Damped-type double tuned filters design for HVDC systems

The ac/dc filters are always needed in HVDC converter stations to suppress harmonic currents/voltages. The ac side filters are also employed to compensate network requested reactive power. Among different types of filters, double tuned passive filters have been widely utilized in HVDC stations, yet these filters are still not considered well developed. This paper presents an algorithm for design of the conventional and damped-type double tuned filters to reduce harmonic distortion and improve power factor in electrical systems. Firstly, the conventional double tuned filters are comprehensively studied, and an algorithm for precisely determining the parameters of this type of filters is presented. Next, the proposed design algorithm is developed for damped-typed double tuned filters. Using this method, the parameters of damped-type double tuned filters are calculated based on the tuned frequencies, the parallel resonance frequency, and the reactive power compensation capacity etc. Finally, the performance of the design algorithm is tested for a 6-pulse HVDC converter simulated on the MATLAB. The results clearly show the effectiveness of proposed design method in harmonics elimination and power factor correction.