A harmonic elimination approach based on moving average filter for cascaded DSTATCOM

Distribution STATic synchronous COMpensator (DSTATCOM) has been proved an effective approach to compensate reactive and harmonic current in distribution network. However, DC-link voltages of H-bridge cascaded DSTATCOM contain 100Hz (double grid frequency) voltage harmonics due to reactive compensation current, these harmonics will also exist in the output of DC-link voltage balancing controller which could ultimately cause low frequency harmonics in compensation current. As a result, compensation precision will be deteriorated, especially when harmonic voltage ripples are fairly high because of large compensation current or small DC-link capacitance. This paper proposes a harmonic elimination approach to DC-link voltage balancing control based on moving average filters (MAFs) for cascaded DSTATCOM, MAFs are used to eliminate the 100Hz harmonic components from the detected DC-link voltages. Finally, simulation and experimental results from H-bridge cascaded DSTATCOM show that better compensation performance can be obtained under both inductive and capacitive operation, thus verify the feasibility of the proposed technique.