Grid-connected inverter and grid frequency fluctuation suppression method

摘要

PROBLEM TO BE SOLVED: To provide a grid interconnection inverter and a grid frequency fluctuation suppressing method capable of suppressing fluctuations in the grid frequency due to sudden changes in load and fluctuations in output of a renewable energy power source in a short time. An inverter that is connected to a power system 10 to which a synchronous generator 30 is connected and that suppresses fluctuations in the system frequency by operating according to an output active power command generated by a VSG function, and controlling the same. The circuit is represented by the sum of the output active power setting of the inverter, the deviation between the system frequency and the reference frequency multiplied by the pseudo damping coefficient, and the derivative of the system frequency multiplied by the pseudo inertia coefficient. In the grid interconnection inverter that drives the inverter main circuit 100 according to the output active power command, the control circuit of the inverter causes the pseudo inertial coefficient after the grid frequency reaches the frequency fluctuation maximum point to reach the frequency fluctuation maximum point. Means for adjusting to be smaller than the previous pseudo inertia coefficient is provided. [Selection diagram] Figure 1