Insulation resistance detection circuit, detection method, and detection apparatus

Patent metadata

Field	Value
Publication number	US-11243259-B2
Application number	US-201916673666-A
Country	US
Kind code	B2
Filing date	Nov 4, 2019
Priority date	May 3, 2017
Publication date	Feb 8, 2022
Grant date	Feb 8, 2022

Abstract

An insulation resistance detection circuit, detection method, and detection apparatus are provided. The circuit includes an alternating-current signal source, a resonant cavity, a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, and a second switch. The alternating-current signal source is sequentially connected to the first resistor, the resonant cavity, the first switch, the second resistor, and the third resistor in series to form a loop. The first resistor is connected to a positive electrode of the alternating-current signal source, and the third resistor is connected to a negative electrode of the alternating-current signal source. One end of the second switch is connected to a negative electrode of a to-be-detected battery, the other end of the second switch is connected to the fourth resistor, and the other end of the fourth resistor is connected to ground.

First claim

What is claimed is:

1. An insulation resistance detection circuit, comprising:
an alternating-current signal source, a resonant cavity, a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, and a second switch; and
a first voltage sampling unit and a second voltage sampling unit, wherein the first voltage sampling unit is connected to the first resistor in parallel, to detect a voltage at two ends of the first resistor; and the second voltage sampling unit is connected to the third resistor in parallel, to detect a voltage at two ends of the third resistor, wherein
the alternating-current signal source is sequentially connected to the first resistor, the resonant cavity, the first switch, the second resistor, and the third resistor in series to form a loop, wherein the first resistor is connected to a positive electrode of the alternating-current signal source, and the third resistor is connected to a negative electrode of the alternating-current signal source;
a positive electrode of a to-be-detected battery is connected between the first switch and the resonant cavity, and the negative electrode of the alternating-current signal source is connected to ground;
one end of the second switch is connected to a negative electrode of the to-be-detected battery, the other end of the second switch is connected to the fourth resistor, and the other end of the fourth resistor is connected to the ground;
the resonant cavity comprises a capacitor and an inductor that are connected in series, and
when the to-be-detected battery is detected, the alternating-current signal source is configured to provide an alternating-current signal.

2. The insulation resistance detection circuit according to claim 1 , further comprising a fifth resistor and a third switch, wherein
the fifth resistor is connected between the alternating-current signal source and the resonant cavity in series, and the third switch is connected to two ends of the fifth resistor in parallel.

3. An insulation resistance detection circuit, comprising:
an alternating-current signal source, a resonant cavity, a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, and a second switch,
a first voltage sampling unit and a second voltage sampling unit, wherein the first voltage sampling unit is connected to the first resistor in parallel, to detect a voltage at two ends of the first resistor; and the second voltage sampling unit is connected to the third resistor in parallel, to detect a voltage at two ends of the third resistor, wherein
the alternating-current signal source is sequentially connected to the first resistor, the resonant cavity, the first switch, the second resistor, and the third resistor in series to form a loop, wherein the first resistor is connected to a positive electrode of the alternating-current signal source, and the third resistor is connected to a negative electrode of the alternating-current signal source;
a negative electrode of a to-be-detected battery is connected between the first switch and the resonant cavity, and the negative electrode of the alternating-current signal source is connected to ground;
one end of the second switch is connected to a positive electrode of the to-be-detected battery, the other end of the second switch is connected to the fourth resistor, and the other end of the fourth resistor is connected to the ground;
the resonant cavity comprises a capacitor and an inductor that are connected in series, and
when the to-be-detected battery is detected, the alternating-current signal source is configured to provide an alternating-current signal.

4. The insulation resistance detection circuit according to claim 3 , further comprising a fifth resistor and a third switch, wherein
the fifth resistor is connected between the alternating-current signal source and the resonant cavity in series, and the third switch is connected to two ends of the fifth resistor in parallel.

5. An insulation resistance detection apparatus comprising:
a processor configured to:
control the alternating-current signal source to provide an alternating-current signal,
detect a voltage of a first resistor;
construct an equation based on the alternating-current signal and the voltage of the first resistor;
obtain an insulation resistance parallel value and a parasitic capacitance parallel value of a to-be-detected battery; and
determine, based on the insulation resistance parallel value, whether an insulation failure occurs on the to-be-detected battery, wherein the insulation failure occurs when the insulation resistance parallel value is less than half of the resistance threshold.

6. The apparatus according to claim 5 , wherein the processor is further configured to:
determine that no insulation failure occurs on the to-be-detected battery, wherein the insulation resistance parallel value is greater than a reset resistance threshold.

7. The apparatus according to claim 5 , wherein the processor is further configured to:
control to disconnect a first switch and a second switch;
control the alternating-current signal source to inject a sine signal with a frequency ω 1 and an amplitude value U s , and detect that a voltage at two ends of the first resistor is U m1 ; and
control the alternating-current signal source to inject a sine signal with a frequency ω 2 and an amplitude value U s , and detect that a voltage at the two ends of the first resistor is U m2 ; and
wherein the constructing an equation based on the alternating-current signal and the voltage of the first resistor, and obtaining an insulation resistance parallel value and a parasitic capacitance parallel value of a to-be-detected battery comprises:
constructing an equation (1) based on U s and U m1 :



U

m
⁢

⁢
1



=

R
r

⁢

(

ω
1

⁢

⁢

C
b

⁢

R
b

)

2

+

1
2

(

Assignees

• Huawei Tech Co Ltd

Inventors

• Tong Wenping
• Zhou Kui
• Wang Wencheng

Classifications

• G01R27/025 Primary

  Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters · CPC title

• G01R31/385

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

• G01R31/389 Primary

  Measuring internal impedance, internal conductance or related variables · CPC title

• G01R27/02

  Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) · CPC title

• G01R31/3648

  comprising digital calculation means, e.g. for performing an algorithm · CPC title