Energy recovery filter with variable quality factor

This paper presents further investigations into using an energy recovery (ER) filter for mitigating harmonic instabilities in integrated AC/DC power systems. For certain system conditions, a low quality factor (Q) filter is desirable and for other conditions a high Q is better. This inspired the concept of a “controllable Q filter” in which the power absorbed in the filter is controllable by electronic means. The controllable Q filter uses an ER link so that this power is recovered. The investigations are conducted through computer simulation using an electromagnetic transient simulation program. The CIGRE benchmark model is selected as the base system. The results show that the controllable Q filter helps the system recover from faults