1. Field of the Invention
The invention relates to an inverter transformer, more particularly to an inverter transformer adapted to drive illumination of discharge lamps.
2. Description of the Related Art
An inverter circuit is the main component that drives illumination of discharge lamps. When an inverter is adapted for driving a plurality of discharge lamps simultaneously, supply of balanced current outputs to the discharge lamps is the key to ensuring uniform illumination among the discharge lamps.
Therefore, the object of the present invention is to provide an inverter transformer that is adapted to supply balanced current outputs to discharge lamps so as to ensure uniform illumination.
According to one aspect of the present invention, there is provided an inverter transformer that includes a coil unit and a transformer core unit. The coil unit includes a bobbin formed with a core-receiving compartment, and a plurality of windings including two primary windings and two secondary windings wound around the bobbin. The secondary windings are disposed adjacent to each other and are coupled electromagnetically and respectively to the primary windings. The transformer core unit includes an internal core part that extends into the core-receiving compartment of the bobbin, and an external core part that forms a magnetic circuit path with the internal core part. The external core part includes a main segment extending externally at one side of the bobbin and a protrusion segment extending from the main segment toward a portion of the bobbin that is disposed between the secondary windings.
According to another aspect of the present invention, there is provided an inverter transformer that includes a plurality of coil units and a plurality of transformer core units. Each of the coil units includes a bobbin formed with a core-receiving compartment, and a plurality of windings including primary, secondary and tertiary windings wound around the bobbin. The secondary and tertiary windings are coupled electromagnetically to the primary winding. Each of the transformer core units has an internal core part that extends into the core-receiving compartment of a respective one of the coil units. The tertiary windings of the coil units are interconnected to form a closed circuit loop.
According to still another aspect of the present invention, there is provided an inverter transformer that includes a plurality of coil units and a plurality of transformer core units. Each of the coil units includes a bobbin formed with a core-receiving compartment, and a plurality of windings including two primary windings and two secondary windings wound around the bobbin. The secondary windings of each of the coil units are disposed adjacent to each other and are coupled electromagnetically and respectively to the primary windings of the corresponding one of the coil units. Each of the transformer core units includes an internal core part that extends into the core-receiving compartment of the bobbin of a respective one of the coil units, and an external core part that forms a magnetic circuit path with the internal core part. The external core part includes a main segment extending externally at one side of the bobbin of the respective one of the coil units and a protrusion segment extending from the main segment toward a portion of the bobbin of the respective one of the coil units that is disposed between the secondary windings.
The plurality of windings of each of the coil units further includes a tertiary winding wound around the bobbin of the respective one of the coil units and coupled electromagnetically to the primary windings of the respective one of the coil units. The tertiary windings of the coil units are interconnected.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
As shown in
The coil unit 20 includes a bobbin 24 formed with a core-receiving compartment 240, two primary windings 21, and two secondary windings 22 disposed adjacent to each other and coupled electromagnetically and respectively to the primary windings 21.
The primary windings 21 are connected in series to each other. During operation, the secondary windings 22 have electromagnetic fields that oppose each other. The secondary windings 22 are adapted to be coupled electrically to the loads 90. In this embodiment, each end of each of the secondary windings 22 is adapted to be connected electrically to a corresponding end of a corresponding one of the loads 90. The other ends of the loads 90 are connected to each other.
The transformer core unit 30 includes an internal core part 31 that extends into the core-receiving compartment 240 of the bobbin 24, and an external core part 32 that is disposed outside of the core-receiving compartment 240 of the bobbin 24. The external core part 32 forms a magnetic circuit path with the internal core part 31. The external core part 32 includes a main segment 321 extending externally at one side of the bobbin 24, and a protrusion segment 322 extending from the main segment 321 toward a portion of the bobbin 24 that is disposed between the secondary windings 22. In this embodiment, the external core part 32 is configured as an E-shaped core, and the main segment 321 extends parallel to the bobbin 24.
The following relation is applicable to the design of the protrusion segment 322 extending toward the portion of the bobbin 24 that is disposed between the secondary windings 22:
This way, the effective magnetic path length is increased, and cross interference between induced fluxes in the secondary windings 22 due to mutual inductance established therebetween is reduced, thereby achieving the object of balancing and stabilizing currents flowing through the secondary windings 22.
As shown in
As shown in
This way, the mutual inductance established between the secondary windings 22 is reduced, thereby achieving the object of balancing and stabilizing currents flowing through the secondary windings 22.
As shown in
As shown in
The inverter transformer 200d further includes a plurality of transformer core units 30d, each of which has an internal core part (not shown) that extends into the core-receiving compartment 240 of a respective one of the coil units 20d, and an external core part 32d that is disposed externally of the core-receiving compartment 240 and that forms a magnetic circuit path with the internal core part.
In this embodiment, since each of the coil units 20d only includes one secondary winding 22, the mutual inductance established between the secondary windings 22 of the previous embodiments is eliminated. In addition, by connecting the tertiary windings 23 of the coil units 20d in series to each other, the object of establishing balanced and stable output currents at the secondary windings 22 is achieved.
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
This application is a continuation-in-part (CIP) of U.S. patent application Ser. No. 11/240,942, entitled “INVERTER TRANSFORMER”, filed on Sep. 29, 2005.
Number | Date | Country | |
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Parent | 11240942 | Sep 2005 | US |
Child | 12043947 | US |