Disturbance-robust Current Control Technique for Large-scale PV Inverter

抄録

A disturbance-robust current control technique for large-scale PV inverter whose rating is several hundred kW is described. The biggest disturbance against current control of grid-connected inverters is the grid fault. The goal of this development is set as to be able to ride through three-phase grounding faults whose residual voltage is down to zero. The main development point of the scheme is to introduce sophisticated voltage feedforward control and improved sampling technique in the current control system. The idea is to make the AC output voltage of the IGBT assemblies follow the quick change in the grid voltage with a small time delay in order to reduce the AC current overshoot caused by grid faults. The validity of the control scheme is confirmed by a simulation study and full-load fault-ride-through tests.