Harmonic cancellation for HVDC using a novel control scheme

How to eliminate harmonics is one of the key technologies of high-voltage direct current (HVDC) transmission systems. In order to cancel harmonics, hybrid filters, consisting of passive filter (PF) and active power filter (APF), are employed in some recent projects. This paper proposes a novel scheme, which can take full advantage of passive filter, which is good at canceling low frequency harmonics with large power and active power filters, which is good at canceling high frequency harmonics with less power. What is more, the scheme can reduce the requirement of additional DC source in the DC part of active power filter and achieve expected effect.