This application claims priority to European Patent Application No. 20183915.6, filed on Jul. 3, 2020, which is hereby incorporated by reference in its entirety.
The present disclosure relates to a method of manufacturing a common mode inductor or differential mode inductor. The present disclosure also relates to such a common mode or differential mode inductor.
Outdoor power supply systems are commonly used to supply power to outdoor power consuming systems. One example of such outdoor power consuming systems is telecom equipment, such as telecom base stations. Such a telecom base station is typically supplied with a 48V direct current (DC) voltage delivered from a power supply system located adjacent to, or in the proximity of, the base station.
The power supply system may include an alternating current (AC)/DC converter for converting an AC voltage from the AC mains (or a fossil-fueled AC generator etc.).
Alternatively, the power supply system may include a DC/DC converter for converting a DC voltage (from a solar panel system, or another type of DC power source).
The power supply system may further include rechargeable batteries to provide UPS (uninterrupted power supply) functionality.
The outdoor power supply system further includes a cabinet in which electrical equipment is protected from the environment. The cabinet provides protection from fine particles (dust, sand etc.) and humidity (rain, snow etc.).
As the converter and other parts of the power supply system generates heat, a cooling system is needed to cool the air within the cabinet. The cooling system may be a heat exchanger, an air conditioner or a fan-filter. The cooling system has several disadvantages; it reduces the overall power efficiency, it increases the size of the cabinet, it increases the costs of the overall power supply system and it reduces the reliability of the overall system. As shown in
The converter module of
Another type of inductor which may be used in such converters is the differential mode (DM) inductor. The DM inductor has typically one coil of insulated copper wire wound on a single, typically ring-shaped core. CM inductors typically have high permeability cores with low saturation capability, while DM cores have lower permeability materials, with higher saturation capability.
One object of the embodiment of the present disclosure is to reduce tolerances during manufacturing of CM and DM inductors. This will reduce scrapping, and hence reduce costs per produced usable CM and DM inductor. This will also make it easier to robotize the mounting and soldering process. In addition, the object of the embodiment of the present disclosure is to improve how such CM and DM inductors can be cooled.
The present disclosure relates to a common mode or differential mode inductor. One embodiment of the present disclosure provides a common mode or differential mode inductor for connection to a printed circuit board (PCB), wherein the inductor includes:
In one embodiment, the core may be cylindrical or torus-shaped, it may be shaped like a rectangular or oval toroid. It may also be shaped as a cube having an opening through the cube.
In one embodiment, the base element includes wire guides for guiding ends of the first insulated wire of the first coil with respect to the supporting device.
In one embodiment, the ends of the first insulated wire are slidingly engaged with the wire guides.
In one embodiment, the ends of the insulated wire of the first coil are protruding from the base element in a direction away from the alignment plane. The ends are sufficiently long to penetrate openings of the printed circuit board and to be soldered to the side of the printed circuit board being opposite of the supporting device.
In one embodiment, the longitudinal center axis of the core is oriented perpendicular to the PCB contacting surface.
In one embodiment, the inductor further includes:
In one embodiment, ends of the second insulated wire of the second coil are slidingly engaged with the wire guides.
In one embodiment, the inductor includes a coil separation element for separating the first coil from the second coil. The coil separation element sets a separation distance between turns of the first coil from turns of the second coil.
In one embodiment, the coil separation element is provided at least partially inside the opening of the core. In one embodiment, the entire coil separation element is provided between the alignment plane and the base element.
In one embodiment, the coil separation element includes an aligning surface aligned with the alignment plane. In one embodiment, the coil separation element is connected to, or provided as part of, the supporting device.
In one embodiment, the core, the first coil and/or the second coil are fastened to the supporting device by an adhesive.
As the coil or the coils are wound around the core, the adhesive will also fasten the core to the supporting device. The adhesive may also fasten the coil separation element to the coil or coils and/or to the supporting device.
In one embodiment, the supporting device further includes:
In one embodiment, this second distance between the PCB contacting surface and the distal end of the second alignment element is equal to the distance between the PCB contacting surface and the distal end of the first alignment element. In this case, the alignment plane is parallel to the PCB contacting surface and hence the plane of the printed circuit board.
The distal end of the first alignment element and the distal end of the second alignment element may be parallel lines. Alternatively, the distal end of the first alignment element may be a line and the distal end of the second alignment element may be a point not on that line or vice versa.
In one embodiment, the supporting device includes one single alignment element, wherein the distal end of the one single first alignment element includes an end surface defining the alignment plane.
In one embodiment, the one single alignment element is provided through the opening of the core. In one embodiment, the end surface defining the alignment plane is substantially circular.
In one embodiment, the supporting device further includes:
In one embodiment, this third distance between the PCB contacting surface and the distal end of the third alignment element is equal to the distance between the PCB contacting surface and the distal end of the first alignment element and also equal to the distance between the PCB contacting surface and the distal end of the second alignment element. Again, this case the alignment plane is parallel to the PCB contacting surface and hence the plane of the printed circuit board.
In one embodiment, the supporting device is made as one, single body. Alternatively, the base element and alignment element are made as separate bodies fixed to, or secured to, each other.
In one embodiment, the supporting device is made of a plastic material.
In one embodiment, one purpose of the supporting device is to support the core and the coil with respect to the printed circuit board. One further purpose is to support the core and the coil in a preferred position with respect to the printed circuit board and with respect to a cooling surface, the cooling surface being located at a distance from the printed circuit board.
The present disclosure also relates to a method for manufacturing a common mode inductor or a differential mode inductor. One embodiment of the present disclosure provides a method for manufacturing a common mode inductor or a differential mode inductor including the steps of:
In one embodiment, the step of supporting the core and the first coil on the supporting device includes the step of:
In one embodiment, the ends of the first insulated wire are slidingly engaged with the wire guides.
In one embodiment, the step of securing the core and the first coil with respect to the supporting device includes the step of:
In one embodiment, the adhesive is in contact with the core, the first coil and the supporting device. However, as the wire of the first coil is wounded around the core, it is sufficient that the adhesive is in contact between the first coil and the supporting device, as this indirectly will cause the core to be adhered to the supporting device.
In one embodiment, the step of pushing the core and the first coil includes:
In one embodiment, each turn of the first insulated wire has a point furthest from the first end plane a distance in a normal direction towards the alignment plane, wherein the step of pushing the core and the first coil includes:
In one embodiment, the step of pushing the core and the first coil includes:
According to the above inductor and method for manufacturing of such an inductor, it is achieved that none of the turns of the coil is protruding further away from the first end plane than the alignment plane. Hence, all inductors will fit in its assigned position between the printed circuit board and an outer housing, making robot manufacturing simpler.
Preferably, the outer housing is made of a heat conducting material, and hence, the housing serves the purpose of transporting heat away from the inductor. Typically, a thermally conducting material, for example a thermally conducting pad, a thermally conducting gap filler or a solidified liquid gap filler, is used between the inductor and the outer housing. Due to the alignment of the coil with the alignment plane, it is achieved that fewer and/or thinner pads may be used. Moreover, it is achieved that the variation between different inductors is reduced and hence the variation in required pad thickness is reduced.
The present disclosure also relates to an electric circuit system. One embodiment of the present disclosure provides an electric circuit system including:
Embodiments of the disclosure will now be described in detail with respect to the enclosed drawings, wherein:
An introduction of the embodiments of the present disclosure will now be described with reference to 3a, 3b, 4a and 4b. In
The distribution circuit 20 includes cable connectors, circuit breakers/relays, a controller for controlling power through the converter(s), for controlling the output voltage, for battery management etc., while the converter module 40 includes an AC/DC converter, a DC/DC converter, and/or a DC/AC converter, depending on the input power and load requirement. UPS functionality may also be provided by connecting a rechargeable battery to the distribution circuit 20.
In
When supplied with electric power, the electric components of the converter module 40, including the inductors 100, produce heat, which must be removed from the inside of the housing 31 to prevent overheating.
The system 1 therefore includes a passive cooling system 70, where the housing 31 is a part of the cooling system, where heat is dissipated from the housing 31 to the environment. The housing 31 is therefore made of a thermally conducting material, such as a metal. In one aspect, the cooling system includes cooling fins 71 provided on the outer surface of the housing 31.
Preferably, the system 1 is designed for outdoor use. In such a case, the housing 31 is a protective housing 31 protecting the inside (i.e. the PCB and the electric components) of the housing 31 from an outdoor environment. The system 1 may for example have an IP65 classification.
Preferably, the housing 31 is made of aluminum or an aluminum alloy. The cooling fins 71 of the passive cooling system 70 may be manufactured together with the converter module housing in a die casting process or a machining process.
Embodiments of the common mode inductor 100 will now be described in detail below.
It is now referred to
The core 102 is shown in
An alternative core 102 is shown in
Alternatively, the core 102 may be a cylinder with chamfered edges, or it may even be torus-shaped.
The coil 104 includes an insulated wire 105 wound with a number of turns a1, a2,. . . , aN around the core 102. The insulated wire 105 has two ends 105a intended to be conductively mounted to the printed circuit board PCB.
In the embodiment, the inductor 100 is a common mode inductor with two coils. Hence, the coil 104 is referred to as a first coil 104, and a second coil is referred to as 106. The second coil 106 includes a second insulated wire 107 wound with a number of turns b1, b2, . . . , bN around the core 102. Also two ends 107a of the second wire 107 are intended to be conductively mounted to the printed circuit board PCB.
The present embodiment of the supporting device 110 is shown in
The base element 112 further includes wire guides 114 for guiding ends 105a of the first insulated wire 105 of the first coil 104 with respect to the base element 112 and for guiding ends 107a of the second insulated wire 107 of the second coil 106. The wire guides 114 may be provided as openings in the base element 112 or as U- or V-shaped notches in the base element 112. The ends 105a, 107a of the wires 105, 107 are slidingly engaged with the wire guides 114.
The ends 105a, 107a of the insulated wire 105, 107 are protruding from the base element 112 in a direction away from the alignment plane AP. The ends 105a are sufficiently long to penetrate openings of the printed circuit board PCB and to be soldered to the side of the printed circuit board PCB being opposite of the supporting device 110.
The supporting device 110 further includes a first alignment element 120 having a proximal end 120b connected to the base element 112 and a distal end 120a provided at a distance D (
The supporting device 110 further includes a second alignment element 125 having a proximal end 125b connected to the base element 112 and a distal end 125a provided at a second distance from the PCB contacting surface 113.
In
Hence, the distal end 120a of the first alignment element 120 and the distal end 125a of the second alignment element 125 are defining parallel lines L120a, L125a. The distal end 120a of the first alignment element 120 and the distal end 125a of the second alignment element 125 together are defining an alignment plane AP as indicated in
As shown in
It is also shown that the longitudinal center axis I1 of the core 102 is oriented in parallel with the printed circuit board PCB.
In
In this embodiment, the coil separation element 140 is provided at least partially inside the opening of the core 102.
In addition, the core 102, the first coil 104 and the second coil 106 may be fastened to the supporting device 110 by an adhesive (illustrated by an adhesive container in
The manufacturing of the first embodiment of the inductor 100 will now be described.
In a first step, the first insulated wire 105 is wound a number of turns a1, a2, . . . , aN around the core 102, and forming a first coil 104 around the core 102.
In the same way, the second insulated wire 107 is wound a number of turns b1, b2, . . . , bN around the core 102, and forming a second coil 104 around the core 102.
It should be noted that the coils 104, 106 shown in
It is now referred to
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In a final step shown in
Optionally, the ends 105a, 107a may be cut off to a suitable length as illustrated in
It is now referred to
As described above with reference to
It is now referred to
Hence, in case the inductor 100 has two coils 104, 106, it is the turn having the largest distance Da1, Da2, DaN, Db1, Db2, , DbN from the first end plane 102a which will be aligned with the alignment plane AP.
In practice, some of the turns may have the same distance from the planar surface 102 and hence more than one of the turns of the same coil or of different coils may be aligned with the aligning plane AP.
It may also be the case that the step of pushing the core 102 and the first coil 104 will cause a reduction in the distance Da1, Da2, , DaN, Db1, Db2, , DbN of at least one of the turns a1, a2, . . . , aN, b1, b2, bN of the first insulated wires 105, 107. This will typically require a deformation of the wires 105, 107.
It is now referred to
Also here, the supporting device 110 includes a base element 112 and a PCB contacting surface 113. However, the supporting device 110 here only includes one single alignment element 120. This one single alignment element 120 must here have a distal end 120a extending in two different directions, i.e. the distal end 120a must itself define the alignment plane AP.
Here, the one single alignment element 120 is provided through the opening 102d of the core 102. The end surface 121 defining the alignment plane AP is substantially circular.
It is also shown that the alignment element 120 includes a slit 122 in its distal end, the slit 122 being adapted to receive the separation element 140.
The coil separation element 140 includes an aligning surface 142, which will be aligned with the alignment plane AP during the manufacturing step of pushing the coil (together with the core) against the planar surface PS.
It is now referred to
The third alignment element 128 is here provided through the opening 102d of the core 102, similar to the second embodiment above. Hence, this third embodiment may be seen as a combination of the first and second embodiment above.
It is now referred to
The distal end 120a of the first alignment element 120 and the distal end 125a of the second alignment element 125 together are defining the alignment plane AP.
It is now referred to
The distal end 120a of the first alignment element 120, the distal end 125a of the second alignment element 125 and the distal end 128a of the third alignment element 128 together are defining the alignment plane AP.
As is apparent from the above embodiments, there are several ways that such an alignment plane AP can be defined by means of one or more distal ends of one or more supporting elements.
In the above embodiments, the supporting device 110 is made as one, single body. It may be made of a non-conducting material, such as a plastic material. Alternatively, the base element 112 and the alignment element(s) may be made as separate bodies fixed to, or secured to, each other.
According to the above, the purpose of the supporting device 110 is to support the core 102 and the coil(s) with respect to the printed circuit board PCB. A further purpose is to support the core 102 and the coils in a preferred position with respect to the printed circuit board PCB and also with respect to a cooling surface, the cooling surface being located at a distance from the printed circuit board PCB.
One embodiment of the present disclosure provides an electric circuit system achieved by using the inductor 100 shown in
AP between the inductor 100 and the protective housing 31. In one embodiment, the thermally conducting material 48 is a thermally conductive pad. The thermally conductive pad 48 has been provided between the inductor 100 and the inside of the upper housing 31, to improve heat transfer from the inductor 100 to the upper housing 31.
According to the above inductor and method for manufacturing of such an inductor, it is achieved that none of the turns a1, a2, . . . , aN, b1, b2, . . . , bN is protruding further away from the first end plane 102a than the alignment plane AP. Hence, all inductors 100 will fit in its assigned position between the printed circuit board and an outer housing and none of the inductors will prevent the assembly of the electric circuit system.
Due to the alignment of the coil(s) with the alignment plane AP, it is achieved that fewer or thinner pads may be used. Moreover, it is achieved that the variation between different inductors is reduced.
It should be noted that if the inside of the housing is inclined, i.e. not parallel with, the printed circuit board PCB, then the alignment plane AP may also be inclined with respect to the PCB plane.
It would be possible to integrate the coil separation element 140 with the supporting device 110, i.e. that the coil separation element 140 is provided as part of the supporting device 110.
It should be noted that the inductor 100 may have one, two or more than two coils wound around the core 102.