Voltage detecting device and battery pack monitoring system

Patent metadata

Field	Value
Publication number	US-10094883-B2
Application number	US-201615378271-A
Country	US
Kind code	B2
Filing date	Dec 14, 2016
Priority date	May 9, 2016
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A voltage detecting device detects a differential voltage between two input nodes having a non-zero common mode voltage. A differential voltage detecting circuit 5 detects the differential voltage by sampling each voltage of the input nodes and outputs a detection voltage indicating a detection result. A leak canceling circuit generates a compensating current, which flows in opposition to a leak current flowing out from the input nodes in correspondence to an operation of the differential voltage detecting circuit. An operation control part controls the leak canceling circuit to perform or stop a canceling operation. A failure diagnosing part performs a failure diagnosis about the leak canceling circuit based on a first detection value and a second detection value of the detection voltages, which are detected during periods when the leak canceling circuit performs and stops the canceling operation.

First claim

What is claimed is:

1. A voltage detecting device for detecting a differential voltage between two input nodes having a common mode voltage, which is not zero, the voltage detecting device comprising:
a differential voltage detecting circuit for detecting the differential voltage by sampling each voltage of the two input nodes and for outputting a detection voltage indicating a detection result;
a leak canceling circuit for generating a compensating current, which flows in an opposite direction to a leak current leaking from two input node sides due to an operation of the differential voltage detecting circuit;
an operation control part for controlling the leak cancelling circuit to perform or stop a leak cancelling operation; and
a failure diagnosing part for performing a failure diagnosis about the leak canceling circuit based on a difference between a first detection value and a second detection value, the first detection value and the second detection value indicating values of the detection voltages detected in periods, during which the leak canceling circuit is controlled to perform and stop the leak canceling operation, respectively.

2. The voltage detecting device according to claim 1 , wherein:
the failure diagnosing part determines that the leak canceling circuit is falling when the difference between the first detection value and the second detection value is smaller than a predetermined lower limit reference value.

3. The voltage detecting device according to claim 2 , wherein:
the failure diagnosing part determines that the leak canceling circuit is failing when the difference between the first detection value and the second detection value is larger than a predetermined upper limit reference value larger than the lower limit reference value.

4. The voltage detecting device according to claim 1 , further comprising:
an inspection voltage application part for applying a predetermined inspection voltage between the input nodes to be detected as the differential voltage by the differential voltage detecting circuit,
wherein the failure diagnosing part performs the failure diagnosis about the leak canceling circuit based on a value of the detection voltage detected in a period, during which the inspection voltage is applied between the input nodes with the leak canceling circuit being controlled to perform the leak canceling operation by the operation control part.

5. The voltage detecting device according to claim 4 , wherein:
the failure diagnosing part determines that the leak canceling circuit is falling when the value of the detection voltage is outside a predetermined range, which is determined based on a voltage value of the inspection voltage.

6. The voltage detecting device according to claim 1 , wherein:
the failure diagnosing part performs the failure diagnosis at time of activation of the voltage detecting device.

7. The voltage detecting device according to claim 1 , wherein:
the failure diagnosing part repeats the failure diagnosis at every elapse of a predetermined period after activation of the voltage detecting device.

8. A battery pack monitoring system for monitoring a voltage of each battery cell forming a battery pack, the battery pack monitoring system comprising:
the voltage detecting device according to claim 1 ; and
a filter provided between two terminals of the each battery cell and the two input nodes of the voltage detecting device; and
an A/D converter for converting the detection voltage outputted from the differential voltage detecting circuit into digital data,
wherein the voltage detecting device detects the differential voltage of each battery cell by oversampling detection method.

9. The voltage detecting device according to claim 8 , wherein:
the voltage detecting device detects the differential voltage of either one of battery cells.

10. The voltage detecting device according to claim 1 , wherein:
the voltage detecting device detects a voltage of a block of a predetermined number of battery cells.

11. The voltage detecting device according to claim 1 , wherein:
the leak canceling circuit includes a D/A converter for converting the digital data outputted from the A/D converter into an analog voltage and generates the compensating current by using the analog voltage;
a switchover part for selectively applying either one of the detected voltage and the analog voltage to the A/D converter; and
a test data inputting part for inputting predetermined test data to the D/A converter in place of the digital data;
the failure diagnosing part performs a failure diagnosis about the D/A converter based on the digital data when the predetermined test data is inputted to the D/A converter and the analog voltage is inputted to the A/D converter by the switchover part.

12. A voltage detecting device for detecting a differential voltage between two input nodes having a common mode voltage, which is not zero, the voltage detecting device comprising:
a differential voltage detecting circuit for detecting the differential voltage by sampling each voltage of the two input nodes and for outputting a detection voltage indicating a detection result;
a leak canceling circuit for generating a compensating current, which flows in an opposite direction to a leak current leaking from two input node sides due to an operation of the differential voltage detecting circuit;
an inspection voltage application part for applying a predetermined inspection voltage between the input nodes; and
a failure diagnosing part for performing a failure diagnosis about the leak canceling circuit based on a value of the detection voltage detected in a period, during which the inspection voltage is applied between the input nodes.

Assignees

• Denso Corp

Inventors

• Yamamoto Shunya
• Honda Kazutaka
• Tomonaga Yukihiro
• Miura Ryotaro

Classifications

• G01R22/00

  Arrangements for measuring time integral of electric power or current, e.g. electricity meters · CPC title

• G01R13/38

  using the steady or oscillatory displacement of a light beam by an electromechanical measuring system · CPC title

• G01R11/465

  Oscillatory meters · CPC title

• H01Q1/2233

  used in consumption-meter devices, e.g. electricity, gas or water meters · CPC title

• G01R31/3658 Primary

  Physics · mapped topic