Hybrid circuit breaker with improved current capacity per device size

Patent metadata

Field	Value
Publication number	US-12586739-B2
Application number	US-202017626507-A
Country	US
Kind code	B2
Filing date	Jul 9, 2020
Priority date	Jul 16, 2019
Publication date	Mar 24, 2026
Grant date	Mar 24, 2026

Abstract

A hybrid circuit breaker includes: input connectors configured to receive electrical energy from a power grid; output connectors configured to transfer electrical energy to a load; current paths, each connecting a respective input connector, of the input connectors, and a respective output connector, of the output connectors; an electro-mechanical bypass switch in at least one of the current paths; a semiconductor circuit in parallel with the electro-mechanical bypass switch; a controller configured to control a commutation from the current path in which the electro-mechanical bypass switch is arranged to the semiconductor circuit in a switching operation; and an active cooling device in a vicinity of the electro-mechanical bypass switch. The active cooling device is adopted to cool movable parts of the electro-mechanical bypass switch.

First claim

The invention claimed is:

1 . A hybrid circuit breaker, the hybrid circuit breaker comprising:
input connectors configured to receive electrical energy from a power grid; output connectors configured to transfer electrical energy to a load; current paths, each connecting a respective input connector, of the input connectors, and a respective output connector, of the output connectors; an electro-mechanical bypass switch in at least one of the current paths; a semiconductor circuit in parallel with the electro-mechanical bypass switch; a controller configured to control a commutation from the at least one current path in which the electro-mechanical bypass switch is arranged to the semiconductor circuit in a switching operation; and an active cooling device in a direct vicinity of the electro-mechanical bypass switch, the active cooling device being adapted to cool movable parts of the electro-mechanical bypass switch, wherein the hybrid circuit breaker is configured to satisfy:

A
<

n
·

0.25
·

I
cu

di

wherein A is an active chip area of the semiconductor circuit in cm 2 , n is a number of power switching elements in the semiconductor circuit, I cu is a short circuit current switching capacity of the hybrid circuit breaker in Ampere, and di is a current density of a single power switching element in A/cm 2 .

2 . The hybrid circuit breaker according to claim 1 , wherein the active cooling device comprises a fan, and
wherein the hybrid circuit breaker comprises air ducts configured to guide an air stream caused by the fan over a fixed switching contact and a movable switching contact of the electro-mechanical bypass switch.

3 . The hybrid circuit breaker according to claim 1 , wherein a varistor is switched in parallel with the electro-mechanical bypass switch, and
wherein the hybrid circuit breaker is configured to satisfy:

V
<

2.54
·

10

-
2

[
HA
]

·

I
cu

dE

wherein V is a volume of the varistor in cm 3 , I cu is a short circuit current switching capacity of the hybrid circuit breaker in Ampere, and dE is an energy density of the varistor in J/cm 3 , wherein the energy density dE refers to an effective volume of the varistor.

4 . The hybrid circuit breaker according to claim 1 , wherein the active cooling device comprises a fan placed in a direct vicinity of a fixed switching contact and a movable switching contact of the electro-mechanical bypass switch.

5 . The hybrid circuit breaker according to claim 4 , wherein the active cooling device is arranged such that a distance between the fan and the movable switching contact of the electro-mechanical bypass switch is less than 20 mm and is configured to guide an air stream of the fan directly over the movable switching contact.

6 . The hybrid circuit breaker according to claim 5 , wherein the active cooling device includes a housing and the electro-mechanical bypass switch includes a base body, and wherein the housing is attached to the base body such that the housing and base body together direct the air stream of the active cooling device over the movable switching part.

7 . A method for operating a hybrid circuit breaker, the hybrid circuit breaker comprising:
input connectors configured to receive electrical energy from a power grid; output connectors configured to transfer electrical energy to a load; current paths each connecting a respective input connector, of the input connectors, and a respective output connector, of the output connectors; an electro-mechanical bypass switch in at least one of the current paths; a semiconductor circuit in parallel with the electro-mechanical bypass switch; a controller configured to control a commutation from the at least one current path, in which the electro-mechanical bypass switch is arranged, to the semiconductor circuit in case of a switching operation; and an active cooling device arranged in a direct vicinity of the electro-mechanical bypass switch, the method comprising:
operating the active cooling device to actively cool movable parts of the electro-mechanical bypass switch,
wherein the hybrid circuit breaker is configured to satisfy:
A<n· 0.25· I cu /di

wherein A is an active chip area of the semiconductor circuit in cm 2 , n is a number of power switching elements in the semiconductor circuit, I cu is a short circuit current switching capacity of the hybrid circuit breaker in Ampere, and di is a current density of a single power switching element in A/cm 2 .

8 . The method as claimed in claim 7 , wherein a thermal coupling between the active cooling device and the electro-mechanical bypass switch is higher than a thermal coupling between the active cooling device and the semiconductor circuit.

9 . The method as claimed in claim 7 , wherein the active cooling device of the hybrid circuit breaker is in its on-state when the electro-mechanical bypass switch is closed.

10 . The method as claimed according to claim 7 wherein the active cooling device is in its on-state >90% of the operating time of the hybrid circuit breaker.

11 . The method as claimed according to claim 7 , wherein the active cooling device generates a flow of a cooling fluid when the electro-mechanical bypass switch is closed and/or >90% of the operating time of the hybrid circuit breaker.

12 . The method as claimed according to claim 7 , wherein the active cooling device is in its on-state at least in a current range reaching from 90% to 100% of a tripping current of the hybrid circuit breaker.

13 . The method as claimed according to claim 7 , wherein the active cooling device is in its on-state at least in a current range reaching from a nominal current of the hybrid circuit breaker to a tripping current of the hybrid circuit breaker.

14 . The method as claimed according to claim 7 , wherein a cooling power of the active cooling device is increased when a current over the electro-mechanical bypass switch increases and/or when current-time characteristics change over to more robust ones.

15 . The method as claimed according to claim 7 , wherein an air stream of the active cooling device, which comprises a fan, is increased before the electro-mechanical bypass switch is closed.

16 . The method as claimed according to claim 7 , wherein a time span between a time point, at which an electrical fault occurs, and a time point, at which a current flowing over the semiconductor circuit drops to zero, is <450 μs.

17 . A hybrid circuit breaker, the hybrid circuit breaker comprising:
input connectors configured t

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Askan Kenan

Classifications

• H02J3/36

  Arrangements for transfer of electric power between AC networks via high-voltage DC [HVDC] links; Arrangements for transfer of electric power between generators and networks via HVDC links · CPC title

• H01H2009/546

  the static switching means being triggered by the voltage over the mechanical switch contacts · CPC title

• H01H9/542

  Contacts shunted by static switch means · CPC title

• H01H1/62

  Heating or cooling of contacts · CPC title

• H02H7/222

  for switches · CPC title