Method for limiting a switch-on current in an electrical system

Patent metadata

Field	Value
Publication number	US-9236731-B2
Application number	US-201113813946-A
Country	US
Kind code	B2
Filing date	Jun 7, 2011
Priority date	Aug 4, 2010
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

The disclosure describes a method for limiting a switch-on current in an electrical system which is supplied with power by a battery. During a switch-on process, an electrical load is connected to the electrical system and precharged by means of a precharging resistor. A monitoring unit regularly records operating data of at least one variable which influences a temperature of the precharging resistor and estimates the temperature of the precharging resistor on the basis of said operating data. The disclosure also describes an apparatus and a battery which are designed to execute the method according to the disclosure.

First claim

The invention claimed is:

1. A method for limiting a switch-on current of a circuit configured to receive current from a battery, the method comprising:
connecting an electrical load to the battery during a switch-on operation;
pre-charging the electrical load via a pre-charging resistor during the switch-on operation;
regularly recording operating data including at least one variable that influences a temperature of the pre-charging resistor with a monitoring unit;
estimating the temperature of the pre-charging resistor based on the recorded operating data;
generating a warning signal in response to the estimated temperature of the pre-charging resistor exceeding a first temperature threshold value; and
preventing pre-charging of the electrical load via the pre-charging resistor in response to the estimated temperature of the pre-charging resistor exceeding a second temperature threshold value that is greater than the first temperature threshold value.

2. The method as claimed in claim 1 , the regularly recording further comprising:
regularly recording at least one of a current flowing through the pre-charging resistor, a voltage applied to the battery, a number of switch-on operations per unit time, a duration of a switch-on operation, and an ambient temperature.

3. The method as claimed in claim 1 , the estimating the temperature of the pre-charging resistor further comprising:
estimating the temperature of the pre-charging resistor based on a temperature model that predicts an inherent heating of the pre-charging resistor as a function of the recorded operating data.

4. A device for limiting a switch-on current of a circuit configured to receive current from a battery, the device comprising:
a connecting unit configured to connect an electrical load to the battery during a switch-on operation;
a pre-charging unit configured to pre-charge the electrical load via a pre-charging resistor during the switch-on operation;
a monitoring unit configured to regularly record operating data including at least one variable that influences a temperature of the pre-charging resistor;
an estimating unit configured estimate the temperature of the pre-charging resistor based on the recorded operating data; and
a protection unit configured to (i) generate a warning signal in response to the estimated temperature of the pre-charging resistor exceeding a first temperature threshold value and (ii) prevent pre-charging of the electrical load via the pre-charging resistor in response to the estimated temperature of the pre-charging resistor exceeding a second temperature threshold value that is greater than the first temperature threshold value.

5. The device as claimed in claim 4 , further comprising:
a control device,
wherein the control device includes the monitoring unit.

6. The device as claimed in claim 5 , wherein the control device and the battery are connected to a CAN field bus.

7. The device as claimed in claim 4 , wherein a first relay is connected in series with the pre-charging resistor and a second relay is connected in parallel to the first relay with the pre-charging resistor.

8. A battery comprising:
a pre-charging resistor configured to pre-charge an electrical load; and
a monitoring unit configured to:
regularly record operating data including at least one variable that influences a temperature of the pre-charging resistor;
estimate the temperature of the pre-charging resistor based on the recorded operating data; and
generate a warning signal in response to the estimated temperature of the pre-charging resistor exceeding a first temperature threshold value; and
prevent pre-charging of the electrical load via the pre-charging resistor in response to the estimated temperature of the pre-charging resistor exceeding a second temperature threshold value that is greater than the first temperature threshold value.

9. The battery as claimed in claim 8 , wherein the battery is configured (i) to connect an electrical load to the electrical network during a switch-on operation, and (ii) to pre-charge the electrical load via the pre-charging resistor during the switch-on operation.

Assignees

• Steck Armin
• Piscol Ralf
• Bosch Gmbh Robert

Inventors

• Steck Armin
• Piscol Ralf

Classifications

• B60L2270/20

  Inrush current reduction, i.e. avoiding high currents when connecting the battery · CPC title

• B60L2240/36

  Temperature of vehicle components or parts · CPC title

• B60L2250/10

  by alarm · CPC title

• B60L58/10

  for monitoring or controlling batteries · CPC title

• H02H9/001

  limiting speed of change of electric quantities, e.g. soft switching on or off (progressive control of electronic switches for eliminating interferences H03K17/16) · CPC title