Low Voltage Ride-Through Capability for Wind Turbines based on Current Source Inverter Topologies

This paper proposes a circuital solution, aimed at a class of current-source inverter topologies, that provides the ability to ride-through temporary low voltage, as well as open circuit conditions at the mains without opening the mains circuit breakers. Although the proposed solution has broader applications, it is described in the framework of a previously published current-source inverter topology for modern wind turbines. For such systems, the low voltage ride-through capability is becoming a necessary feature. The current source topology considered exploits the cable length between the nacelle and the ground to provide a significant portion of the DC-link inductance. Prior work discussed the control strategy, flexibility, design rules, protection and experimental results of this topology and acknowledged the need for low-voltage ride through capability. One possible solution, derived from an already proposed protection scheme, is presented together with selected simulation and experimental results.