A planar transformer comprising a printed circuit board; a primary planar winding disposed within the printed circuit board; a secondary planar winding disposed within the printed circuit board; a magnetic material disposed within the printed circuit board between the primary planar winding and the secondary planar winding, the magnetic material configured to generate a secondary magnetic flux path; and a magnetic core disposed around and through the printed circuit board and magnetically coupled to the primary planar winding and the secondary planar winding, the magnetic core configured to generate a primary magnetic flux path.

An adjustable leakage inductance transformer includes a magnetic core, a primary side coil and a secondary side coil. The magnetic core includes a magnetic core column structure, which has a central column, a first outer column and a second outer column. The primary side coil is wound on the first outer column and the second outer column by a first primary side coil loop number and a second primary side coil loop number, respectively. The secondary side coil is wound on the first outer column and the second outer column by a first secondary side coil loop number and a second secondary side coil loop number, respectively, the first primary side coil loop number is not equal to the first secondary side coil loop number, and the second primary side coil loop number is not equal to the second secondary side coil loop number.

An isolated resonant converter is provided, including a first side circuit, a second side circuit, and a resonant tank circuit. The resonant tank circuit includes a first resonant capacitor, a second resonant capacitor, and an integrated magnetic element. The integrated magnetic element includes a first side winding, a second side winding and a spaced groove provided between the first side winding and the second side winding. And the spaced groove stores leakage inductance energy, thereby forming at least part of resonant inductance required. Therefore, a number and volume of magnetic elements in the resonant converter are reduced.

The invention relates to a transformer core with at least one additional leg. Said additional leg is used to form a leakage path. In order to optimize the installation space and for easier connection of the transformer windings, the transformer legs and the additional leakage path legs are not arranged along a common line.

The invention relates to a transformer core with at least one additional leg. Said additional leg is used to form a leakage path. In order to optimize the installation space and for easier connection of the transformer windings, the transformer legs and the additional leakage path legs are not arranged along a common line.

A system for determining an operational state of an atmospheric pressure plasma. The system has a transformer for coupling power into the atmospheric pressure plasma, a current sampling circuit configured to sample at least one current pulse flowing through a primary winding of the transformer, and a programmed microprocessor configured to determine, from a waveform of the current pulse, the operational state of the atmospheric pressure plasma. The operational state is one of: a no plasma state, a plasma origination state indicative of an ignited arc expanding into a plasma by gas flow thereinto, and a plasma maintenance state indicative of the plasma being expanded.

An insulating transformer includes a plurality of sub-insulating transformers connected in series. Polarity directions of all sub-windings are identical. When a current I flows from a first main terminal to a third main terminal through the first sub-winding, an interphase capacitance, and the second sub-winding, excitation inductance of the first sub-winding and excitation inductance of the second sub-winding are configured to have opposite polarities.

An insulating transformer includes a plurality of sub-insulating transformers connected in series. Polarity directions of all sub-windings are identical. When a current I flows from a first main terminal to a third main terminal through the first sub-winding, an interphase capacitance, and the second sub-winding, excitation inductance of the first sub-winding and excitation inductance of the second sub-winding are configured to have opposite polarities.

A coil device including a bobbin, a first wire having a first coil part wound around the bobbin, a second wire having a second coil part wound around the bobbin, and cores and installed to the bobbin. Main inner leg sections and of the cores and are arranged at the inside of the first coil part and the second coil part. First sub-inner leg sections and of the cores and are arranged at the inside of the first coil part and an outside of the second coil part. Second sub-inner leg sections and of the cores and are arranged at the inside of the second coil part and at an outside of the first coil part.

A coil device including a bobbin, a first wire having a first coil part wound around the bobbin, a second wire having a second coil part wound around the bobbin, and cores and installed to the bobbin. Main inner leg sections and of the cores and are arranged at the inside of the first coil part and the second coil part. First sub-inner leg sections and of the cores and are arranged at the inside of the first coil part and an outside of the second coil part. Second sub-inner leg sections and of the cores and are arranged at the inside of the second coil part and at an outside of the first coil part.