BRIEF DESCRIPTION OF THE DRAWINGS
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:
FIG. 1 is a partly exploded perspective view of a first type of a conventional one-to-many transformer;
FIG. 2 is a schematic diagram, illustrating magnetic coupling established between a primary winding and each of secondary windings of the first type of the conventional one-to-many transformer;
FIG. 3 is an equivalent circuit of FIG. 2 when the magnetic coupling established between the primary winding and each of the secondary windings is large;
FIG. 4 is an equivalent diagram of FIG. 3, illustrating a parallel connection of the lamps;
FIG. 5 is a schematic diagram of a second type of the conventional one-to-many transformer;
FIG. 6 is a schematic diagram, illustrating magnetic coupling established between a primary winding and each of secondary windings of the second type of the conventional one-to-many transformer;
FIG. 7 is an equivalent circuit of FIG. 6 when the magnetic coupling established between the primary winding and each of the secondary windings is large;
FIG. 8 is an equivalent circuit of FIG. 7, illustrating two parallel load circuits formed by the lamps;
FIG. 9 is a schematic diagram of a third type of the conventional one-to-many transformer;
FIG. 10 is a perspective view of a fourth type of the conventional one-to-many transformer;
FIG. 11 is a schematic diagram of another conventional transformer;
FIG. 12 is a schematic diagram of a first implementation of the first preferred embodiment of a transformer according to the present invention;
FIG. 13 is a schematic side view of a second implementation of the first preferred embodiment;
FIG. 14 is a partly exploded perspective view of the second implementation of the first preferred embodiment;
FIG. 15 is a perspective view of a third implementation of the first preferred embodiment;
FIG. 16 is a perspective view of a fourth implementation of the first preferred embodiment;
FIG. 17 is an exploded perspective view of a fifth implementation of the first preferred embodiment;
FIG. 18 is an assembled perspective view of the fifth implementation of the first preferred embodiment;
FIG. 19 is a schematic side view of a first implementation of the second preferred embodiment of a transformer according to the present invention;
FIG. 20 is a schematic side view of a second implementation of the second preferred embodiment of a transformer according to the present invention;
FIG. 21 is a perspective view of a third implementation of the second preferred embodiment;
FIG. 22 is a perspective view of a fourth implementation of the second preferred embodiment;
FIG. 23 is a perspective view of a first implementation of the third preferred embodiment of a transformer according to the present invention;
FIG. 24 is a perspective view of a second implementation of the third preferred embodiment;
FIG. 25 is a schematic view of the fourth preferred embodiment of a transformer according to the present invention;
FIG. 26 is a schematic diagram of a first implementation of the fifth preferred embodiment of a transformer according to the present invention;
FIG. 27 is a schematic diagram of a second implementation of the fifth preferred embodiment;
FIG. 28 is a schematic side view of a first implementation of the sixth preferred embodiment of a transformer according to the present invention;
FIG. 29 is a schematic side view of a second implementation of the sixth preferred embodiment; and
FIG. 30 is a schematic diagram of the seventh preferred embodiment of a transformer according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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.
Referring to FIG. 12, according to the first preferred embodiment of the present invention, a method for adjusting mutual inductance is adapted for use in a transformer 600. As shown in FIG. 12, in a first implementation of the first preferred embodiment, the transformer 600 includes a main core 61 and two windings 60 that are wound on the main core 61 and that have the mutual inductance established therebetween. The method includes the steps of:
(A) disposing an adjusting core 62 between the windings 60 and adjacent to the main core 61, the adjusting core 62 having a cross-sectional area smaller than that of the main core 61; and
(B) without resulting in division of flux of the mutual inductance established between the windings 60, and division of an exciting magnetic flux into a plurality of independent magnetic paths, adjusting position of the adjusting core 62 relative to the main core 61 to vary the mutual inductance established between the two windings 60.
Preferably, the cross-sectional area of the adjusting core 62 is not greater than an effective cross-sectional area of the main core 61. The main core 61 has a core portion farthest from the adjusting core 62 and having a cross-sectional area greater than the effective cross-sectional area of the main core 61.
In this embodiment, the adjusting core 62 is disposed in contact with the main core 61. A contact area 622 between the adjusting core 62 and the main core 61 is adjusted in step (B). The main core 61 is formed from two U-shaped core parts 610, and includes a first side portion on which two primary windings 611 are wound, and a second side portion opposite to the first side portion on which two secondary windings 612 are wound. The adjusting core 62 is disposed to extend across the first and second side portions and between the primary windings 611 and between the secondary windings 612. The primary windings 611 are connected directly in series to each other. In other embodiments of the invention, the primary windings 611 are connected in series via an external circuit (not shown). The position of the adjusting core 62 is adjusted by moving the adjusting core 62 along a longitudinal direction (X) to vary the mutual inductance established between the secondary windings 612. It should be noted herein that the position of the adjusting core 62 can also be adjusted to vary the mutual inductance established between the primary windings 611 in other embodiments of the present invention. Further, the adjusting core 62 can be glued to the main core 61 after adjustment of the position thereof has been completed.
By adjusting the position of the adjusting core 62, cross interference between induced fluxes in the windings 60 due to the mutual inductance established therebetween can be improved based on the following relation:
By increasing the effective magnetic path length, a major magnetic path of the transformer 600 simultaneously has loose coupling and tight coupling effects, thereby achieving the objects of balancing and stabilizing currents flowing through the windings 60.
It should be further noted that since the cross-sectional area of the core portion of the main core 61 that is farthest from the adjusting core 62 is greater than the effective cross-sectional area of the main core 61, portions of the secondary windings 612 that are proximate to the primary windings 611 have tight couplings established thereat, while portions of the secondary windings 612 that are proximate to the adjusting core 62 have loose couplings established thereat. Consequently, less traveling waves enter the transformer 600 from the core portion of the main core 61 that is farthest from the adjusting core 62, thereby minimizing the formation of standing waves.
As shown in FIG. 13 and FIG. 14, in a second implementation of the first preferred embodiment, the transformer 600a further include a rack body 63, which is disposed to extend across the first and second side portions of the main core 61 in the longitudinal direction (X), and which is n-shaped. The adjusting core 62 extends through the rack body 63, and is slidable therein along the longitudinal direction (X) when adjusting the position of the adjusting core 62 relative to the main core 61. In addition, numeral 621 denotes the cross-sectional area of the adjusting core 62, numerals 614 denote the cross-sectional areas of the core portions of the main core 61 that are farthest from the adjusting core 62, and numeral 613 denotes the effective cross-sectional area of the main core 61.
As shown in FIG. 15, in a third implementation of the first preferred embodiment, the transformer 600b further includes a coil bracket 66 that is disposed to cover the main core 61, and that has the primary and secondary windings (not shown) wound thereon. The coil bracket 66 includes a plurality of projections 661 for positioning the adjusting core 62 in a center of the coil bracket 66. The position of the adjusting core 62 relative to the main core 61 is adjusted by exerting an external force in the longitudinal direction (X) sufficient to overcome the force applied by the projections 661 to the adjusting core 62.
As shown in FIG. 16, a transformer 600c according to a fourth implementation of the first preferred embodiment differs from the third implementation in that the transformer 600c further includes a screw bolt 67 disposed at the center of an open side of the coil bracket 66. The screw bolt 67 abuts against the adjusting core 62, and has varying radial dimensions. The position of the adjusting core 62 relative to the main core 61 is adjusted by rotating the screw bolt 67 such that the adjusting core 62 is pushed by the screw bolt 67 to slide along the coil bracket 66.
As shown in FIG. 17 and FIG. 18, a transformer 600d according to a fifth implementation of the first preferred embodiment differs from the first implementation in that the transformer 600d further includes first and second coil brackets 81, 82 that are disposed to surround the main core 61, i.e., the main core 61 extends through the first and second coil brackets 81, 82, and a coupling frame 83 that couples the first and second coil brackets 81, 82 together. The primary and secondary windings (not shown) are wound on the first and second coil brackets 81, 82, respectively. The coupling frame 83 includes a first frame body 831 coupled to the first coil bracket 81, and a second frame body 832 coupled to the second coil bracket 82. The first and second frame bodies 831, 832 are coupled to each other. The coupling frame 83 is formed with an extension space 834 that extends from the first frame body 831 to the second frame body 832. In this embodiment, the first and second frame bodies 831, 832 are coupled to each other via a plurality of male and female block structures 833 formed thereon.
The adjusting core 62 extends through the coupling frame 83, and is disposed in the extension space 834. The position of the adjusting core 62 relative to the main core 61 is adjusted by pushing the adjusting core 62 such that the adjusting core 62 slides in the extension space 834 so as to vary the mutual inductance established between the windings, e.g., the secondary windings (not shown) in this embodiment.
Referring to FIG. 19 and FIG. 20, according to the second preferred embodiment of the present invention, the method for adjusting mutual inductance differs from the first preferred embodiment in the manner in which the position of the adjusting core 62 relative to the main core 61 is adjusted. In this embodiment, size of an air gap 623 between the adjusting core 62 and the main core 61 is adjusted in step (B).
In a first implementation of the second preferred embodiment shown in FIG. 19, other than the main core 61, the adjusting core 62, and the windings 60, the transformer 600e further includes a rack body 63′ and an insulating washer 64. The rack body 63′ has the adjusting core 62 extending therethrough. The insulating washer 64 is disposed in the rack body 63′ between the main core 61 and the adjusting core 62. The position of the adjusting core 62 relative to the main 61 is adjusted by adjusting the size of the air gap 623 between the main core 61 and the adjusting core 62 in a vertical direction (Y) perpendicular to the longitudinal direction (X) (the air gap 623 is also referred to as a vertical air gap 623a). The insulating washer 64 provides the air gap 623 between the main core 61 and the adjusting core 62, i.e., the size of the vertical air gap 623a is equal to the thickness of the insulating washer 64. Therefore, by adjusting the thickness of the insulating washer 64, the size of the vertical air gap 623a is adjusted.
In a second implementation of the second preferred embodiment shown in FIG. 20, the transformer 600f further includes a rack body 63″ extending across the first and second side portions of the main core 61, and an eccentric wheel 65 that is disposed rotatably on the rack body 63″. The adjusting core 62 is disposed to abut against the eccentric wheel 65, and the air gap 623 extends in the vertical direction (Y) (the air gap 623 is also referred to as the vertical air gap 623a). By rotating the eccentric wheel 65, the adjusting core 62 is moved relative to the main core 61, thereby adjusting the size of the air gap 623.
As shown in FIG. 21, in a third implementation of the second preferred embodiment, other than the main core 61, the adjusting core 62, and the windings (not shown), the transformer 600g further includes a coil bracket 66, a biasing member 68, and a screw bolt 67′. The coil bracket 66 is disposed to cover the main core 61, has the windings (not shown) wound thereon, and is formed with a groove. The biasing member 68 is disposed at one side of the groove. The screw bolt 67′ is disposed at another side of the groove. The adjusting core 62 is disposed in the groove and between the biasing member 68 and the screw bolt 67′. The position of the adjusting core 62 relative to the main core 61 is adjusted in terms of the size of the air gap (not shown) between the adjusting core 62 and the main core 61 by rotating the screw bolt 67′ such that the adjusting core 62 pivots about the biasing member 68 in the vertical direction (Y).
As shown in FIG. 22, according to a fourth implementation of the second preferred embodiment, in the transformer 600h, the position of the adjusting core 62 relative to the main core 61 is adjusted by adjusting the size of the air gap 623 between the adjusting core 62 and the main core 61 in the longitudinal direction (X) (The air gap 623 is also referred to as a horizontal air gap 623b). The size of the longitudinal air gap 623b is adjusted by moving the adjusting core 62 along the longitudinal direction (X) relative to the portion of the main core 61 that has the windings 60 wound thereon. It should be noted herein that the windings 60 are connected in series via an external circuit 70 configured on a circuit board in this implementation.
As shown in FIG. 23, according to the third preferred embodiment of the present invention, the method for adjusting mutual inductance differs from the first preferred embodiment also in the manner in which the position of the adjusting core 62 relative to the main core 61 is adjusted. In a first implementation of the third preferred embodiment shown in FIG. 23, the transformer 600i has an air gap formed between the adjusting core 62 and the main core 61 in the vertical direction (Y). A projection area 624 of the adjusting core 62 on the main core 61 is adjusted in step (B) by moving the adjusting core 62 along the longitudinal direction (X).
As shown in FIG. 24, in a second implementation of the third preferred embodiment, other than the main core 61, the adjusting core 62j, and the windings (not shown), the transformer 600j further includes a coil bracket 66 that is disposed to cover the main core 61, that has the windings wound thereon, and that is formed with a groove. The adjusting core 62j is an elongated screw 69 that extends through the coil bracket 66 and that is disposed in the groove. The position of the adjusting core 62j relative to the main core 61 is adjusted by adjusting the projection area 624, which is achieved through rotating the elongated screw 69 into and out of the groove.
As shown in FIG. 25, according to the fourth preferred embodiment of a transformer 600k of the present invention, the main core 61′ of the transformer 600k includes opposite first and second side portions. Each of the first and second side portions has a primary winding 611 and a secondary winding 612 wound thereon. The adjusting core 62 is disposed to extend between the first and second side portions. The position of the adjusting core 62 is adjusted to vary the mutual inductance established between the secondary windings 612, i.e., the secondary windings 612 serve as the windings 60 in this embodiment. However, it should be noted herein that the primary windings 611 can also serve as the windings 60 in other embodiments, where the mutual inductance established between the primary windings 611 is varied by adjusting the position of the adjusting core 62. The position of the adjusting core 62 relative to the main core 61′ can be adjusted in manners identical to those disclosed hereinabove in connection with the previous embodiments.
As shown in FIG. 26 and FIG. 27, according to the fifth preferred embodiment of the present invention, primary and secondary windings 611, 612 are wound on a same side of the main core 61″. In particular, the main core 61″ of the transformer 600m, 600n includes a first side portion on which the primary and secondary windings 611, 612 are wound, and a second side portion opposite to the first side portion. In a first implementation of the fifth preferred embodiment shown in FIG. 26, the secondary windings 612 are interposed between the primary windings 611. The primary windings 611 are connected to each other in series. The adjusting core 62 is disposed to extend across the first and second side portions and between the secondary windings 612. The position of the adjusting core 62 relative to the main core 61″ is adjusted to vary the mutual inductance established between the secondary windings 612, i.e., the secondary windings 612 serve as the windings 60 in this implementation. In a second implementation of the fifth preferred embodiment shown in FIG. 21, the primary windings 611 are interposed between the secondary windings 612 and are connected to each other in series. The adjusting core 62 is disposed to extend across the first and second side portions and between the primary windings 611. The position of the adjusting core 62 relative to the main core 61″ is adjusted to vary the mutual inductance established between the primary windings 611, i.e., the primary windings 611 serve as the windings 60 in this implementation.
As shown in FIG. 28 and FIG. 29, the sixth preferred embodiment of the present invention differs from the first preferred embodiment in that the sixth preferred embodiment utilizes the magnetic conductivity characteristic of the main core for achieving the adjustment of the mutual inductance. In particular, tight coupling is established when permeability of the main core is high, effective cross-sectional area of the main core is large, and magnetic reluctance of the main core is low. On the other hand, loose coupling is established when the permeability of the main core is low, the effective cross-sectional area of the main core is small, and when the magnetic reluctance of the main core is high. In a transformer where magnetic coupling is established between primary and secondary windings to form an exciting loop, tight coupling needs to be formed where the primary and secondary windings are proximate to each other so as to increase efficiency of the transformer, and loose coupling needs to be formed where the two primary windings and two secondary windings are proximate to each other so as to avoid interference from leakage flux.
Therefore, according to the sixth preferred embodiment, the main core 61p, 61q has a loose coupling end 615, and two tight coupling ends 616 that are distal from the loose coupling end 615. Each of the tight coupling ends 616 has a reluctance smaller than that of the loose coupling end 615. Magnetic permeability of each of the tight coupling ends 616 is greater than that of the loose coupling end 615. The transformer 600p, 600q further includes two windings 60, each of which is wound on the main core 61p, 61q between the loose coupling end 615 and a respective one of the tight coupling ends 616. The two windings 60 have the mutual inductance established therebetween. In the previous embodiments, an adjusting core 62 (see FIG. 12) is disposed between the windings 60 for increasing magnetic path length, so as to achieve high reluctance and loose coupling effects between the windings 60. However, according to the sixth preferred embodiment, the method for adjusting the mutual inductance includes the step of: while maintaining a cross-sectional area 614p, 614q of each of the tight coupling ends 616 to be greater than an effective cross-sectional area 613p, 613q of the loose coupling end 615, adjusting the cross-sectional areas 614p, 614q of the tight coupling ends 616 to vary the mutual inductance established between the two windings 60. The cross-sectional areas 614p, 614q of the tight coupling ends can be adjusted in different ways.
In a first implementation of the sixth preferred embodiment shown in FIG. 28, a plurality of adjusting cores 62p are disposed on the tight coupling ends 616 to adjust the cross-sectional areas 614p of the tight coupling ends 616, such that the reluctances at the tight coupling ends 616 are lowered, thereby forming tighter magnetic couplings at the tight coupling ends 616, and looser magnetic couplings at the loose coupling end 615. Consequently, the mutual inductance between the windings 60 is reduced, and formation of standing waves is avoided. Preferably, the cross-sectional areas 614p of the tight coupling ends 616 are at least 1.2 times the effective cross-sectional area 613p of the loose coupling end 615.
According to a second implementation of the sixth preferred embodiment shown in FIG. 29, in the transformer 600q, core portions of the tight coupling ends 616 are removed by grinding so as to adjust the cross-sectional areas 614q of the tight coupling ends 616. The main core 61q can be purposely made larger to provide room for subsequent grinding.
As shown in FIG. 30, according to the seventh preferred embodiment of a transformer 600r of the present invention, the transformer 600r is provided with two of the adjusting cores 62′, as opposed to one in the first preferred embodiment (see FIG. 12), for adjusting the mutual inductance. The main core 61 includes a first side portion on which primary windings 611 are wound, and a second side portion opposite to the first side portion on which secondary windings 612 are wound. In step (A), the two adjusting cores 62′ are respectively disposed between the primary windings 611 and the secondary windings 612 and adjacent to the main core 61. In step (B), a distance (D) between the two adjusting cores 62′ is adjusted.
In sum, as is evident from the various embodiments disclosed above, with reference to FIG. 12 and FIG. 28, the present invention is capable of adjusting mutual inductance established between two windings 60, whether the windings 60 are primary windings 611 or secondary windings 612, by adjusting the position of the adjusting core 62 relative to the main core 61 without resulting in division of flux of the mutual inductance established between the windings 60, and division of an exciting magnetic flux into a plurality of independent magnetic paths, or by adjusting the cross-sectional areas 614p of the tight coupling ends 616 of the main core 61p while maintaining the cross-sectional area 614p of each of the tight coupling ends 616 to be greater than an effective cross-sectional area 613p of the loose coupling end 615 of the main core 61p. Consequently, the currents flowing through the windings 60 can be balanced and stabilized, thereby achieving the object of the present invention.
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.
Patent Application
20080068118
