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IMPROVED HEAT SINK STRUCTURE FOR DYNAMIC BRAKE

IP.com Disclosure Number: IPCOM000235900D
Publication Date: 2014-Mar-28
Document File: 4 page(s) / 116K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention includes an improved heat sink structure for dynamic brakes. The heat sink used on the dynamic brake IGBTs uses an air-cooled copper technology. The initial temperature starts at an air temperature, such as, 40 degree Celsius (C), which is much lower than the coolant temperature. The proposed heat sink has high thermal resistance for long continuous IGBT power dissipation. The proposed heat sink has high thermal mass, which is more important for the short time of dynamic brake operation.

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IMPROVED HEAT SINK STRUCTURE FOR DYNAMIC BRAKE

BACKGROUND

The present invention relates generally to a heat sink and more particularly to an improved heat sink structure for dynamic brakes.

In general, dynamic brake insulated gate bipolar transistors (IGBT) are typically off, with no power dissipation. When the IGBTs need to operate, the dynamic brake IGBT operates for a very short period of time with extreme power dissipation. The dynamic brakes are limited by delta T, starting at an initial heat sink temperature, and becomes necessary to shut-off when junction temperature reaches its limit. Since, IGBT operates for a short time period, typically less than 1 second, low thermal resistance is important only for the first half second. This implies that thermal mass of heat sink is more important than thermal resistance.

A conventional heat sink technique used for dynamic brakes IGBTs includes liquid-cooled aluminum technology. However, the technique has several problems. Figure 1 depicts conventional IGBT or heat sink structure for dynamic brakes.

Figure 1

As illustrated in the above figure, the two main characteristics of conventional technique are both limitations for a dynamic brake.  Firstly, initial temperature starts at the coolant temperature, which starts at a relatively high temperature, such as, 60 degree Celsius(C). Secondly, the dynamic brake has low thermal resistance for long continuous IGBT power dissipation, but relatively low thermal mass.    

Therefore there is a need in the art for a new heat sink structure that is used for dynamic brakes.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts conventional IGBT or heat sink structure for dynamic brakes.

Figure 2 depicts proposed IGBT or heat sink structure for dynamic brakes.

DETAILED DESCRIPTION

The present invention includes an improved heat sink structure for dynamic brakes. The heat sink used on the dynamic brake IGBTs uses an air-cooled copper technology. The proposed heat sink structure overcomes limitations of conventional liquid-cooled aluminum heat sink.

Figure 2 depicts proposed IGBT or heat sink structure for dynamic brakes.

Figure 2

As illustrated in the figure abov...