A Review on Power Quality İmprovement of Grid Connected PV with Lithium-Ion and Super Capacitor Based Hybrid Energy Storage System Using a New Control Strategy

Abstract

Renewable energy sources are widely adopted globally in order to meet the challenges faced by the global energy and it has various impacts on the environment, which especially leads to the production of undesirable harmonics either in voltage or current, variations in voltages of feeders and flickers at the distribution side, the issues in quality of power and also the issues related to protection and reliability. In this paper, HESS made with Li-ion battery and SC combination is designed with a developed EMS, which is the standard for allocation of various energy storage systems and the performance of the HESS for improving power quality issues are decided by specifically voltage fluctuations and harmonics and to mitigate the effects of dynamic power exchanges over the lifespan of batteries. Here, two levels of control system are proposed: (i) low-level control system for regulating the currents flowing and voltages of DC buses through the whole HESS elements can be controlled taking high-level control system’s output as a reference. (ii) High-level control system for SoC management and power allocation. SoC management means SOC monitoring and control which takes various data as reference inputs like generation forecasts, load prediction and weather forecast as it is applied for RES (both solar and wind). Here, a new control strategy for HESS topology is used, in which only one DC-to-DC converter, i.e. a bilateral in nature is connected so that the battery and supercapacitor circuit can be isolated electrically from the DC bus and here by this arrangement of isolation, we can control all the parameters of battery and supercapacitor like current of SC, current flowing through battery and the voltages of DC buses. As we know during charging operation, the nature of both the characteristics of battery and supercapacitor is complex and is also the same in discharging case also. The rule-based approach control method is adopted. Various simulations and comparisons have also been demonstrated.