Comparison of Control Strategies to Meet Low Voltage Ride-Through Requirements in Distributed Power Generation Systems

Low Voltage Ride-Through requirements demand wind power plant to remain connected to the network in presence of grid voltage dips. Most of dips present positive, negative and zero sequence components. Then, the use of regulators based on symmetrical components is a good tool to control grid-connected converters, under grid fault condition. This work compares three different current controllers based on symmetrical components and Linear Quadratic Regulator. Controller performance is evaluated on Low Voltage Ride-Through requirement fulfillment, dc link voltage ripple, grid current balancing and oscillating power flow. A Neutral-Point-Clamped topology has been considered, because trends in wind power lead to increasing power and voltage levels. Simulations show that all three controllers work properly. Controller selection depends on the application and system constraints.