Insulation detection circuit of charging pile of new energy battery swap station and detection method thereof

Abstract

The invention discloses an insulation detection circuit of a charging pile of a new energy battery swap station and a detection method thereof, the insulation detection circuit comprises a plug-in port, and a first detection circuit and a second detection circuit which are connected with the plug-in port, and the first detection circuit and the second detection circuit are respectively connected with a relay circuit; the first detection circuit comprises a control unit, an isolation amplifier unit and a differential amplifier unit, wherein the isolation amplifier unit and the differential amplifier unit are connected with the control unit. The control unit is connected with a plurality of charging piles which are connected in series. The second detection circuit comprises a control unit, an isolation amplifier unit and a differential amplifier unit, wherein the isolation amplifier unit and the differential amplifier unit are connected with the control unit. The control unit is connected with a plurality of charging piles which are connected in series. According to the invention, the detection circuit is used to integrate the insulation detection module into the pcb, so that extra purchase of insulation detection equipment is avoided, and the equipment cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy battery swap stations, and specifically relates to an insulation detection circuit and a detection method for a charging pile of a new energy battery swap station. Background Art

[0002] In the new energy battery replacement industry, new energy battery charging is generally done through a charging and distribution cabinet to charge the battery in each compartment. For specific charging control architecture, refer to Figure 3 It can be found that the main functions including communication with the charging module, vehicle battery, insulation detection module, etc. are all achieved by purchasing standard detection units. There are only very basic charging functions, the overall cost is high, the equipment wiring is complicated, and the integration is low.

[0003] The charging pile is a device that can charge electric vehicles. Its operation requires electricity to be provided by a power supply. According to national standards, when using the charging pile, we need to pay attention to the safety of the charging pile. The insulation resistance of the charging pile must meet the specified requirements during charging. Otherwise, there will be electrical hazards in the charging pile, which will not only affect the charging effect, but may also pose a threat to personal safety. Summary of the invention

[0004] In order to solve the above technical problems, a technical solution adopted by the present invention is as follows:

[0005] An insulation detection circuit of a charging pile of a new energy battery swap station comprises a plug-in interface and a first detection circuit and a second detection circuit connected to the plug-in interface, wherein the first detection circuit and the second detection circuit are respectively connected to a relay circuit;

[0006] The first detection circuit includes a first control unit and a first isolation amplifier unit and a first differential amplifier unit connected to the first control unit, and the first control unit is connected to a plurality of charging piles connected in series;

[0007] The second detection circuit includes a second control unit and a second isolation amplifier unit and a second differential amplifier unit connected to the second control unit, and the second control unit is connected to a plurality of charging piles connected in series.

[0008] Furthermore, the plug interface is connected to the MCU main control board.

[0009] A detection method for an insulation detection circuit of a charging pile of a new energy battery swap station comprises the following steps:

[0010] S1): The relay circuit disconnects the switch and detects the positive and negative channel voltages Ur: The relay circuit controls the switch to open and measures the voltages at the two detection circuit terminals, recorded as U ra0 , U rb0 ;

[0011] S2): Calculate the circuit voltage U r0 :Calculate the loop voltage U based on the voltage at the two channel endpoints r0 , the formula is U r0 =U ra0 -U rb0 ; where U ra0 is the voltage at the first detection circuit terminal, U rb0 is the terminal voltage of the second detection circuit;

[0012] S3): Determine the circuit voltage U r0 Size:

[0013] When U r0 When ≥150, proceed to the next step;

[0014] When U r0 When <150, end the measurement;

[0015] S4): closing the second detection circuit switch: controlling the relay circuit to close the second detection circuit switch and delaying for 1-3 seconds, the delay is used to wait for the circuit to reach a steady state;

[0016] S5): Calculate the circuit voltage U at this time r1 :Calculate the loop voltage U based on the voltage at the two channel endpoints r1 , the formula is U r1 =U ra1 -U rb1 ; where U ra1 is the voltage at the first detection circuit terminal, U rb1 is the terminal voltage of the second detection circuit;

[0017] S6): closing the first detection circuit switch: controlling the relay circuit to disconnect the second detection circuit switch, and closing the first detection circuit switch, with a delay of 1-3S, the delay is used to wait for the circuit to reach a steady state;

[0018] S7): Calculate the circuit voltage U at this time r2 : Calculate the loop voltage U based on the voltages at the two channel endpoints r2 , the formula is U r2 =U ra2 -U rb2 ; where U ra2 is the voltage at the first detection circuit terminal, U rb2 is the terminal voltage of the second detection circuit;

[0019] S8): disconnect the first detection circuit switch;

[0020] S9): Calculate the insulation resistance R: Calculate the positive resistance R based on the measured voltage a and the negative electrode resistor R b, the calculation formula is:

[0021] R a =(U rb2 -U rb1 ) / U rb1 *1000;

[0022] R b =(U rb2 -U rb1 ) / (U rb0 -U ra0 -U rb2 )*1000;

[0023] When R > 500 Ω / V, it is regarded as safe and normal charging;

[0024] When 100 Ω / V < R < 500 Ω / V, an insulation abnormality alarm is given, but normal charging can still be carried out;

[0025] When R < 100 Ω / V, it is regarded as an insulation failure and charging is stopped.

[0026] Furthermore, the measurement formula for the voltage Ur in step 1 is:

[0027] U r =[(U * (R / R 总 ))] * K1 * K2)+U ref ;

[0028] U ref =(U 参 * Z) / resolution;

[0029] Y=(U r / U reference)

[0030] where U is the output voltage of the control unit;

[0031] R is a single resistor in the input voltage;

[0032] R 总 is the total resistance in the circuit;

[0033] K1 = 8 isolation amplifier amplification factor;

[0034] K2 = 1 differential amplifier amplification factor;

[0035] U ref is the bias voltage;

[0036] U reference is the reference voltage;

[0037] Z is the zero - point sampling value, taking the constant 2050 or given during debugging;

[0038] The resolution is a constant of 4096;

[0039] Y is the ADC sampling value.

[0040] Furthermore, in step 3 and step 7, if the loop voltage U r1 or U r2 If it is less than 0, the input polarity is wrong.

[0041] Beneficial effects of the present invention:

[0042] 1. The present invention meets various usage scenarios, integrates the commonly used core component insulation detection module into one, and only adds one component on the control board, avoiding the need to purchase additional insulation detection equipment, reducing external wiring and overall equipment costs.

[0043] 2. The present invention directly measures the insulation resistance of the charging pile by measuring the voltage of the two channels, and monitors whether it is within the safe range. If it exceeds the safe range, the power is immediately cut off to improve the charging safety.

[0044] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the circuit principle of the present invention;

[0046] Figure 2 It is a schematic diagram of the relay circuit principle of the present invention;

[0047] Figure 3 It is a general schematic diagram of the charging control board architecture;

[0048] Figure 4 This is a schematic diagram of the charging control board structure of the present invention;

[0049] Description of reference numerals:

[0050] 1. First detection circuit; 11. First control unit; 12. First isolation amplifier unit; 13. First differential amplifier unit; 2. Second detection circuit; 21. Second control unit; 22. Second isolation amplifier unit; 23. Second differential amplifier unit; 3. Plug interface; 4. Relay circuit. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0053] As shown in the figure, an insulation detection circuit of a charging pile of a new energy battery swap station includes a plug-in interface 3 and a first detection circuit 1 and a second detection circuit 2 connected to the plug-in interface 3, and the first detection circuit 1 and the second detection circuit 2 are respectively connected to a relay circuit 4; specifically, the plug-in interface 3 is connected to an MCU main control board.

[0054] The first detection circuit 1 includes a first control unit 11 and a first isolation amplifier unit 12 and a first differential amplifier unit 13 connected to the first control unit 11, and the first control unit 11 is connected to a plurality of charging piles connected in series;

[0055] The second detection circuit 2 includes a second control unit 21 and a second isolation amplifier unit 22 and a second differential amplifier unit 23 connected to the second control unit 21 . The second control unit 21 is connected to a plurality of charging piles connected in series.

[0056] A detection method for an insulation detection circuit of a charging pile of a new energy battery swap station comprises the following steps:

[0057] S1): The relay circuit disconnects the switch and detects the positive and negative channel voltages U r :The relay circuit control switch is turned on, and the voltages at the two detection circuit terminals are measured respectively, recorded as U ra0 , U rb0 ;

[0058] S2): Calculate the circuit voltage U r0 :Calculate the loop voltage U based on the voltage at the two channel endpoints r0 , the formula is U r0 =U ra0 -U rb0 ; where U ra0 is the voltage at the first detection circuit terminal, U rb0 is the terminal voltage of the second detection circuit;

[0059] S3): Determine the circuit voltage U r0 Size:

[0060] When U r0 When ≥150, proceed to the next step;

[0061] When U r0 When <150, end the measurement;

[0062] S4): closing the second detection circuit switch: controlling the relay circuit to close the second detection circuit switch and delaying for 1-3 seconds, the delay is used to wait for the circuit to reach a steady state;

[0063] S5): Calculate the circuit voltage U at this time r1: Calculate the loop voltage U based on the voltages at the two-channel endpoints r1 , and the formula is U r1 = U ra1 - U rb1 ; where U ra1 is the voltage at the endpoints of the first detection circuit, and U rb1 is the voltage at the endpoints of the second detection circuit;

[0064] S6): Close the switch of the first detection circuit: Control the relay circuit to open the switch of the second detection circuit and close the switch of the first detection circuit, and delay for 1 - 3S. The delay is used to wait for the circuit to reach a steady state;

[0065] S7): Calculate the loop voltage U r2 at this time: Calculate the loop voltage U r2 based on the voltages at the two-channel endpoints, r2 and the formula is U ra2 = U rb2 - U ra2 ; where U rb2 is the voltage at the endpoints of the first detection circuit, and U

[0066] S8): Open the switch of the first detection circuit;

[0067] S9): Calculate the insulation resistance R: Calculate the positive pole resistance R a and the negative pole resistance R b based on the measured voltage, and the calculation formula is:

[0068] R a = (U rb2 - U rb1 ) / U rb1 * 1000;

[0069] R b = (U rb2 - U rb1 ) / (U rb0 - U ra0 - U rb2 ) * 1000;

[0070] When R > 500Ω / V, it is regarded as safe and normal charging;

[0071] When 100Ω / V < R < 500Ω / V, an insulation abnormality alarm is given, but normal charging can still be carried out;

[0072] When R < 100Ω / V, it is regarded as an insulation failure and charging is stopped.

[0073] Further, the measurement formula for the voltage U r in step 1 is:

[0074] U r =[(U*(R / R 总 )]*K1*K2)+U ref ;

[0075] U ref =(U 参 *Z) / resolution;

[0076] Y=(U r / U 参 )

[0077] Wherein U is the output voltage of the control unit, which is 3.3V in this embodiment;

[0078] R is a single resistor added to the input voltage;

[0079] R 总 is the total resistance in the loop;

[0080] K1 = 8 isolation amplifier gain;

[0081] K2 = 1 differential amplifier gain;

[0082] U ref is the bias voltage;

[0083] U 参 is the reference voltage;

[0084] Z is the zero point sampling value, which is a constant of 2050 or is given during debugging;

[0085] The resolution is a constant of 4096;

[0086] Y is the ADC sampling value.

[0087] Therefore, reference Figure 1 , it can be seen

[0088] Ur=[(3.3*(R 143 / R 90 +R 91 +R 92 +R 93 +R 94 +R 95 +R 96 +R 97 +R 98 +R 99 +R 142

[0089] +R 143 +R 122 +R 123 +R 124 +R 125 +R126 +R 127 )]*8*1)+(3.3*2050) / 4096

[0090] Furthermore, in step 3 and step 7, if the loop voltage U r1 or U r2 If it is less than 0, the input polarity is wrong.

[0091] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An insulation detection circuit for a charging pile of a new energy battery swap station, used to obtain the resistance of the charging pile to be tested, characterized in that: It includes an insertion interface (3), a first detection circuit (1) and a second detection circuit (2) connected to the plug-in interface (3), and the first detection circuit (1) and the second detection circuit (2) are respectively connected to a relay circuit (4); The first detection circuit (1) includes a first control unit (11), a first isolation amplifier unit (12) and a first differential amplifier unit (13) connected to the first control unit (11), and the first control unit (11) is connected to a plurality of charging piles connected in series; The second detection circuit (2) includes a second control unit (21), a second isolation amplifier unit (22) and a second differential amplifier unit (23) connected to the second control unit (21), and the second control unit (21) is connected to a plurality of charging piles connected in series.

2. The insulation detection circuit of a charging pile of a new energy battery swap station according to claim 1 is characterized in that: The insertion interface (3) is connected to the MCU main control board.

3. A detection method for an insulation detection circuit of a charging pile of a new energy battery swap station according to claims 1-2, characterized in that: It includes the following steps: S1): The relay circuit disconnects the switch and detects the positive and negative channel voltages U r :The relay circuit control switch is turned on, and the voltages at the two detection circuit terminals are measured respectively, recorded as U ra0 , U rb0 ; S2): Calculate the circuit voltage U r0 :Calculate the loop voltage U based on the voltage at the two channel endpoints r0 , the formula is U r0 =U ra0 -U rb0 ; where U ra0 is the voltage at the first detection circuit terminal, U rb0 is the terminal voltage of the second detection circuit; S3): Determine the circuit voltage U r0 Size: When U r0 When ≥150, proceed to the next step; When U r0 When <150, end the measurement; S4): Close the second detection circuit switch: Control the relay circuit to close the second detection circuit switch and delay for 1 - 3S. The delay is used to wait for the circuit to reach a steady state; S5): Calculate the circuit voltage U at this time r1 :Calculate the loop voltage U based on the voltage at the two channel endpoints r1 , the formula is U r1 =U ra1 -U rb1 ; where U ra1 is the voltage at the first detection circuit terminal, U rb1 is the terminal voltage of the second detection circuit; S6): Close the first detection circuit switch: Control the relay circuit to open the second detection circuit switch and close the first detection circuit switch, and delay for 1 - 3S. The delay is used to wait for the circuit to reach a steady state; S7): Calculate the circuit voltage U at this time r2 : Calculate the loop voltage U based on the voltages at the two channel endpoints r2 , the formula is U r2 =U ra2 -U rb2 ; where U ra2 is the voltage at the first detection circuit terminal, U rb2 is the terminal voltage of the second detection circuit; S8): Open the first detection circuit switch; S9): Calculate the insulation resistance R: Calculate the positive resistance R based on the measured voltage a and the negative electrode resistor R b , the calculation formula is: R a =(U rb2 -IN rb1 ) / IN rb1 *1000; R b =(U rb2 -IN rb1 ) / (IN rb0 -IN ra0 -IN rb2 )*1000; When R > 500Ω / V, it is regarded as safe and normal charging; When 100Ω / V < R < 500Ω / V, an insulation abnormality alarm is given, but normal charging can still be carried out; When R < 100Ω / V, it is regarded as an insulation failure and charging is stopped.

4. The vehicle lifting mechanism of a new energy battery swap station according to claim 3 is characterized in that: Voltage U in step 1 r The measurement formula is: IN r =[(U*(R / R 总 )]*K1*K2)+U ref ; U ref =(U 参 *Z) / resolution; Y=(U r / U 参 ) Where U is the output voltage of the control unit; R is a single resistor added to the input voltage; R 总 is the total resistance in the loop; K1 = 8 is the amplification factor of the isolation amplifier; K2 = 1 is the amplification factor of the differential amplifier; U ref is the bias voltage; U 参 is the reference voltage; Z is the zero-point sampling value, taking the constant 2050 or given during debugging; The resolution takes the constant 4096; Y is the ADC sampling value.

5. The vehicle lifting mechanism of a new energy battery swap station according to claim 3 is characterized in that: In step 3 and step 7, if the circuit voltage U r1 or U r2 If it is less than 0, the input polarity is wrong.

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