AC Filter Design for Capacitor Commutated Converter

Similar to the conventional line commutated converter (LCC), the capacitor commutated converter (CCC) is also a source of harmonics during the commutation process. It will generate even more harmonic components on the AC side. For the CCC based high voltage direct current (CCC-HVDC) system, it is necessary to install AC filters on the AC side, which can provide reactive power compensation and effectively suppress the AC harmonics. This paper provides a design method of the AC filters for the CCC on the inverter side. Firstly, the fundamental principle of the AC filter is demonstrated. Subsequently, the design methods of the performance calculation and the steady-state rated calculation are shown. Finally, a practical AC filter design example for the CCC on the inverter side is presented. By comparing to the LCC, the result shows that the CCC technology can provide a certain amount of reactive power through commutation capacitors and reduce the number of the parallel capacitors in AC filters.