Improved current control method of LCL type active power filter suitable for power grid frequency fluctuation scene

The invention relates to an LCL type active power filter improved current control method suitable for a power grid frequency fluctuation scene. The main circuit is used for collecting pulse signals, manufacturing harmonic compensation currents with the same size and opposite phases through a three-phase inverter and injecting the harmonic compensation currents into a power grid; the control system is used for detecting harmonic current generated by a load, obtaining harmonic current signals needing to be compensated for by the APF according to the detected load current, obtaining fundamental wave instruction current according to the detected direct current bus capacitor voltage, obtaining instruction current needing to be compensated by adding the harmonic wave instruction current to the fundamental wave instruction current, and outputting the instruction current needing to be compensated. The command current is compared with the actual output current of the inverter, an error value is obtained for current cl