SHORT DESCRIPTION OF THE DRAWINGS
In the following, the invention will be described in more detail by the aid of an embodiment with reference to the attached drawings, wherein
FIG. 1 presents the transfer of dissipation power to a prior-art air cooler.
FIG. 2 presents the transfer of dissipation power to an air cooler according to the invention.
FIG. 3 presents a perspective drawing of the cooling appliance of a frequency converter according to the invention, and
FIG. 4 presents another cooling appliance of a frequency converter according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 presents how the dissipated power transfers to the cooler in a prior-art air cooler 1. Dissipated power is generated in the power semiconductor piece 3 contained in the power module 2, from where it transfers inside the cooler as is well known at a certain angle towards the cooling fins. Thus only a certain part of the array of fins of the cooler functions effectively (shaded part 4).
FIG. 2 presents the principle of the cooling solution according to the invention. In the figure a pipe 4 containing liquid is disposed in the shared metal frame 1 under the power module, which pipe transfers the dissipated power of the power semiconductor piece 3 to the condenser part 5, of which the whole cooling surface area is utilized since the liquid pipe extends to the whole finned area.
FIG. 3 presents a practical embodiment of a cooling appliance of a frequency converter according to the invention for cooling the power components 10 of the power stage, typically power semiconductor switches, e.g. IGBTs. In the appliance the frame part of the cooling solution is an integral right-angled metal part 11, in which are face surfaces 111, of which semiconductor switches are situated on one, end surfaces 112, and side surfaces 113, and in which one half functions as a cooler 12, with which the transfer of thermal power from the power components to the liquid is achieved, and the other half as a condenser 13, by means of which the transfer of thermal power from the liquid into the air is achieved (so-called primary cooling), and inside which are parallel and longitudinal (see the arrow between the cooler part and the condenser part) channels 15, provided with a turbulator 14, for arranging enclosed cooling liquid circulation between the ends, in which case a liquid circulation is achieved inside the cooler. In addition to the channels, an expansion tank can be disposed e.g. at the end of the condenser. The liquid can be water, which is circulated with a pump 16, which contains a frame part 17, which is connected at its side surface to the side of the metal frame 11 of the appliance.
The liquid can also be water under low pressure, which boils in the cooling part and liquefies by means of the heating pipes and the heating appliance in the condenser part, and in which the liquid/vapour circulation between the parts occurs without a pump. The liquid/vapour circulation can also be implemented in another manner suited to the purpose.
A metallic array of fins 17 is joined to one of the face surfaces or to both face surfaces (top and bottom surfaces) of the condenser part 13 for transferring dissipated power to the air duct under the force of the fan. Alternatively e.g. a separate liquid element can be connected to the condenser part for transferring thermal power to an external liquid circulation.
FIG. 4 presents another embodiment of a cooling appliance according to the invention, which has two right-angled frame parts 21 and 31, on which are face surfaces 211, 311, end surfaces 212, 312 and side surfaces 213, 313, and in which the frame parts are joined tightly together at the end surface 212 of one part and at the face surface 311 of the other part, and in both of which frame parts is cooling piping on the inside such that when joined together they form an integral cooling piping. IGBTs are arranged on the face surface of one frame part, which functions as a cooler, and a cooling array of fins to the other face surface of the other frame part, which can be comprised of two different fin array parts 27, 37, and which thus functions as a condenser.
It is obvious to the person skilled in the art that the different embodiments of the invention are not limited solely to the example described above, but that they may be varied within the scope of the claims presented below. Also other condenser solutions (so-called secondary cooling) can be used instead of a cooling array of fins. The solution according to the invention enables variation of the secondary cooling appliance, depending on the application and the usage site, at the latest possible stage, and no separate structures for secondary cooling are needed in the solution according to the invention.
Patent Application
20080078529
