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MAXIMIZING THE LIFE TIME OF AN IGBT-MODULE

IP.com Disclosure Number: IPCOM000249830D
Publication Date: 2017-Apr-12
Document File: 5 page(s) / 96K

Publishing Venue

The IP.com Prior Art Database

Related People

Salmia Teemu: AUTHOR [+3]

Abstract

The novel method maximizes the life time of an IGBT-module in a cyclic use of a frequency converter. The life time of the IGBT-module can be maximized by keeping the cyclical variation of the temperature Tc of the bottom plate and of the temperature Tj in the joint between the bottom plate and the semiconductor as small as possible. This can be done by minimizing the maximum value Tj,max of the temperature Tj and by maximizing the minimum value Tj,min of the temperature Tj in a cycle. The novel method can be realized by actively regulating the flow rate of the cooling liquid of the frequency converter according to the loading of the frequency converter.

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Page 1 of 5  FI-1642901.1282

© Copyright [2017] ABB. All rights reserved.

MAXIMIZING THE LIFE TIME OF AN IGBT-MODULE

Abstract

The novel method maximizes the life time of an IGBT-module in a cyclic use of a

frequency converter. The life time of the IGBT-module can be maximized by keeping the

cyclical variation of the temperature Tc of the bottom plate and of the temperature Tj in

the joint between the bottom plate and the semiconductor as small as possible. This can

be done by minimizing the maximum value Tj,max of the temperature Tj and by

maximizing the minimum value Tj,min of the temperature Tj in a cycle.

The novel method can be realized by actively regulating the flow rate of the cooling liquid

of the frequency converter based on the loading of the frequency converter.

The regulation may be done without steps with a control valve or with steps with a

magnetic valve. Parallel channels for the flow of liquid may quickly be opened and closed

with magnetic valves. Already one valve (two parallel channels for the cooling liquid) can

result in a significant benefit. The response time of one or more magnetic valves is fast

compared to a control valve (in the order of 10 to 100 milliseconds). The method may be

used in a frequency converter provided with an active calculation of the temperature Tj

based on the power loss of the apparatus. The method may also be used in a frequency

converter where there is no calculation of temperature, but only the magnitude of e.g. the

output current is known. The flow rate of the cooling liquid may be regulated with a control

valve or with a magnetic valve to a maximum value when the loading of the frequency

converter is high (a great Tj value, a great power loss, a great output current etc.). This

will keep the maximum value Tj,max of the temperature Tj in a cycle at a minimum. The

flow rate of the cooling liquid may on the other hand be regulated to a minimum (or it may

be stopped completely) when the loading of the frequency converter is small (a small Tj

value, a small power loss, a small output current etc.). This will keep the minimum value

Tj,min of the temperature Tj in a cycle at a maximum. The cyclic variation of the

temperature Tj will thus remain as small as possible in a cyclic drive and the life time of

the IGBT-module (and at the same time also the life time of the frequency converter) will

be maximized.

Page 2 of 5  FI-1642901.1282

© Copyright [2017] ABB. All rights reserved.

Description of a prior art solution

A frequency converter is typically used in cyclic drives. Cyclic drives are e.g. drives in

means of transport, elevators, as well as different crane solutions. The first component to

brake in a cyclic drive frequency converter is a semiconductor such as the IGBT-module.

The life time of the IGBT-module is restricted by the different thermal expansion of

different materials in the IGBT-module, which is caused by temperature variations in the

pn-joint (Tj) between the bottom plate (Tc)...