CN108051642B - High-voltage direct-current bus insulation resistance detection device and detection method - Google Patents
High-voltage direct-current bus insulation resistance detection device and detection method Download PDFInfo
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- CN108051642B CN108051642B CN201711215194.7A CN201711215194A CN108051642B CN 108051642 B CN108051642 B CN 108051642B CN 201711215194 A CN201711215194 A CN 201711215194A CN 108051642 B CN108051642 B CN 108051642B
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Abstract
The invention discloses a high-voltage direct-current bus insulation resistance detection device which comprises a microprocessor, a bus voltage sampling circuit, an excitation voltage sampling circuit, a control power supply, a power supply positive and negative switching circuit, an excitation power supply conversion circuit and a voltage dividing resistance voltage sampling circuit, wherein the bus voltage sampling circuit is connected with the excitation voltage sampling circuit; the control power supply is connected with the microprocessor, the bus voltage sampling circuit, the excitation voltage sampling circuit and the divider resistance voltage sampling circuit are all connected with the microprocessor, the microprocessor is connected with the excitation power supply conversion circuit, the excitation power supply conversion circuit is connected with the sampling circuit of the insulation resistance, the microprocessor is connected with the power supply anode and cathode switching circuit, the power supply anode and cathode switching circuit is connected with the divider resistance voltage sampling circuit, and the microprocessor is connected with the CAN communication. According to the invention, through the generation of excitation voltage and the switching of the relay, the insulation resistance of the positive electrode or the negative electrode of the high-voltage bus to the shell is calculated, and then whether the insulation resistance of the bus to the shell is reduced or not is judged, so that the potential safety hazard caused by too low insulation resistance of the high-voltage bus is eliminated.
Description
Technical Field
The invention belongs to the field of direct-current insulation resistance detection, high-voltage power supply and safe power utilization, and relates to a high-voltage direct-current bus insulation resistance detection device and a detection method.
Background
At present, insulation resistance detection modes of a low-voltage power supply system are more, detection is mostly carried out under the condition of no bus voltage, and a current transformer is used for detecting the insulation resistance in the traditional mode, so that the volume is larger; in order to solve a series of problems that the insulation resistance of a direct-current high-voltage power supply and distribution system bus to a shell is reduced, the safety of a human body is threatened, cable combustion can be caused, even fire disasters occur and the like, the invention detects the insulation resistance of the system, can realize early warning when the insulation resistance is small, and improves the power utilization safety. A series of threats generated by operators are eliminated, and the insulation resistance detection system does not adopt a sensor to measure the current to calculate the insulation resistance, so that the volume of the insulation resistance detection system is reduced.
Disclosure of Invention
The invention aims to provide a high-voltage direct-current bus insulation resistance detection device and a detection method, which are used for calculating the insulation resistance of a positive electrode or a negative electrode of a high-voltage bus to a shell through the generation of excitation voltage and the switching of a relay so as to judge whether the insulation resistance of the bus to the shell is reduced or not, thereby eliminating the potential safety hazard caused by the excessively low insulation resistance of the high-voltage bus.
The purpose of the invention can be realized by the following technical scheme:
the high-voltage direct-current bus insulation resistance detection device comprises a microprocessor, a bus voltage sampling circuit, an excitation voltage sampling circuit, a control power supply, a power supply positive and negative switching circuit, an excitation power supply conversion circuit and a voltage dividing resistor voltage sampling circuit;
the control power supply is connected with the microprocessor and supplies power to the microprocessor through the control power supply;
the bus voltage sampling circuit, the excitation voltage sampling circuit and the voltage dividing resistor sampling circuit are all connected with the microprocessor, and the microprocessor sends instructions to sample the bus voltage, the excitation voltage and the insulation resistor;
the microprocessor is connected with the excitation power supply conversion circuit, the excitation power supply conversion circuit is connected with the sampling circuit of the insulation resistor, the microprocessor controls the conversion of DC24V into DC200V excitation power supply through the excitation power supply conversion circuit and controls the conversion of the excitation power supply, and the converted DC200V excitation power supply supplies power for the voltage sampling circuit of the divider resistor;
the microprocessor is connected with the power supply positive and negative switching circuit, the power supply positive and negative switching circuit is connected with the voltage dividing resistor voltage sampling circuit, the microprocessor controls the power supply positive and negative switching circuit, a double-switch relay in the power supply positive and negative switching circuit controls the positive and negative poles of the power supply to be selectively connected, and the detection requirements of the voltage dividing resistor R0 under different states are met; meanwhile, the microprocessor is connected with CAN communication.
Further, the voltage sampling circuit of the voltage dividing resistor comprises a 200V power supply, the 200V power supply is a DC200V excitation power supply converted by an excitation power conversion circuit controlling DC24V, the 200V power supply is connected with 7 series resistors through a diode, one end of the 7 series resistors is connected with a voltage dividing resistor R15, one end of the voltage dividing resistor R15 is connected with a 2 pin of an isolation operational amplifier chip E1, the other end of the voltage dividing resistor R15 is connected with a test access point, a 1 pin of the isolation operational amplifier chip E1 is connected with the test access point through a capacitor, the test access point is connected with a positive and negative electrode switching control circuit of the power supply, the end is connected with a 3 pin and a 4 pin of an isolation operational amplifier chip E1, two ends of the voltage dividing resistor R15 are connected with a diode and two capacitors in parallel, an 8 pin of the isolation operational amplifier chip E1 is connected with a +5V power supply, the isolation operational amplifier chip E1 is powered through a +5V power supply, a 7 pin of the isolation operational amplifier chip E1 is connected with, the 6 pins of the isolation operational amplifier chip E1 are connected with the 2 pins of the operational amplifier N1A through a resistor R12, and the output 1 end of the operational amplifier N1A is connected with the AD sampling port of the microprocessor through a resistor R11.
Further, the excitation power conversion circuit comprises a +24V power supply, the +24V power supply is connected with a pin 1 of an inductor L1, a pin 2 of the inductor L1 is connected with a pin 2 of a DC-DC power module U1 through a capacitor C4 and an electrolytic capacitor C10 which are connected in parallel, the other end of a electrolytic capacitor C10 is connected with a pin 1 of a power module U1, a pin 5 of a power module U1 is connected with one end of an electrolytic capacitor C1, a pin 3 is connected with the other end of an electrolytic capacitor C1, two ends of the electrolytic capacitor C1 are connected in parallel with a capacitor C2, one end of the capacitor C2 is grounded, one end of the capacitor C2 is connected with a 200V power supply, two ends of the capacitor C2 are connected in parallel with a capacitor C3, a resistor R2 and a diode, a pin 6 of the power module U1 is connected with a pin 4 of an electric coupler E1, a pin 1 of the electric coupler E, the power supply of the E1 is electrically coupled through a +5V power supply, and the 1 pin of the E1 is connected with the microprocessor.
The power supply positive and negative switching circuit comprises a thermocouple E3, a microprocessor is connected with 2 pins of the thermocouple E3, a base electrode of a triode is connected with 3 pins through a resistor and a capacitor which are connected in parallel, a collector electrode of the triode is grounded, an emitter electrode of the triode is connected with 2 pins of a relay, 4 pins of the thermocouple E3 are connected with 1 pin of the relay through a resistor, 3 pins of the relay are grounded through three series resistors, 4 pins of the relay are connected with a test access point, and the test access point is connected with a voltage sampling circuit of a divider resistor.
The method for detecting the insulation resistance of the high-voltage direct-current bus comprises the following steps:
s1: the microprocessor samples the voltage through a divider resistorVoltage U across a shunt resistor R01ROAnd U2ROThe excitation voltage value is collected through an excitation voltage sampling circuit, and meanwhile, the microprocessor collects bus voltage Vbus through a bus voltage sampling circuit;
s2: the microprocessor collects the voltage U1ROAnd U2ROInsulation resistance calculation formula of high-voltage bus negative pole to shell by excitation voltage value and bus voltage V bus input
Formula for calculating insulation resistance of medium or high voltage bus anode to shell
Calculating to obtain the resistance values of the insulation resistors Rb and Rc;
s3: the microprocessor compares the calculated resistance values of the insulation resistors Rb and Rc with a set value, reports the resistance values through the CAN bus when the calculated insulation resistance values are smaller than the set value, and flickers through an alarm indicator lamp to remind an operator to process the insulation resistance values.
The invention has the beneficial effects that:
the invention has simple circuit principle and few components, and can be transplanted to various devices needing to monitor the insulation resistance;
the invention is suitable for a wide range of power supply systems, and can be applied to power supply systems from dozens of volts to thousands of volts.
The invention has high safety and reduces the accidents of casualties caused by over-low insulation resistance.
The detection modes of the invention are various, and not only the condition that the bus is not electrified but also the condition that the bus is electrified can be detected.
The invention has strong anti-interference capability, and can accurately calculate the resistance value of the insulation resistor even if the bus voltage is jumping by sampling the bus voltage.
The invention has strong anti-vibration performance, and the resistors are connected in series in the switching loop, thereby preventing the relay from being instantaneously short-circuited to burn out the relay in the harsh vibration impact environment and ensuring the safety.
Drawings
In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.
FIG. 1 is a schematic structural diagram of a high-voltage direct-current bus insulation resistance detection device according to the present invention;
FIG. 2 is a voltage sampling circuit of the divider resistor of the present invention;
FIG. 3 is a bus voltage sampling circuit of the present invention;
FIG. 4 is an excitation voltage sampling circuit of the present invention;
FIG. 5 is an excitation power conversion circuit of the present invention;
FIG. 6 is a circuit for switching the polarity of the power supply according to the present invention;
FIG. 7 is a circuit for switching the polarity of the power supply according to the present invention;
FIG. 8 illustrates a power detection circuit according to the present invention;
FIG. 9 is a first power supply cathode detection circuit according to the present invention;
FIG. 10 is a second power supply cathode detection circuit according to the present invention;
FIG. 11 is a first power supply positive detection circuit according to the present invention;
FIG. 12 is a second power supply positive detection circuit according to the present invention;
FIG. 13 is a schematic diagram illustrating a first power supply positive detection circuit according to the present invention;
FIG. 14 is a schematic diagram illustrating a detection process of the first power supply cathode detection circuit according to the present invention;
FIG. 15 is a schematic diagram of a second power supply cathode detection circuit according to the present invention;
FIG. 16 is a schematic diagram illustrating a detection process of the second power negative detection circuit according to the present invention.
Detailed Description
The high-voltage direct-current bus insulation resistance detection device comprises a microprocessor, a bus voltage sampling circuit, an excitation voltage sampling circuit, a control power supply, a power supply positive and negative switching circuit, an excitation power supply conversion circuit and a divider resistor voltage sampling circuit, wherein the bus voltage sampling circuit, the excitation voltage sampling circuit, the control power supply, the power supply positive and negative switching circuit, the excitation power supply conversion circuit and the divider resistor voltage sampling circuit are arranged in;
the control power supply is connected with the microprocessor and supplies power to the microprocessor through the control power supply; the bus voltage sampling circuit, the excitation voltage sampling circuit and the voltage dividing resistor sampling circuit are all connected with the microprocessor, and the microprocessor sends instructions to sample the bus voltage, the excitation voltage and the insulation resistor; the microprocessor is connected with the excitation power supply conversion circuit, the excitation power supply conversion circuit is connected with the sampling circuit of the insulation resistor, the microprocessor controls the conversion of DC24V into DC200V excitation power supply through the excitation power supply conversion circuit and controls the conversion of the excitation power supply, and the converted DC200V excitation power supply supplies power for the voltage sampling circuit of the divider resistor; the microprocessor is connected with the power supply positive and negative switching circuit, the power supply positive and negative switching circuit is connected with the voltage sampling circuit of the divider resistor, and the microprocessor controls the power supply positive and negative switching circuit to realize that a double-switch relay in the power supply positive and negative switching circuit controls the positive and negative selection access of the power supply, so that the detection requirements of the divider resistor R0 in different states are met; meanwhile, the microprocessor is connected with the CAN for communication;
as shown in fig. 2, the voltage dividing resistor voltage sampling circuit includes a 200V power supply, the 200V power supply is a DC200V excitation power supply converted from an excitation power conversion circuit controlling DC24V, the 200V power supply is connected to 7 series resistors through diodes, one end of the 7 series resistors is connected to a voltage dividing resistor R15, and a voltage at two ends of the voltage dividing resistor R15 is U1ROAnd U2ROOne end of the divider resistor R15 is connected with the 2 pin of the isolation operational amplifier chip E1, the other end is connected with the test access point, the 1 pin of the isolation operational amplifier chip E1 is connected with the test access point through a capacitor, the test access point is connected with the power supply anode and cathode switching control circuit, meanwhile, the end is connected with a pin 3 and a pin 4 of an isolation operational amplifier chip E1, two ends of a divider resistor R15 are connected with a diode and two capacitors in parallel, a pin 8 of the isolation operational amplifier chip E1 is connected with a +5V power supply, the power supply of the isolation operational amplifier chip E1 is supplied by a +5V power supply, a pin 1 of the isolation operational amplifier chip E1 is connected with a test access point through two capacitors connected in parallel, a pin 7 of the isolation operational amplifier chip E1 is connected with a pin 3 of an operational amplifier N1A through a resistor R10, a pin 6 of the isolation operational amplifier chip E1 is connected with a pin 2 of the operational amplifier N1A through a resistor R12, and an output 1 end of the operational amplifier N1A is connected with an AD sampling port of a microprocessor through a resistor R11; by passingThe voltage divided by the voltage dividing resistor R15 is U1ROOr U2ROThe signal is amplified by an isolation operational amplifier chip E1 and is sent to an AD sampling port of the single chip microcomputer, the signal is sampled by the single chip microcomputer AD, and the single chip microcomputer compares and judges with a set value after operation to determine whether to alarm or not;
as shown in fig. 3, the bus voltage sampling circuit includes a DC900V bus power supply, the DC900V bus power supply is connected with 6 series resistors, the two series resistors are connected with a voltage dividing resistor R27, one end of the voltage dividing resistor R27 is connected with pin 2 of an isolation operational amplifier chip E2, the other end is connected with pin 3 and pin 4 of the isolation operational amplifier chip E2, the other end is grounded, two ends of the voltage dividing resistor R27 are connected in parallel with a diode and two capacitors, pin 6 and pin 7 of the isolation operational amplifier chip E2 are respectively connected with an inverting terminal and a non-inverting terminal of an operational amplifier N1B, and an output terminal of the operational amplifier N1B is connected with an AD sampling port of a microprocessor through a resistor; the bus voltage sampling circuit is used for judging whether the live detection is carried out or not;
as shown in fig. 4, the excitation voltage sampling circuit includes a DC200V excitation power supply, the DC200V excitation power supply is connected to a voltage dividing resistor R43 through two series resistors, one end of the voltage dividing resistor R43 is connected to a pin 2 of an isolation operational amplifier chip E3, the other end is connected to a pin 3 and a pin 4 of an isolation operational amplifier chip E3, the other end is grounded, two ends of a voltage dividing resistor R43 are connected in parallel to two capacitors, a pin 6 and a pin 7 of the isolation operational amplifier chip E3 are respectively connected to an inverting terminal and a non-inverting terminal of an operational amplifier N2A, and an output terminal of the operational amplifier N2A is connected to an AD sampling port of a microprocessor through a resistor; the voltage sampling of the excitation power supply DC200V is used for reducing detection errors caused by excitation power supply change;
as shown in fig. 5, the excitation power conversion circuit includes a +24V power supply, the +24V power supply is connected to pin 1 of an inductor L1, pin 2 of the inductor L1 is connected to pin 2 of a DC-DC power module U1 through a capacitor C4 and an electrolytic capacitor C10 which are connected in parallel, the other end of the electrolytic capacitor C10 is connected to pin 1 of a power module U1, pin 5 of the power module U1 is connected to one end of an electrolytic capacitor C1, pin 3 is connected to the other end of an electrolytic capacitor C1, two ends of the electrolytic capacitor C1 are connected in parallel to a capacitor C2, one end of the capacitor C2 is grounded, one end is connected to a 200V power supply, two ends of the capacitor C2 are connected in parallel to a capacitor C3, a resistor R2 and a diode, pin 6 of the power module U1 is connected to pin 4 of an electric coupler E1, pin 1 of the electric coupler E1 is connected to the +5V power supply, the power supply of the thermocouple E1 is supplied by a +5V power supply, and a 1 pin of the thermocouple E1 is connected with a microprocessor; the power utilization circuit is connected to two ends of the capacitor C2, a control signal is sent out through the microprocessor, a pin 6 of the power supply module U1 is controlled to output a low level, the power supply module U1 stops working, the power supply voltage of +24 outputs 0V voltage, and the power utilization circuit directly supplies power through a 200V power supply; when the microprocessor controls the pin 6 of the power module U1 to output a high level, the power voltage of +24 is converted into 200 voltages through the power module U1, as shown in fig. 15, after being connected in series with the voltage provided by the 200V power supply in the circuit, the total voltage is 0V, and the input voltage of the power utilization circuit is 0V, as shown in fig. 16;
as shown in fig. 6 and 7, the positive and negative switching circuit of the power supply comprises an electric coupler E3, a pin 2 of the electric coupler E3 is connected with a microprocessor, a pin 3 is connected with a base electrode of a triode through a resistor and a capacitor which are connected in parallel, a collector of the triode is grounded, an emitter of the triode is connected with a pin 2 of a relay, a pin 4 of the electric coupler E3 is connected with a pin 1 of a relay through a resistor, a pin 3 of the relay is grounded through three series resistors, a pin 4 of the relay is connected with a test access point, and the test access point is connected with a voltage divider resistor voltage sampling circuit;
the method for detecting the insulation resistance of the high-voltage direct-current bus comprises the following specific steps:
s1: the microprocessor collects the voltage U at the two ends of the divider resistor R0 of the voltage sampling circuit of the divider resistor1ROAnd U2ROThe excitation voltage value is collected through an excitation voltage sampling circuit, and meanwhile, the microprocessor collects bus voltage Vbus through a bus voltage sampling circuit;
s2: the microprocessor collects the voltage U1ROAnd U2ROInsulation resistance calculation formula of high-voltage bus negative pole to shell by excitation voltage value and bus voltage V bus input
Formula for calculating insulation resistance of medium or high voltage bus anode to shell
Calculating to obtain the resistance values of the insulation resistors Rb and Rc;
s3: the microprocessor compares the calculated resistance values of the insulation resistors Rb and Rc with a set value, reports the resistance values through the CAN bus when the calculated insulation resistance values are smaller than the set value, and flickers through an alarm indicator lamp to remind an operator to process the insulation resistance values.
Taking a DC900V electrical system as an example, a calculation formula of the insulation resistance Rc of the high-voltage bus negative pole to the shell or the insulation resistance Rb of the high-voltage bus positive pole to the shell is obtained through a power supply detection circuit;
as shown in fig. 8, the power detection circuit includes a DC900V bus power supply, a DC200V controllable excitation power supply, a sampling divider resistor R0, a minimum instantaneous insulation resistance Ra at the measurement stage, Ra > R0, an electrical system cathode-to-case insulation resistance Rb, an electrical system anode-to-case insulation resistance Rc, a diode V1 for preventing reverse connection of the excitation power supply, the DC200V power supply is connected with the anode of a diode V1, the cathode of the diode V1 is connected with one end of a resistor R1, the other end of the resistor Ra is connected with a resistor R0 in series, one end of the resistor R0 is connected with the a terminal of a relay, the B terminal of the relay is connected with the cathode of the DC900V bus power supply, the C terminal of the relay is connected with the anode of the DC900V bus power supply through the resistor Rb, and one end of the resistor;
as shown in fig. 9 and 10, when the a terminal of the relay of the power detection circuit is connected to the B terminal, the power detection circuit forms a power negative detection circuit, the power negative detection circuit performs detection in two circuit forms, namely a first power negative detection circuit and a second power negative detection circuit, in the second power negative detection circuit, the a terminal of the relay of the power detection circuit is connected to the B terminal, the DC200V power supply, the resistor R0, the resistor Ra and the resistor Rb form a series circuit to form the first power negative detection circuit, and the DC900V bus power supply is directly grounded and is not connected in the circuit; in the second power supply negative electrode detection circuit, a DC24V power supply is connected between the terminal B and the terminal C of the relay of the power supply detection circuit, the terminal A of the relay is connected to the terminal B, the negative electrode of the DC24V power supply is connected to the terminal B of the relay, and a resistor Rb and a resistor Rc form a parallel circuit to form the second power supply negative electrode detection circuit;
as shown in fig. 11 and 12, when the a terminal of the relay of the power detection circuit is connected to the B terminal, the power detection circuit forms a power positive detection circuit, which detects the power through two circuit types, namely a first power positive detection circuit and a second power positive detection circuit, in the first power positive detection circuit, the a terminal of the relay of the power detection circuit is connected to the C terminal, the DC200V power supply, the resistor R0, the resistor Ra, the DC900V bus power supply and the resistor Rc form a series circuit to form the first power positive detection circuit, and the resistor Rb is not connected to the circuit; in the second power supply positive electrode detection circuit, a DC24V power supply is connected between the terminal B and the terminal C of a relay of the power supply detection circuit, the terminal A of the relay is connected to the terminal C, the negative electrode of the DC24V power supply is connected to the terminal C of the relay, and a resistor Rb and a resistor Rc form a parallel circuit to form the second power supply positive electrode detection circuit;
(1) the insulation resistance of the high-voltage bus positive electrode or negative electrode to the shell is measured by the first power supply positive electrode detection circuit and the first power supply negative electrode detection circuit, as shown in fig. 13 and 14, the specific measurement method is as follows:
the first power positive electrode detection circuit measures: when the end A of the relay is connected to the end C through the power supply positive and negative electrode control circuit, the power supply detection circuit forms a first power supply positive electrode detection circuit, the DC200V power supply, the resistor R0, the resistor Ra, the DC900V bus power supply and the resistor Rc form a series circuit, and the current of the series circuit is Ia;
the calculation can obtain: rc ═ 200/Ia) -R1;
the first power supply negative electrode detection circuit measures: when the end A of the relay is connected to the end B through the power supply positive and negative electrode control circuit, the power supply detection circuit forms a power supply negative electrode detection circuit, the DC200V power supply, the resistor R0, the resistor Ra and the resistor Rb form a series circuit, and the current of the series circuit is Ib;
the calculation can obtain: rb ═ 200/Ib) -R1;
(2) the insulation resistance of the high-voltage bus positive electrode or negative electrode to the shell is measured by the second power supply negative electrode detection circuit, as shown in fig. 15 and 16, the specific measurement method is as follows:
a freewheeling diode V2 is connected between a DC200V power supply and one parallel end of a resistor Rb and a resistor Rc of the second power supply negative electrode detection circuit, the anode of a diode V2 is respectively connected with one end of the resistor Rb and the resistor Rc and the ground, the cathode of a diode V2 is connected with the DC200V power supply, and a controllable power supply is connected in parallel between the anode and the cathode of a diode V2;
when the output voltage of the DC200V controllable excitation power supply is controlled to be 200V after being controlled by the excitation conversion circuit, the current flowing through the resistor Ra is I1, and the voltage at the two ends of the resistor R0 is U1ROThe voltage across the resistor Rb is U1;
U1R0＝I1*R0
I1*Ra＝DC200V+U1
finishing to obtain:
when the output voltage of the DC200V controllable excitation power supply is controlled to be 0V after being controlled by the excitation conversion circuit, the current flowing through the resistor Ra is I2, and the voltage at the two ends of the resistor R0 is U2ROThe voltage across the resistor Rb is U2;
I2*Ra＝U2
finishing to obtain:
parallel resistor RM of insulation resistors Rb and Rc, bus voltage VFemale
① subtracting ②, the following results:
① with ② giving:
the following can be obtained through simplification:
rb and Rc are obtained from ③ and ④;
the preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims (4)
1. The high-voltage direct-current bus insulation resistance detection device is characterized by comprising a microprocessor, a bus voltage sampling circuit, an excitation voltage sampling circuit, a control power supply, a power supply positive and negative switching circuit, an excitation power supply conversion circuit and a voltage dividing resistance voltage sampling circuit;
the control power supply is connected with the microprocessor and supplies power to the microprocessor through the control power supply;
the bus voltage sampling circuit, the excitation voltage sampling circuit and the voltage dividing resistor sampling circuit are all connected with the microprocessor, and the bus voltage, the excitation voltage and the insulation resistor are sampled by sending instructions through the microprocessor;
the microprocessor is connected with the excitation power supply conversion circuit, the excitation power supply conversion circuit is connected with the sampling circuit of the insulation resistor, the microprocessor controls the conversion of DC24V into DC200V excitation power supply through the excitation power supply conversion circuit and controls the conversion of the excitation power supply, and the converted DC200V excitation power supply supplies power for the voltage sampling circuit of the divider resistor;
the microprocessor is connected with the power supply positive and negative switching circuit, the power supply positive and negative switching circuit is connected with the voltage sampling circuit of the divider resistor, and the microprocessor controls the power supply positive and negative switching circuit to realize that a double-switch relay in the power supply positive and negative switching circuit controls the positive and negative selection access of the power supply, so that the detection requirements of the divider resistor R0 under different states are met; meanwhile, the microprocessor is connected with CAN for communication;
the specific detection method of the high-voltage direct-current bus insulation resistance comprises the following steps:
s1: the microprocessor collects the voltage U at the two ends of the divider resistor R0 of the voltage sampling circuit of the divider resistor1ROAnd U2ROThe excitation voltage value is collected through an excitation voltage sampling circuit, and meanwhile, the microprocessor collects bus voltage Vbus through a bus voltage sampling circuit;
s2: the microprocessor collects the voltage U1ROAnd U2ROInsulation resistance calculation formula of high-voltage bus negative pole to shell by excitation voltage value and bus voltage V bus input
Formula for calculating insulation resistance of medium or high voltage bus anode to shell
Calculating to obtain the resistance values of the insulation resistors Rb and Rc;
s3: the microprocessor compares the calculated resistance values of the insulation resistors Rb and Rc with a set value, reports the resistance values through the CAN bus when the calculated insulation resistance values are smaller than the set value, and flickers through an alarm indicator lamp to remind an operator to process the insulation resistance values.
2. The high-voltage direct-current bus insulation resistance detection device of claim 1, wherein the voltage dividing resistor voltage sampling circuit comprises a 200V power supply, the 200V power supply is a DC200V excitation power supply converted from DC24V controlled by an excitation power conversion circuit, the 200V power supply is connected with 7 series resistors through diodes, one end of the 7 series resistors is connected with a voltage dividing resistor R15, one end of the voltage dividing resistor R15 is connected with a 2 pin of an isolation operational amplifier chip E1, the other end of the voltage dividing resistor R15 is connected with a test access point, a 1 pin of the isolation operational amplifier chip E1 is connected with the test access point through a capacitor, the test access point is connected with a positive and negative switching control circuit of the power supply, the end is connected with 3 pins and 4 pins of an isolation operational amplifier chip E1, two ends of the voltage dividing resistor R15 are connected in parallel with a diode and two capacitors, and an 8 pin of the isolation operational amplifier chip E, the power supply of the isolation operational amplifier chip E1 is supplied by a +5V power supply, a pin 7 of the isolation operational amplifier chip E1 is connected with a pin 3 of the operational amplifier N1A through a resistor R10, a pin 6 of the isolation operational amplifier chip E1 is connected with a pin 2 of the operational amplifier N1A through a resistor R12, and an output 1 end of the operational amplifier N1A is connected with an AD sampling port of the microprocessor through a resistor R11.
3. The high-voltage direct-current bus insulation resistance detection device according to claim 1, wherein the excitation power conversion circuit comprises a +24V power supply, the +24V power supply is connected with pin 1 of an inductor L1, pin 2 of the inductor L1 is connected with pin 2 of a DC-DC power module U1 through a capacitor C4 and an electrolytic capacitor C10 which are connected in parallel, the other end of a electrolytic capacitor C10 is connected with pin 1 of a power module U1, pin 5 of the power module U1 is connected with one end of an electrolytic capacitor C1, pin 3 is connected with the other end of an electrolytic capacitor C1, two ends of an electrolytic capacitor C1 are connected in parallel with a capacitor C2, one end of a capacitor C2 is grounded, one end of the capacitor C2 is connected with a 200V power supply, two ends of a capacitor C3, a resistor R2 and a diode are connected in parallel, pin 6 of the power module U1 is connected with pin 4 of an electric coupler E1, pin 1 of the electric coupler E1 is connected with a +5V power supply through a resistor 1, and is used for, the 1 pin of the E1 is electrically coupled to the microprocessor.
4. The high-voltage direct-current bus insulation resistance detection device is characterized in that the power supply positive and negative switching circuit comprises a power supply E3, a 2-pin connection microprocessor of the power supply E3, a 3-pin connection triode base electrode through a resistor and a capacitor which are connected in parallel, a collector electrode of the triode is grounded, an emitter electrode of the triode is connected with a 2-pin of the relay, a 4-pin connection E3 of the power supply E is connected with a 1-pin of the relay through a resistor, a 3-pin of the relay is grounded through three series resistors, a 4-pin connection test access point of the relay is connected, and the test access point is connected with a voltage dividing resistor voltage sampling.
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| CN201711215194.7A CN108051642B (en) | 2017-11-28 | 2017-11-28 | High-voltage direct-current bus insulation resistance detection device and detection method |
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| CN108627688B (en) * | 2018-08-03 | 2024-05-10 | 长春七角星科技发展有限公司 | Monitoring device and monitoring method for high-voltage bus of electric vehicle |
| CN110927462B (en) * | 2019-12-13 | 2021-11-09 | 中国北方车辆研究所 | Electric vehicle voltage injection type insulation resistance real-time detection circuit |
| CN110927463A (en) * | 2019-12-20 | 2020-03-27 | 李彦吉 | Insulation resistance tester for safety tools and instruments |
| CN114236226B (en) * | 2021-12-20 | 2023-07-07 | 上海瑞浦青创新能源有限公司 | Voltage measuring circuit |
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| CN106405354B (en) * | 2016-11-24 | 2024-01-16 | 北京共元科技有限公司 | DC insulation monitoring circuit and method |
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