A Multiobjective GI-Based Control for Effective Operation of PV Pumping System under Abnormal Grid Conditions

The increasing renewable energy penetration has encouraged solar water pumping (SWP) as an effective solution to escalating water demand in remote areas. Despite receiving wide-spread popularity, such systems exhibit an unreliable operation due to intermittent weather conditions. As the utility grid integration enables the bidirectional power flow, it has emerged as a viable solution for uninterrupted pumping. However, since most of the SWP systems are remotely installed at radial ends of the distribution network, they encounter problems associated with abnormal grid conditions, which degrade their performance. A generalized integrator (GI) is used to deal with these issues. However, convention GI structures are incapable of effectively mitigating them. Therefore, a multiresonant cascaded second-order generalized integrator (MC-SOGI) based control approach is developed in this article to deal with these issues. The proposed MC-SOGI structure provides effective dc-offset rejection along with filtering of harmonics as well as subharmonics. Therefore, the proposed control approach is capable of effectively extracting the balanced fundamental positive sequence components even under unbalanced distorted grid voltages and maintaining unity displacement power factor under all conditions. An enhanced system efficiency is achieved by employing a permanent magnet synchronous motor (PMSM) for driving the pump. The well-known vector control technique and an incremental conductance algorithm are used for controlling the speed of PMSM and optimum power harvesting, respectively. The estimation of rotor speed and position is carried out by using voltage and current templates for eliminating the encoder thereby enhancing the system reliability and reducing the cost. The system performance is investigated experimentally and the acquired results validate the system feasibility.