US 10,890,612 B2
Insulation resistance measuring device
Pao Hung Lin, New Taipei (TW); Po Shen Chen, New Taipei (TW); Kuo Ho Cheng, New Taipei (TW); Ming Chun Chang, New Taipei (TW); and Tsai Fu Lin, New Taipei (TW)
Assigned to Foxlink Automotive Technology (Kunshan) Co., Ltd., Kun Shan (CN)
Filed by Foxlink Automotive Technology (Kunshan) Co., Ltd., Kun Shan (CN)
Filed on Dec. 10, 2018, as Appl. No. 16/215,572.
Claims priority of application No. 107124736 A (TW), filed on Jul. 16, 2018.
Prior Publication US 2020/0018786 A1, Jan. 16, 2020
Int. Cl. G01R 31/00 (2006.01); G01R 31/12 (2020.01)
CPC G01R 31/007 (2013.01) [G01R 31/1272 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An insulation resistance measuring device for detecting insulation resistance of an electric vehicle which comprises a ground side and a battery system having a positive side and a negative side, the insulation resistance measuring device comprising:
a measuring unit comprising:
a circuit module comprising a plurality of resistances,
wherein the circuit module is connected to both the positive side and the negative side of the battery system,
a first switch connected between the circuit module and the ground side of the electric vehicle,
a second switch connected between the circuit module and the negative side of the battery system, and
a voltage detecting unit arranged at a first connecting node of the circuit module;
a control unit configured to control the operation of the first switch and the operation of the second switch;
a power management system;
a triggering unit;
a calculation unit, wherein the voltage detecting unit is electrically connected to the first connecting node of the circuit module, and the calculation unit, respectively,
wherein the power management system is connected to the calculation unit and the battery system, and wherein the calculation unit is connected to the voltage detecting unit and configured to:
acquire a first voltage of the first connecting node via the voltage detecting unit when the first switch and the second switch are in a first state,
calculate a second voltage between the positive side and the negative side of the battery system by using the first voltage in a first circuit equation,
acquire a third voltage of the first connecting node via the voltage detecting unit when the first switch and the second switch are in a second state,
calculate a fourth voltage between the ground side of the electric vehicle and negative side of the battery system by using the third voltage in a second circuit equation,
acquire a fifth voltage of the first connecting node via the voltage detecting unit when the first switch and the second switch are in a third state,
calculate a sixth voltage between the ground side of the electric vehicle and negative side of the battery system by by using the fifth voltage in a third circuit equation,
calculate a seventh voltage between the positive side and the ground side of the electric vehicle when the first switch and the second switch are in the second state, wherein the seventh voltage is equal to the second voltage minus the fourth voltage,
calculate an eighth voltage between the positive side of the battery system and the ground side of the electric vehicle when the first switch and the second switch are in the third state, wherein the eighth voltage is equal to the second voltage minus the sixth voltage,
operate a first function M*, said first function M* comprising a relationship between the fourth voltage, the sixth voltage, the seventh voltage and the eighth voltage;
calculate a negative electrode insulation resistance Rn which is an insulation resistance between the negative side of the battery system and the ground side of the electric vehicle by using the first function M* and a second function, and
calculate a positive electrode insulation resistance Rp which is an insulation resistance between the positive side of the battery system and the ground side of the electric vehicle by using the first function M*, the second function and a third function,
wherein the power management system is connected to the calculation unit, the triggering unit, and the battery system, the power management system configured to:
acquire the positive electrode insulation resistance Rp and the negative electrode insulation resistance Rn from the calculation unit, and then
determine whether the positive electrode insulation resistance Rp and the negative electrode insulation resistance Rn exceed a default value, and then
if the positive electrode insulation resistance Rp or the negative electrode insulation resistance Rn exceeds the default value, the power management system is configured to plan a triggering even for operating the control unit by closing the battery system.