CN112240954A - Insulation detection circuit and method - Google Patents
Insulation detection circuit and method Download PDFInfo
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Abstract
The invention provides an insulation detection circuit and a method, wherein the insulation detection circuit comprises a high-voltage power supply to be detected, and the insulation detection circuit also comprises: a first voltage dividing circuit, a first resistor R1 and a resistance value variable unit; a second voltage division circuit including a second resistor R2 and a third resistor R3; a third voltage dividing circuit including a fourth resistor R4 and a first switch S1; the first voltage acquisition unit is used for acquiring the voltage to ground of the middle point of the first resistor R1 and the resistance value variable unit; the second voltage acquisition unit is used for acquiring the voltage to ground of a middle point of the second resistor R2 and the third resistor R3; and the processing unit is connected with the first voltage acquisition unit and the second voltage acquisition unit and used for calculating the insulation resistance to the ground of the anode and the cathode of the high-voltage power supply to be detected according to the voltages acquired by the first voltage acquisition unit and the second voltage acquisition unit. After the technical scheme is adopted, the error of insulation detection calculation caused by the voltage fluctuation of the high-voltage power supply to be detected can be avoided, and meanwhile, the existence of a detection blind area can be avoided.
Description
Technical Field
The invention relates to the technical field of insulation detection, in particular to an insulation detection circuit and method.
Background
The measurement of the insulation resistance value of the positive pole and the negative pole of the high-voltage power supply to the ground directly influences the safe work of a high-voltage system, when the measured insulation resistance value is lower than a certain safety value, a circuit needs to be disconnected in time to guarantee safety, if the insulation resistance value measured value is smaller than an actual value, the circuit can be disconnected due to misoperation, the stable work of the circuit is not facilitated, and if the insulation resistance value measured value is larger than the actual value, the actual insulation resistance value is lower than the safety value and cannot be found in time, and potential safety hazards are brought. Referring to fig. 1, in the conventional insulation detection method, a first resistor R1, a first switch S1, a second resistor R2, a third resistor R3, a second switch S2 and a fourth resistor R4 are sequentially connected in series and connected to two ends of a high-voltage power supply to be detected, and a middle point between the second resistor R2 and the third resistor R3 is grounded. In order to measure the insulation resistance value of the high-voltage power supply, 3 states of the switches S1 and S2 are needed, in the 1 st state, the switches S1 and S2 are closed, and the voltage V1 at the two ends of the second resistor R2 and the voltage V2 at the two ends of the third resistor R3 are obtained; the 2 nd state, closing S1, opening S2, obtaining the voltage V1_1 at the two ends of the second resistor R2; the 3 rd state, closing S2, opening S1, obtaining the voltage V2_1 across the third resistor R3; then, according to the obtained V1, V2, V1_1 and V2_1, the insulation resistance Rp of the positive pole of the high-voltage power supply to the ground and the insulation resistance Rn of the negative pole of the high-voltage power supply to the ground can be calculated. For example, when R1 ═ R4 ═ R6, R2 ═ R3 ═ R5, R1+ R2 ═ R3+ R4 ═ RS,
Rp＝(-RS*V1-RS*V2-RS*V1_1+RS*V2_1)/V2_1
Rn＝(RS*V1-RS*V2-RS*V1_1+RS*V2_1)/V1_1
the existing detection method has the problems that voltage fluctuation when the high-voltage power supply works with a load cannot be avoided, and the voltage cannot fluctuate between the on-off state of a switch for many times when the accurate insulation resistance value is required to be obtained.
When an electric vehicle is static, a power load does not work (such as a motor and the like), the voltage of the high-voltage battery pack is basically stable, and the insulation resistance value can be accurately calculated at the moment; when the electric automobile works, a power load works normally (such as a motor and the like), the voltage of the high-voltage battery pack fluctuates along with the change of the power load (such as the speed of the rotating speed of the motor, sudden stop, sudden start and the like), and the measurement of the insulation resistance value introduces errors due to noise voltage introduced during the work of the load, and the larger the voltage fluctuation of the high-voltage battery pack is, the larger the measurement error of the insulation resistance value is.
Meanwhile, the existing insulation detection has a blind area, and in the detection process, if the insulation resistance values of the anode and the cathode of the high-voltage power supply to the ground change simultaneously and meet corresponding conditions, the voltage of a sampling point does not change, and the insulation detection circuit cannot detect the changed insulation resistance value.
Therefore, it is necessary to develop an insulation detection circuit and method that can effectively avoid the influence of voltage fluctuation on insulation detection accuracy and avoid insulation detection blind areas.
Disclosure of Invention
In order to overcome the technical defects, the invention aims to provide an insulation detection circuit and method which can effectively avoid the influence of voltage fluctuation on insulation detection accuracy and can avoid an insulation detection blind area.
The invention discloses an insulation detection circuit, which comprises a high-voltage power supply to be detected and also comprises:
a first voltage dividing circuit including a first resistor R1 and a resistance variable unit, wherein a first end of the first resistor R1 is connected to a first pole of the high-voltage power supply to be detected, a second end of the first resistor R1 is connected to a first end of the resistance variable unit, and a second end of the resistance variable unit is grounded;
the second voltage division circuit comprises a second resistor R2 and a third resistor R3, the first end of the third resistor R3 is connected with the second pole of the high-voltage power supply to be detected, the second end of the third resistor R3 is connected with the first end of the second resistor R2, and the second end of the second resistor R2 is grounded;
a third voltage dividing circuit, including a fourth resistor R4 and a first switch S1, wherein a first end of the fourth resistor R4 is connected to a first pole of the high-voltage power supply to be detected, a second end of the fourth resistor R4 is connected to a first end of the first switch S1, and a second end of the first switch S1 is grounded;
the first voltage acquisition unit is used for acquiring the voltage to ground of the middle point of the first resistor R1 and the resistance value variable unit;
the second voltage acquisition unit is used for acquiring the voltage to ground of a middle point of the second resistor R2 and the third resistor R3;
and the processing unit is connected with the first voltage acquisition unit and the second voltage acquisition unit and used for calculating the ground insulation resistance of the anode and the cathode of the high-voltage power supply to be detected according to the voltages acquired by the first voltage acquisition unit and the second voltage acquisition unit.
Preferably, the resistance variable unit includes a fifth resistor R5, a sixth resistor R6, and a second switch S2, a first end of the fifth resistor R5 is connected to a second end of the first resistor R1, a second end of the fifth resistor R5 is connected to a first end of the sixth resistor R6, a second end of the sixth resistor R6 is grounded, a first end of the second switch S2 is connected to a first end of the sixth resistor R6, and a second end of the second switch S2 is connected to a second end of the sixth resistor R6.
Preferably, the resistance value of the first resistor R1 is equal to the resistance value of the third resistor R3;
the sum of the resistance values of the fifth resistor R5 and the sixth resistor R6 is equal to the resistance value of the second resistor R2;
the sum of the resistances of the first resistor R1, the fifth resistor R5 and the sixth resistor R6 is equal to the resistance of the fourth resistor R4.
Preferably, the resistance value variable unit is a digital potentiometer.
Preferably, the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are all constant value resistors.
Preferably, the switch S1 is a switching transistor.
Preferably, the switching transistor is a mos transistor.
Preferably, the first voltage acquisition unit and the second voltage acquisition unit are both analog-to-digital converters.
Preferably, the processing unit is a single chip microcomputer.
The invention also discloses an insulation detection method, which adopts the insulation detection circuit, and the detection steps comprise:
s1: closing a first switch S1, collecting a voltage V1_1 to ground of an intermediate point of the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_1 to ground of an intermediate point of the second resistor R2 and the third resistor R3;
s2: opening a first switch S1, collecting a voltage V1_2 to ground at an intermediate point of the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_2 to ground at an intermediate point of the second resistor R2 and the third resistor R3;
s3: calculating the ground insulation resistance values Rp _ S1 and Rn _ S1 of the positive electrode and the negative electrode of the high-voltage power supply to be detected according to the voltages V1_1, V2_1, V1_2 and V2_ 2;
s4: opening a first switch S1, changing the resistance of the resistance value variable unit, collecting a voltage V1_3 to ground at an intermediate point between the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_3 to ground at an intermediate point between the second resistor R2 and the third resistor R3;
s5: calculating the ground insulation resistance values Rp _ S1 and Rn _ S1 of the positive electrode and the negative electrode of the high-voltage power supply to be detected according to the voltages V1_2, V2_2, V1_3 and V2_ 3;
s6: and comparing whether Rp _ S1 is equal to Rp _ S2 or not, comparing whether Rn _ S1 is equal to Rn _ S2 or not, and judging whether the insulation resistance to the ground of the anode and the cathode of the high-voltage power supply to be detected changes simultaneously or not.
After the technical scheme is adopted, compared with the prior art, the method has the following beneficial effects:
1. the voltage acquisition unit can always acquire the voltage of the high-voltage battery pack, so that the influence of voltage fluctuation on the accuracy of insulation detection can be avoided;
2. the insulation detection blind area can be effectively avoided, and the accuracy of insulation detection is improved.
Drawings
FIG. 1 is a schematic diagram of a prior art insulation detection circuit;
FIG. 2 is a schematic diagram of an insulation detection circuit according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an insulation detection circuit according to another embodiment of the invention.
DigiPOT-digital potentiometer
Detailed Description
The advantages of the invention are further illustrated in the following description of specific embodiments in conjunction with the accompanying drawings.
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.
The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It is to be understood that although the terms first, second, third, etc. may be used herein to describe various information, such information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present disclosure. The word "if" as used herein may be interpreted as "at … …" or "when … …" or "in response to a determination", depending on the context.
In the description of the present invention, unless otherwise specified and limited, it is to be noted that the terms "mounted," "connected," and "connected" are to be interpreted broadly, and may be, for example, a mechanical connection or an electrical connection, a communication between two elements, a direct connection, or an indirect connection via an intermediate medium, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.
In the following description, suffixes such as "module", "component", or "unit" used to denote elements are used only for facilitating the explanation of the present invention, and have no specific meaning in themselves. Thus, "module" and "component" may be used in a mixture.
Referring to fig. 2, a schematic diagram of an insulation detection circuit according to an embodiment of the present invention is shown, where the insulation detection circuit includes a high-voltage power supply to be detected, the high-voltage power supply to be detected may be a high-voltage battery pack on a vehicle, and the vehicle may be an electric vehicle. The high-voltage power supply to be detected is usually connected with a load to supply power to the load. The insulation detection circuit of the present application includes:
-a first voltage divider circuit
The high-voltage power supply circuit comprises a first resistor R1 and a resistance variable unit, wherein a first end of the first resistor R1 is connected with a first pole of the high-voltage power supply to be detected, a second end of the first resistor R1 is connected with a first end of the resistance variable unit, and a second end of the resistance variable unit is grounded. The first pole of the high-voltage power supply to be detected can be the anode or the cathode of the high-voltage power supply to be detected, and correspondingly, the second pole of the high-voltage power supply to be detected is the pole opposite to the first pole. In this embodiment, the first electrode of the high voltage power supply to be detected is a positive electrode. Referring to fig. 2, in this embodiment, the resistance variable unit includes a fifth resistor R5, a sixth resistor R6, and a second switch S2, a first end of the fifth resistor R5 is connected to a second end of the first resistor R1, a second end of the fifth resistor R5 is connected to a first end of the sixth resistor R6, a second end of the sixth resistor R6 is grounded, a first end of the second switch S2 is connected to a first end of the sixth resistor R6, and a second end of the second switch S2 is connected to a second end of the sixth resistor R6. The second switch S2 short-circuits the sixth resistor R6 when closed, so that the resistance value of the resistance value variable unit is different when the second switch S2 is opened and closed, the resistance value of the resistance value variable unit is R5+ R6 when the second switch S2 is opened, the resistance value of the resistance value variable unit is R5 when the second switch S2 is closed, and the resistance value of the resistance value variable unit is changed by the opening and closing of the second switch S2. The second switch S2 is preferably a switching transistor. Preferably, the switching transistor is a mos transistor. Referring to fig. 3, in another embodiment of the present invention, the resistance variable unit is a Digital Potentiometer (Digital Potentiometer), and the Digital Potentiometer is controlled to change the resistance.
-a second voltage divider circuit
The detection circuit comprises a second resistor R2 and a third resistor R3, wherein the first end of the third resistor R3 is connected with the second pole of the high-voltage power supply to be detected, the second end of the third resistor R3 is connected with the first end of the second resistor R2, and the second end of the second resistor R2 is grounded.
-a third voltage dividing circuit
The high-voltage power supply circuit comprises a fourth resistor R4 and a first switch S1, wherein the first end of the fourth resistor R4 is connected with the first pole of the high-voltage power supply to be detected, the second end of the fourth resistor R4 is connected with the first end of the first switch S1, and the second end of the first switch S1 is grounded. The first switch S1 is preferably a switching transistor. Preferably, the switching transistor is a mos transistor.
-a first voltage acquisition unit
The voltage to ground of the middle point of the first resistor R1 and the resistance value variable unit is collected. Preferably, the first voltage collecting unit includes an analog-to-digital converter, collects a voltage to ground at a midpoint between the first resistor R1 and the resistance variable unit, that is, a voltage across the resistance variable unit, and converts the voltage to a digital signal.
-a second voltage acquisition unit
The voltage to ground of the middle point of the second resistor R2 and the third resistor R3 is collected. Preferably, the second voltage collecting unit includes an analog-to-digital converter, collects a voltage to ground at a middle point between the second resistor R2 and the third resistor R3, that is, a voltage across the second resistor R2, and converts the voltage to a digital signal.
-a processing unit
And the ground insulation resistance of the anode and the cathode of the high-voltage power supply to be detected is calculated according to the voltages acquired by the first voltage acquisition unit and the second voltage acquisition unit. Preferably, the processing unit is a single chip microcomputer. Preferably, the resistance value variable unit is connected with the processing unit and is controlled by the processing unit to change the resistance. Preferably, the first switch S1 is connected to the processing unit and is controlled by the processing unit to be turned on and off. When the earth insulation resistance of the anode and the cathode of the high-voltage power supply to be detected needs to be measured, the processing unit is turned on and off through the control switch S1, the resistance variable unit is controlled to change the resistance, and the earth insulation resistance Rp and Rn of the anode and the cathode of the high-voltage power supply to be detected can be calculated according to the voltages acquired by the first voltage acquisition unit and the second voltage acquisition unit and the resistance values of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4 and the resistance variable unit. Preferably, the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are all constant value resistors.
Specifically, the method for detecting the insulation resistance to the ground of the anode and the cathode of the high-voltage power supply to be detected by adopting the insulation detection circuit comprises the following steps:
s1: closing a first switch S1, collecting a voltage V1_1 to ground of an intermediate point of the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_1 to ground of an intermediate point of the second resistor R2 and the third resistor R3;
s2: opening a first switch S1, collecting a voltage V1_2 to ground at an intermediate point of the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_2 to ground at an intermediate point of the second resistor R2 and the third resistor R3;
s3: calculating the ground insulation resistance values Rp _ S1 and Rn _ S1 of the positive electrode and the negative electrode of the high-voltage power supply to be detected according to the voltages V1_1, V2_1, V1_2 and V2_ 2;
s4: opening a first switch S1, changing the resistance of the resistance value variable unit, collecting a voltage V1_3 to ground at an intermediate point between the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_3 to ground at an intermediate point between the second resistor R2 and the third resistor R3;
s5: calculating the ground insulation resistance values Rp _ S1 and Rn _ S1 of the positive electrode and the negative electrode of the high-voltage power supply to be detected according to the voltages V1_2, V2_2, V1_3 and V2_ 3;
s6: and comparing whether Rp _ S1 is equal to Rp _ S2 or not, comparing whether Rn _ S1 is equal to Rn _ S2 or not, and judging whether the insulation resistance to the ground of the anode and the cathode of the high-voltage power supply to be detected changes simultaneously or not.
For the embodiment of fig. 2, in step S1, the first switch S1 is closed and the second switch S2 is open;
in step S2, the first switch S1 is opened, and the second switch S2 is opened;
in step S3, the calculation process is as follows:
establishing an equation set:
solving to obtain:
Rp_S1＝Rp＝-(R1*R4*V1_1*V2_2-R1*R4*V1_2*V2_1+R4*R5*V1_1*V2_2-R4*R5*V1_2*V2_1+R4*R6*V1_1*V2_2-R4*R6*V1_2*V2_1)/(R1*V1_1*V2_2+R4*V1_1*V2_2-R4*V1_2*V2_1+R5*V1_1*V2_2+R6*V1_1*V2_2)
Rn_S1＝Rn＝(R2*R4*R5*V1_1*V2_2-R2*R4*R5*V1_2*V2_1+R2*R4*R6*V1_1*V2_2-R2*R4*R6*V1_2*V2_1+R3*R4*R5*V1_1*V2_2-R3*R4*R5*V1_2*V2_1+R3*R4*R6*V1_1*V2_2-R3*R4*R6*V1_2*V2_1)/(R1*R2*V1_1*V1_2+R2*R5*V1_1*V1_2+R2*R6*V1_1*V1_2-R4*R5*V1_1*V2_2+R4*R5*V1_2*V2_1-R4*R6*V1_1*V2_2+R4*R6*V1_2*V2_1)
in step S4, the first switch S1 is opened, the second switch S2 is closed, and the resistance of the resistance value variable unit is changed by closing the second switch S2.
In step S5, the calculation process is as follows:
establishing an equation set:
solving to obtain:
Rp_S2＝Rp＝-(R5^2*V1_3*V2_2-R5^2*V1_2*V2_3-R1*R5*V1_2*V2_3+R1*R5*V1_3*V2_2+R1*R6*V1_3*V2_2-R5*R6*V1_2*V2_3+R5*R6*V1_3*V2_2)/(R5*V1_3*V2_2-R5*V1_2*V2_3+R6*V1_3*V2_2)
Rn_S2＝Rn＝(R2*R5^2*V1_3*V2_2-R2*R5^2*V1_2*V2_3-R3*R5^2*V1_2*V2_3+R3*R5^2*V1_3*V2_2-R1*R2*R5*V1_2*V2_3+R1*R2*R5*V1_3*V2_2+R1*R2*R6*V1_3*V2_2-R1*R3*R5*V1_2*V2_3+R1*R3*R5*V1_3*V2_2+R1*R3*R6*V1_3*V2_2-R2*R5*R6*V1_2*V2_3+R2*R5*R6*V1_3*V2_2-R3*R5*R6*V1_2*V2_3+R3*R5*R6*V1_3*V2_2)/(R5^2*V1_2*V2_3-R5^2*V1_3*V2_2+R1*R5*V1_2*V2_3-R1*R5*V1_3*V2_2-R1*R6*V1_3*V2_2+R2*R6*V1_2*V1_3+R5*R6*V1_2*V2_3-R5*R6*V1_3*V2_2)
in step S6, it is determined whether Rp _ S1 is equal to Rp _ S2, Rn _ S1 is equal to Rn _ S2, and whether the insulation resistances to ground of the positive and negative electrodes of the high-voltage power supply to be detected have changed simultaneously. If Rp _ S1 is not equal to Rp _ S2, and Rn _ S1 is not equal to Rn _ S2, it is proved that the ground insulation resistance values of the anode and the cathode of the high-voltage power supply to be detected change simultaneously in the detection process, and the detection result in the insulation detection period is inaccurate. Therefore, steps S1-S6 may be performed again, with Rp _ S1 equal to Rp _ S2 and Rn _ S1 equal to Rn _ S2 as the final ground insulation resistance value. The equality referred to herein may mean complete equality or a difference within a predetermined reasonable range.
For the embodiment of fig. 2, to simplify the calculation, it is preferable to make the resistance value of the first resistor R1 equal to the resistance value of the third resistor R3; the sum of the resistance values of the fifth resistor R5 and the sixth resistor R6 is equal to the resistance value of the second resistor R2; the sum of the resistances of the first resistor R1, the fifth resistor R5 and the sixth resistor R6 is equal to the resistance of the fourth resistor R4. That is, R1 ═ R3, R5+ R6 ═ R2, R4 ═ R1+ R5+ R6 ═ R2+ R3 ═ RS. At this time, in step S3, let K ═ R2/(R2+ R3) ═ R5+ R6)/(R1+ R5+ R6), the equation set of step S3 can be simplified as:
solving to obtain:
Rp_S1＝Rp＝(RS*V1_1*V2_2-RS*V1_2*V2_1)/(V1_2*V2_1-2*V1_1*V2_2)
Rn_S1＝Rn＝(RS*V1_1*V2_2-RS*V1_2*V2_1)/(V1_1*V1_2-V1_1*V2_2+V1_2*V2_1)
in step S5, let K — R2/(R2+ R3) and K _1 — R5/(R1+ R5), the equation set in step S5 can be simplified as follows:
solving to obtain:
Rp_S2＝Rp＝-(K*RS^2*V1_3*V2_2-K_1*RS^2*V1_2*V2_3-K*R6*RS*V1_3*V2_2+K_1*R6*RS*V1_2*V2_3)/(K*RS*V1_3*V2_2+K_1*R6*V1_2*V2_3-K_1*RS*V1_2*V2_3)
Rn_S2＝Rn＝(K*RS^2*V1_3*V2_2-K_1*RS^2*V1_2*V2_3-K*R6*RS*V1_3*V2_2+K_1*R6*RS*V1_2*V2_3)/(K*R6*V1_2*V1_3+K*R6*V1_3*V2_2-K*RS*V1_3*V2_2-K_1*R6*V1_2*V2_3+K_1*RS*V1_2*V2_3)
the technical scheme of this application, because can gather the voltage that waits to detect high voltage power supply all the time when detecting, can not lose the cycle like prior art, consequently can avoid voltage fluctuation to cause the influence to the accuracy that the insulation detected. Meanwhile, the resistance is changed through the resistance value adjustable unit in the detection process, and the ground insulation resistance is calculated under the condition that the resistance values in the detection circuit are different, so that the detection blind area can be effectively avoided, and the accuracy of the detection result is ensured. Specifically, only by performing steps S1 to S3, the ground insulation resistance values of the positive and negative electrodes of the high-voltage power supply to be detected can be calculated without changing the resistance values of the resistance value variable cells (in this case, the resistance value variable cells can be regarded as constant value resistors). However, such detection has a blind area, if in the two processes of steps S1 and S2, the ground insulation resistance values Rp and Rn of the positive and negative electrodes of the high-voltage power supply to be detected both change at the same time, and when a specific condition is satisfied (the insulation resistance value change satisfies a specific calculation formula), the voltage at the sampling point (i.e., the voltage collected by the first voltage collecting unit and the second voltage collecting unit) does not change, so in this case, the ground insulation resistance value calculated in step S3 is inaccurate, and the detection calculation method has a blind area, i.e., the changed ground insulation resistance value cannot be effectively detected. This application changes the resistance value through setting up the variable unit of resistance value, changes the resistance value, carries out voltage acquisition and insulation resistance again and calculates, and the specific condition that Rp and Rn change simultaneously and sampling point voltage unchangeable needs satisfy can be broken in the change of the variable unit resistance value of resistance value to whether Rp and Rn change simultaneously can be judged out through the insulation resistance value to ground of comparing two calculations. Therefore, the insulation detection blind area can be effectively avoided, and the accuracy of the insulation detection result is ensured.
It should be noted that the embodiments of the present invention have been described in terms of preferred embodiments, and not by way of limitation, and that those skilled in the art can make modifications and variations of the embodiments described above without departing from the spirit of the invention.
Claims (10)
1. An insulation detection circuit, including waiting to examine the high voltage power supply, its characterized in that still includes:
a first voltage dividing circuit including a first resistor R1 and a resistance variable unit, wherein a first end of the first resistor R1 is connected to a first pole of the high-voltage power supply to be detected, a second end of the first resistor R1 is connected to a first end of the resistance variable unit, and a second end of the resistance variable unit is grounded;
the second voltage division circuit comprises a second resistor R2 and a third resistor R3, the first end of the third resistor R3 is connected with the second pole of the high-voltage power supply to be detected, the second end of the third resistor R3 is connected with the first end of the second resistor R2, and the second end of the second resistor R2 is grounded;
a third voltage dividing circuit, including a fourth resistor R4 and a first switch S1, wherein a first end of the fourth resistor R4 is connected to a first pole of the high-voltage power supply to be detected, a second end of the fourth resistor R4 is connected to a first end of the first switch S1, and a second end of the first switch S1 is grounded;
the first voltage acquisition unit is used for acquiring the voltage to ground of the middle point of the first resistor R1 and the resistance value variable unit;
the second voltage acquisition unit is used for acquiring the voltage to ground of a middle point of the second resistor R2 and the third resistor R3;
and the processing unit is connected with the first voltage acquisition unit and the second voltage acquisition unit and used for calculating the ground insulation resistance of the anode and the cathode of the high-voltage power supply to be detected according to the voltages acquired by the first voltage acquisition unit and the second voltage acquisition unit.
2. The insulation detection circuit of claim 1,
the resistance value variable unit comprises a fifth resistor R5, a sixth resistor R6 and a second switch S2, wherein a first end of the fifth resistor R5 is connected with a second end of the first resistor R1, a second end of the fifth resistor R5 is connected with a first end of the sixth resistor R6, a second end of the sixth resistor R6 is grounded, a first end of the second switch S2 is connected with a first end of the sixth resistor R6, and a second end of the second switch S2 is connected with a second end of the sixth resistor R6.
3. The insulation detection circuit of claim 2,
the resistance value of the first resistor R1 is equal to that of the third resistor R3;
the sum of the resistance values of the fifth resistor R5 and the sixth resistor R6 is equal to the resistance value of the second resistor R2;
the sum of the resistances of the first resistor R1, the fifth resistor R5 and the sixth resistor R6 is equal to the resistance of the fourth resistor R4.
4. The insulation detection circuit of claim 1,
the resistance value variable unit is a digital potentiometer.
5. The insulation detection circuit of claim 1,
the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are all constant-value resistors.
6. The insulation detection circuit of claim 1,
the switch S1 is a switching transistor.
7. The insulation detection circuit of claim 6,
the switching triode is a mos tube.
8. The insulation detection circuit of claim 1,
the first voltage acquisition unit and the second voltage acquisition unit are analog-to-digital converters.
9. The insulation detection circuit of claim 1,
the processing unit is a single chip microcomputer.
10. An insulation detection method, characterized in that, with the insulation detection circuit according to any one of claims 1 to 9, the detection step comprises:
s1: closing a first switch S1, collecting a voltage V1_1 to ground of an intermediate point of the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_1 to ground of an intermediate point of the second resistor R2 and the third resistor R3;
s2: opening a first switch S1, collecting a voltage V1_2 to ground at an intermediate point of the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_2 to ground at an intermediate point of the second resistor R2 and the third resistor R3;
s3: calculating the ground insulation resistance values Rp _ S1 and Rn _ S1 of the positive electrode and the negative electrode of the high-voltage power supply to be detected according to the voltages V1_1, V2_1, V1_2 and V2_ 2;
s4: opening a first switch S1, changing the resistance of the resistance value variable unit, collecting a voltage V1_3 to ground at an intermediate point between the first resistor R1 and the resistance value variable unit, and collecting a voltage V2_3 to ground at an intermediate point between the second resistor R2 and the third resistor R3;
s5: calculating the ground insulation resistance values Rp _ S1 and Rn _ S1 of the positive electrode and the negative electrode of the high-voltage power supply to be detected according to the voltages V1_2, V2_2, V1_3 and V2_ 3;
s6: and comparing whether Rp _ S1 is equal to Rp _ S2 or not, comparing whether Rn _ S1 is equal to Rn _ S2 or not, and judging whether the insulation resistance to the ground of the anode and the cathode of the high-voltage power supply to be detected changes simultaneously or not.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112986684A (en) * | 2021-02-02 | 2021-06-18 | 深圳车库电桩科技有限公司 | Fill electric pile insulation detection circuitry |
| CN113945760A (en) * | 2021-10-18 | 2022-01-18 | 北京电子科技职业学院 | Electric vehicle insulation resistance detection system |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279318A (en) * | 2011-06-23 | 2011-12-14 | 广东易事特电源股份有限公司 | On-line detection system for ground insulation resistance of photovoltaic grid-connected inverter |
| CN104378068A (en) * | 2014-11-21 | 2015-02-25 | 江苏兆伏爱索新能源有限公司 | Detection method and circuit for ground insulation resistance of photovoltaic module array |
| CN205246760U (en) * | 2014-11-21 | 2016-05-18 | 艾思玛新能源技术（上海）有限公司苏州高新区分公司 | Photovoltaic module array insulation against ground impedance detection circuitry |
| CN106093739A (en) * | 2016-08-23 | 2016-11-09 | 山东泰开自动化有限公司 | A kind of charging pile insulation monitoring and warning device of special bridge method design |
| CN107643449A (en) * | 2017-08-18 | 2018-01-30 | 深圳市朗能动力技术有限公司 | Detection circuit and detection method of the high pressure to the insulaion resistance of low pressure |
| CN108398645A (en) * | 2018-01-31 | 2018-08-14 | 山东魔方新能源科技有限公司 | A kind of electric automobile insulation impedance detection method |
| CN109239461A (en) * | 2018-09-29 | 2019-01-18 | 宝沃汽车（中国）有限公司 | The test method and system of the insulation resistance of electric car |
| CN109720235A (en) * | 2018-12-29 | 2019-05-07 | 蜂巢能源科技有限公司 | Insulation Inspection System and electric car based on full-bridge insulation detecting circuit |
-
2019
- 2019-07-17 CN CN201910643379.0A patent/CN112240954A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102279318A (en) * | 2011-06-23 | 2011-12-14 | 广东易事特电源股份有限公司 | On-line detection system for ground insulation resistance of photovoltaic grid-connected inverter |
| CN104378068A (en) * | 2014-11-21 | 2015-02-25 | 江苏兆伏爱索新能源有限公司 | Detection method and circuit for ground insulation resistance of photovoltaic module array |
| CN205246760U (en) * | 2014-11-21 | 2016-05-18 | 艾思玛新能源技术（上海）有限公司苏州高新区分公司 | Photovoltaic module array insulation against ground impedance detection circuitry |
| CN106093739A (en) * | 2016-08-23 | 2016-11-09 | 山东泰开自动化有限公司 | A kind of charging pile insulation monitoring and warning device of special bridge method design |
| CN107643449A (en) * | 2017-08-18 | 2018-01-30 | 深圳市朗能动力技术有限公司 | Detection circuit and detection method of the high pressure to the insulaion resistance of low pressure |
| CN108398645A (en) * | 2018-01-31 | 2018-08-14 | 山东魔方新能源科技有限公司 | A kind of electric automobile insulation impedance detection method |
| CN109239461A (en) * | 2018-09-29 | 2019-01-18 | 宝沃汽车（中国）有限公司 | The test method and system of the insulation resistance of electric car |
| CN109720235A (en) * | 2018-12-29 | 2019-05-07 | 蜂巢能源科技有限公司 | Insulation Inspection System and electric car based on full-bridge insulation detecting circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112986684A (en) * | 2021-02-02 | 2021-06-18 | 深圳车库电桩科技有限公司 | Fill electric pile insulation detection circuitry |
| CN113945760A (en) * | 2021-10-18 | 2022-01-18 | 北京电子科技职业学院 | Electric vehicle insulation resistance detection system |
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