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The contribution of power because of the nonconventional energy sources is enhancing day by day. This gives rise to power converter connected to the grid for an integration and to utilize the nonconventional energy sources economically and efficiently. However, this causes the distortion in the grid voltages and currents. All advanced high precision operating machines and measuring instruments are sensitive to the harmonics of the grid voltages. Therefore, this work illustrates an improved control to supress the grid voltage and current harmonics caused by an integration of non‐conventional energy source and nonlinear loads. An enhanced resonant two‐degree of freedom proportional–integral–derivative (ER‐2‐DOF‐PID) controller is used to extract fundamental components from load currents. It uses a resonant controller in shunt with PI controller to suppress the multi‐order harmonics and steady state error. A DC‐offset is used in parallel of this combination to suppress the sub‐order harmonics. To suppress the peak overshoot during the load transients and insolation changes, a 2‐DOF‐PID controller is used. The presented control is investigated by developing its model in MATLAB environment and this is validated on a prototype developed in the laboratory. The controller is modelled and investigated for stability analysis using a Bode mathematical tool.. [ABSTRACT FROM AUTHOR]

The contribution of power because of the nonconventional energy sources is enhancing day by day. This gives rise to power converter connected to the grid for an integration and to utilize the nonconventional energy sources economically and efficiently. However, this causes the distortion in the grid voltages and currents. All advanced high precision operating machines and measuring instruments are sensitive to the harmonics of the grid voltages. Therefore, this work illustrates an improved control to supress the grid voltage and current harmonics caused by an integration of non-conventional energy source and nonlinear loads. An enhanced resonant two-degree of freedom proportional–integral–derivative (ER-2-DOF-PID) controller is used to extract fundamental components from load currents. It uses a resonant controller in shunt with PI controller to suppress the multi-order harmonics and steady state error. A DC-offset is used in parallel of this combination to suppress the sub-order harmonics. To suppress the peak overshoot during the load transients and insolation changes, a 2-DOF-PID controller is used. The presented control is investigated by developing its model in MATLAB environment and this is validated on a prototype developed in the laboratory. The controller is modelled and investigated for stability analysis using a Bode mathematical tool.. [ABSTRACT FROM AUTHOR]

This work presents an improved phase‐locked loop (IPLL)‐based control for grid‐integrated photovoltaic (PV) system (GIPVS). It is used to extract amplitude, frequency, and phase angle of distorted load currents to control PV‐grid‐interfaced voltage source converter (VSC). The VSC controls active and reactive powers at unbalances and distortions in the grid voltages. The control algorithm of VSC includes power feed‐forward term, DC‐link voltage, and grid voltages. The feed‐forward term improves the dynamic performance of a GIPVS and enhances the utilisation of VSC. Three‐phase IPLLs extract the in‐phase components of three‐phase load currents at utility frequency. Further, these in‐phase components of load currents are used for estimation of reference‐grid currents. The proposed IPLL‐based control algorithm offers good dynamic response even under unbalanced load condition. The efficient working of IPLL‐based control algorithm is realised by extracting maximum power from PV‐grid system and through its power‐quality improvement. The perturb and observe (P & O) control algorithm is used for optimum utilisation of a PV array. A developed prototype of PV‐grid system is used to implement an IPLL‐based control algorithm under different operating conditions. [ABSTRACT FROM AUTHOR]