Cooling device for cooling components of the power electronics, said device comprising a micro heat exchanger

Abstract

The present invention relates to a cooling device, in particular for cooling of components of power electronics, using a coolant which flows through a micro heat exchanger (10) having a good heat contact with the component (1), and wherein the coolant is selected in such a way that it evaporates in the micro heat exchanger (10) at the desired component temperature.

Description

BACKGROUND INFORMATION[0001] The present invention relates to a cooling device, in particular for cooling of components of power electronics, using a coolant which flows through a micro heat exchanger having a good heat contact with the component.[0002] Such a cooling device has been described in INT. J. Heat Mass Transfer, volume 37, No. 2, pages 321-332, 1994, by M. P. Bowers and I. Mudawar, under the title: "High flux boiling in low flow rate, low pressure drop mini-channel and micro-channel heat sinks."[0003] Generally, components or modules of power electronics, such as pulse-controlled inverters for example, are presently predominantly cooled using solid heat sinks made of aluminum or copper. Heat is dissipated here via a liquid coolant which flows through bore holes in the heat sinks.[0004] Alternative heat dissipation via boiling bath cooling is known for power electronics components. Heat is dissipated here by evaporation of an electrically non-conductive fluid, which has d...

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Benefits of technology

[0007] The object of the present invention is to design a cooling device, in particular for cooling of components of power electronics, in such a way which allows large heat flows to be dissipated on a small surface at low temperatures, and low weight of the heat exchanger utilized by using small amounts of coolants and where there is no contact between the coolant and the electronic components.[0008] The essence of the present invention is the combination of the phase transition for cooling the power electronics components, e.g., in evaporation cooling, and the utilization of a micro heat exchanger. Micro heat exchangers are patterns featuring channel systems having very small dimensions in the sub-millimeter range.[0009] The utilization of a micro heat exchanger offers several advantages:[0010] small dimensions along with low weight,[0011] large heat transfer surface of the channels for the coolant and thus good local cooling of the electronic components.[0012] Heat dissipation in micro heat exchangers usually takes place by heat transfer to a fluid flowing through.[0013] Important advantages result from a suitable coolant flowing through the micro heat exchanger, the coolant evaporating at the desired component temperature. Because of a plurality of flow-through channels, micro heat exchangers have a large heat transfer surface and, when a suitable coolant flows through them, are thus in the position to dissipate large heat flows at the desired temperature. In addition, the temperature difference along the cooling channels is smaller than in single-phase convective heat transfer because a large portion of the heat is transferred at the phase transition temperature. Thus, uniform temperature distribution takes place also in the area of the components to be cooled. Because of their small channel diameter micro heat exchangers are suitable for operation under high pressures. Sealing problems may also be solved more easily than in boiling bath cooling.

Problems solved by technology

The methods of cooling power electronics components, utilized hitherto, have disadvantages due to the large volumes and weights of the solid heat sinks, which are 30 mm thick, for example.

Because of the limited cooling effect of such solid heat sinks, large waste heat flows of the power electronics components result in a significant rise in component temperatures.

High component temperatures cause an inferior efficiency of the electronic components and may result in the destruction of the same.

By utilizing boiling bath cooling, this is only possible to a limited degree.

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