volt-ampere values of the load. The non-sinusoidal mains voltage problem is resolved by using phase locked loop (PLL) system. Pulse width modulation (PWM) signal generation is based on hysteresis control comparators to obtain the switching signals.ű Various simulation and experimental results are presented under steady state and transient conditions. [ABSTRACT FROM AUTHOR]