LVRT Capabilities of Solar Energy Conversion System Enabling Power Quality Improvement

Abstract

The adaptive observer-based control algorithm is proposed for low-voltage ride-through capabilities of double-stage grid-tied solar energy conversion system (SECS). The adaptive observer-based control strategy provides multi-functionalities such as harmonic mitigation, unity power factor operation, minimizes VSC (voltage source converter)losses and ride-through capabilities under balanced and unbalanced faults in the grid side network. As per to amended grid code IEEE-1547 standard, the renewable energy system must support to ride-through operation under perturbation in the system during faults in the grid side network. For ride-through features of SECS, a limit is superimposed on solar photovoltaic power generation to prevent the overcurrent of the VSC and to obstruct the energy aggregation on DC link voltage, which diminishes the life span of the DC link capacitor. The reactive power is supplied through a solar photovoltaic array (SPVA)coupled VSC as per revised grid code IEEE-1547.4. The power quality (PQ)features are ensured using adaptive observer technique, which has preciosuly assured to estimate the magnitude of the fundamental component of the load current. Simulation results show the effectiveness of the proposed ride-through control strategy for unbalanced L-G fault. Test results exhibit satisfactory response for various conditions such as distribution static compensator (DSTATCOM)-SPV A mode, grid currents balancing features and variation of solar irradiations.