A Comprehensive Investigation On the Selection of High-Pass Harmonic Filters

In recent years, there is an increased use of passive filters in both transmission and distribution systems due to the proliferation of power electronic devices. However, the problem of filter design has not been well addressed in the past and one example is the application of high-pass filters in a filter package. Three types of HP filters are widely used to mitigate multiple harmonics, i.e., 2nd HP filter, 3rd HP filter and C-type filter. There is still a lack of research to clearly reveal the characteristics of each filter, which makes it difficult for the designer to select the optimal filter topology under different circumstances. The main goal of this paper is to solve the problem of how to select a proper configuration among three HP filter candidates for a given harmonic problem. Unlike the conventional optimization-based filter studies, this paper investigates three HP filters in an analytical way. As a result, the paper provides a deep insight into the inherent characteristics of the filter and the conclusions drawn in the paper are universal; thus can be used in different applications, ranging from low voltage levels to high voltage levels. The research results lead to a recommended application scope of each HP filter, which is very useful to guide the design of filter packages and help designers to evaluate the design results.