Multi-loop direct-current electric energy meter

Abstract

The invention belongs to the technical field of electric energy meters, and mainly relates to a multi-loop direct-current electric energy meter which comprises a body and input modules arranged on the two sides of the body and integrally designed with mounting bayonets. The input module comprises a power supply module used for connecting an external power supply to the multi-loop DC electric energy meter and a sampling module used for connecting an external loop to be measured to the multi-loop DC electric energy meter. The body is provided with a control module and a display module electrically connected with the control module; the control module is electrically connected with the sampling module; the sampling module comprises a voltage detection unit and a current detection unit; the voltage detection unit is used for transmitting a detected voltage signal of a loop to be detected to the control module; the current detection unit is used for transmitting a detected current signal of the loop to be detected to the control module; the at least two voltage detection units and the at least two current detection units are used for detecting to-be-detected loops in different voltage and current ranges; through the above design, the electrical parameters among the photovoltaic power generation group strings can be effectively monitored.

Description

Technical Field

[0001] The invention belongs to the technical field of electric energy meters, and mainly relates to a multi-circuit direct current electric energy meter. Background Art

[0002] With the global energy transformation and the improvement of environmental awareness, photovoltaic power generation has gradually been widely used as a clean and renewable energy. Existing DC power meters play a vital role in photovoltaic power generation systems. These power meters can monitor the voltage, current, power and other electrical parameters of photovoltaic power generation systems in real time, help users understand the power generation status of photovoltaic panels, and calculate the total power generation, thereby providing users with basic data for power statistics and fee settlement. In addition, DC power meters can also be linked with monitoring systems to promptly detect abnormal conditions in the power generation system and improve the safety and reliability of the system.

[0003] However, although the existing single-circuit DC energy meters meet the basic needs of photovoltaic power generation systems to a certain extent, they have many defects that limit the performance and efficiency of photovoltaic power generation systems. First, single-circuit energy meters can usually only provide monitoring of the overall power generation, and cannot be refined to monitor the electrical parameters between each string of photovoltaic panels, resulting in the inability to timely detect the reduction in power generation efficiency caused by problems such as broken grids, hidden cracks, stratification, fragmentation or dirt. Secondly, the single-circuit system cannot monitor energy loss in real time during the power generation process, resulting in delayed analysis of power generation efficiency and increased difficulty in maintenance and management. Finally, due to the lack of refined monitoring, the inspection and maintenance of photovoltaic power generation systems often rely on experience judgment, which increases the risk of equipment failure, fails to maximize the power generation potential of the equipment, and affects the economic benefits of users.

[0004] Based on this, it is urgent to improve the existing DC electric energy meter to solve the many technical defects existing in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-circuit DC electric energy meter which can simultaneously detect the electric quantity of multiple circuits to be tested in view of the deficiencies of the prior art.

[0006] In order to achieve the above technical objectives, this application implements the following technical solutions:

[0007] A multi-circuit DC electric energy meter comprises a body and at least two input modules arranged on both sides of the body, wherein the input module and the mounting bayonet are designed as an integrated whole; the input module comprises a power module and a sampling module, wherein the power module is used to connect an external power supply to the multi-circuit DC electric energy meter, and the sampling module is used to connect an external receiving and measuring circuit to the multi-circuit DC electric energy meter;

[0008] Furthermore, the body is provided with a control module and a display module electrically connected to the control module; the control module is electrically connected to the sampling module; the sampling module includes a voltage detection unit and a current detection unit, the voltage detection unit is used to transmit the voltage signal of the circuit to be tested after detection to the control module; the current detection unit is used to transmit the current signal of the circuit to be tested after detection to the control module;

[0009] Furthermore, at least two voltage detection units are provided, each of which is used to detect a circuit to be tested with a different voltage range; at least two current detection units are provided, each of which is used to detect a circuit to be tested with a different current range.

[0010] The above technical solution produces the following technical effects:

[0011] First, by setting up multiple voltage detection units and current detection units, the present application can independently detect the voltage and current of multiple circuits to be tested, thereby realizing accurate monitoring of the electrical parameters of each string. This helps to promptly discover and solve the reduction in power generation efficiency caused by component problems, and improve the performance and efficiency of the entire photovoltaic power generation system. Secondly, since the energy loss of each string can be monitored in real time, the power generation efficiency analysis is more timely and accurate, thereby reducing the difficulty of maintenance and management, and improving the safety and reliability of the system. The monitoring data implemented above makes the inspection and maintenance of the photovoltaic power generation system no longer rely on empirical judgment, but is based on actual monitoring data, reducing the risk of equipment failure, maximizing the use of the power generation potential of the equipment, and thus improving the economic benefits of users.

[0012] As a further improvement to a multi-circuit DC electric energy meter of the present invention, the current detection unit detects the circuit to be measured through a Hall sensor, and the signal detected by the Hall sensor is processed by a digital-to-analog converter and then transmitted to the control module.

[0013] As a further improvement to the multi-circuit DC electric energy meter of the present invention, the output signal V H It is expressed as:

[0014] V H =K·|I|+V offset

[0015] Where K is the sensitivity of the Hall sensor; |I| is the absolute value of the current in the circuit to be measured, V offset is the zero-point bias voltage, indicating the output voltage when there is no current; the Hall sensor will output a signal V H is transmitted to the control module, and the control module outputs a signal V H Convert to the absolute value of the current in the circuit to be measured |I|.

[0016] As a further improvement of the multi-circuit DC electric energy meter of the present invention, the control module includes a metering unit, which is used to convert the output signal V collected by the Hall sensor into H Convert to the absolute value of the current in the circuit to be measured |I|.

[0017] As a further improvement to a multi-circuit DC electric energy meter of the present invention, the current detection unit includes a sampling resistor R1 and a voltage-dividing resistor R2 connected in series, and the Hall sensor is used to detect the voltage of the sampling resistor R1.

[0018] As a further improvement to the multi-circuit DC electric energy meter of the present invention, the resistance value of the sampling resistor R1 is 10 kΩ; the value range of the voltage divider resistor R2 is: 1 kΩ-10 kΩ.

[0019] As a further improvement of a multi-circuit DC power meter of the present invention, the power module is used to convert the electric energy of an external power supply into a DC low voltage through wireless induction charging; the voltage detection unit directly collects the DC voltage signal of the circuit to be tested through wireless induction.

[0020] As a further improvement to the multi-circuit DC electric energy meter of the present invention, the control module exchanges data and communicates with other devices or systems through a standard communication protocol.

[0021] As a further improvement to a multi-circuit DC electric energy meter of the present invention, the voltage detection unit includes a sampling resistor R3 and a voltage-dividing resistor R4 connected in series, and the voltage of the sampling resistor R3 is the voltage signal of the circuit to be tested received by the control module.

[0022] As a further improvement to a multi-circuit DC electric energy meter of the present invention, the voltage signal of the sampling resistor R3 is processed by a digital-to-analog converter and transmitted to a voltage signal that can be recognized by the control module. The resistance range of the sampling resistor R3 is: 1KΩ-35KΩ, and the resistance of the voltage divider resistor R4 is 1MΩ. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 It is a front view of the structural schematic diagram of Example 1 of the present invention;

[0025] Figure 2 It is a side view of the structural schematic diagram of Example 1 of the present invention;

[0026] Figure 3 One of the circuit topology diagrams of Example 1 of the present invention;

[0027] Figure 4 This is the second circuit topology diagram of Example 1 of the present invention;

[0028] Figure 5 This is a working diagram of the current detection unit in Example 1 of the present invention;

[0029] Figure 6 This is a working diagram of a voltage detection unit in Example 3 of the present invention;

[0030] in:

[0031] 1-Ontology;

[0032] 11- control module;

[0033] 111 - Unit of measurement;

[0034] 12-display module;

[0035] 2- Input module;

[0036] 21-power module;

[0037] 22-sampling module;

[0038] 221- voltage detection unit;

[0039] 222-current detection unit;

[0040] 223-Hall sensor;

[0041] 224-digital-to-analog converter;

[0042] 3- Install the bayonet. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0044] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the claims. Any technical personnel in this field may make several possible changes and modifications without departing from the concept of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

[0046] The present invention is further described in detail below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto.

[0047] Example 1

[0048] like Figure 1-5 In order to alleviate the limitation of the existing DC power meter on the performance and efficiency of the photovoltaic power generation system, the electrical parameters between the various strings of the photovoltaic panel power generation circuit to be tested are effectively monitored. This application improves the existing DC power meter. Specifically, a multi-circuit DC power meter includes a main body 1 and at least two input modules 2 arranged on both sides of the main body 1, and the input module 2 and the mounting bayonet 3 are designed as an integrated whole; the internal circuit is protected from the influence of the external environment through the integrated design and the shell of the main body 1.

[0049] Furthermore, the input module 2 includes a power module 21 and a sampling module 22, wherein the power module 21 is used to connect an external power supply to a multi-circuit DC power meter, and the sampling module 22 is used to connect an external test circuit to a multi-circuit DC power meter; the body 1 is provided with a control module 11 and a display module 12 electrically connected to the control module 11; wherein the control module 11 is responsible for processing the signal from the input module 2 and displaying the processed data on the display module 12. The display module 12 may be an LCD or LED display screen, which is used to intuitively display the power data and status information of each circuit.

[0050] Furthermore, the control module 11 is electrically connected to the sampling module 22; the sampling module 22 includes a voltage detection unit 221 and a current detection unit 222, the voltage detection unit 221 is used to transmit the voltage signal of the circuit to be tested after detection to the control module 11; the current detection unit 222 is used to transmit the current signal of the circuit to be tested after detection to the control module 11;

[0051] Specifically, at least two voltage detection units 221 are provided, and each voltage detection unit 221 is used to detect the circuit to be tested in different voltage ranges; at least two current detection units 222 are provided, and each current detection unit 222 is used to detect the circuit to be tested in different current ranges. Through the design of multiple voltage detection units 221 and current detection units 222 with different ranges, accurate measurement of circuits in different voltage and current ranges can be achieved, thereby meeting the needs of different application scenarios. In addition, both the voltage detection unit 221 and the current detection unit 222 use high-precision sensors to ensure the accuracy and reliability of the measurement data.

[0052] Furthermore, the current detection unit 222 detects the circuit to be tested through the Hall sensor 223 , and the signal detected by the Hall sensor 223 is processed by the digital-to-analog converter 224 and then transmitted to the control module 11 .

[0053] The output signal V of the Hall sensor 223 is H It is expressed as:

[0054] V H =K·|I|+V offset

[0055] Wherein, K is the sensitivity of the Hall sensor 223; |I| is the absolute value of the current in the circuit to be measured, V offset is the zero-point bias voltage, indicating the output voltage when there is no current; the Hall sensor 223 outputs a signal V H is transmitted to the control module 11, and the control module 11 outputs a signal V H Converted to the absolute value of the current in the circuit to be measured |I|. According to the principle of the Hall sensor 223, the output of the Hall sensor 223 is directly related to the direction of the current, so its output voltage expression usually contains positive and negative symbols. When current flows through the Hall sensor 223, it generates an output voltage according to the direction of the current. For example, a current in the positive direction may produce a positive output voltage, while a current in the reverse direction may produce a negative output voltage. However, in the specific implementation, the expression can be simplified so that it does not contain positive and negative symbols, and the specific simplified expression is as described above.

[0056] Furthermore, since the signal output by the Hall sensor 223 is still a voltage signal, the present application uses the metering unit 111 in the control module 11 (specifically the MCU processor) to convert the output signal V collected by the Hall sensor 223 into H The output signal V collected by the Hall sensor 223 is converted into the absolute value |I| of the current in the circuit to be measured. H The expression becomes the expression of the absolute value |I| of the current in the circuit to be measured.

[0057] Furthermore, it is known that there are multiple current detection units 222 in the present application, and the detection range of each current detection unit 222 is different. In order to implement the above technical solution, further, the current detection unit 222 includes a sampling resistor R1 and a voltage divider resistor R2 connected in series, and the Hall sensor 223 is used to detect the voltage of the sampling resistor R1.

[0058] Furthermore, the output signal V collected by the Hall sensor 223 H It can be further expressed as V out , where V out The output signal V collected by the Hall sensor 223 H The relationship between them is:

[0059]

[0060] Combined with the Hall sensor 223 output signal V H The above formula can be rewritten as:

[0061]

[0062] Furthermore, in this application, the current range to be measured is divided into several sections, and different voltage divider resistors are selected accordingly to meet different current measurement requirements. Among them, the resistance value of the sampling resistor R1 is 10kΩ; the value range of the voltage divider resistor R2 is: 1kΩ-10kΩ. The following is the adjustment of the resistance value of the sampling resistor and the voltage divider resistor for different current measurement requirements of the circuit to be measured:

[0063] When the current range is: 0-10A, the values ​​of the sampling resistor R1 and the voltage divider resistor R2 are: R1 = 1kΩ, R2 = 10kΩ; at this time, the output voltage V out The expression is:

[0064]

[0065] Assume that the value of K in the above expression is 0.1V / A, V offset is 0.1V, at this time the output voltage V out The maximum value of satisfies:

[0066]

[0067] Therefore, when the measured loop current is 5A, the Hall sensor 223 outputs a signal V H satisfy:

[0068] V H =0.1·5+0.1=0.6V

[0069] The output voltage after voltage division is V outThe expression satisfies:

[0070] Assume that the value of K in the above expression is 0.1V / A, V offset is 0.1V, at this time the output voltage V out The maximum value of satisfies:

[0071]

[0072] When the current range is: 10-30A, the values ​​of the sampling resistor R1 and the voltage divider resistor R2 are: R1 = 2kΩ, R2 = 10kΩ; at this time, the output voltage V out The expression is:

[0073]

[0074] Assume that the value of K in the above expression is 0.1V / A, V offset is 0.1V, at this time the output voltage V out The maximum value of satisfies:

[0075]

[0076] At this time, since the maximum acceptable voltage of the control module 11 and the digital-to-analog converter 1 is no more than 4V, when the Hall sensor 223 is directly used to detect the measured circuit with a current of 10-30A, the current output by the Hall sensor 223 will exceed the range that the control module 11 and the digital-to-analog converter cannot recognize. Therefore, the present application uses the design of the voltage divider resistor and the sampling resistor to keep the output voltage below 3.4V, which basically meets the acceptable range of the control module 11. Through the above design, the measurement accuracy and stability within different current ranges can be ensured. The metering unit 111 has been introduced into the current detection unit 222 to calculate the output voltage V out The calculation formula is that the absolute value of the measured circuit current can be further calculated through deduction and calculation.

[0077] Furthermore, when the current range is: 30-50A, the values ​​of the sampling resistor R1 and the voltage divider resistor R2 are: R1 = 1kΩ, R2 = 10kΩ; at this time, the output voltage V out The expression is:

[0078]

[0079] Assume that the value of K in the above expression is 0.1V / A, V offset is 0.1V. At this time, when the measured loop current is 40A, the Hall sensor 223 outputs a signal V H satisfy:

[0080] V H=0.1·40+0.1=4.1V

[0081] The output voltage after voltage division is V out The expression satisfies:

[0082]

[0083] At this time, the output voltage after voltage division still meets the range requirement of the voltage signal that can be recognized by the control module 11, while the output signal of the Hall sensor 223 exceeds the range. Therefore, the present application can accurately detect signals of different current ranges through the multi-circuit DC electric energy meter of the present application by appropriately selecting the sensitivity of the Hall sensor 223 and combining different voltage divider resistors. In the specific implementation process, it is ensured that each current range can obtain a usable output signal through the corresponding voltage divider configuration. It can be seen that the design of the present application provides a flexible current detection solution, which can be adjusted and optimized according to system requirements.

[0084] Furthermore, in order to improve the stability and anti-interference ability of the system, the present application also introduces a filter circuit in the current detection unit 222. The filter circuit can effectively filter out noise and interference in the signal, ensuring the accuracy of the measured data. The filter circuit usually includes capacitors and inductors, and by reasonably designing its parameters, an ideal filtering effect can be achieved.

[0085] Example 2

[0086] like Figure 1-5 As shown, in order to further improve the power detection performance of the multi-circuit DC power meter of the present application. Specifically, the power module 21 is used to convert the power from the external power supply into a DC low voltage by wireless induction charging; the voltage detection unit 221 directly collects the DC voltage signal of the circuit to be tested by wireless induction. Among them, the power module 21 includes a wireless induction charging circuit and a voltage conversion circuit. The wireless induction charging circuit uses the principle of electromagnetic induction to wirelessly receive the energy emitted by the external power supply and convert it into a DC low voltage. The voltage conversion circuit further converts the DC low voltage output by the wireless induction charging circuit into a stable DC voltage suitable for use by the voltage detection unit 221. The voltage detection unit 221 directly collects the DC voltage signal of the circuit to be tested by wireless induction. The unit includes an induction coil, a rectifier circuit and a filter circuit. The induction coil receives the voltage signal in the circuit to be tested and converts it into an AC signal by electromagnetic induction. The rectifier circuit converts the AC signal into a DC signal, and the filter circuit further filters out the noise and interference in the signal to ensure the accuracy of the voltage signal.

[0087] In order to improve the performance of electric energy detection, the control module 11 of the present application is also provided with an electric energy calculation module. The electric energy calculation module calculates the electric energy consumption of the circuit to be tested by collecting the DC voltage signal output by the voltage detection unit 221 and the current signal in the control module 11. The electric energy calculation module includes a multiplier and an integrator. The multiplier multiplies the voltage signal and the current signal to obtain an instantaneous power signal. The integrator integrates the instantaneous power signal to obtain the electric energy consumption value. In order to further improve the stability and anti-interference ability of the system, the present application also introduces a digital filter in the electric energy calculation module. The digital filter filters the collected voltage and current signals through a software algorithm, effectively filters out noise and interference in the signal, and ensures the accuracy of the electric energy calculation.

[0088] Furthermore, the energy consumption value, voltage value, and current value detected in the present application can be displayed by the display module 12. The display module 12 uses an LCD display screen to display information such as power, current, and voltage, and can support multiple display modes, such as time-sharing display and cumulative display. The storage module uses an EEPROM memory to store the configuration parameters, power, historical data, etc. of the energy meter for identification and interaction with the host computer connected to the control module 11.

[0089] Furthermore, the control module 11 exchanges data and communicates with other devices or systems through standard communication protocols. The control module 11 is also provided with a communication module, wherein the communication module has two communication modes: a wireless communication interface (such as LoRa, NB-I oT) and a wired communication interface (such as RS-485). In a specific implementation, the present application uses a standard communication protocol (such as Modbus-RTU) to exchange data and communicate with other devices or systems. Furthermore, the control module 11 is implemented by an MCU (microcontroller), which is responsible for various control and operation functions of the electric energy meter, such as parameter setting, calibration, data reading, etc.

[0090] The other details that are the same as those in Example 1 are not described in detail in this example.

[0091] Example 3

[0092] like Figure 1-6 As shown, the difference from Example 1 is that: in order to further improve the detection of the voltage of the circuit to be measured by the multi-circuit DC energy meter of the present application. Specifically, the voltage detection unit 221 includes a sampling resistor R3 and a voltage divider resistor R4 connected in series, and the voltage of the sampling resistor R3 is the voltage signal of the circuit to be measured received by the control module 11. Among them, the voltage signal of the sampling resistor R3 is processed by the digital-to-analog converter 224 and transmitted to the voltage signal that can be recognized by the control module 11. The resistance range of the sampling resistor R3 is: 1KΩ-35KΩ, and the resistance value of the voltage divider resistor R4 is 1MΩ.

[0093] Specifically, in order to achieve the expected achievement index mentioned in this application: DC0-1500V, the range can be divided into several levels (for example: 0-100V, 100-500V, 500-1000V, 1000-1500V), the specific scheme is as follows:

[0094] Design the voltage divider resistors to satisfy the following expression

[0095]

[0096] Among them, V in is the voltage value directly measured when the voltage detection unit 221 does not include a voltage divider resistor and a sampling resistor, V out is the final voltage value of the output and control module 11 and the digital-to-analog converter 224 .

[0097] When the voltage range of the circuit to be tested is 0-100V, in order to divide the highest voltage of the circuit to be tested within the range of 100V to 3.3V (which can be recognized by the control module 11 and the digital-to-analog converter 224), the sampling resistance needs to be less than 33.4KΩ. That is, when the sampling resistance is 33.4KΩ, the following expression is satisfied:

[0098]

[0099] When the voltage range of the circuit to be tested is 100-500V, in order to divide the highest voltage of the circuit to be tested within the range of 500V to 3.3V (which can be recognized by the control module 11 and the digital-to-analog converter 224), the sampling resistance needs to be less than 6.8KΩ. That is, when the sampling resistance is 6.8KΩ, the following expression is satisfied:

[0100]

[0101] When the voltage range of the circuit to be tested is 500-1000V, in order to divide the highest voltage of the circuit to be tested within the range of 1000V to 3.3V (which can be recognized by the control module 11 and the digital-to-analog converter 224), the sampling resistance needs to be less than 1.5KΩ, that is, when the sampling resistance is 6.8KΩ, the following expression is satisfied:

[0102]

[0103] When the voltage range of the circuit to be tested is 1000-1500V, in order to divide the highest voltage of the circuit to be tested within the range of 1500V to 3.3V (which can be recognized by the control module 11 and the digital-to-analog converter 224), the sampling resistance needs to be less than 1KΩ, that is, when the sampling resistance is 6.8KΩ, the following expression is satisfied:

[0104]

[0105] In summary,

[0106] In order to ensure the accuracy and stability of the energy meter in different voltage ranges, the matching relationship between the voltage divider resistor and the sampling resistor must be considered when designing the voltage divider resistor. In Example 3, we have given the resistance range of the sampling resistor and the resistance value of the voltage divider resistor for different voltage ranges.

[0107] Other details that are the same as those in Example 1 are not described in detail in this application.

[0108] The above is only a preferred embodiment of the voltage detection unit 221 of the present application, and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-circuit DC electric energy meter, characterized in that: include: A body (1) and at least two input modules (2) arranged on both sides of the body (1), wherein the input modules (2) and the mounting bayonet (3) are designed as an integral whole; The input module (2) comprises a power module (21) and a sampling module (22), wherein the power module (21) is used to connect an external power source to the multi-circuit DC power meter, and the sampling module (22) is used to connect an external test circuit to the multi-circuit DC power meter; The body (1) is provided with a control module (11) and a display module (12) electrically connected to the control module (11); the control module (11) is electrically connected to the sampling module (22); The sampling module 22 (22) comprises a voltage detection unit (221) and a current detection unit (222), wherein the voltage detection unit (221) is used to transmit the voltage signal of the circuit to be tested after detection to the control module (11); and the current detection unit (222) is used to transmit the current signal of the circuit to be tested after detection to the control module (11); At least two voltage detection units (221) are provided, and each voltage detection unit (221) is used to detect a circuit to be tested in a different voltage range; At least two current detection units (222) are provided, and each current detection unit (222) is used to detect a circuit to be tested with a different current range.

2. A multi-circuit DC electric energy meter according to claim 1, characterized in that: The current detection unit (222) detects the circuit to be tested via a Hall sensor (223); the signal detected by the Hall sensor (223) is processed by a digital-to-analog converter (224) and then transmitted to the control module (11).

3. A multi-circuit DC electric energy meter according to claim 2, characterized in that: The output signal V of the Hall sensor (223) H It is expressed as: V H =K·|I|+V offset Wherein, K is the sensitivity of the Hall sensor (223); |I| is the absolute value of the current of the loop to be measured, V offset is the zero-point bias voltage, indicating the output voltage when there is no current; the Hall sensor (223) converts the output signal V H is transmitted to the control module (11), and the control module (11) converts the output signal V H Converted into the absolute value |I| of the current of the circuit to be measured.

4. A multi-circuit DC electric energy meter according to claim 3, characterized in that: The control module (11) comprises a metering unit (111), wherein the metering unit (111) is used to convert the output signal V collected by the Hall sensor (223) into H Converted into the absolute value |I| of the current of the circuit to be measured.

5. A multi-circuit DC electric energy meter according to claim 3, characterized in that: The current detection unit (222) comprises the sampling resistor R1 and the voltage-dividing resistor R2 connected in series, and the Hall sensor (223) is used to detect the voltage of the sampling resistor R1.

6. A multi-circuit DC electric energy meter according to claim 5, characterized in that: The resistance value of the sampling resistor R1 is 10 kΩ; the value range of the voltage divider resistor R2 is: 1 kΩ-10 kΩ.

7. A multi-circuit DC electric energy meter according to claim 1, characterized in that: The power module (21) is used to convert the electric energy of the external power supply into a DC low voltage by means of wireless induction charging; and the voltage detection unit (221) directly collects the DC voltage signal of the circuit to be tested by means of wireless induction.

8. A multi-circuit DC electric energy meter according to claim 1, characterized in that: The control module (11) exchanges data and communicates with other devices or systems via a standard communication protocol.

9. A multi-circuit DC electric energy meter according to claim 1, characterized in that: The voltage detection unit (221) comprises a sampling resistor R3 and a voltage-dividing resistor R4 connected in series, and the voltage of the sampling resistor R3 is the voltage signal of the circuit to be tested received by the control module (11).

10. A multi-circuit DC electric energy meter according to claim 9, characterized in that: The voltage signal of the sampling resistor R3 is processed by a digital-to-analog converter (224) and then transmitted as a voltage signal that can be recognized by the control module (11). The resistance range of the sampling resistor R3 is 1KΩ-35KΩ, and the resistance of the voltage divider resistor R4 is 1MΩ.

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