A device for current detection of combiner box
By designing components such as sampling resistor module, differential protection module and multiple conversion switch module in the bus box current detection device, the problem of high voltage damage during the electrical blocking circuit is solved, and the normal operation and measurement accuracy of the device are achieved.
Patent Information
- Application Number
- CN201811002415.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2018-08-30
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2038-08-30
AI Technical Summary
The existing bus box current detection device introduces external high voltage when the circuit is blocked, resulting in damage to the measurement circuit.
Design a device including sampling resistor module, differential protection module, multi-channel conversion switch module, differential amplifier module, analog-to-digital converter, microcontroller and communication module. The differential protection module is embedded with high voltage and the multi-channel conversion switch module is switched. A device for collecting signals, differential amplification modules converting and amplifying signals, and a microcontroller processing and transmitting data.
It can still work normally when the external high voltage is introduced when the resistor module is disconnected, avoiding damage to the measurement circuit and ensuring detection accuracy and safety.
Smart Images
Figure CN109116094B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a current detection device, in particular to a device for current detection in a combiner box. Background Art
[0002] With the expansion of the scale of the new energy industry, higher requirements are placed on cost and performance. At present, the current detection devices of the combiner box are increasingly using resistor devices to replace Hall devices to complete the detection of the current of each channel in the combiner box. However, when the resistor works abnormally and breaks the circuit, the external high voltage is directly introduced into both ends of the resistor. The high voltage breaks through and burns the measurement circuit in an instant, causing direct damage to the measurement device in the combiner box. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide a device for current detection in a combiner box which can still work normally when a resistor is disconnected and external high voltage is introduced.
[0004] The technical solution of the present invention to solve the above technical problems is as follows: A device for current detection in a combiner box, comprising a sampling resistor module, a differential protection module, a multi-way conversion switch module, a differential amplifier module, an analog-to-digital converter, a microcontroller and a communication module connected in series in sequence, and the multi-way conversion switch module is also electrically connected to the microcontroller.
[0005] The beneficial effects of the present invention are as follows: a device for current detection of a junction box of the present invention converts an external current signal into a voltage signal through a sampling resistor module; a differential protection module can embed the external high voltage introduced at both ends of the sampling resistor when the sampling resistor module is abnormally disconnected at a predetermined voltage; the multi-way conversion switch module is controlled by a microcontroller and switches between different differential protection modules to collect the voltage signals generated by the sampling resistor modules on different channels; the differential amplifier module converts the high-impedance voltage signal from the multi-way conversion switch module into a low-impedance voltage signal, and further amplifies the low-impedance voltage signal to meet the requirements of the analog-to-digital converter for the level signal; the microcontroller exchanges information with external devices through a communication module for the corresponding current signals of each channel converted by the analog-to-digital converter. The device of the present invention can still work normally when the sampling resistor module is disconnected and an external high voltage is introduced.
[0006] Based on the above technical solution, the present invention can also be improved as follows.
[0007] Furthermore, the communication module is electrically connected to the microcontroller, and the communication module is specifically an RS232 chip or an RS485 chip or a CAN chip.
[0008] Furthermore, it also includes a power supply, which is used to supply power to the resistance module, the differential protection module, the multi-way conversion switch module, the differential amplifier module, the analog-to-digital converter and the microcontroller.
[0009] Furthermore, the sampling resistor module is provided with one or more, each of which is composed of one or more alloy resistors R s Parallel composition.
[0010] Further, the number of the differential protection modules is the same as the number of the sampling resistor modules, and each of the differential protection modules includes two resistor units and one diode unit; the resistor unit includes one or more resistors R connected in series; the diode unit includes a diode D1, a diode D2, a diode D3 and a diode D4, and the diodes D1, D2, D3 and D4 are connected end to end in sequence to form a loop, a voltage VREF is input to the common end of the diode D1 and the diode D4, and the common end of the diode D2 and the diode D3 is grounded; one end of one of the resistor units is connected to the common end of the diode D1 and the diode D2, and one end of the other resistor unit is connected to the common end of the diode D3 and the diode D4; and the two ends of each of the sampling circuit modules are respectively connected to the other ends of the two resistor units in a corresponding differential protection module.
[0011] Furthermore, the total resistance of the resistor unit Rn≥U MAX 2 / P R , where U MAX is the highest voltage introduced externally, P R is the rated power of resistor R.
[0012] Furthermore, the number of the multi-way conversion switch module is the same as the number of the differential protection modules. The multi-way conversion switch module includes a multi-way electronic switch and a multi-way relay. The number of the electronic switches is the same as the number of the relays. Each of the electronic switches is connected in series with a corresponding one of the relays.
[0013] Further, the differential amplifier module includes a first operational amplifier, a second operational amplifier and a third operational amplifier, the positive input terminal of the first operational amplifier and the positive input terminal of the second operational amplifier are respectively connected to any two channels of the multi-channel conversion switch module, the negative input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the negative input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier; the output terminal of the first operational amplifier and the output terminal of the second operational amplifier are respectively connected through two corresponding resistors R i is connected to the positive input terminal and the negative input terminal of the third operational amplifier, and the positive input terminal of the third operational amplifier is also connected to the positive input terminal of the third operational amplifier through a resistor R fis connected to the output terminal of the third operational amplifier, and the negative input terminal of the third operational amplifier is also connected to the output terminal of the third operational amplifier through another resistor R f Ground.
[0014] Furthermore, the input voltage of the analog-to-digital converter is V AD =(R i / R f )*I*R S , where I is the maximum external current flowing in. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is an overall module diagram of a device for current detection of a combiner box according to the present invention;
[0016] Figure 2 The present invention is a specific circuit diagram of a device for current detection in a combiner box. DETAILED DESCRIPTION
[0017] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0018] like Figure 1 As shown, a device for current detection in a combiner box includes a sampling resistor module, a differential protection module, a multi-way conversion switch module, a differential amplifier module, an analog-to-digital converter, a microcontroller and a communication module connected in series in sequence, and the multi-way conversion switch module is also electrically connected to the microcontroller.
[0019] In this specific embodiment, the communication module is electrically connected to the microcontroller, and the communication module is specifically an RS232 chip or an RS485 chip or a CAN chip.
[0020] The present invention also includes a power supply, which is used to supply power to the resistance module, the differential protection module, the multi-way conversion switch module, the differential amplifier module, the analog-to-digital converter and the microcontroller.
[0021] Figure 2 The present invention is a specific circuit diagram of a device for current detection in a combiner box.
[0022] like Figure 2 As shown, the sampling resistor module is provided with one or more, each of which is composed of one or more low-value alloy resistors R s The sampling resistor module is used to convert the external current signal into a voltage signal. The sampling resistor module follows Ohm's law U S =I*R S , I is the maximum external current, R S is the alloy resistance R s resistance value.
[0023] like Figure 2 As shown, the number of the differential protection modules is the same as the number of the sampling resistor modules, and each of the differential protection modules includes two resistor units and one diode unit; the resistor unit includes one or more resistors R connected in series; the diode unit includes a diode D1, a diode D2, a diode D3 and a diode D4, and the diodes D1, D2, D3 and D4 are connected end to end in sequence to form a loop, and a voltage VREF is input to the common end of the diode D1 and the diode D4, and the common end of the diode D2 and the diode D3 is grounded; one end of one of the resistor units is connected to the common end of the diode D1 and the diode D2, and one end of the other resistor unit is connected to the common end of the diode D3 and the diode D4; the two ends of each sampling circuit module are respectively connected to the other ends of the two resistor units in a corresponding differential protection module. The differential protection module is used to embed the high voltage introduced by the sampling resistor module at a predetermined voltage. The total resistance of the resistor unit connected in series in the differential protection module is calculated according to the external maximum voltage and the maximum power of a single resistor R in the resistor unit. The total resistance of the resistor unit Rn≥U MAX 2 / P R , where U MAX is the highest voltage introduced externally, P R is the rated power of resistor R.
[0024] The number of the multi-way conversion switch module is the same as the number of the differential protection modules. The multi-way conversion switch module includes a multi-way electronic switch and a multi-way relay. The number of the electronic switch is the same as the number of the relays. Each electronic switch is connected in series with a corresponding relay. The multi-way conversion switch module is controlled by a microcontroller to switch between different differential protection modules to collect voltage signals generated by sampling resistor modules on different channels.
[0025] like Figure 2 As shown, the differential amplifier module includes a first operational amplifier, a second operational amplifier and a third operational amplifier, the positive input terminal of the first operational amplifier and the positive input terminal of the second operational amplifier are respectively connected to any two channels of the multi-channel conversion switch module, the negative input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the negative input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier; the output terminal of the first operational amplifier and the output terminal of the second operational amplifier are respectively connected through two corresponding resistors R iis connected to the positive input terminal and the negative input terminal of the third operational amplifier, and the positive input terminal of the third operational amplifier is also connected to the positive input terminal of the third operational amplifier through a resistor R f The negative input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier, and the negative input terminal of the third operational amplifier is also grounded through another resistor Rf.
[0026] In the differential amplifier module, the first operational amplifier and the second operational amplifier form a follower circuit group to convert the high impedance voltage signal from the multiplexer module into a low impedance voltage signal, and the third operational amplifier further amplifies the low impedance voltage signal to meet the requirements of the analog-to-digital converter for the level signal. The differential gain of the third operational amplifier is A=R i / R f .
[0027] The analog-to-digital converter can be integrated with the internal AD of the microcontroller to meet the requirements, or it can be completed with a commercially available AD chip. The input voltage of the analog-to-digital converter is V AD =A*U S =(R i / R f )*I*R S By adjusting R i , R f , R S These three resistors meet the input voltage requirements of the analog-to-digital converter.
[0028] The microcontroller can be composed of commercially available MCU and DSP chips. For example, the model of the microcontroller can be 80296SA. The microcontroller is used to control the multi-channel switch module and to exchange information with external devices through the communication module regarding the corresponding current signals of each channel converted by the analog-to-digital converter.
[0029] The present invention is a device for current detection of a junction box. The device converts an external current signal into a voltage signal through a sampling resistor module. The differential protection module can embed the external high voltage introduced at both ends of the sampling resistor when the sampling resistor module is abnormally disconnected at a predetermined voltage, so that the subsequent circuit will not be damaged by the high voltage. The multi-way conversion switch module is controlled by a microcontroller and switches between different differential protection modules to collect the voltage signals generated by the sampling resistor modules on different channels. The differential amplifier module converts the high-impedance voltage signal from the multi-way conversion switch module into a low-impedance voltage signal, and further amplifies the low-impedance voltage signal to meet the requirements of the analog-to-digital converter for the level signal. The microcontroller exchanges information with external devices through a communication module using the corresponding current signal of each channel converted by the analog-to-digital converter. The device of the present invention can still work normally when the sampling resistor module is disconnected and an external high voltage is introduced.
[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A device for current detection in a combiner box, characterized in that: It includes a sampling resistor module, a differential protection module, a multi-way conversion switch module, a differential amplifier module, an analog-to-digital converter, a microcontroller and a communication module which are sequentially connected in series, and the multi-way conversion switch module is also electrically connected to the microcontroller; The sampling resistor module is provided with one or more; the number of the differential protection modules is the same as the number of the sampling resistor modules, and each of the differential protection modules includes two resistor units and one diode unit; the resistor unit includes one or more resistors R connected in series; the diode unit includes a diode D1, a diode D2, a diode D3 and a diode D4, and the diodes D1, D2, D3 and D4 are connected end to end in sequence to form a loop, a voltage VREF is input to the common end of the diode D1 and the diode D4, and the common end of the diode D2 and the diode D3 is grounded; one end of one of the resistor units is connected to the common end of the diode D1 and the diode D2, and one end of the other resistor unit is connected to the common end of the diode D3 and the diode D4; the two ends of each of the sampling resistor modules are respectively connected to the other ends of the two resistor units in a corresponding differential protection module.
2. The device for current detection of a combiner box according to claim 1, characterized in that: The communication module is electrically connected to the microcontroller, and the communication module is specifically an RS232 chip or an RS485 chip or a CAN chip.
3. A device for combining box current detection according to claim 1 or 2, characterized in that: Also includes a power supply, the power supply is used to supply power to the resistance module, the differential protection module, the multi-way conversion switch module, the differential amplifier module, the analog-to-digital converter and the microcontroller; Each of the sampling resistor modules is composed of one or more alloy resistors R s Parallel composition.
4. The device for current detection of a combiner box according to claim 1, characterized in that: The total resistance of the resistance unit Rn≥U MAX 2 / P R , where U MAX is the highest voltage introduced externally, P R is the rated power of resistor R.
5. A device for combining box current detection according to claim 1 or 4, characterized in that: The number of the multi-way conversion switch module is the same as the number of the differential protection modules. The multi-way conversion switch module includes a multi-way electronic switch and a multi-way relay. The number of the electronic switches is the same as the number of the relays. Each electronic switch is connected in series with a corresponding relay.
6. The device for combining box current detection according to claim 5, characterized in that: The differential amplifier module includes a first operational amplifier, a second operational amplifier and a third operational amplifier. The positive input terminal of the first operational amplifier and the positive input terminal of the second operational amplifier are respectively connected to any two channels of the multi-channel conversion switch module. The negative input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier, and the negative input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier. The output terminal of the first operational amplifier and the output terminal of the second operational amplifier are respectively connected to the output terminal of the second operational amplifier through two corresponding resistors R i The negative input terminal of the third operational amplifier is connected to the positive input terminal and the negative input terminal of the third operational amplifier. The negative input terminal of the third operational amplifier is also connected to the positive input terminal and the negative input terminal of the third operational amplifier through a resistor R f The positive input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier, and the positive input terminal of the third operational amplifier is also grounded through another resistor Rf.
7. The device for combining box current detection according to claim 6, characterized in that: The input voltage of the analog-to-digital converter is V AD =(R i / R f )*I*R S , where I is the maximum external current flowing into the device.