Branch detection unit

Abstract

The utility model discloses a branch detection unit, which comprises an MCU (Microprogrammed Control Unit), an insulation resistance detection module connected with the MCU and a dial switch module connected with the MCU. The insulation resistance value detection module detects the insulation resistance value and measures the resistance value of the insulation branch circuit by applying a test voltage to the insulation branch circuit. According to the utility model, the branch detection unit is internally provided with the insulation resistance value detection module, the insulation resistance value of the DC system is detected by the insulation resistance value detection module, and the insulation performance is evaluated by applying a certain test voltage VTEST on the insulation branch of the system and measuring the insulation resistance RINS. Detection data obtained by the insulation resistance value detection module is processed by the MCU, errors between the obtained measured insulation resistance value and the leakage current and actual values are very small, and the measurement precision is improved. And the branch detection unit adopts an RS485 communication interface and a standard Modbus communication protocol, so that rapid and stable data exchange can be carried out.

Description

Technical Field

[0001] The utility model relates to the technical field of battery detection, in particular to a branch circuit detection unit. Background Art

[0002] Traditional DC detection units usually consist of a voltage detection module and a current detection module. The voltage detection module usually uses a voltage transformer or a voltage divider to collect voltage signals, while the current detection module uses a current transformer or a current sensor to collect current signals. This solution is simple and reliable and is suitable for general DC monitoring needs.

[0003] At present, the accuracy of most DC detection units on the market is limited by sensors such as voltage transformers and current transformers, making it difficult to achieve high-precision detection. Traditional modules usually require regular calibration and maintenance, have high maintenance costs, and are easily affected by environmental factors.

[0004] Therefore, traditional battery detection technology needs to be improved. Utility Model Content

[0005] In view of the deficiencies in the prior art, the technical problem to be solved by the utility model is to provide a branch detection unit. The purpose of designing the branch detection unit is to automatically detect current and voltage in real time, and transmit the data to the background through RS485 communication, so as to meet the accuracy requirements of various parameters while improving the detection efficiency, saving time and being efficient.

[0006] In order to solve the above technical problems, the utility model is implemented by the following scheme: A branch detection unit of the utility model includes an MCU and also includes:

[0007] An insulation resistance detection module electrically connected to the MCU and detecting the insulation resistance of the DC system, measuring the resistance on the insulation branch by applying a test voltage on the insulation branch;

[0008] A dip switch module electrically connected to the MCU.

[0009] Furthermore, the MCU is an 8-bit single-chip microcomputer based on the 8051 core, which has flash memory and RAM and supports ISP programming and IAP programming.

[0010] Further, the insulation resistance detection module includes a multi-channel multiplexer U3, the multi-channel multiplexer U3 has an 8-channel I / O input port, the 8-channel I / O input port is connected to a first resistor, each first resistor is a current limiting resistor, the other end of any current limiting resistor is connected to a second resistor and a first capacitor, the other end of each second resistor is interconnected and connected to VCC, the other end of each first capacitor is interconnected and grounded, and each second resistor constitutes a pull-up row group RN1;

[0011] The non-grounded end of each first capacitor is connected to a leakage current sensor;

[0012] Pin 9 C of the multi-channel multiplexer U3, pin 10 B of the multi-channel multiplexer U3, and pin 11 A of the multi-channel multiplexer U3 are connected to three control pins of the MCU one by one, and the three control pins of the MCU correspondingly control the on and off of pin 9 C, pin 10 B, and pin 11 A;

[0013] The 3-pin I / O of the multi-channel multiplexer U3 is electrically connected to the first end of the resistor R22, and the second end of the resistor R22 is connected to the non-inverting input end of the operational amplifier U2B;

[0014] Pin 7 VEE of the multi-channel multiplexer U3 is connected to the first end of the capacitor C14 and outputs a -12V voltage, and the second end of the capacitor C14 is grounded;

[0015] The 6th pin INH of the multi-channel multiplexer U3 and the 8th pin VSS of the multi-channel multiplexer U3 are connected to each other and connected to the ground terminal of the capacitor C14;

[0016] Pin 16 VDD of the multi-channel multiplexer U3 is connected to VCC and the first end of the capacitor C11, and the second end of the capacitor C11 is grounded;

[0017] The non-inverting input terminal of the operational amplifier U2B is also connected to a capacitor C9, and the other end of the capacitor C9 is grounded;

[0018] The inverting input terminal of the operational amplifier U2B is connected to the output terminal of the operational amplifier U2B, the first terminal of the resistor R23, and the first terminal of the capacitor C8. The second terminal of the capacitor C8 is connected to the non-inverting input terminal of the operational amplifier U2B. The second terminal of the resistor R23 is connected to the first terminal of the capacitor C10, the first terminal of the resistor R24, and the first terminal of the resistor R30. The second terminal of the capacitor C10 is grounded. The second terminal of the resistor R24 ​​is connected to the ADC of the MCU.

[0019] The second end of the resistor R30 is connected to the output end of the operational amplifier U2A and the inverting input end of the operational amplifier U2A;

[0020] The in-phase input terminal of the operational amplifier U2A is connected to the first end of the resistor R28 and the first end of the capacitor C13, the second end of the capacitor C13 is grounded, and the second end of the resistor R28 is connected to VREF;

[0021] The power supply + interface of the operational amplifier U2A is connected to the +12V power supply and the first end of the capacitor C12, and the second end of the capacitor C12 is grounded. The power supply - of the operational amplifier U2A is connected to the -12V power supply and the first end of the capacitor C15, and the second end of the capacitor C15 is connected to the ground end of the capacitor C12.

[0022] Furthermore, the leakage current sensor is a 10mA leakage current sensor.

[0023] Furthermore, the VREF is a stable 5V reference source.

[0024] Furthermore, the branch detection unit uses an RS485 communication interface to transmit signals.

[0025] Compared with the prior art, the beneficial effects of the utility model are:

[0026] 1. The branch detection unit of the utility model is provided with an insulation resistance detection module, which detects the insulation resistance of the DC system by applying a certain test voltage V TEST On the insulated branch of the system, measure the insulation resistance R INS The test data obtained by the insulation resistance detection module is processed by the MCU data, and the error between the measured insulation resistance and leakage current and the actual value is very small, which improves the measurement accuracy.

[0027] 2. The branch detection unit adopts RS485 communication interface and standard Modbus communication protocol, which can carry out fast and stable data exchange. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a principle block diagram of the branch detection unit of the utility model.

[0029] Figure 2-Figure 3 After connection, the utility model insulation resistance detection module is formed

[0030] Figure 4 This is the branch output circuit of the utility model. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model, so that the advantages and features of the utility model can be more easily understood by those skilled in the art, thereby making a clearer and more explicit definition of the protection scope of the utility model. Obviously, the embodiments described in the utility model are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0032] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Embodiment 1: The specific structure of the utility model is as follows:

[0034] Please refer to the attached Figure 1 The utility model discloses a branch detection unit, including an MCU, and the MCU chip model used is STC8A8K32S4. The STC8A8K32S4 chip is an 8-bit single-chip microcomputer based on the 8051 core. This single-chip microcomputer has 8KB of flash memory and 256 bytes of RAM, supports ISP programming and IAP programming, and is suitable for various low-end and mid-end embedded control systems. The single-chip microcomputer has built-in multiple peripheral interfaces, such as UART serial port, timer / counter, PWM output, etc., as well as abundant I / O ports, making it an ideal choice for home appliances, industrial control, and intelligent instrumentation. STC8A8K32S4 is widely used for its high performance, low power consumption, and easy development.

[0035] The MCU is connected to a voltage detection module: the voltage detection module samples the DC system voltage, and the voltage is obtained through a voltage divider circuit. out1 , V out1 =A1V out (A1 is the amplification gain, which is usually less than 1), V out1 As the input signal of the MCU's (P1.5 / P1.6 / P1.7) pin (ADC), ADC is V out1 Perform multiple sampling, filtering, quantization and conversion to obtain the sampled value ADC DATA , and then get the ADC reference voltage VREF, VREF = ADC REF *ADC resolution / ADC DATA , ADC REF is the internal test voltage of ADC, which is 1.344V. resolution is the resolution of the 12-bit ADC, which is 4095. Finally, the actual voltage value V voltage :V voltage = VREF * ADC DATA / ADC resolution Through multiple filtering and quantization of the sampled values, the obtained sampled voltage value is very close to the actual voltage value, and the measurement accuracy is not less than 99.7%, which can greatly improve the battery voltage detection accuracy.

[0036] Please refer to the attached Figure 1-2 , the utility model branch detection unit also includes:

[0037] An insulation resistance detection module electrically connected to the MCU and detecting the insulation resistance of the DC system, measuring the resistance on the insulation branch by applying a test voltage on the insulation branch;

[0038] The DIP switch module electrically connected to the MCU has four DIP switches connected one by one to the P4.3, P0.2, P0.1, and P0.1 pins of the STC8A8K32S4 chip. When the switch is pressed, it outputs a low level, and when it is disconnected, it outputs a high level. The 4-bit switch state is represented by 0 and 1 to form a 4-bit BCD code, which can be combined into different 1 to 16 values. Through the DIP switch, 16 branch detection units can be connected at the same time and different addresses can be set for these 16 branch detection units.

[0039] A preferred technical solution of this embodiment: the branch detection unit uses an RS485 communication interface to transmit signals.

[0040] A preferred technical solution of this embodiment: the insulation resistance detection module includes a multi-channel multiplexer U3, the multi-channel multiplexer U3 has 8-channel I / O input ports, the 8-channel I / O input ports are all connected to a first resistor, each first resistor is a current limiting resistor, the other end of any current limiting resistor is connected to a second resistor and a first capacitor, the other end of each second resistor is interconnected and connected to VCC, the other end of each first capacitor is interconnected and grounded, and each second resistor forms a pull-up row group RN1;

[0041] The non-grounded end of each first capacitor is connected to a leakage current sensor, which is a 10mA leakage current sensor.

[0042] Pin 9 C of the multi-channel multiplexer U3, pin 10 B of the multi-channel multiplexer U3, and pin 11 A of the multi-channel multiplexer U3 are connected one-to-one to three control pins of the MCU, and the three control pins of the MCU correspondingly control the on and off of pin 9 C, pin 10 B, and pin 11 A.

[0043] The 3-pin I / O of the multi-channel multiplexer U3 is electrically connected to the first end of the resistor R22, and the second end of the resistor R22 is connected to the non-inverting input end of the operational amplifier U2B; the model of the operational amplifier U2B is OP07.

[0044] Pin 7 VEE of the multi-channel multiplexer U3 is connected to the first end of the capacitor C14 and outputs a -12V voltage, and the second end of the capacitor C14 is grounded.

[0045] The 6th pin INH of the multi-channel multiplexer U3 and the 8th pin VSS of the multi-channel multiplexer U3 are connected to each other and connected to the ground terminal of the capacitor C14.

[0046] Pin 16 VDD of the multi-channel multiplexer U3 is connected to VCC and a first end of a capacitor C11 , and a second end of the capacitor C11 is grounded.

[0047] The non-inverting input terminal of the operational amplifier U2B is also connected to a capacitor C9, and the other end of the capacitor C9 is grounded.

[0048] The inverting input terminal of the operational amplifier U2B is connected to the output terminal of the operational amplifier U2B, the first end of the resistor R23, and the first end of the capacitor C8. The second end of the capacitor C8 is connected to the non-inverting input terminal of the operational amplifier U2B. The second end of the resistor R23 is connected to the first end of the capacitor C10, the first end of the resistor R24, and the first end of the resistor R30. The second end of the capacitor C10 is grounded. The second end of the resistor R24 ​​is connected to the ADC of the MCU.

[0049] The second end of the resistor R30 is connected to the output end of the operational amplifier U2A and the inverting input end of the operational amplifier U2A.

[0050] The in-phase input terminal of the operational amplifier U2A is connected to the first end of the resistor R28 and the first end of the capacitor C13, the second end of the capacitor C13 is grounded, and the second end of the resistor R28 is connected to VREF, which is a stable 5V reference source.

[0051] The power supply + interface of the operational amplifier U2A is connected to the +12V power supply and the first end of the capacitor C12, and the second end of the capacitor C12 is grounded. The power supply - of the operational amplifier U2A is connected to the -12V power supply and the first end of the capacitor C15, and the second end of the capacitor C15 is connected to the ground end of the capacitor C12. The model of the operational amplifier U2A is OP07.

[0052] The insulation resistance detection module detects the insulation resistance of the DC system by applying a certain test voltage V TEST On the insulated branch of the system, measure the insulation resistance R INS When the test voltage is applied to the insulated branch, a resistance network is formed, R INS is the total resistance of the network, R INS =V TEST / I LEAKAGE , I LEAKAGE is the leakage current. The leakage current can be measured by the current sensor module. When detecting the leakage current, the current sensor generates a voltage signal V proportional to the current size. ITEMP Then the amplifier amplifies the weak voltage signal output by the current sensor to a range suitable for ADC input and performs digital processing to obtain the voltage value V input to the ADC. IN1 ,V IN1 =V ITEMP* A (A is the amplifier gain). ADC to V IN1 Perform multiple sampling, filtering, quantization and conversion to obtain the sampled value ADC I , through the sampled value ADC I Get ADC reference voltage V REF, and then get the actual voltage value V voltage :V voltage =V REF *ADC I / ADC resolution Finally, the leakage current I LEAKAGE , I LEAKAGE =V voltage / B, B is the ratio of voltage to current in the current sensor. Through special data processing, the error between the measured insulation resistance and leakage current and the actual value is small, which improves the measurement accuracy.

[0053] The leakage current detection circuit connected to the insulation resistance detection module is equipped with an external 10mA leakage current sensor. The signal collected by the sensor is input by S_IN01-S_IN36, and is sent to the multi-channel multiplexer U3 through the current limiting resistor. The model of the multi-channel multiplexer U3 is CD4051B. The multi-channel multiplexer U3 has 8 I / O ports. The MCU controls the on and off of CD_A, CD_B, and CD_C of the multi-channel multiplexer U3. The third pin I / O of the multi-channel multiplexer U3 is output to the operational amplifier U2B. VREF is a stable reference source of 5V, and then it is followed by the operational amplifier U2A to ensure that its temperature drift is low. The resistor R24 ​​is connected to the ADC of the MCU, and the resistance to ground is calculated in conjunction with the internal program of the MCU.

[0054] like Figure 2 As shown, when the insulation resistance detection module is used for switch quantity detection, the air switch is equipped with auxiliary contacts, S_IN01-S_IN36 and GND are connected to the auxiliary contacts, RN1 is a 100K pull-up resistor, so S_IN01-S_IN36 is +5V in each path under normal circumstances. When any switch of the 36 branches is tripped, that is, any one of S_IN01-S_IN36 is closed to GND, +5V will be pulled down to 0V, and then from CD4051B and OP07 to MCU, and an alarm will be issued to the user to remind which switch is tripped.

[0055] Please refer to the attached Figure 3 The MCU of the utility model is also connected to a branch output circuit, which is composed of 6 F3AA012E power relays. It can provide an output capacity of 250VAC / 5A, DC30 / 5A. In conjunction with the switch input detection circuit, the detected fault can be more intuitively prompted to the user through an external light or an audible and visual alarm.

[0056] In summary, the branch detection unit of the utility model is provided with an insulation resistance detection module, which detects the insulation resistance of the DC system by applying a certain test voltage V TEST On the insulated branch of the system, measure the insulation resistance RINS To evaluate the insulation performance. The test data obtained by the insulation resistance detection module is processed by the MCU data, and the error between the measured insulation resistance and leakage current and the actual value is very small, which improves the measurement accuracy. The branch detection unit adopts RS485 communication interface and standard Modbus communication protocol, which can carry out fast and stable data exchange.

[0057] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A branch detection unit, including an MCU, characterized in that: Also includes: An insulation resistance detection module electrically connected to the MCU and detecting the insulation resistance of the DC system, measuring the resistance on the insulation branch by applying a test voltage on the insulation branch; A dip switch module electrically connected to the MCU; The insulation resistance detection module includes a multi-channel multiplexer U3, which has 8-channel I / O input ports, each of which is connected to a first resistor, each of which is a current limiting resistor, and the other end of any current limiting resistor is connected to a second resistor and a first capacitor, the other end of each second resistor is connected to each other and connected to VCC, the other end of each first capacitor is connected to each other and grounded, and each second resistor constitutes a pull-up row group RN1; The non-grounded end of each first capacitor is connected to a leakage current sensor; Pin 9 C of the multi-channel multiplexer U3, pin 10 B of the multi-channel multiplexer U3, and pin 11 A of the multi-channel multiplexer U3 are connected to three control pins of the MCU one by one, and the three control pins of the MCU correspondingly control the on and off of pin 9 C, pin 10 B, and pin 11 A; The 3-pin I / O of the multi-channel multiplexer U3 is electrically connected to the first end of the resistor R22, and the second end of the resistor R22 is connected to the non-inverting input end of the operational amplifier U2B; Pin 7 VEE of the multi-channel multiplexer U3 is connected to the first end of the capacitor C14 and outputs a -12V voltage, and the second end of the capacitor C14 is grounded; The 6th pin INH of the multi-channel multiplexer U3 and the 8th pin VSS of the multi-channel multiplexer U3 are connected to each other and connected to the ground terminal of the capacitor C14; Pin 16 VDD of the multi-channel multiplexer U3 is connected to VCC and the first end of the capacitor C11, and the second end of the capacitor C11 is grounded; The non-inverting input terminal of the operational amplifier U2B is also connected to a capacitor C9, and the other end of the capacitor C9 is grounded; The inverting input terminal of the operational amplifier U2B is connected to the output terminal of the operational amplifier U2B, the first terminal of the resistor R23, and the first terminal of the capacitor C8. The second terminal of the capacitor C8 is connected to the non-inverting input terminal of the operational amplifier U2B. The second terminal of the resistor R23 is connected to the first terminal of the capacitor C10, the first terminal of the resistor R24, and the first terminal of the resistor R30. The second terminal of the capacitor C10 is grounded. The second terminal of the resistor R24 ​​is connected to the ADC of the MCU. The second end of the resistor R30 is connected to the output end of the operational amplifier U2A and the inverting input end of the operational amplifier U2A; The in-phase input terminal of the operational amplifier U2A is connected to the first end of the resistor R28 and the first end of the capacitor C13, the second end of the capacitor C13 is grounded, and the second end of the resistor R28 is connected to VREF; The power supply + interface of the operational amplifier U2A is connected to the +12V power supply and the first end of the capacitor C12, and the second end of the capacitor C12 is grounded. The power supply - of the operational amplifier U2A is connected to the -12V power supply and the first end of the capacitor C15, and the second end of the capacitor C15 is connected to the ground end of the capacitor C12.

2. The branch detection unit according to claim 1, characterized in that: The MCU is an 8-bit single-chip microcomputer based on the 8051 core, has flash memory and RAM, and supports ISP programming and IAP programming.

3. The branch detection unit according to claim 1, characterized in that: The leakage current sensor is a 10mA leakage current sensor.

4. The branch detection unit according to claim 1, characterized in that: The VREF is a stable 5V reference source.

5. The branch detection unit according to claim 1, characterized in that: The branch detection unit uses an RS485 communication interface to transmit signals.

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