A Selective Harmonic Optimization Method for STATCOM in Steady State Based on the Sliding DFT

The low-order harmonic components in the output current of a three-phase three-wire Static Synchronous Compensator (STATCOM) with an LCL filter are inevitable due to the dead time of the switching devices and the tracking speed of the PI controllers when using the inverter-side inductance current as the control object. In order to suppress the selective harmonic components in the steady-state output current, a control method for STATCOM based on the sliding DFT harmonic detection, closed-loop control by the inverter-side inductance current and feed-forward compensation by the selective harmonic current of the grid-side inductance is proposed. The simulation results in Mat lab demonstrate the effectiveness of the proposed selective harmonic optimization method.