A Low Voltage Ride Through Scheme for three phase grid connected PV inverter with an adaptive window based MAF-PLL

摘要

Balancing the rift between demand and production of energy has become one of the major growing concerns globally. This has prompted the technocrats, policy-makers, etc. to contemplate on the potency of renewable energy (RES) sources. The outcome has resulted in the world-wide adoption of RES to meet energy deficits. However various grid codes govern their integration to the grid. These monitor the functioning of the RES power converters and impose active and reactive power injection requirements. This is termed as the low voltage ride-through capability of the power converters in order to ensure unnecessary tripping of the interfacing converter resulting in sudden demand-shift on the conventional sources. Cascaded failures and blackouts could be an immediate result. Furthermore proper, fast and dynamic tracking and synchronization of the grid angle also emerges as a necessity in order to respond to the scenario of sudden grid disconnection. But the vulnerability of the grid-interfacing converters to disconnection due to grid voltage and frequency distortions contributes to the fragile interconnection. Taking into consideration all the discussed issues the need for a control law accounting for synchronization and grid distortions emerges as a foreseeable solution. This paper investigates the functioning of adaptive window-based MAF-PLL and the operation of an LVRT scheme for low voltage interfaced PV inverters. Extensive simulations in MATLAB/Simulink have been investigated under different scenarios to validate the proposed scheme.