Online resistance detection circuit, insulation resistance detection circuit and automobile

Abstract

The present application relates to an online resistance detection circuit, an insulation resistance detection circuit and an automobile. The online resistance detection circuit is provided with a standard resistance unit, an online verification switch array circuit, a voltage-dividing resistance unit and a sampling resistance, and the multiple voltage-dividing resistances connected in series in the voltage-dividing resistance unit are electrically connected to the sampling resistance in sequence by using the online verification switch array circuit, and the detection unit of the insulation resistance detection circuit determines the current resistance value of the sampling resistance based on the standard resistance value of the standard resistance unit when the standard resistance unit is connected to the sampling resistance, and determines the online resistance value of the voltage-dividing resistance based on the current resistance value when each voltage-dividing resistance is connected to the sampling resistance; the insulation resistance detection circuit includes two-way port switches, two-way insulation detection circuits and a phase-changing unit, and the two-way insulation detection circuits are reused by the phase-changing unit. Through the present application, the beneficial effects of improving the insulation resistance detection accuracy and ensuring the reliability of the detection circuit are achieved.

Description

Technical Field

[0001] The present application relates to the field of automobile technology, and in particular to an online resistance detection circuit, an insulation resistance detection circuit and an automobile. Background Art

[0002] During driving, vehicles are often in harsh environments such as vibration, high temperature, high humidity, and gas corrosion. The insulation properties are prone to change. Once the insulation performance deteriorates, flashover may easily occur between the electrodes of the power battery pack, breaking down the battery and causing huge property losses or posing a huge threat to the personal safety of the vehicle's occupants.

[0003] The insulation resistance detection technologies in the related arts are all based on the detection calculation based on the known resistance value of the detection voltage divider resistor. However, due to the factory errors of the insulation detection voltage divider resistor, aging due to long-term operation in harsh environments, etc., there is a deviation between the known value of the measured detection voltage divider resistor and the actual value during the insulation resistance detection, which can easily cause the corresponding insulation resistance detection function to fail and cause false alarms in the insulation judgment.

[0004] There is no effective solution to the problem in the related art that the insulation resistance detection accuracy of the power battery pack is reduced due to the deviation between the known value of the measured detection voltage divider resistance and the actual value during the insulation resistance detection. Summary of the invention

[0005] The present application provides an online resistance detection circuit, an insulation resistance detection circuit and a car, so as to at least solve the problem in the related art that the insulation resistance detection accuracy of a power battery pack is reduced due to the deviation between the known value of the measured detection voltage divider resistance and the actual value during the insulation resistance detection.

[0006] In a first aspect, the present application provides a resistance online detection circuit, which is used for detecting the voltage-dividing resistor of the insulation resistance detection circuit of an automobile. The resistance online detection circuit includes a standard resistance unit, an online verification switch array circuit, a voltage-dividing resistor unit and a sampling resistor. The standard resistance unit is electrically connected to a first power supply and the sampling resistor, respectively. The online verification switch array circuit is coupled and electrically connected between the first power supply and the voltage-dividing resistor unit and between the voltage-dividing resistor unit and the sampling resistor, respectively. The voltage-dividing resistor unit is also electrically connected between the standard resistance unit and the sampling resistor. The standard resistance unit includes a third switch and a standard resistor. The input end of the standard resistor is electrically connected to the first power supply. , the output end of the standard resistor is electrically connected to the third switch, the other end of the third switch away from the one electrically connected to the standard resistor is connected to the sampling resistor, the sampling resistor is also electrically connected to the detection unit of the insulation resistance detection circuit, wherein the online verification switch array circuit is used to electrically connect the multiple voltage-dividing resistors connected in series with the voltage-dividing resistor unit in sequence to the sampling resistor; the detection unit is used to determine the current resistance value of the sampling resistor based on the standard resistance value corresponding to the standard resistance unit when the standard resistance unit is connected to the sampling resistor, and determine the online resistance value of the voltage-dividing resistor based on the current resistance value when each voltage-dividing resistor is connected to the sampling resistor.

[0007] In a second aspect, the present application provides an insulation resistance detection circuit, including: a first port switch and a second port switch, wherein one end of the first port switch is electrically connected to the positive electrode of the power battery pack, and the other end is electrically connected to the first insulation detection circuit, and one end of the second port switch is electrically connected to the negative electrode of the power battery pack, and the other end is electrically connected to the second insulation detection circuit, wherein the first insulation detection circuit and the second insulation detection circuit both include the online resistance detection circuit described in the first aspect, and the sampling resistor corresponding to the first insulation detection circuit and the sampling resistor corresponding to the second insulation detection circuit are electrically connected and grounded, wherein the first port switch is used to control the on and off of the positive electrode of the power battery pack and the first insulation detection circuit; the second port switch is used to control the negative electrode of the power battery pack and the The on and off of the second insulation detection circuit; when the positive electrode of the power battery pack is electrically connected to the first insulation detection circuit, the detection unit is used to detect the first sampling voltage corresponding to the corresponding sampling resistor through the first insulation detection circuit; when the negative electrode of the power battery pack is electrically connected to the second insulation detection circuit, the detection unit is used to detect the second sampling voltage corresponding to the corresponding sampling resistor through the second insulation detection circuit; the detection unit is also used to detect the insulation resistance corresponding to the power battery pack based on the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit corresponding to the first insulation detection circuit, the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit corresponding to the second insulation detection circuit, the first sampling voltage and the second sampling voltage.

[0008] In a third aspect, a car is provided, comprising a control board, wherein an insulation resistance detection circuit is disposed on the control board, and wherein the insulation resistance detection circuit is the insulation resistance detection circuit described in the second aspect.

[0009] Compared with the related art, the present embodiment provides an online resistance detection circuit, an insulation resistance detection circuit and an automobile. The online resistance detection circuit sets a standard resistance unit, an online verification switch array circuit, a voltage-dividing resistance unit and a sampling resistor, and uses the online verification switch array circuit to electrically connect multiple voltage-dividing resistors connected in series in the voltage-dividing resistance unit to the sampling resistor in sequence, and determines the current resistance value of the sampling resistor based on the standard resistance value corresponding to the standard resistance unit when the standard resistance unit is connected to the sampling resistor through the detection unit of the insulation resistance detection circuit, and determines the online resistance value of the voltage-dividing resistor based on the current resistance value when each voltage-dividing resistor is connected to the sampling resistor. The online resistance detection circuit solves the problem that the known value of the voltage-dividing resistor measured in the related art is different from the actual value when the insulation resistance is detected, thereby causing In order to solve the problem of reduced insulation resistance detection accuracy of a power battery pack, an online verification calculation is performed on the resistance value of each voltage-dividing resistor, and the obtained precise resistance value is involved in the calculation process of the detected insulation resistance, thereby achieving the beneficial effect of improving the insulation resistance detection accuracy; at the same time, the insulation resistance detection circuit includes a first port switch, a second port switch, a first insulation detection circuit and a second insulation detection circuit. The insulation resistance is detected by alternating the first insulation detection circuit and the second insulation detection circuit. The insulation resistance detection circuit also includes a phase switching unit, through which the first insulation detection circuit and the second insulation detection circuit are reused, thereby increasing the system redundancy of the corresponding insulation resistance detection circuit or the insulation resistance detection system, ensuring the reliability of the corresponding insulation resistance detection circuit or the insulation resistance detection system, and extending the service life.

[0010] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0013] Figure 1 It is a topological circuit diagram of a resistor online detection circuit provided in an embodiment of the present application;

[0014] Figure 2 is an online verification equivalent circuit diagram of the sampling resistor of an embodiment of the present application;

[0015] Figure 3 The online verification equivalent circuit of the voltage divider resistor of the embodiment of the present application is Figure 1 ;

[0016] Figure 4 The online verification equivalent circuit of the voltage divider resistor of the embodiment of the present application is Figure 2 ;

[0017] Figure 5 is a topological circuit diagram of an insulation resistance detection circuit according to an embodiment of the present application;

[0018] Figure 6 is a topological circuit diagram of an insulation resistance detection circuit of a preferred embodiment of the present application;

[0019] Figure 7 It is an equivalent circuit diagram of the phase switching unit of the embodiment of the present application when working. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0021] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0022] Figure 1 This is a topological circuit diagram of an online resistance detection circuit provided by an embodiment of the present application. The embodiment of the present application provides an online resistance detection circuit, which is used in the insulation resistance detection circuit of a power battery pack of an automobile, and is used to perform online verification and detection of the voltage divider resistor before the insulation resistance detection circuit detects the corresponding insulation resistance. By performing online verification and calculation on the resistance value of each voltage divider resistor, the obtained precise resistance value is involved in the calculation process of the insulation resistance being detected, thereby achieving the beneficial effect of improving the insulation resistance detection accuracy.

[0023] See also Figures 1 to 4The embodiment of the present application provides an online resistance detection circuit, which includes a standard resistance unit 100, an online verification switch array circuit 200, a voltage-dividing resistance unit 300 and a sampling resistor 400. The standard resistance unit 100 is electrically connected to a first power supply VCC and the sampling resistor 400, respectively. The online verification switch array circuit 200 is coupled and electrically connected between the first power supply Vcc and the voltage-dividing resistance unit 300 and between the voltage-dividing resistance unit 300 and the sampling resistor 400, respectively. The voltage-dividing resistance unit 300 is also electrically connected between the standard resistance unit 100 and the sampling resistor 400. The standard resistance unit 100 includes a third switch K f1 And the standard resistor R f1 , standard resistance R f1 The input end is electrically connected to the first power supply Vcc, and the standard resistor R f1 The output end is electrically connected to the third switch K f1 , the third switch K f1 Deviation from standard resistance R f1 The other end of the electrical connection is connected to the sampling resistor 400, and the sampling resistor 400 is also electrically connected to the detection unit 500 of the insulation resistance detection circuit, wherein,

[0024] The standard resistor unit 100 is used to determine the current resistance value of the sampling resistor 400 based on the standard resistance value corresponding to the standard resistor unit 100 when it is electrically connected to the sampling resistor 400 to form a first voltage divider circuit.

[0025] In this embodiment, the standard resistance value corresponding to the standard resistance unit 100 refers to the standard resistance of the standard resistance unit 100 (reference Figure 1 or Figure 2 R f1 ), the standard resistor is a high-precision, high-stability standard resistor, and its resistance value can be used as the standard resistance value corresponding to the standard resistor unit 100. At the same time, when determining the current resistance value of the sampling resistor 400, that is, online verifying the resistance value of the sampling resistor 400, the standard resistor unit 100 and the sampling resistor 400 form a first voltage divider circuit, and the voltage of the corresponding sampling resistor 400 on the first voltage divider circuit is checked by the inspection unit 500, thereby verifying the current resistance value of the sampling resistor 400 online.

[0026] The online verification switch array circuit 200 is used to connect a plurality of voltage-dividing resistors (reference Figure 1 R p1 , R p2 , R p3 , R p4 , …, R pn-1 , R pn ) and the sampling resistor 400 (reference Figure 1 Rs1 )Electrical connection.

[0027] In this embodiment, through the closing rule of the preset switch array, a plurality of voltage-dividing resistors are electrically connected to the sampling resistor 400 in sequence to form a corresponding voltage-dividing circuit. The voltage of the corresponding sampling resistor 400 on the voltage-dividing circuit is checked by the checking unit 500, so as to verify the online resistance value of each voltage-dividing resistor online.

[0028] The detection unit 500 is used to determine the current resistance value of the sampling resistor 400 based on the standard resistance value corresponding to the standard resistance unit 100 when the standard resistance unit 100 is connected to the sampling resistor 400, and to determine the online resistance value of the voltage divider resistor based on the current resistance value when each voltage divider resistor is connected to the sampling resistor 400.

[0029] After completing the online verification of the current resistance value of the sampling resistor 400 and the online resistance values ​​of the multiple voltage-dividing resistors, the current resistance value of the sampling resistor 400 and the online resistance values ​​of the multiple voltage-dividing resistors are used in the insulation resistance detection operation to calculate the accurate insulation resistance, and the insulation detection, judgment and warning of the power battery pack of the vehicle are performed based on the insulation resistance.

[0030] Figure 2 is an online calibration equivalent circuit diagram of the sampling resistor of the embodiment of the present application, refer to Figure 1-2 In order to realize online detection of the sampling resistor, in some embodiments,

[0031] The third switch K f1 , used to control the standard resistor R f1 The connection and disconnection of the sampling resistor 400.

[0032] The detection unit 500 is used to connect the sampling resistor 400 and the standard resistor R f1 When connected electrically, based on the standard resistance R f1 The standard resistance value of the sampling resistor R s1 The current resistance value.

[0033] In this embodiment, the online sampling resistor R s1 When performing verification calculation, close the third switch K f1 At this time, all switches of the online verification switch array circuit 200 are disconnected, and the standard resistor R f1 The corresponding standard resistance value is R f1 , the sampling resistance R measured by the detection unit 500 s1 The voltage away from the ground is U s1-Rs1 , the voltage of the first power supply VCC is V CC , calculate the sampling resistance R based on the following formula s1 The current resistance value Rs1-C :

[0034]

[0035] Figure 3 The online verification equivalent circuit of the voltage divider resistor of the embodiment of the present application is Figure 1 ; Figure 4 The online verification equivalent circuit of the voltage divider resistor of the embodiment of the present application is Figure 2 In order to realize online verification and calculation of the online resistance value of the voltage divider resistor, refer to Figure 1 , Figure 3 to Figure 4 In some embodiments, the online verification switch array circuit 200 includes a multi-channel gating circuit 21, each of which corresponds to a voltage dividing resistor (reference Figure 2 R p1 , R p2 , R p3 , R p4 , …, R pn-1 , R pn ), each gating circuit 21 includes a first switch electrically connected to the detection unit 500 (reference Figure 2 K pv1 , K pv2 , K pv3 , K pv4 , …, K pvn-1 , K pvn ) and the second switch (reference Figure 2 K pg1 , K pg2 , K pg3 , K pg4 , …, K pgn-1 ), the input end of the first switch is electrically connected to the first power supply VCC, and the output end of the first switch is electrically connected to the corresponding voltage dividing resistor (reference Figure 2 R p1 , R p2 , R p3 , R p4 , …, R pn-1 , R pn ), the input end of the second switch is electrically connected to the voltage divider resistor (reference Figure 2 R p1 , R p2 , R p3 , R p4 , …, R pn-1 , R pn ), the output end of the second switch is electrically connected to the sampling resistor R s1 ,in,

[0036] In this embodiment, the voltage divider resistor R pnThe corresponding gating circuit 21 has no corresponding second switch, and the voltage dividing resistor R pn The end away from the end electrically connected to the corresponding first switch is directly connected to the sampling resistor R s1 Electrical connection.

[0037] In this embodiment, the first switch and the second switch are both controllably connected to the detection unit 500, that is, when performing online verification of the corresponding voltage divider resistor, the detection unit 500 controls the first switch and the second switch corresponding to the corresponding selection path 21 to close.

[0038] The first switch is used to selectively connect the first power supply VCC to the corresponding voltage dividing resistor (R p1 , R p2 , R p3 , R p4 , …, R pn-1 , R pn One of them) connection.

[0039] The second switch is used to selectively connect the voltage divider resistor to the sampling resistor R s1 Electrical connection.

[0040] In this embodiment, after the first switch connects the first power source VCC to the corresponding voltage divider resistor, the corresponding second switch connects the voltage divider resistor to the sampling resistor R s1 Make a connection (refer to Figure 4 or Figure 5 ), thereby forming a corresponding voltage dividing circuit with a selection path 21 and a corresponding voltage dividing resistor.

[0041] The detection unit 500 is used to electrically connect the first power supply VCC to the corresponding voltage-dividing resistor, and the corresponding voltage-dividing resistor is electrically connected to the sampling resistor R s1 When connected electrically, based on the sampling resistor R s1 Current resistance value R s1-C , determine the online resistance value of the voltage divider resistor.

[0042] Specifically, refer to Figure 3 , when the first switch K is closed pg1 and the second switch K pg1 , the first switch and the second switch corresponding to the other selection paths 21 are both disconnected, and the sampling resistor R detected by the detection unit 500 s1 The voltage away from the ground is U s1-Rp1 , the voltage of the first power supply VCC is V CC , the measured resistance R s1 The current resistance value is R s1-C , then the voltage divider resistor R is as follows p1 The online resistance value R p1-C :

[0043]

[0044] refer to Figure 4 , when the first switch K is closed pg2 and the second switch K pg2 , the first switch and the second switch corresponding to the other selection paths 21 are both disconnected, and the sampling resistor R detected by the detection unit 500 s1 The voltage away from the ground is U s1-Rp2 , the voltage of the first power supply VCC is V CC , the measured resistance R s1 The current resistance value is R s1-C , then the voltage divider resistor R is as follows p2 The online resistance value R p2-C :

[0045]

[0046] It should be noted that, in this embodiment, after completing the detection of the online resistance value of the voltage-dividing resistor, the detection unit 500 can also be used to judge whether the detected online resistance value meets the preset resistance value range. When it is judged that the corresponding resistance value range is not met, it indicates that the voltage-dividing resistor is abnormal. In this way, the state of each voltage-dividing resistor (normal, short circuit, open circuit, too large, too small) can be judged, and the specific position, quantity and fault type of the faulty voltage-dividing resistor can be accurately located, and it can be judged whether the corresponding insulation resistance detection circuit can continue to work and issue an alarm for the fault.

[0047] Of course, the same state judgment can also be performed on the sampling resistor, and the specific judgment process will not be repeated here.

[0048] In some of these embodiments, reference Figure 2 In order to achieve the isolation of the low voltage power supply (for example, the first power supply) and the high voltage power supply (for example, the power battery pack), the online resistance calibration circuit also includes an isolation switch K v1 , isolating switch K v1 One end is electrically connected to the first power supply Vcc, and the other end is electrically connected to the input end of the online verification switch array circuit 200 and the standard resistance unit 100, wherein the isolation switch K v1 , used to control the first power supply VCC to output corresponding power to the online verification switch array circuit 200 and the standard resistance unit 100.

[0049] In this embodiment, the isolating switch K v1 Isolate high voltage from low voltage to ensure the safety of low voltage circuit and power supply. Figure 3 and Figure 4 , isolating switch K v1Closed, indicating that the online calibration calculation of the voltage divider resistance begins.

[0050] Figure 5 It is a topological circuit diagram of the insulation resistance detection circuit of the embodiment of the present application. The embodiment of the present application provides an insulation resistance detection circuit for insulation resistance detection of a power battery pack of a vehicle, and the insulation resistance detection circuit is based on the online resistance detection circuit of the above embodiment. The online resistance detection circuit of the above embodiment performs online verification calculation on the current resistance value of the adopted resistor and the online resistance value of each voltage-dividing resistor, and the obtained precise resistance value is involved in the calculation process of the insulation resistance being detected, thereby improving the insulation resistance detection accuracy.

[0051] See also Figures 1 to 5 The insulation resistance detection circuit provided in the embodiment of the present application includes a first port switch K1 and a second port switch K2, one end of the first port switch K1 is electrically connected to the positive electrode BAT+ of the power battery pack 600, and the other end is electrically connected to the first insulation detection circuit 700, one end of the second port switch K2 is electrically connected to the negative electrode BAT- of the power battery pack 600, and the other end is electrically connected to the second insulation detection circuit 800, wherein the first insulation detection circuit 700 and the second insulation detection circuit 800 both include the online resistance detection circuit in the above embodiment, and the sampling resistor corresponding to the first insulation detection circuit 700 (reference Figure 5 R S1 ) and the sampling resistor corresponding to the second insulation detection circuit 800 (reference Figure 5 R S2 ) are electrically connected and grounded, wherein,

[0052] The first port switch K1 is used to control the connection between the positive electrode BAT+ of the power battery pack 600 and the first insulation detection circuit 700;

[0053] The second port switch K3 is used to control the connection between the negative electrode BAT- of the power battery pack 600 and the second insulation detection circuit 800;

[0054] When the positive electrode BAT+ of the power battery pack 600 is electrically connected to the first insulation detection circuit 700, the detection unit 500 is used to detect the corresponding sampling resistance (reference Figure 5 R S1 ) corresponds to the first sampling voltage U s1 ;

[0055] When the negative electrode BAT- of the power battery pack 600 is electrically connected to the second insulation detection circuit 008, the detection unit 500 is used to detect the corresponding sampling resistance (reference Figure 5 R S2) corresponds to the second sampling voltage U s2 ;

[0056] The detection unit 500 is further used to detect the online resistance value of all the voltage-dividing resistors of the voltage-dividing resistor unit 300 corresponding to the first insulation detection circuit 700, the online resistance value of all the voltage-dividing resistors of the voltage-dividing resistor unit 300 corresponding to the second insulation detection circuit 800, and the first sampling voltage U s1 and the second sampling voltage U s2 , detect the insulation resistance corresponding to the power battery pack 600.

[0057] It should be noted that when performing insulation resistance detection, the first port switch K1 and the second port switch K3 are alternately turned on, so that the first insulation detection circuit 700 and the second insulation detection circuit 800 work alternately to complete the insulation resistance detection; it should be emphasized that when detecting the insulation resistance, the first insulation detection circuit 700 and the second insulation detection circuit 800 do not work at the same time.

[0058] The specific insulation resistance detection process is as follows:

[0059] The resistances corresponding to the two ends of the equivalent insulation resistance are set as R P and R n , detect insulation resistance R P And insulation resistance R n The process is as follows:

[0060] The first port switch K1 is closed, the second port switch K3 is opened, and the sampling resistor R corresponding to the first insulation detection circuit 700 is S1 The current resistance value is R s1-C , the online detection values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit 300 corresponding to the first insulation detection circuit 700 are: R p1-C , R p2-C , R p3-C , R p4 -C, ..., R pn-C , the first sampling voltage measured by the first detection unit 500 is U s1 , calculate the voltage U across the equivalent insulation resistance according to the following formula p1 and U n1

[0061]

[0062] U n1 =U bus -U p1

[0063]

[0064] The second port switch K3 is closed, and the second port switch K3 is opened. The sampling resistor R corresponding to the second insulation detection circuit 008 s2 The current resistance value is R s2-C , the online detection values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit 300 corresponding to the second insulation detection circuit 008 are: R n1-C , R n2-C , R n3-C , R n4-C , …, R nn-C , the second sampling voltage measured by the first detection unit 500 is U s2 , calculate the voltage U across the equivalent insulation resistance according to the following formula p2 and U n2

[0065]

[0066] U p2 =U bus -U n2

[0067]

[0068] In summary, the insulation resistance R can be calculated P And insulation resistance R n for:

[0069]

[0070] Figure 6 is a topological circuit diagram of the insulation resistance detection circuit of the preferred embodiment of the present application, refer to Figure 6 In some embodiments, in order to realize insulation resistance detection when one of the two insulation detection circuits is abnormal, the insulation resistance detection circuit further includes a phase switching unit 900, which is electrically connected to the power battery pack 600, the first insulation detection circuit 700 and the second insulation detection circuit 800, respectively, wherein,

[0071] The phase switching unit 900 is used to control the abnormal insulation detection circuit to be offline when one of the insulation detection circuits of the first insulation detection circuit 700 and the second insulation detection circuit 008 is abnormal, and control the other insulation detection circuit to be alternately connected to the two electrodes of the power battery pack 600;

[0072] The detection unit 500 is used to perform insulation resistance detection through another insulation detection circuit.

[0073] In this embodiment, when one of the first insulation detection circuit 700 and the second insulation detection circuit 008 fails, the phase switching unit 900 switches the port switch corresponding to the failed insulation detection circuit to the normally working insulation detection circuit, thereby satisfying the requirement of alternating operation of the two insulation detection circuits during insulation resistance detection to realize insulation resistance detection. By setting the phase switching unit 900, the system redundancy of the corresponding insulation resistance detection circuit or the insulation resistance detection system is increased, thereby ensuring the reliability of the corresponding insulation resistance detection circuit or the insulation resistance detection system and extending the service life.

[0074] In some of these embodiments, reference Figure 6 The phase-changing unit 900 includes a first phase-changing switch K5 and a second phase-changing switch K4, one end of the first phase-changing switch K5 is electrically connected to the positive electrode BAT+ of the power battery pack 600 and the electrical connection point of the first port switch K1, the other end of the first phase-changing switch K5 is electrically connected to the electrical connection point of the second port switch K3 and the second insulation detection circuit 008, one end of the second phase-changing switch K4 is electrically connected to the negative electrode BAT- of the power battery pack 600 and the electrical connection point of the second port switch K3, and the other end of the second phase-changing switch K4 is electrically connected to the electrical connection point of the first port switch K1 and the first insulation detection circuit 700, wherein,

[0075] When the first insulation detection circuit 700 is abnormal, the first port switch K1 and the second phase-changing switch K4 control the first insulation detection circuit 700 to be offline, and the second port switch K3 and the first phase-changing switch K5 alternately control the second insulation detection circuit 008 to be connected to the corresponding electrode of the power battery pack 600;

[0076] When the second insulation detection circuit 800 is abnormal, the second port switch K3 and the first phase-changing switch K5 control the second insulation detection circuit 008 to be offline, and the first port switch K1 and the second phase-changing switch K4 alternately control the first insulation detection circuit 700 to be connected to the corresponding electrodes of the power battery pack 600;

[0077] The detection unit 500 is used to control the second insulation detection circuit 800 to perform insulation resistance detection when the first insulation detection circuit 700 is offline, and to control the first insulation detection circuit 700 to perform insulation resistance detection when the second insulation detection circuit 800 is offline.

[0078] Figure 7 is an equivalent circuit diagram of the commutation unit of the embodiment of the present application when it is working, refer to Figure 6 to Figure 7 Specifically, when the second insulation detection circuit 800 is abnormal, all switches of the online verification switch array circuit 200 are disconnected. At this time, the second port switch K3 and the first phase-changing switch K5 are disconnected, and the second insulation detection circuit 800 is offline. At this time, the insulation resistance R PAnd insulation resistance R n The process is as follows:

[0079] The first port switch K1 is closed. At this time, the multiple voltage-dividing resistors and resistance values ​​corresponding to the first insulation detection circuit 700 are: R p1-C-rd , R p2-C-rd , R p3-C-rd , R p4 -C-rd, ..., R pn -C-rd, sampling resistor R of the first insulation detection circuit 700 s1 The corresponding current resistance value is R S1-C-rds , the sampling resistor R of the first insulation detection circuit 700 s1 The voltmeter facing away from the ground is U s1-1-rd , through U s1-1-rd U can be calculated p1-rd and U n1-rd， The calculation formula is as follows:

[0080]

[0081] U n1-rd =U bus -U p1-rd

[0082]

[0083] Then, the first port switch K1 is opened, and the second phase-changing switch K4 is closed to realize phase-changing. The sampling resistor R s1 The voltmeter facing away from the ground is U s1-2-rd , through U s1-2-rd U can be calculated p2-rd and U n2-rd， The calculation formula is as follows:

[0084]

[0085] U p2-rd =U bus -U n2-rd

[0086]

[0087] Comprehensively calculate the insulation resistance R P And insulation resistance R n for:

[0088]

[0089] In this embodiment, the closing of the first port switch K1 and the second phase-changing switch K4 should have a sufficiently long dead time to prevent the positive electrode BAT+ and the negative electrode BAT- of the power battery pack from being short-circuited.

[0090] It should be noted that when and only when one of the insulation detection circuits fails and cannot work, the insulation detection circuit can be reused by orderly switching the detected ports and phase-changing switches, thereby increasing system redundancy, combating environmental instability, and improving system reliability and service life.

[0091] In some of these embodiments, reference Figure 6 to Figure 7 The insulation resistance detection circuit also includes a third port switch K2, one end of the third port switch K2 is connected to the casing of the power battery pack 006, and the other end of the third port switch K2 is connected to the ground end of the sampling resistor 400. The casing ground (PE) and the digital ground (GND) are turned on and off by opening and closing the third port switch K2.

[0092] In some of these embodiments, reference Figure 5 and Figure 6 The detection unit 500 includes a control unit 51, a first voltage detection circuit 52 and a second voltage detection circuit 53. The input end of the first voltage detection circuit 52 is connected to a sampling resistor (refer to R in the figure) corresponding to the first insulation detection circuit 700. S1 ) is electrically connected, the input end of the second voltage detection circuit 53 is electrically connected to the sampling resistor (refer to R in the figure) corresponding to the second insulation detection circuit 800 S2 ) are electrically connected, and the output ends of the first voltage detection circuit 52 and the second voltage detection circuit 53 are both electrically connected to the control unit 51, wherein,

[0093] A first voltage detection circuit 52, used for detecting a first sampling voltage;

[0094] A second voltage detection circuit 53, used for detecting a second sampling voltage;

[0095] The control unit 51 is also used to determine the insulation resistance corresponding to the power battery pack 600 based on the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit 300 corresponding to the first insulation detection circuit 700, the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit 300 corresponding to the second insulation detection circuit 800, the first sampling voltage and the second sampling voltage.

[0096] In some embodiments, the first voltage detection circuit 52 and the second voltage detection circuit 53 are both in-phase input addition circuits, and the in-phase input addition circuits are corresponding in-phase input addition circuits in the related art; at the same time, for the control functions of insulation resistance detection and online resistance detection, in one embodiment of the present application, the control unit 51 includes one of the following: a single-chip microcomputer, an FPGA, and a DSP. The control unit 51 serves as the control center of the corresponding detection circuit, controls the corresponding first switch, second switch, first port switch, second port switch, third port switch, first phase-changing switch, and second phase-changing switch, and controls the first voltage detection circuit 52 and the second voltage detection circuit 53 to complete the sampling voltage output. It should be understood that the control unit 51 that satisfies the control of the corresponding detection circuit is suitable for the control unit 51 of this embodiment.

[0097] The following is based on Figure 5 and Figure 6 The circuit structure and working process in the embodiment of the present application are further described as follows:

[0098] Circuit Structure

[0099] The insulation resistance detection circuit of the embodiment of the present application mainly includes a first insulation detection circuit 700, a second insulation detection circuit 800, a port switch part, a phase change unit and a detection unit. At the same time, the equivalent insulation resistance part and the power battery pack part do not involve improvements with the embodiment of the present application.

[0100] Circuit components

[0101] refer to Figure 5 and Figure 6 , Rp and Rn are the insulation resistance values ​​of bus positive electrode BAT+ and bus negative electrode BAT- to the casing respectively; R s1 , R s2 With R p1 , R p2 , R p3 , R p4 ,....,R pn-1 , R pn and R n1 , R n2 , R n3 , R n4 ,....,R nn-1 , R nn As the voltage divider resistor, R s1 , R s2 It is called voltage sampling resistor, R f1 , R f2is a standard resistor; K1, K2, and K3 are port switch devices. The insulation resistance values ​​Rp and Rn can be calculated by opening and closing K1, K2, and K3 in an orderly manner; K4 and K5 are commutation switch devices. Phase switching is achieved by opening and closing K4 and K5 in an orderly manner; Kv1 and Kv2 are isolation protection switch devices. After the online verification calculation process of the insulation detection voltage divider resistor is completed, Kv1 and Kv2 are disconnected to isolate the high voltage from the low voltage Vcc for a second time to ensure the safety of the low voltage circuit. pv1 , K pv2 , K pv3 , K pv4 , ..., K pvn-1 , K pvn , K f1 , K pg1 , K pg2 , K pg3 , K pg4 ,....,K pgn-1 is the switch array in the first insulation detection circuit. By sequentially opening and closing the switches of the corresponding online detection switch array circuit, all resistance values ​​of the first insulation detection circuit can be accurately calculated; K nv1 , K nv2 , K nv3 , K nv4 , ..., K nvn-1 , K nvn , K f2 , K ng1 , K ng2 , K ng3 , K ng4 ,....,K ngn-1 is the switch array in the second insulation detection circuit. By sequentially opening and closing the switches of the corresponding online detection switch array circuit, all resistance values ​​of the second insulation detection circuit can be accurately calculated; B1, B2, ..., Bn are vehicle-mounted power batteries.

[0102] The insulation resistance test workflow is as follows:

[0103] The working process of the insulation detection circuit of the embodiment of the present application is described as follows:

[0104] The first step is to perform online calibration calculation of the voltage divider resistor;

[0105] The second step is insulation resistance status detection and action:

[0106] (1) If the dual-circuit insulation detection circuit is normal, perform insulation resistance detection;

[0107] (2) If a single-channel insulation detection circuit is damaged, the redundancy mechanism is activated first, and then the insulation resistance test is performed;

[0108] (3) If the dual-circuit insulation detection circuit is damaged, the insulation resistance detection function failure alarm will be activated;

[0109] (4) If the insulation resistance is too small, the battery insulation failure alarm is activated.

[0110] In this embodiment, the sampling voltage U s1 , U s2 The signal is processed by the detection unit.

[0111] Among them, the specific calculation process can refer to the online verification calculation of the sampling resistor, the verification calculation of the voltage divider resistor, the calculation of the insulation resistance when the dual-path insulation detection circuit is working, and the calculation of the insulation resistance under the phase change situation in the above-mentioned embodiment, which will not be repeated here.

[0112] The embodiment of the present application also provides an automobile, including a control board, on which an insulation resistance detection circuit is provided, wherein the insulation resistance detection circuit is the insulation resistance detection circuit in the above embodiment.

[0113] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0114] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A resistance online detection circuit, used for detecting the voltage divider resistance of the insulation resistance detection circuit of an automobile, characterized in that: The online resistance detection circuit includes a standard resistance unit, an online verification switch array circuit, a voltage-dividing resistance unit and a sampling resistor. The standard resistance unit is electrically connected to a first power supply and the sampling resistor, respectively. The online verification switch array circuit is coupled and electrically connected between the first power supply and the voltage-dividing resistance unit and between the voltage-dividing resistance unit and the sampling resistor, respectively. The voltage-dividing resistance unit is also electrically connected between the standard resistance unit and the sampling resistor. The standard resistance unit includes a third switch and a standard resistor. The input end of the standard resistor is electrically connected to the first power supply, and the output end of the standard resistor is electrically connected to the third switch. The other end of the third switch away from the electrical connection with the standard resistor is connected to the sampling resistor. The sampling resistor is also electrically connected to the detection unit of the insulation resistance detection circuit, wherein: The online verification switch array circuit is used to electrically connect the plurality of voltage-dividing resistors connected in series in the voltage-dividing resistor unit to the sampling resistor in sequence; The detection unit is used to determine the current resistance value of the sampling resistor based on the standard resistance value corresponding to the standard resistance unit when the standard resistance unit is connected to the sampling resistor, and to determine the online resistance value of the voltage divider resistor based on the current resistance value when each voltage divider resistor is correspondingly connected to the sampling resistor.

2. The online resistance detection circuit according to claim 1, characterized in that: The online verification switch array circuit includes a multi-channel gating circuit, each of which corresponds to a voltage-dividing resistor, and each of which includes a first switch and a second switch electrically connected to the detection unit, the input end of the first switch is electrically connected to the first power supply, the output end of the first switch is electrically connected to the corresponding voltage-dividing resistor, the input end of the second switch is electrically connected to the voltage-dividing resistor, and the output end of the second switch is electrically connected to the sampling resistor, wherein: The first switch is used to selectively connect the first power source to the corresponding voltage-dividing resistor; The second switch is used to selectively electrically connect the voltage dividing resistor to the sampling resistor; The detection unit is used to determine the online resistance value of the voltage-dividing resistor based on the current resistance value when the first power supply is electrically connected to the corresponding voltage-dividing resistor and the voltage-dividing resistor is electrically connected to the sampling resistor.

3. The online resistance detection circuit according to claim 1, characterized in that: The third switch is used to control the on / off of the standard resistor and the sampling resistor; The detection unit is used to determine the current resistance value of the sampling resistor based on the standard resistance value of the standard resistor when the sampling resistor is electrically connected to the standard resistor.

4. The online resistance detection circuit according to claim 1, characterized in that: The online resistance verification circuit also includes an isolation switch, one end of which is electrically connected to the first power supply, and the other end of which is electrically connected to the input end of the online verification switch array circuit and the standard resistance unit, wherein the isolation switch is used to control the first power supply to output corresponding power to the online verification switch array circuit and the standard resistance unit.

5. An insulation resistance detection circuit, characterized in that: It comprises a first port switch and a second port switch, wherein one end of the first port switch is electrically connected to the positive electrode of the power battery pack, and the other end is electrically connected to a first insulation detection circuit, and one end of the second port switch is electrically connected to the negative electrode of the power battery pack, and the other end is electrically connected to a second insulation detection circuit, wherein the first insulation detection circuit and the second insulation detection circuit both comprise the online resistance detection circuit according to any one of claims 1 to 4, and the sampling resistor corresponding to the first insulation detection circuit and the sampling resistor corresponding to the second insulation detection circuit are electrically connected and grounded, wherein, The first port switch is used to control the connection and disconnection between the positive electrode of the power battery pack and the first insulation detection circuit; The second port switch is used to control the connection and disconnection between the negative electrode of the power battery pack and the second insulation detection circuit; When the positive electrode of the power battery pack is electrically connected to the first insulation detection circuit, the detection unit is used to detect a first sampling voltage corresponding to the corresponding sampling resistor through the first insulation detection circuit; When the negative electrode of the power battery pack is electrically connected to the second insulation detection circuit, the detection unit is used to detect the second sampling voltage corresponding to the corresponding sampling resistor through the second insulation detection circuit; The detection unit is further used to detect the insulation resistance corresponding to the power battery pack based on the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit corresponding to the first insulation detection circuit, the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit corresponding to the second insulation detection circuit, the first sampling voltage and the second sampling voltage.

6. The insulation resistance detection circuit according to claim 5, characterized in that: The insulation resistance detection circuit further includes a phase switching unit, which is electrically connected to the power battery pack, the first insulation detection circuit and the second insulation detection circuit respectively, wherein: The phase switching unit is used to control the abnormal insulation detection circuit to be offline when one of the first insulation detection circuit and the second insulation detection circuit is abnormal, and control the other insulation detection circuit to be alternately connected to the two electrodes of the power battery pack; The detection unit is used to perform insulation resistance detection through another insulation detection circuit.

7. The insulation resistance detection circuit according to claim 6, characterized in that: The phase-changing unit includes a first phase-changing switch and a second phase-changing switch, one end of the first phase-changing switch is electrically connected to the positive electrode of the power battery pack and the electrical connection point of the first port switch, the other end of the first phase-changing switch is electrically connected to the electrical connection point of the second port switch and the second insulation detection circuit, one end of the second phase-changing switch is electrically connected to the negative electrode of the power battery pack and the electrical connection point of the second port switch, and the other end of the second phase-changing switch is electrically connected to the electrical connection point of the first port switch and the first insulation detection circuit, wherein, When the first insulation detection circuit is abnormal, the first port switch and the second phase-changing switch control the first insulation detection circuit to be offline, and the second port switch and the first phase-changing switch alternately control the second insulation detection circuit to be connected to the electrode corresponding to the power battery pack; When the second insulation detection circuit is abnormal, the second port switch and the first phase-changing switch control the second insulation detection circuit to be offline, and the first port switch and the second phase-changing switch alternately control the first insulation detection circuit to be connected to the electrodes corresponding to the power battery pack; The detection unit is used to control the second insulation detection circuit to perform insulation resistance detection when the first insulation detection circuit is offline, and to control the first insulation detection circuit to perform insulation resistance detection when the second insulation detection circuit is offline.

8. The insulation resistance detection circuit according to claim 6, characterized in that: The insulation resistance detection circuit further includes a third port switch, one end of the third port switch is connected to the housing of the power battery pack, and the other end of the third port switch is connected to the ground end of the sampling resistor.

9. The insulation resistance detection circuit according to claim 6, characterized in that: The detection unit includes a control unit, a first voltage detection circuit and a second voltage detection circuit, the input end of the first voltage detection circuit is electrically connected to the sampling resistor corresponding to the first insulation detection circuit, the input end of the second voltage detection circuit is electrically connected to the sampling resistor corresponding to the second insulation detection circuit, and the output ends of the first voltage detection circuit and the second voltage detection circuit are both electrically connected to the control unit, wherein: The first voltage detection circuit is used to detect the first sampling voltage; The second voltage detection circuit is used to detect the second sampling voltage; The control unit is further used to determine the insulation resistance corresponding to the power battery pack based on the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit corresponding to the first insulation detection circuit, the online resistance values ​​of all the voltage-dividing resistors of the voltage-dividing resistor unit corresponding to the second insulation detection circuit, the first sampling voltage and the second sampling voltage.

10. The insulation resistance detection circuit according to claim 9, characterized in that: The first voltage detection circuit and the second voltage detection circuit are both in-phase input addition circuits.

11. An automobile, comprising a control panel, wherein an insulation resistance detection circuit is provided on the control panel, characterized in that: The insulation resistance detection circuit is the insulation resistance detection circuit according to any one of claims 5 to 10.

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