Method for monitoring the state of the earthing contacts of a contactor controllable by means of an exciter coil

Patent metadata

Field	Value
Publication number	US-10242828-B2
Application number	US-201515300870-A
Country	US
Kind code	B2
Filing date	Mar 23, 2015
Priority date	Apr 4, 2014
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

The present invention relates to a method for monitoring the state of the earthing contacts of a contactor controlled by an exciter coil, said contactor being operated as part of an isolation unit for galvanically isolating a voltage source from an electric consumer device connected to the voltage source, wherein a first power loss ( 22 ), which is transferred via the earthing contacts, and a second power loss ( 23 ), which is transferred via the exciter coil, are detected, and the first power loss ( 22 ) and the second power loss ( 23 ) are fed as input variables to a thermal model ( 21 ) of the contactor, the thermal model ( 21 ) determines an earthing contact temperature ( 24 ) according to at least one of the input variables and provides said contactor temperature as an output variable, and the provided earthing contact temperature ( 24 ) is evaluated.

First claim

The invention claimed is:

1. A method for monitoring the state of earthing contacts ( 4 ) of a contactor ( 3 ) controllable by an exciter coil ( 5 ), said contactor operated as part of an isolation unit ( 2 ) for galvanically isolating a voltage source from an electric consumer device connected to the voltage source, the method comprising:
calculating a first power loss ( 22 ), transferred via the earthing contacts ( 4 ) by a computing unit subtracting a measured link voltage ( 14 ) from a measured pack voltage ( 13 ); and multiplying the difference by a measured pack current ( 17 ), and
calculating a second power loss ( 23 ), transferred via the exciter coil ( 5 ) by the computing unit multiplying a measured coil voltage ( 15 , 16 ) by a measured coil current ( 18 , 19 ),
feeding the first power loss ( 22 ) and the second power loss ( 23 ) as input variables to a thermal model ( 21 ) of the contactor ( 3 ),
the thermal model ( 21 ) determining an earthing contact temperature ( 24 ) based on at least one of the input variables and provides said earthing contact temperature as an output variable, and the provided earthing contact temperature ( 24 ) is evaluated.

2. The method according to claim 1 , wherein a correction variable ( 30 ) is fed as a further input variable to the thermal model ( 21 ), said correction variable being taken into account when the thermal model ( 21 ) determines the earthing contact temperature ( 24 ).

3. The method according to claim 1 , wherein the thermal model ( 21 ) determines a first exciter coil temperature ( 25 ) according to at least one of the input variables and provides said exciter coil temperature as a further output variable and that a second exciter coil temperature ( 29 ) is determined independently of the thermal model ( 21 ), wherein a difference is formed between the first exciter coil temperature ( 25 ) and the second exciter coil temperature ( 29 ), and the difference is fed as a correction variable ( 30 ) to the thermal model.

4. The method according to claim 3 , wherein the electrical resistance of the exciter coil ( 5 ) is determined and the second exciter coil temperature ( 29 ) is determined as a function of the determined resistance.

5. The method according to claim 3 , wherein an exciter coil voltage ( 27 ), which drops across the exciter coil ( 5 ), and an exciter coil current ( 28 ), which flows through the exciter coil ( 5 ), are determined; the exciter coil voltage ( 27 ) and the exciter coil current ( 28 ) are fed as input variables to a resistance model ( 26 ); the resistance model ( 26 ) determines an exciter coil resistance from the supplied input variables, and the second exciter coil temperature ( 29 ) is determined as a function of the exciter coil resistance and is provided as an output variable.

6. The method according to claim 5 , wherein the resistance model ( 26 ) is initially calibrated offline, wherein the input variables of the resistance model ( 26 ) are varied and the exciter coil temperatures occurring in each case are acquired using measuring technology.

7. The method according to claim 1 , wherein the thermal model ( 21 ) is initially calibrated offline, wherein operating parameters are varied and the earthing contact temperatures occurring in each case or the earthing contact temperatures occurring in each case and the exciter coil temperatures are acquired using measuring technology.

8. The method according to claim 7 , wherein the electric voltages and/or electric currents influencing the first power loss ( 22 ) and/or the second power loss ( 23 ) as operating parameters are varied.

9. The method according to claim 5 , wherein earthing contact temperatures and/or exciter coil temperatures acquired within the scope of the calibration together with the operating parameters and/or the input variables set thereby in each case are stored as values, and said values are associated with one another.

10. The method according to claim 1 , wherein the evaluation of the provided earthing contact temperature ( 24 ) comprises a threshold value comparison ( 33 ), wherein an action is triggered when a predefined threshold value ( 34 ) has been exceeded ( 36 ).

Assignees

• Bosch Gmbh Robert

Inventors

• Cois Olivier

Classifications

• B60L2270/145

  Structure borne vibrations · CPC title

• B60L2240/547

  Voltage · CPC title

• G01K7/427

  Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation · CPC title

• B60L3/04

  Cutting off the power supply under fault conditions (protective devices and circuit arrangements in general H01H; H02H) · CPC title

• B60L3/0046

  relating to electric energy storage systems, e.g. batteries or capacitors · CPC title