Hybrid LC Filter

Hybrid LC filter is a kind of electrical LC filter, which typically contains two conductive foil layers, separated by an insulation material and coiled on a core. Layers are typically made of copper or aluminum. One layer, which is placed between the voltage source, such as inverter, and a load, is called “the main foil”; this layer forms filter inductance.^[1] Another foil, called “the auxiliary foil”, is connected to a neutral potential (e.g. earth), forming the useful capacitance between foils. This way the self-capacitance of the main foil is crucially decreased. Filter is characterized by improved high-frequency performance (working frequency range is at least up to tens of MHz). The mutual inductance between foil layers is rather large, coupling factor is typically about 0.95-0.99. Higher the mutual inductance provided, better the damping properties of the hybrid LC filter.

Hybrid LC filter layout. Construction contains conductive main and auxiliary layers separated by the insulation and coiled on a core.