Insulation resistance measuring device and method

Patent metadata

Field	Value
Publication number	US-10324119-B2
Application number	US-201615531141-A
Country	US
Kind code	B2
Filing date	Mar 10, 2016
Priority date	Mar 10, 2015
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

The present disclosure relates to an insulation resistance measuring device and method, including a parameter resistance connected to a negative electrode terminal of a battery; a shunt resistance connectable to the parameter resistance; a current detection circuit including an operational amplifier configured to detect and output voltage between both ends of the shunt resistance; and a control unit configured to determine the insulation resistance of the battery using a switch control terminal configured to control a switch connected between the parameter resistance and the shunt resistance to an ON or OFF state, a detection signal output terminal configured to selectively apply a first high voltage signal and a first low voltage signal to the shunt resistance, a control signal output terminal configured to apply a control voltage signal to the operational amplifier to adjust an output voltage of the operational amplifier within a predetermined range, an ADC connected to an output terminal of the operational amplifier, and a predefined insulation resistance formula that includes, as a parameter, a first voltage change amount with respect to the output voltage of the operational amplifier being measured through the ADC when the first high voltage signal and the first low voltage signal are applied to the shunt resistance.

First claim

What is claimed is:

1. A device for measuring insulation resistance of a battery, the device comprising:
a parameter resistance of which one end is electrically connected to a negative electrode terminal of the battery;
a current detection circuit including a shunt resistance connectable to the parameter resistance to enable at least a portion of leakage current of the battery flowing in the parameter resistance to flow, and an operational amplifier connected to both terminals of the shunt resistance and configured to detect and output voltage between both ends of the shunt resistance; and
a control unit configured to determine the insulation resistance of the battery using a switch control terminal configured to control a switch connected between the parameter resistance and the shunt resistance to an ON or OFF state, a detection signal output terminal configured to selectively apply a first high voltage signal and a first low voltage signal to the shunt resistance, a control signal output terminal configured to apply a control voltage signal to the operational amplifier to adjust an output voltage of the operational amplifier within a predetermined range, an ADC connected to an output terminal of the operational amplifier, and a predefined insulation resistance formula that includes, as a parameter, a first voltage change being a difference of voltages being applied to both terminals of the shunt resistance amount when the first high voltage signal and the first low voltage signal are applied to the shunt resistance.

2. The device of claim 1 , wherein the control signal output terminal includes a first and second control signal output terminal configured to selectively output a second high voltage signal and a second low voltage signal,
the current detection circuit includes a first and second control resistance connected to the first and second control signal output terminal, respectively, and
the first and second control resistance are connected parallel to each other, and one end thereof is connected to an inverting terminal of the operational amplifier.

3. The device of claim 2 , wherein the current detection circuit further comprises a first connecting resistance configured to connect one end of the shunt resistance to a non-inverting terminal of the operational amplifier, and a second connecting resistance configured to connect the other end of the shunt resistance to the inverting terminal of the operational amplifier.

4. The device of claim 2 , wherein the control unit is configured to apply the first high voltage signal and the first low voltage signal to the shunt resistance at time intervals through the detection signal output terminal, in a state where a switch is controlled to an ON state, and to measure the first voltage change amount with respect to the output voltage of the operational amplifier through the ADC, when the first high voltage signal and the first low voltage signal are being applied to the shunt resistance.

5. The device of claim 4 , wherein the control unit is configured to apply a third high voltage signal and a third low voltage signal to the shunt resistance at time intervals through the detection signal output terminal, in a state where the switch is controlled to an OFF state, to determine a second voltage change amount being a difference of voltages being applied to both terminals of the shunt resistance when the third high voltage signal and the third low voltage are being applied to the shunt resistance, to determine a third voltage change amount corresponding to a difference between the first voltage change amount and the second voltage change amount, and to determine the insulation resistance of the battery using the predefined insulation resistance formula that includes the third voltage change amount as a parameter.

6. The device according to claim 5 , wherein the control unit is configured to selectively apply the second high voltage signal or the second low voltage signal to the first control resistance and the second control resistance through the first and second control signal output terminal until the output voltage of the operational amplifier being measured through the ADC belongs to a predetermined operating voltage range of the ADC, when the output voltage does not belong to the predetermined operational voltage range.

7. The device according to claim 5 , wherein the predefined insulation resistance formula further comprises as a parameter a control voltage change amount being a difference of voltages being applied to an equivalent resistance of the first control resistance and the second control resistance according to a level of the voltage signal being output through the first and second control signal output terminal, when a high voltage signal and a low voltage signal are being applied to the shunt resistance through the detection signal output terminal.

8. The device according to claim 4 , wherein the control unit is configured to selectively apply a second high voltage signal or a second low voltage signal to the first control resistance and the second control resistance through the first and second control signal output terminal until the output voltage of the operational amplifier being measured through the ADC belongs to a predetermined operating voltage range of the ADC, when the output voltage does not belong to the predetermined operational voltage range.

9. The device according to claim 4 , wherein the predefined insulation resistance formula further comprises as a parameter a control voltage change amount being a difference of voltages being applied to an equivalent resistance of the first control resistance and the second control resistance according to a level of the voltage signal being output through the first and second control signal output terminal, when a high voltage signal and a low voltage signal are being applied to the shunt resistance through the detection signal output terminal.

10. The device of claim 2 , wherein the control unit is configured to selectively apply the second high voltage signal or the second low voltage signal to the first control resistance and the second control resistance through the first and second control signal output terminal.

11. The device of claim 1 , further comprising a memory unit configured to store a resistance value of the insulation resistance therein.

12. The device of claim 1 , wherein the control unit is configured to output a resistance value of the insulation resistance to an external control device.

13. A method for measuring insulation resistance of a battery using a parameter resistance connected to a negative electrode terminal of the battery, a shunt resistance, a switch installed between the parameter resistance and the shunt resistance, an operational amplifier connected to both terminals of the shunt resistance and a control resistance coupled to at least one of input terminals of the operational amplifier so that an output voltage of the operational amplifier may be controlled, the method comprising:
(a) controlling the switch to an ON state;
(b) measuring the output voltage of the operational amplifier when a first high voltage signal and a first low voltage signal are applied to the shunt resistance at time intervals;
(c) applying a control voltage signal to one end of the control resistance to control the output voltage of the operational amplifier to be included within a predetermined range;
(d) determining a first voltage change amount with respect to the output voltage of the operational amplifier, the first voltage change amount being a difference of voltages being applied to both terminals of the shunt resistance when the first h

Assignees

• Lg Chemical Ltd

Inventors

• Choi Ho-Been

Classifications

• G01R31/385

  Arrangements for measuring battery or accumulator variables (for monitoring G01R31/382) · CPC title

• G01R27/18

  Measuring resistance to earth {, i.e. line to ground} · CPC title

• G01R15/09

  Autoranging circuits · CPC title

• G01R31/12

  Testing dielectric strength or breakdown voltage {; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing (G01R31/08, G01R31/327 and G01R31/72 take precedence; measuring in plasmas G01R19/0061; measuring dielectric constants G01R27/2617; ESD, EMC or EMP testing of circuits G01R31/002)} · CPC title

• G01R19/15

  Indicating the presence of current · CPC title