CN213813774U - Insulation resistance detection device for new energy vehicle - Google Patents
Insulation resistance detection device for new energy vehicle Download PDFInfo
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- CN213813774U CN213813774U CN202022234897.8U CN202022234897U CN213813774U CN 213813774 U CN213813774 U CN 213813774U CN 202022234897 U CN202022234897 U CN 202022234897U CN 213813774 U CN213813774 U CN 213813774U
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Abstract
The utility model provides an automobile-used insulation resistance detection device of new forms of energy belongs to vehicle high pressure safety field. The unbalanced resistance conversion part of the detection device comprises a first branch circuit, a second branch circuit and a third branch circuit, wherein the third branch circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor which are sequentially connected in series, one end of the third branch circuit is used for connecting the anode of a vehicle high-voltage circuit, and the other end of the third branch circuit is used for connecting the cathode of the vehicle high-voltage circuit; the first branch circuit comprises a first switch, one end of the first branch circuit is connected with a series point of a first resistor and a second resistor, and the other end of the first branch circuit is connected with the negative electrode of the high-voltage loop of the vehicle; the second branch circuit comprises a second switch, one end of the second branch circuit is connected with a series point of a second resistor and a third resistor, and the other end of the second branch circuit is connected with a vehicle body ground; the series connection point of the third resistor and the fourth resistor is a voltage sampling point, and the reference ground of the voltage sampling point is the negative pole of the vehicle high-voltage loop. The detection device has the advantage of high safety when used for detecting the insulation resistance.
Description
Technical Field
The utility model relates to an automobile-used insulation resistance detection device of new forms of energy belongs to new forms of energy car high pressure safety technical field.
Background
At present, a new energy automobile is mainly driven by electric power, in order to ensure that the electric automobile has higher working efficiency and sufficient driving force, a driving power supply of the new energy electric automobile needs to be maintained at a higher voltage platform (far higher than the safe voltage that a human body can bear), the insulation resistance of a vehicle high-voltage system to a vehicle body ground may be changed along with the increase of the running age of the automobile, the occurrence of extreme weather conditions, the aging of an insulation system and the like, not only is the potential safety hazard of electric shock of personnel exist, but also the high-low voltage circuit fault of the automobile and serious accidents such as spontaneous combustion of the automobile may occur, and therefore, the detection of the insulation resistance between a new energy vehicle high-voltage circuit and the vehicle body ground is particularly important.
At present, two insulation resistance detection methods applied to new energy automobiles are available: one is an ac injection method and the other is an unbalanced resistance method.
The alternating current injection method is to inject an alternating current signal with fixed frequency into a loop between a finished automobile high-voltage system and an automobile body ground, and then calculate the amplitude or phase of the alternating current signal and a related insulation resistance value calibrated in advance to calculate the insulation resistance value of the current automobile high-voltage system. However, since an ac signal is injected into the dc system, an interference source is actually introduced into the dc system, which may affect the normal operation of the dc system, and the circuit is complex, costly, and has poor stability.
The unbalanced resistance method is a widely adopted insulation resistance detection method at present, for example, the insulation detection method of an electric vehicle disclosed in the invention patent application document with the application publication number of CN109490632A is a typical unbalanced resistance method, but the voltages to be detected are all referenced to the vehicle body ground (i.e., the low-voltage ground), and the reference ground for detecting the control signal of the high-voltage side switch of the loop is the low-voltage ground, so that the following problems exist: 1. the detection voltage takes a low-voltage ground as a reference ground, voltage sampling is required to be carried out between a high-voltage signal and the low-voltage ground, high-voltage and low-voltage signal conversion is required in the sampling process, and the safety is low; 2. the reference ground of the control signal of the detection loop high-voltage side switch is a low-voltage ground, namely the detection loop high-voltage side switch is controlled by a low-voltage signal, so that potential safety hazards exist, and in order to reduce the potential safety hazards, high-low voltage isolating switches with high isolation and voltage-withstanding functions, such as reed switches or PhotoMOS and the like, need to be used, and the price of the high-low voltage isolating switches is high, so that the cost of the detection device is high.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an automobile-used insulation resistance detection device of new forms of energy for when solving and utilizing unbalanced resistance method to detect insulation resistance at present, measuring voltage uses low-voltage ground as the reference ground, need carry out high, low pressure signal conversion among the voltage sampling process, the low problem of security.
In order to achieve the above object, the utility model provides an automobile-used insulation resistance detection device of new forms of energy, this detection device includes:
the unbalanced resistance conversion part comprises a first branch circuit, a second branch circuit and a third branch circuit, the third branch circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor which are sequentially connected in series, one end of the third branch circuit is used for connecting the anode of a vehicle high-voltage loop, and the other end of the third branch circuit is used for connecting the cathode of the vehicle high-voltage loop; the first branch circuit comprises a first switch, one end of the first branch circuit is connected with a series point of a first resistor and a second resistor, and the other end of the first branch circuit is connected with the negative electrode of the high-voltage loop of the vehicle; the second branch circuit comprises a second switch, one end of the second branch circuit is connected with a series point of a second resistor and a third resistor, and the other end of the second branch circuit is connected with a vehicle body ground; the series connection point of the third resistor and the fourth resistor is a voltage sampling point, and the reference ground of the voltage sampling point is the negative pole of the vehicle high-voltage loop;
and the semaphore acquisition processing part is connected with the voltage sampling point.
The utility model discloses an automobile-used insulation resistance detection device of new forms of energy's beneficial effect is: owing to adopted the utility model discloses an unbalanced resistance transform part of this kind of special form makes and utilizes the utility model discloses a detection device detects time measuring to the automobile-used insulation resistance of new forms of energy, can regard as the reference ground of voltage sampling point with the negative pole (being high pressure ground) of vehicle high-pressure return circuit, and then realizes that voltage sampling is gone on between high-voltage signal and high-pressure ground, because there is not high low-voltage signal conversion process in the voltage sampling process, has the high advantage of security.
Further, in the above-described detection device, the detection device further includes a semaphore filtering section connected in series between the voltage sampling point and the semaphore acquisition processing section.
The beneficial effects of doing so are: the voltage signal of the voltage sampling point is subjected to relevant filtering processing by the semaphore filtering part, so that the voltage signal acquired by subsequent acquisition is more stable and reliable.
Further, in the above detection device, the first switch is further connected to a control circuit, the control circuit is configured to output a control signal of the first switch, and a reference ground of the control signal of the first switch is a negative pole of the vehicle high-voltage circuit.
The beneficial effects of doing so are: because the unbalanced resistance conversion part in the special form of the utility model is adopted, the detection device of the utility model can be used for detecting the insulation resistance of the new energy vehicle, the negative pole (namely, high voltage ground) of the high voltage loop of the vehicle can be used as the reference ground of the control signal of the first switch, and the reference ground of the control signal of the high voltage side switch of the detection device is the high voltage ground because the first switch is the high voltage side switch, the high voltage side switch is controlled by the high voltage signal, the problem that the high voltage side switch is controlled by the low voltage signal does not exist, and the safety is high; and the high-voltage side switch does not need to adopt a high-low voltage isolating switch, so that the cost of the detection device can be reduced.
Drawings
Fig. 1 is a schematic structural diagram of an insulation resistance detection device for a new energy vehicle in an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.
The embodiment of the device is as follows:
as shown in fig. 1, the insulation resistance detection device (hereinafter referred to as detection device) for a new energy vehicle of the present embodiment includes three major parts: the device comprises an unbalanced resistance conversion part, a semaphore filtering part and a semaphore acquisition and processing part; in FIG. 1, RpInsulation resistance value, R, of positive electrode HV + of high-voltage circuit of vehicle to vehicle body groundnIs the insulation resistance value, R, of the negative electrode HV-to-body ground of the high-voltage circuit of the vehiclepAnd RnIs the quantity to be detected by the detecting means, RpAnd RnIs connected to the body ground.
The following describes the detection device in detail:
the unbalanced resistance conversion part comprises a first branch circuit, a second branch circuit and a third branch circuit, wherein the third branch circuit comprises a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4 which are sequentially connected in series, one end of the third branch circuit is used for connecting the anode HV & lt + & gt of the vehicle high-voltage circuit, and the other end of the third branch circuit is used for connecting the cathode HV & lt- & gt of the vehicle high-voltage circuit; the first branch circuit comprises a first switch SW1, one end of the first branch circuit is connected with the series point of a first resistor R1 and a second resistor R2, and the other end of the first branch circuit is used for being connected with the negative electrode HV < - > of the high-voltage circuit of the vehicle; the second branch comprises a second switch SW2, one end of the second branch is connected with the series point of the second resistor R2 and the third resistor R3, and the other end of the second branch is used for being connected with the ground of the vehicle body; the series connection point of the third resistor R3 and the fourth resistor R4 is a voltage sampling point, and the reference ground of the voltage sampling point is the negative pole HV < - > of the vehicle high-voltage circuit; the voltage sampling point is connected with the semaphore acquisition and processing part through the semaphore filtering part. The first switch SW1 is further connected to a control circuit for outputting a control signal of the first switch SW1, and the reference ground of the control signal of the first switch SW1 is the negative pole HV-of the vehicle high-voltage circuit.
In this embodiment, R1 ═ R2.
The unbalanced resistance conversion part mainly plays a role in: the semaphore acquisition processing portion acquires the voltage signal Vs with the first switch SW1 and the second switch SW2 in different states by closing the first switch SW1 and the second switch SW2 in a time-sharing manner.
The semaphore filtering part comprises a pre-designed filter, and the main functions of the semaphore filtering part are as follows: the pre-designed filter is used for carrying out relevant filtering processing on the resistance voltage division value of the front-stage resistor R4, so that the voltage signal Vs acquired by the rear stage is more stable and reliable.
The semaphore acquisition processing part comprises a signal acquisition circuit, an analog-to-digital conversion circuit and a processor, and mainly has the following functions: after the acquired voltage signal Vs is subjected to analog-to-digital conversion, the insulation resistance values of the anode and the cathode of the current vehicle high-voltage circuit to the vehicle body ground respectively are calculated through an algorithm stored in a processor in advance and are used for evaluating the insulation state of the current vehicle high-voltage circuit.
The detection device of the embodiment can realize the insulation resistance (namely R) of the high-voltage circuit of the vehicle to the ground of the vehicle bodyp、Rn) The detection process specifically comprises the following steps:
when a power battery system of the new energy vehicle works:
(1) disconnecting the first switch SW1 and the second switch SW2, and collecting a first voltage value Vs1 of a voltage sampling point;
at this time, the total voltage value (i.e. the total voltage value between the positive pole and the negative pole of the vehicle high-voltage circuit) Vsum of the power battery system is Vs1 × (R1+ R2+ R3+ R4)/R4;
(2) closing the first switch SW1 and the second switch SW2, and collecting a second voltage value Vs2 of the voltage sampling points;
at this time, the positive electrode resistance of the vehicle high-voltage circuit is ResP1 ═ RpThe negative pole resistance is ResN1 ═ Rn/(R3+ R4)// R2,// denotes the parallel resistance; according to the principle of serial voltage division, equation 1 can be obtained:
(3) opening the first switch SW1, closing the second switch SW2, and collecting a third voltage value Vs3 of the voltage sampling point;
at this time, the positive electrode resistance of the vehicle high-voltage circuit is ResP2 ═ Rp/(R1+ R2), the cathode resistance is ResN2 ═ Rn/(R3+ R4); according to the principle of serial voltage division, an equation can be obtained2：
Suppose that:
then the insulation resistance value R of the positive pole of the vehicle high-voltage circuit to the vehicle body ground can be calculated according to the equation 1 and the equation 2pAnd the insulation resistance value R of the negative pole of the vehicle high-voltage circuit to the vehicle body groundn：
When the power battery system works, the steps (1) to (3) are executed in a circulating mode, so that the insulation resistance value of the current vehicle high-voltage loop to the vehicle body ground can be obtained in real time, the high-voltage safety state can be predicted in advance by utilizing the obtained insulation resistance value, and the high-voltage potential safety hazard is reduced.
As another embodiment, the execution sequence among the step (1), the step (2), and the step (3) may be adjusted according to actual needs.
When the power battery system does not work, the first switch SW1 and the second switch SW2 are controlled to be disconnected, and the insulation strength of the high-voltage circuit of the vehicle can be improved.
In summary, due to the adoption of the unbalanced resistance conversion part in the special form shown in fig. 1, when the detection device of the embodiment is used for detecting the new energy vehicle insulation resistance, the negative electrode (i.e. the high-voltage ground) of the vehicle high-voltage loop can be used as the reference ground of the voltage sampling point, so that the voltage sampling is performed between the high-voltage signal and the high-voltage ground, and the advantage of high safety is achieved; meanwhile, the negative pole (namely, a high-voltage ground) of the high-voltage circuit of the vehicle can be used as a reference ground of the control signal of the first switch, and the first switch is a high-voltage side switch, so that the control signal of the high-voltage side switch of the detection device of the embodiment is referenced to the high-voltage ground, the high-voltage side switch is controlled by the high-voltage signal, the problem that the high-voltage side switch is controlled by a low-voltage signal is solved, and the safety is high; the high-voltage side switch does not need to adopt a high-voltage and low-voltage isolating switch, so that the cost of the detection device can be reduced; in addition, the insulation resistance detection and the detection of the total voltage value of the power battery system (namely the total voltage detection) share one reference ground (namely the negative pole of the high-voltage loop of the vehicle), so that the insulation resistance detection and the total voltage detection can share one signal acquisition and processing part, and the cost of the detection device can be further reduced.
It should be noted that the detection device of the present embodiment needs to be treated as a whole, and the unbalanced resistance conversion portion in the detection device cannot be separated from the settings of the voltage sampling point reference ground and the reference ground of the control signal of the first switch, and only if the detection device adopts the unbalanced resistance conversion portion of the form of the present embodiment, the negative pole of the vehicle high-voltage circuit can be used as the reference ground of the voltage sampling point and the negative pole of the vehicle high-voltage circuit can be used as the reference ground of the control signal of the first switch.
Claims (3)
1. The utility model provides an automobile-used insulation resistance detection device of new forms of energy which characterized in that, this detection device includes:
the unbalanced resistance conversion part comprises a first branch circuit, a second branch circuit and a third branch circuit, the third branch circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor which are sequentially connected in series, one end of the third branch circuit is used for connecting the anode of a vehicle high-voltage loop, and the other end of the third branch circuit is used for connecting the cathode of the vehicle high-voltage loop; the first branch circuit comprises a first switch, one end of the first branch circuit is connected with a series point of a first resistor and a second resistor, and the other end of the first branch circuit is connected with the negative electrode of the high-voltage loop of the vehicle; the second branch circuit comprises a second switch, one end of the second branch circuit is connected with a series point of a second resistor and a third resistor, and the other end of the second branch circuit is connected with a vehicle body ground; the series connection point of the third resistor and the fourth resistor is a voltage sampling point, and the reference ground of the voltage sampling point is the negative pole of the vehicle high-voltage loop;
and the semaphore acquisition processing part is connected with the voltage sampling point.
2. The insulation resistance detection device for the new energy vehicle according to claim 1, further comprising a semaphore filtering part, wherein the semaphore filtering part is connected in series between the voltage sampling point and the semaphore acquisition processing part.
3. The insulation resistance detection device for the new energy vehicle according to claim 1 or 2, wherein the first switch is further connected to a control circuit, the control circuit is configured to output a control signal of the first switch, and a reference ground of the control signal of the first switch is a negative pole of a high-voltage circuit of the vehicle.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| TWI802331B (en) * | 2022-03-22 | 2023-05-11 | 新普科技股份有限公司 | An insulation resistance detecting equipment and detecting method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| TWI802331B (en) * | 2022-03-22 | 2023-05-11 | 新普科技股份有限公司 | An insulation resistance detecting equipment and detecting method thereof |
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