Inductor module with improved thermal performances
An inductor module comprising one or several wound inductors in a metallic housing, held in place by potting compound, wherein a surface of the metallic housing is a mechanical and thermal interface to a heat sink, and the distance between the coils and the inner side of the surface is predetermined by a suitable insulating space of potting compound. The invention may be used as PFC inductor in an on-board vehicle charger, among other uses.
1 . An inductor module comprising:
at least one inductor comprising a winding on a magnetic core,
a housing enclosing said inductor in a cavity and having at least one thermal exchange surface fixable on a cooled plate,
at least one electric terminal for connecting said inductor to an external electrical network, wherein,
the cavity is partially filled with a potting compound, creating a thermal link between the inductor and the housing so that said inductor is at least partially surrounded by said potting compound, wherein the inductor module further comprising a lid of an insulating material over the housing, the lid having, above a free surface of the potting compound, a lower face with protrusions that reach downwards into the cavity below the free surface and are bonded to the potting compound holding the lid in position, wherein the winding has terminals that pass through holes traversing the lid and the protrusions, such that the protrusion create an insulated bushing around the terminals configured to increase a creepage distance between the inductor and the housing.
2 . The inductor module of claim 1 , wherein each cavity of the housing is configured to hold the potting compound in a fluid state during the assembly.
3 . The inductor module of claim 1 , wherein the thermal exchange face is the lowermost part of the housing.
4 . The inductor module of claim 1 , comprising two electric terminals configured as input terminal and output terminal, each consist of a contact plate on a top face of the lid.
5 . The inductor module of claim 1 wherein a thickness of potting compound between the inductor and the thermal exchange face is less than 5 mm, preferably less than 2 mm, more preferably less than 1 mm, but more than zero.
6 . The inductor module of claim 1 , wherein the thermal exchange face is opposed to an aperture of the housing closed by the lid.
7 . The inductor module of claim 1 , wherein the lid comprises at least one hole for pouring said potting compound in a fluid state during the assembly.
8 . The inductor module of claim 2 , wherein said potting compound is a synthetic curable resin.
9 . The inductor module of claim 1 , wherein the housing includes an aluminium die-cast part.
10 . The inductor module of claim 4 , wherein the plates are disposed on a top face of the lid opposed to the thermal exchange surface.
11 . The inductor module of claim 1 , wherein said at least one inductor is toroidal.
12 . A use of the inductor module of claim 1 in an electric or hybrid vehicle, for example in a power-factor correction unit of a battery charger.