WO1991006201A1

WO1991006201A1 - Integrated structure for a matrix transformer

Info

Publication number: WO1991006201A1
Application number: PCT/US1990/005770
Authority: WO
Inventors: Edward Herbert; John D. Repp; Stephen E. Cebry
Original assignee: Fmtt, Inc.
Priority date: 1989-10-16
Filing date: 1990-10-09
Publication date: 1991-05-02
Also published as: AU6637890A

Abstract

An integrated compact structure (80) for housing a magnetic transformer and associated electrical and magnetic components to provide high power density, distributed thermal heat sinking and optimal terminal and component placement for high frequency operation includes a chassis body (82) having a base (98) and side walls (84, 86) wherein the semiconductor switching components may be mounted in close proximity to the magnetic elements to minimize lead lengths. The chassis further includes a number of heat sinking stubs (122) arranged to mount rectifying semiconductor components (128) in close proximity to the magnetic elements and in such a manner as to serve as a heat sink such that there are no localized hot spots wherein heat is substantially evenly distributed across the chassis. The terminals (130, 132, 134) connecting to the semiconductors and to the magnetic circuit elements are optimally located for high frequency operation.

Description

INTEGRATED STRUCTURE FOR A MATRIX TRANSFORMER

BACKGROUND OF THE INVENTION

The present invention relates generally to mounting arrangements for electrical and magnetic components and deals more particularly with an integrated, compact structure for housing a matrix transformer and associated electrical and magnetic components to provide high power density, distributed thermal heat sinking and optimal terminal and component place¬ ment for high frequency operation- It is well known that any appreciable distance between electronic and magnetic components severely effects and limits certain circuit operation at high frequencies. It is also known that circuits, such as those utilized in power conversion applications can be greatly reduced in physical size if they can be made to operate at higher frequencies. Circuits employing matrix transformer technology, such as disclosed in U.S. Patents No. 4,665,357 and 4,845,606 to Herbert and assigned to the same assignee as the present invention and which disclosures are incorporated herein by reference, disclose circuit topologies that improve high frequency performance. However, optimum high frequency performance is not always obtained since components are not ideally located to minimize lead lengths. In addition, conventional circuits and arrangements often experience localized hot spots and therefore require bulky and often heavy structures to provide sufficient thermal heat sinking to insure circuit operation and reliabi¬ lity. Electrical equipment utilizing such conventional circuits and arrangements must in turn also be bulky to accommodate the larger structure. Since the conventional structure tends to be larger, distances between electrical components increases and thus high frequency operation is limited. Furthermore, power density is decreased to meet the increased heat dissipation requirements. Accordingly, it is desirable therefore to provide an integrated structure for a matrix transformer that permits high power density, distributed thermal heat sinking and conductivity and optimal electronic and magnetic component placement for high frequency operation.

SUMMARY OF THE INVENTION

In accordance with the present invention, an integrated, compact structure for housing a matrix transformer and associated electrical and magnetic components to provide high power density, distributed thermal heat sinking and conductivity and optimal terminal and component placement for high frequency operation is presented.

The present invention includes an integrated structure having a chassis body, preferably cast, which includes a base surface and a number of heat sinking and locating fins extending generally upward from the base and arranged in a spaced apart relationship with one another and side walls of the base. The fins accommodate cores of a number of interdependent magnetic elements comprising the »matrix transformer. Semiconductor switching and rectifying components are located and mounted in proximity to the matrix transformer in a distributed manner to minimize lead lengths between the semiconductor components and the matrix transformer. The mounting arrangement is such that the structure acts as a heat sink to substantially remove heat from and throughout the structure to achieve a higher power density.

In another aspect of the invention, the terminals of the structure which interconnect the matrix transformer, input terminals and output power busses are optimally located for high frequency operation and are in a configuration to match the respective terminal configurations of the semiconductor devices used.

In a further aspect of the invention, the interdependent magnetic cores of the matrix transformer are wired utilizing a helical winding arrangement to maximize the number of wires possible in the bores of the transformer cores and to minimize the spacing required for wiring to maintain the compact characteristic of the integrated structure. In a yet further aspect of the invention, the interdependent magnetic elements of a matrix transformer and a matrix inductor are wired in very close proximity and in registration with minimal intermediate wiring between the interdependent magnetic elements of the matrix transformer and matrix inductor to optimize the high frequency operating characteristics and to maintain the compact packaging of the integrated structure.

In a still further aspect of the invention, an integrated structure includes two copper plates separated by an insulating sheet and which together with the magnetic circuit elements and switching and rectifying semiconductor components is constructed with optimal locations for the terminals and placement of the components to achieve high frequency operation, high power density and distributed thermal heat sinking.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and advantages of the present invention will become readily apparent from the following written description and the drawings wherein:

Fig. 1 is a top plan view of one embodiment of an integrated structure for housing a high frequency matrix transformer to provide distributed thermal heat sinking and wherein the input and output terminals are optimally located for connection to the transformer and electrical components for high frequency operation.

Fig. 2 is a side elevational view taken along the line 2-2 of Fig. 1.

Fig. 3 is a top plan view of the chassis body of the integrated structure of Fig. 1 with all components removed to reveal the cavity area.

Fig. 4 is a front elevational view taken along the line 4-4 of Fig. 3.

Fig. 5 is a top plan view of the output power busses and output power terminal arrangement of the integrated structure of Fig. 1.

Fig. 6 is an exploded view of the individual output power busses of Fig. 5 with the insulating sheet material between the busses removed.

Fig. 7 is a top plan view of another embodiment of an integrated structure for housing a high frequency matrix transformer, inductor and power semiconductor components arranged to provide substantially evenly distributed thermal heat sinking and wherein input, output and component's terminals are optimally located for interconnection for high frequency operation.

Fig. 8 is a side elevational view showing a mounting arrangement for a number of power semiconductors of the structure of Fig. 7. Fig. 9 is a top plan view of the chassis body of the integrated structure of Fig. 7 with all components removed to reveal the cavity area.

Fig. 10 is a view along the line 10-10 of Fig. 7 illustrating one mounting arrangement for the power rectifier semiconductor devices wherein their respective terminals are optimally located for interwiring with the matrix transformer for high frequency operation.

Fig. 11 is a view along the line 11-11 of Fig. 7 showing a typical arrangement for the magnetic cores of the matrix transformer within the heat sinking and locating fins in the cavity area.

Fig. 12 is a view along the line 12-12 of Fig. 7 showing a typical arrangement for the magnetic cores of the inductors within the heat sinking and locating fins in the cavity area and in close proximity to the matrix transformer cores to minimize wire lengths.

Fig. 13 is a rear elevational view of the insulated circuit board showing optimized terminal locations for inter¬ connection between conductors of the magnetic components and the power semiconductor terminals for high frequency operation.

Fig. 14 illustrates a clip arrangement for securing the power semiconductor rectifier devices to studs on the chassis body.

Fig. 15 is a rear elevational view of the structure of Fig. 7 showing the output power busses.

Fig. 16 is a top plan view of an individual power bus of the structure of Fig. 7.

Fig. 17 is a top plan view of another embodiment of an integrated structure embodying the present invention and illustrating a hybrid circuit located within a central cavity in the chassis body to minimize distances between components for high frequency operation and to accommodate bulkier circuit components. Fig. 18 is a top plan view of another embodiment of an integrated structure embodying the present invention which permits high power density, distributed thermal heat sinking and magnetic and semiconductor component placement for high frequency operation.

Fig. 19 is an end view of the integrated structure of Fig. 18.

Fig. 20 illustrates schematically a conductor arrangement for a core interwired with conductors following a helical path through the bore.

Figs. 20a-20c are cross sectional views through the core of Fig. 20 illustrating schematically the conductor placement along the bore wall at spaced locations in the bore.

Fig. 21 illustrates a helical guide for the bore of a magnetic structure.

DETAIL DESCRIPTION OF PREFERRED EMBODIMENTS

Considering the invention in further detail and referring specifically to Figs. 1-6, a compact, integrated structure for housing a high frequency matrix transformer is illustrated and designated generally 10. The structure 10 comprises a chassis body 12 which may be fabricated as a casting to provide heat sinking properties for the electrical and magnetic components mounted therein and thereon. The casting of the chassis body 12 includes two sidewalls 14,16 which are in opposing faced relationship at opposite sides of the chassis 12 and which extend generally outward from the inner surface 18 of the base 20. The structure 10 further includes a front wall comprising two sections 22 and 24 extending outwardly from the surface 18 of the base 20 and continuous with the respective sidewalls 14 and 16. The two front wall sections 22 and 24 terminate in a spaced apart relationship to provide an open area for receiving an insulated circuit board 26. The circuit board 26 includes a number of terminals 28,28 in a predetermined and spaced relation to accommodate and interconnect with terminal leads from power semiconductors 30,32 (which are shown in phantom) and which may be mounted to the outer face surfaces 34,36 of the respective wall sections 24,22. A rear wall 38 extends the length of the chassis body 12 between the walls 14 and 16 and extends upwardly from the surface 18 of the base 20 to form a resting surface 40 for the output power bus terminals. The side walls 14 and 16 along the wall section 22 and 24, respectively and the rear wall 38 define a cavity generally designated 42 within the chassis body 12.

A number of heat sinking and locating fins 44,44 extend upwardly from the surface 18 of the base 20 and are arranged in a spaced relation with one another and with the side walls 14 and 16. As illustrated in Fig. 1, magnetic cores 46,46 may be located and arranged in the channels formed between the fins 44,44 and between the fins and the outer walls 14 and 16.

The output power busses are fabricated from a bar stock material such as copper and are stacked as illustrated and include output power terminals 50, 52, 54 which are aligned and in registration with terminals of a power semiconductor device package 48 illustrated in phantom in Figs. 1 and 2. The individual output power busses are stacked one atop the other as shown in Fig. 2, and as viewed in Fig. 5, provide output power terminals 50, 52, 54 in a spaced relation to one another and in registry with the terminals of the semiconductor rectifier package 48 so that the rectifier may be electrically connected to the power busses with minimal distance between the semiconductor package 48 and the structure 10. Typically, the power busses carry high AC and/or DC currents and their proximity and arrangement with respect to the terminals of the package 48 minimize lead inductance and oh ic losses.

As shown in Fig. 2, the output power busses are clamped or secured between the surface 40 of the wall 38 and a clamping member 56 which substantially extends the width of the structure 10 and which member 56 is held in place by fastening means which typically may be a screw 58 which is screwed into a complementary threaded opening 60 in the rear wall 38 to compress the power busses and hold them in place. A like receiving complementary threaded opening 62 is located at the opposite end of the wall 38 and likewise receives a screw through the clamping member 56. Typically, the clamping member 56 is made from a non-conductive material. The stacked arrangement of the busses 64, 66 and 68 between the resting surface 40 of the rear wall 38 and the clamping member 56 provides thermal heat sinking for the power output terminals 50, 52, 54. Each of the individual power busses 64, 66, 68 respectively include a number of connection points or openings 70,70 along their respective rear edge portions 71, 73, 75. The rear edge portions 71,75 of the respective individual busses 64 and 68 are bent lengthwise at an angle with respect to a plane coincidental with the surface of the bus so that the rear portions 71,75 of the bus 64 and bus 68 diverge away from a plane extending between the power busses to permit connection of the conductors from a matrix transformer or other circuit component included within or without the cavity 42.

It is seen that individual busses 64 and 68 are identical to one another and are arranged with like face surfaces facing one another so that the rear portions are bent away from one another and from the rear edge portion 73 of the bus 66. The busses 64, 66 and 68 are electrically insulated from one another and from the rear wall 38 by means of an insulating sheet material 72,72 being placed between the surfaces of the busses and the surface of the bus adjacent the rear wall 38.

Although the cavity 42 is illustrated with heat sinking and locating fins 44,44 which serve to align and locate the magnetic cores 46,46 comprising the matrix transformer, it will be recognized that the cavity 42 may be void of the fins 44,44. Other mounting means which accomplish the same objectives of retaining the matrix transformer and matrix inductor interdependent magnetic elements in the proper position relative to one another may be used. For low or moderate power applications, peripheral heat sinking would be sufficient. A.solid block of suitable magnetic material having a number of through bores extending through the block in a spaced relationship and which may be interwired as a matrix transformer may be used in place of the magnetic cores. The conductors of the matrix transformer may be interconnected to the individual busses 64, 66 and 68 and the terminals 28,28. Turning now to Figs. 7-16, another embodiment of the integrated structure embodying the present invention is illustrated wherein the structure is arranged to house the cores of the interdependent magnetic elements of a high frequency matrix transformer, matrix inductors, and power semiconductor devices and associated interwiring connections when wired and wherein the structure is designated generally 80. The structure 80 includes a chassis body 82 comprising two oppositely disposed side walls 84,86 arranged in a face-to-face relationship and extending longitudinally at either side of the chassis body 82. Each of the side walls 84,86 is made up of two wall sections 88,90 and 92,94, respectively. The wall sections 88-92 extend generally upward from the surface 96 of base portion 98 of the chassis 82. The wall portions terminate in a spaced apart relationship to define an intermediate opening to receive an insulated circuit card which includes terminals mounted in a predetermined arrangement for interconnection with the specific terminal configuration of the power semiconductor devices and in close proximity to the magnetic components of the matrix transformer and conductors as described below. As illustrated in Fig. 7, the intermediate opening between walls sections 88 and 90 receive an insulated circuit card generally designated 100. Likewise, the intermediate opening defined between wall portions 92 and 94 of side wall 86 receives an insulated circuit card designated generally 102. A third insulated circuit card generally designated 104 is located transversely between the two side walls 84 and 86 and between the ends of the wall sections 90,94, respectively. The chassis 82 also includes a rear wall portion 106 extending from the surface 96 of the base 98 and generally transverse to the two side wall portions 88 and 92. The end wall 106 includes a surface 108 on which the power busses rest and are clamped by a clamping member 110. As illustrated in Fig. 7, the side walls 84 and 86 and the insulated circuit card 104 and rear wall portion 106 define a cavity area generally designated 112.

A number of heat sinking and locating fins 114,114, as best illustrated in the top plan view shown in Fig. 9, extend upwardly from the surface 96 of the base 98 and are arranged in a spaced relationship with one another and the side wall portions 90 and 94 of the side walls 84 and 86, respectively. A second set of heat sinking and locating fins 116,116 extend upwardly from the surface 96 of the base 98 and are in a spaced relationship with one another and the side wall portions 88 and 92 of the side walls 84 and 86, respectively. In the embodiment illustrated, respective fins 114,114 are in longitudinal registry and alignment with respective fins 116,116 and are disposed in a transverse spaced relation with the fins 114,114 to permit interconnection of magnetic components located between the fins 114,114 and 116,116 with a minimum wiring length between components.

As illustrated in Fig. 7, cores 118,118 may be located in the channel region formed between the side walls and respective fins 114,114 and then interwired as a matrix transformer. Likewise, inductor cores 120,120 may be located in the channel areas formed between the fins 116,116 and the side wall portions 88 and 92 and wired and interconnected as desired.

The integrated structure 80 also includes heat sinking and mounting stubs 122,122 located in a spaced relation with one another and in transverse alignment at the frontal area of the chassis body 82. The stubs 122,122 are arranged such that a power semiconductor is mounted against the face surfaces of 124,126 of the stubs 122. For purposes of explana¬ tion, the power semiconductor devices are designed 128,128 and are illustrated with a terminal spacing and configuration such that terminals 130, 132, 134 are in alignment with respective terminals 136, 138, 140 on the insulated circuit card 104 such that the interconnection between the terminals 130, 132, 134 of the power semiconductor device 128 may be made at an optimal location and with a minimum lead length. The pattern of the terminals 130, 132, 134 of the respective power semiconductor devices 128,128 is repeated at each semiconductor mounting location and corresponds to respective like terminals 136, 138, 140 on the insulated circuit card 104. The power semiconductor devices 128,128 may be screw mounted to the stubs 122 or may be mounted via a spring clip cover designated generally 142 in Fig. 14. As illustrated, the clip 142 includes side extensions 144,146 which provide inward compression to clamp the semiconductor devices 128,128 against the respective faces of the stub 122.

One individual power bus used with the structure 80 is illustrated in Fig. 16 and is designated generally 148. The longitudinal end portion 150 is disposed at the opposite side of the connection terminal 152 and includes a number of connection points or openings 154,154 distributed along the edge portion 150 and which serve as connection points to the circuit elements which may be mounted in the cavity 112. As described above, the respective individual busses 148,148 are mounted with like faces facing one another such that the edge portion 150 of each bus bends away from one another to permit wiring of conductors without incurring electrical shorting or interference. Likewise, the busses 148,148 are electrically insulated from one another and from the wall 106 by means of an insulating sheet material located between the respective surfaces 108 of wall 106 and the surfaces of busses 148,148. Likewise, the busses may be located and held in position by the clamping member 110 via any suitable means well known to those skilled in the art.

In addition to providing mounting locations for the power semiconductors 128,128, provision is also made to mount switching semiconductors 156,156 to the face surfaces of the respective wall portions 88, 90, 92 and 94. The terminals 158, 160 and 162 of the respective semiconductors 156 are electrically connected to corresponding terminals having the same spacial relationship and which are located on the respective insulated circuit cards 100 and 102. Thus, the alignment and the distance between the terminals of the semiconductors and the terminals of the integrated structure are optimally located to minimize lead lengths and to enhance high frequency operation. In addition, the mounting of the semiconductor devices are such that thermal heat sinking is distributed so that hot spots are eliminated.

The integrated high frequency matrix transformer structure embodying the present invention may be constructed using a greater number of heat sinking and mounting stubs which extend outwardly from the surface of the base of the chassis body to accommodate a greater number of semiconductor device packages. The semiconductor packages may be, for example, diode packs having terminals which are in alignment with terminals of a printed circuit card similar to printed circuit card 104. The diode packs would also be are preferably mounted in thermal contact with the faces of the mounting stubs by means of a U-shaped clip which provides compressive force to urge the packs into contact with the stubs as described above.

Turning now to Fig. 17, an alternate embodiment of the integrated structure for a high frequency matrix transformer embodying the present invention is illustrated therein and generally designated 190. As in the previous exemplary embodiments illustrated, the structure 19ø may be fabricated as.a metal casting having a chassis body 192 which includes side walls 194,196 arranged opposite one another and in face-to-face relationship and extending lengthwise along the marginal area of the chassis 192. The walls extend upwardly from the surface 198 of the base 200. The chassis body 192 also includes a frontal wall 202 and a rear wall 204 both of which extend upwardly from the surface 198 of the base 200 and extend transversely to the walls 194 and 196 at the front and rear edge portions respectively of the chassis 192. The walls 194, 196, 202 and 204 define a cavity area 206. A number of heat sinking and locating fins 208,208 are arranged in a spaced relationship between the walls 194 and 196 and within the cavity area 206 to form a number of side-by-side channel regions into which the cores comprising the matrix transformer may be inserted. The cavity area 206 further includes a rectangularly shaped well area generally designated 210 into which a hybrid insulated circuit card containing semiconductor components and other electronic circuit components may be optimally located for interconnection for high frequency operation such that the leads from the components on the hybrid insulated circuit card are in alignment with and proximity to the magnetic components of the transformer and inductors located within the cavity area. The semiconductors, generally designated 212 on the hybrid circuit card 210, may be heat sinked to the surface 198 of the base 200. The side walls 194 and 196 have intermediate openings for receiving a insulated circuit card 214,216, respectively each of which carry terminals 218,218. Power busses 220 and 222 are arranged in a similar manner as described for the above exemplary embodiments.

A feature of the embodiment of Fig. 17 is the provision of room for bulkier circuit components which may be mounted above the hybrid circuit but within the well area. Such components may be capacitors and snubber resistors which are used in the normal manner. Cores 209,209 comprising the inductive magnetic elements are located in the frontal portion of the cavity 206 and in proximity to the hybrid circuit board 210.

Turning now to Figs. 18 and 19, another exemplary embodiment of the integrated structure embodying the present invention is illustrated and designated generally 230. The magnetic and semiconductor components are mounted, located and interwired to provide optimal terminal placement for high frequency operation. The structure 23ø includes two conductive plates, preferably rather heavy copper plates 232 and 234 each having similar and generally rectangular shapes and each being electrically insulated from one another by a sheet of insulating material 236. The insulating sheet 236 extends somewhat beyond the edges of the copper plates 232 and 234 to prevent electrical shorting of the plates 232 and 234 to one another. The surface area of each of the respective plates 232 and 234 are electrically conductive with one plate being of one voltage polarity and the opposite plate being of the opposite voltage polarity when a circuit is present and excited in accordance with a given design. The structure 230 is intended to be mounted in a clamping arrangement so that contact is made with the marginal edge surface area of each plate, for example the marginal area generally designated 238 and 240 of plate 232 and likewise similar marginal areas 242 and 244 of plate 234. In the illustrated embodiment of Figs 18 and 19, a chassis body 246 has a rectangular shape similar to the plates 232 and 234. The chassis body 246 is somewhat smaller in dimension than the plates and is used to contain and mount the cores 248,248 of a matrix transformer and the cores 250,250 of inductors. The chassis body 246 includes a number of sets of terminals generally designated 252,252 extending from the respective edges 254,256 of the chassis body 246 and each set is generally located one each at each of the respective end regions of the respective edges 254,256. The individual terminals comprising a terminal set 252 are located in close proximity to semiconductor switching devices 258,258 each being located in a respective corner region of the plate 232 and each having their respective leads 260, 262, 264 in alignment with corresponding interconnection terminals 266,266. The terminals 266,266 are physically mounted or connected to the structure 230 but may electrically isolated from the structure 230 using isolation techniques well known to those skilled in the art. The location of the terminals 266,266 are in close proximity to a respective terminal set 252 on the chassis body 246 to minimize wiring lengths between an associated semiconductor device and the terminals located on the chassis body and ultimately the magnetic elements of the matrix transformer to which it may be connected. For purposes of explanation, an input DC voltage may be connected to terminals 268 and 270, respectively and interwired according to the desired matrix transformer configuration.

Output power semiconductor rectifier devices 272,272 may also be mounted to the surface of the plate 232 and have their respective leads 274, 276, 278 in alignment with respective connection terminals in terminal sets generally designated 280,280 extending from the front and rear edges 282,284 respectively of the chassis body 246. The individual terminals of the terminal sets 280 are in alignment with and are very close to the leads of the semiconductor rectifier devices to which they are connected resulting in an optimal location for high frequency operation. The power rectifier devices 272 are typically dual, common cathode semiconductor devices and are well known to those skilled in the art. Although Fig. 18 illustrates in a top plan view the placement of terminals 266 and the chassis body 246 with its associated terminals 252 at the optimal locations for the semiconductor devices 272, it will be recognized from Fig. 19 that a similar physical arrangement for the terminals, chassis body and semiconductor applies to the plate 234.

The wiring of the matrix transformer cores, inductor cores, semiconductor devices and input and output terminals and respective interconnections are made at their optimal locations, one-by-one as the matrix transformer is assembled to form a "true" integrated structure. Since cores are usable on both sides of the structure, the windings may readily start and end at the same location without undue return paths. The matrix transformer and inductors, after they are interwired, may be potted in the chassis body or may be bonded to the respective surfaces of the plates.

In order to fully take advantage of the features of the integrated high frequency matrix transformer structure of the present invention it is necessary to be able to interwire the cores comprising the matrix transformer with a minimal of end space outside the core in order to ensure that the magnetic elements are placed as close as possible to the terminals of the power semiconductors and other electrical and magnetic components comprising the circuit. The problem of excessive end space requirements occurs, for example, wherein four matrix transformer cores are arranged with the bores of each respective core parallel to one another and an electrical conductor is wound through successive bores wherein the conductor typically enters the bore at one side of the core and exits at the opposite side crossing transversely through the bore. The conductor then enters the next successive core at the same side that it exited the adjacent core and crosses transversely through the bore exiting the bore at the same side that it entered the adjacent core. The pattern is repeated for the remaining successive cores. It can be seen that a second conductor will have little room in the bore to pass since the first conductor crosses the center of the bore tending to block the bore opening.

Fig.. 20 illustrates somewhat schematically that the congestion of the conductors in the bore can be eliminated to a great degree and therefore increase the density of fill of conductors in the bore by constraining the conductors to follow a helical path through the bore opening. The wires could be formed to follow the inner wall of the bore in a 180 degree helical pattern as illustrated. Fig. 20a is a schematic representation of a cross sectional area taken along the line 20a-20a of Fig. 20 illustrating the two conductors following along one side of the bore wall leaving a substantial window area. Fig. 20b is schematic cross sectional area along the line 20b-20b of Fig. 20 intermediate two ends of the bore illustrating the two conductors following the helical path leaving a substantial window in the bore. Fig. 20c is a schematic cross sectional area taken along the line 20c-20c of Fig. 20 illustrating the conductors following along the opposite wall of the bore as the conductors follow the helical path leaving a substantial window.

Although the wires can be formed to follow a helical path through the bore as disclosed above, it is preferable to provide a helical guide through the bore. Fig. 21 illustrates a helical guide generally designated 302 passing through a bore of a core 304. The helical guide 302 may be made from a flat strip of metal having a width approximately equal to the diameter of the bore and a length substantially equal to or greater than the longitudinal length of the core 304. As illustrated, the strip is twisted in a helical configuration which together with the walls of the bore form a conduit for an electrical conductor of the winding to guide the conductor through the bore. The guide 302 may be removed once the windings are passed through the core or the guide 302 may be left in place and used as a safety shield or safety ground by electrically grounding one end of the guide. If the helical guide is used as a safety shield or safety ground it is preferred that it be insulated. Although the helical guide is disclosed as a metal strip, any suitable material such as, for example, a plastic insert may be used.

The helical guide may be made from a pair of helical conduits each being semicircular in cross-section essentially providing a D-hole shaped path along the helical conduit. A separation follows along the flat portion of the face-to-face D-hole shaped conduits and which separation may accommodate a safety shield or safety ground as described above. Likewise, the separation may accommodate an insulating strip if additional insulation is required. The D-hole shaped helical conduit may be formed by heat shrinking tubing on a helical form to impart the D-shaped cross-sectional area and helical configuration to the conduit.

An integrated high frequency matrix transformer structure has been presented in several preferred embodiments for purposes of illustration. It will be recognized that numerous modifications and changes may be made without departing from the spirit and scope of the invention and therefore the invention has been presented by way of illustra¬ tion rather than limitation.

Claims

WE CLAIM

1. An integrated structure for a matrix transformer wherein the matrix transformer includes a plurality of interdependent magnetic elements arranged in a matrix and having at least two windings interconnecting the interdependent magnetic elements, said structure comprising: a chassis body assembly including chassis body means for physically mounting and locating the interdependent magnetic elements of a matrix transformer in a spaced relationship to one another to minimize the distance between adjacent magnetic elements and to distribute thermal heat sinking, said chassis body having first and second side walls, a rear wall and a front wall; said chassis body having a cavity including an inner surface, said cavity being defined by said first and second side walls disposed opposite one another in face-to-face relationship and each extending longitudinally along the outermost, marginal edge portions of said chassis body and in substantially parallel alignment with one another and by front and rear walls disposed opposite one another in face-to-face relationship and transversely to said first and second side walls, said front wall extending along the frontmost marginal edge portion of said chassis body and said rear wall extending along the rearmost marginal edge portion of said chassis body, said first and second side walls, said rear wall and said front wall extending generally upwardly from said inner surface; said chassis body further including a first plurality of fins within said cavity and extending generally upwardly from said inner surface, said fins being intermediate to and parallel with said first and second side walls and in a spaced relationship to one another and to said first and second side walls so that the distance between adjacent fins and between an outermost fin and a respective side wall is dimensioned to accommodate an interdependent magnetic element placed therebetween; output power bus means carried by said chassis assembly for providing at least one electrical interconnection between said integrated structure and external electrical circuit means; input voltage terminal means carried by said chassis assembly for providing at least one electrical interconnection between said integrated structure and an external voltage power source, and power semiconductor device mounting means located on one or more of said first, second, rear and front walls for fixedly attaching said power semiconductor devices to said integrated structure to provide heat sinking for said devices and for locating the terminals of said devices in close proximity to said plurality of interdependent magnetic elements to minimize the lead lengths between said devices and a winding of the matrix transformer for high frequency operation.

2. An integrated structure as defined in claim 1 further characterized in that said input voltage terminal means comprises terminals carried on a first insulated circuit card and that said front wall has a cut-out portion intermediate said first and second side walls for receiving said first insulated circuit card, said cut-out portion being dimensioned for complementary engagement with edge portions of said first insulated card.

3. An integrated structure as defined in claim 1 further characterized in that said output power bus means further comprises a substantially rectangularly shaped bus bar having first and second surfaces and a plurality of physical and electrical connection points defined by a corresponding number of openings through the bus bar along one longitudinal marginal edge area of said bus bar, said one longitudinal marginal edge area being bent at an angle away from a plane coextensive with said first surface, said bus bar further having a tab extending from a longitudinal edge opposite said one longitudinal marginal edge area and being offset from a medial portion of said bus bar, said bus bars being arranged with said second surface of one in face-to-face relation with said second surface of another and with insulation means for separating the adjacent bus bars to prevent electrical continuity between said bus bars, and clamping means for holding said bus bars in registry with one another and to said chassis assembly, said longitudinal marginal edge area of one bus bar bending away from said longitudinal marginal edge area of an adjacent bus bar to provide sufficient space between said bus bars for making electrical interconnections in the space formed between said bus bars along the bent longitudinal marginal edge area and a winding of the matrix transformer.

4. An integrated structure as defined in claim 1 further characterized by a second plurality of fins within said cavity and extending generally upwardly from said inner surface, said fins being intermediate to and parallel with said first and second side walls and in a spaced relationship to one another and to said first and second side walls, said second plurality of fins being spaced from said first plurality of fins thereby defining a channel extending transversely between said first and second walls, said second plurality of fins being spaced so that the distance between adjacent fins and between an outermost fin and a respective side wall is dimensioned to accommodate a magnetic core of a matrix inductor, said matrix inductor magnetic core being placed between said adjacent fins and said outermost fin and a respective side wall; said chassis body further including a flange portion extending longitudinally from and coextensive with said inner surface of said cavity; a third plurality of fins located on said flange portion and extending generally upwardly and generally parallel with said first and second plurality of fins, said third plurality of fins being in' a spaced relationship with one another and defining power semiconductor device mounting means for fixedly attaching power semiconductor devices to said integrated structure to provide heat sinking for said devices and for locating the terminals of said devices in close proximity to a second insulated circuit card located intermediate said third plurality of fins and said chassis body, said front wall having a cut-out portion intermediate said first and second side walls for receiving said second insulated card, said cut-out portion being dimensioned for complementary engagement with edge portions of said second insulated card; terminal means carried by said second insulated circuit card for providing at least one electrical interconnection between a winding associated with a matrix transformer and a power semiconductor device attached to said semiconductor device mounting means, said terminals carried by said second insulated circuit card being arranged on said card to correspond to the terminal configuration of a power semiconductor device to which said circuit card terminals are interconnected so as to locate said power semiconductor devices in close proximity to said terminals on said circuit card to minimize lead lengths between said power semiconductor devices and a winding of the matrix transformer for high frequency operation.

5. An integrated structure as defined in claim 4 further characterized in that said input voltage terminal means includes terminals carried on a third and fourth insulated circuit card and that first side wall has a cut-out portion intermediate said front and rear walls for receiving said third insulated circuit card and said second side wall has a cut-out portion intermediate said front and rear walls for receiving said fourth insulated circuit card, said cut-out portions in each of said first and second side walls being dimensioned for complementary engagement with edge portions of said third and fourth insulated circuit cards, respectively, said terminals carried on said third and fourth circuit cards being arranged to correspond to the terminal configuration of a power semiconductor device to which said circuit card terminals are interconnected so as to locate said power semiconductor devices in close proximity to said terminals on said third and fourth cards, respectively to minimize lead lengths between said power semiconductor devices and a winding of the matrix transformer for high frequency operation.

6. An integrated structure as defined in claim 1 further characterized in that said chassis body is a cast structure.

7. An integrated structure as defined in claim 1 further characterized in that said chassis assembly includes: conductive plate means for carrying at least one chassis body, said conductive plate means comprising a first and second heavy plate; insulation means for electrically insulating said first and second heavy plates from one another to prevent electrical shorting between plates, said first and second plates sandwiching said insulation; said sandwiched plates having a plurality of holes extending therethrough and corresponding generally to the placement of a corresponding interdependent magnetic element located within said chassis body, a first chassis body being carried on one surface of said first plate such that the open portion of said cavity in said chassis body is in face-to-face relation with the surface of said first plate and a second chassis body being carried on one surface of said second plate such that the open portion of said cavity in said chassis body is in face-to-face relation with the surface of said second plate and in registry with said chassis body carried by said first plate, said interdependent magnetic elements carried by said first chassis body being in close proximity to said interdependent magnetic elements carried by said second chassis body to minimize lead lengths connecting said power semiconductor devices to a winding of the matrix transformer for high frequency operation; said output power bus means being defined by said surface of said first plate and said surface of said second plate, said surface of said first plate carrying an output voltage potential having a first polarity and said surface of said second plate carrying an output voltage potential having a second polarity with respect to said first polarity; said power semiconductor device mounting means further including means for fixedly attaching power semiconductor devices to at least one of said surfaces of said first and second plates, respectively in a spaced relationship to one another and along said front and rear walls, said first and second plates providing heat sinking for said power semiconductor; said chassis body having terminal means for connecting a winding of the matrix transformer to power semiconductor devices mounted on said surfaces of said first and second plates, respectively, said chassis body having terminals being located in close proximity to and being arranged in the same configuration as the semiconductor terminals to minimize lead length between the power semiconductor devices and a winding of the matrix transformer for high frequency operation, said winding of the matrix transformer being connected to said chassis body terminals.

8. An integrated matrix transformer and matrix inductor structure, comprising: a matrix transformer having a plurality of interdependent magnetic elements having windings interconnecting the interdependent magnetic elements; a matrix inductor having a plurality of matrix inductor magnetic elements having windings and being in close proximity to, and in registration with the matrix transformer magnetic elements; chassis means for retaining the magnetic elements of the matrix transformer and the matrix inductor in relationship one to the other and for providing heat sinking; electrical termination means located in close proximity to and in registration with the matrix transformer and the matrix inductor for terminating conductors from the matrix transformer and matrix inductor; interconnecting means defined by the windings of the matrix transformer, the windings of the matrix inductor, electrical connections between windings of the matrix transformer and the matrix inductor and the electrical connections between the matrix transformer and the matrix inductor and said electrical termination means for interconnecting the integrated matrix transformer and matrix inductor structure to make a matrix transformer and matrix inductor circuit characterized by having very short wiring lengths for minimum inductance and ohmic resistance.

9. The integrated matrix transformer and matrix inductor structure of claim 8 further comprising: mounting and heat sinking means incorporated within said chassis means arranged for connecting at least one semiconductor device to the matrix transformer and matrix inductor circuit, said mounting and heat sinking means disposed and located such that said at least one semiconductor device is located proximate to, and in registration with at least a portion of said termination means such that the lead inductance and ohmic resistance in a lead from said at least one semiconductor device and at least a portion of said electrical termination means are minimized.

10. The integrated matrix transformer and matrix inductor structure of claim 8 wherein said chassis means is one of a casting or a machined part having a base plate with a first surface disposed opposite a second surface and a plurality of fins extending outwardly from at least one of said first and second surfaces of said base plate, said plurality of fins of at least one of said first and second surfaces of said base plate being arranged and disposed relative to one another to retain the plurality of' interdependent elements of the matrix transformer and the plurality of elements of the matrix inductor in relationship one to the other and to provide heat sinking for removing heat from the structure.

11. The integrated matrix transformer and matrix inductor structure of claim 8 wherein said chassis means further comprises: a first conductive plate; a second conductive plate proximate to and in registration with the first conductive plate; an insulating plate between said first and second conductive plates; at least one of said first and said second conductive plates having mounting and heat sinking means for at least one semiconductor device attached thereto, said mounting and heat sinking means disposed and located such that said at least one semiconductor device is located proximate to, and in registration with at least a portion of said termination means such that the lead inductance and ohmic resistance in a lead from said at least one semiconductor device and at least a portion of said electrical termination means are minimized; said conductive plate further being electrically coupled to and interconnected with the matrix transformer and matrix inductor circuit to provide a first electrical termination having a first voltage potential and polarity; said second conductive plate further being electrically coupled to and interconnected with the matrix transformer and matrix inductor circuit to provide a second electrical termination having a second voltage potential and polarity; said first and second conductive plates each further having a marginal area in registration one to the other to provide electrical and thermal conduction from the integrated matrix transformer and matrix inductor structure.

12. An integrated matrix transformer structure, comprising: a matrix transformer having a plurality of interdependent matrix transformer magnetic elements having windings interconnecting the interdependent magnetic elements; chassis means for retaining the plurality of interdependent matrix transformer magnetic elements in relationship one to the other and for providing heat sinking; electrical termination means located in close proximity to and in registration with the matrix transformer for terminating conductors from the matrix transformer; interconnecting means defined by the windings of the matrix transformer and electrical connections between windings of the matrix transformer and said electrical termination means for interconnecting the integrated matrix transformer structure to make a matrix transformer circuit characterized by having very short wiring lengths for minimum inductance and ohmic resistance.

13. The integrated matrix transformer structure of claim 12 further comprising: mounting and heat sinking means incorporated within said chassis means arranged for connecting at least one semiconductor device to the matrix transformer circuit and mounting and heat sinking means disposed and located such that said at least one semiconductor device is located proximate to, and in registration with at least a portion of said termination means such that the lead inductance and ohmic resistance in a lead from said at least one semiconductor device and at least a portion of said electrical termination means are minimized.

14. The integrated matrix transformer structure of claim 12 wherein the chassis means is one of a casting or a machined part having a base plate with a first surface disposed opposite a second surface and a plurality of fins extending outwardly from at least one of said first and second surfaces of said base plate, said plurality of fins of at least one of said first and second surfaces of said base plate being arranged and disposed relative to one another to retain the plurality of interdependent elements of the matrix transformer in relationship one to the other and to provide heat sinking for removing heat from the structure.

15. The integrated matrix transformer structure of claim 12 wherein said chassis means further comprises: a first conductive plate; a second conductive plate proximate to and in registration with the first conductive plate; an insulating plate between said first and second conductive plates; at least one of said first and said second conductive plates having mounting and heat sinking means for at least one semiconductor device attached thereto, said mounting and heat sinking means disposed and located such that said at least one semiconductor device is located proximate to and in registration with at least a portion of said termination means such that the lead inductance and ohmic resistance in a lead from said at least one semiconductor device and at least a portion of said electrical termination means are minimized; said first conductive plate further being electrically coupled to and interconnected with the matrix transformer circuit to provide a first electrical termination having a first voltage potential and polarity; said second conductive plate further being electrically coupled to ant interconnected with the matrix transformer circuit to provide a second electrical termination having a second voltage potential and polarity; said first and second conductive plates each further having a marginal area in registration one to the other to provide electrical and thermal conduction from the integrated matrix transformer structure.