Harmonic Elimination using Giant-K Planar Filters

In this paper design of low loss passive planar low pass filter for reducing harmonics in a frequently used voltage source type nonlinear load in low voltage distribution system is proposed. The filter is comprised of a lumped high impedance line inductor made of fused silica and an interdigitated capacitor that is made of La0.5Na0.5Cu3Ti4O12 giant K material. An extensive simulation of single phase diode bridge rectifier with designed filter is carried out by employing Spice software. The subsequent analyses reveal very low insertion loss for the proposed filter. Furthermore, low total harmonic distortion values conforming to IEEE standards and 3dB cut-off in the range of 75Hz, are obtained. This enables the designed low pass filter to effectively eliminate higher order harmonics over the entire wide band in single stretch. The usage of fractal based capacitor structure with giant K resulting in large capacitance value of the order of 3mF, small size, and the effective harnessing of temperature dependent resistance in the inductor leading to stable cut-off frequency even amidst dynamic load variation form the crux of the present work