A high-precision DC power detection device and method

Abstract

The present invention relates to a high-precision DC electric energy detection device and method. A high-precision DC electric energy detection device comprises: a management unit, a measuring chip, an isolation voltage detection unit, a first current detection unit, a second current detection unit and a shunt; the management unit has an AD channel; the first current detection unit and the second current detection unit are respectively connected to the shunt; the isolation voltage detection unit and the first current detection unit are respectively connected to the measuring chip; the measuring chip is connected to the management unit; the second current detection unit is connected to the AD channel. The detection device implements current sampling in two ways through the shunt, one way through the measuring chip and the other way through the AD channel of the management unit, and performs electric energy measurement and accumulation respectively, and finally selects the measurement data in sections through the fuzzy algorithm to improve the measurement accuracy, thereby improving the detection range and accuracy of DC electric energy.

Description

Technical Field

[0001] The present invention relates to the electrical field, and in particular to a high-precision direct current electric energy detection device and method. Background Art

[0002] At present, direct current is widely used in photovoltaic power generation, electric vehicles, high-voltage power transmission, rail transit, large-scale industry and substations. Among them, photovoltaic power generation, as an emerging industry, has received strong support from the country. The General Administration of Quality Supervision, Inspection and Quarantine, State Grid Corporation of China and China Southern Power Grid Corporation have successively issued relevant standards for photovoltaic power generation and its ancillary equipment, and the State Council and other relevant departments have also issued a series of support policies for photovoltaic power generation. Since the characteristics of the electric energy generated by photovoltaic power generation are often direct current, direct current power measurement is involved in the transmission and power consumption of photovoltaic power generation. At the same time, the current direct current power measurement technology is mainly used in photovoltaic power generation, electric vehicle charging piles, tower base station direct current distribution and other fields. In addition to the requirements for DC voltage and DC current measurement in the above-mentioned application occasions, the main required DC power data, so the stability of DC power data measurement directly affects the settlement of operating expenses.

[0003] The voltage specifications required for DC electric energy metering are 700V and 1000V, and the current specifications are 50A, 100A, 300A, and 500A. Electric energy metering has a combination of the above voltage and current specifications. It can be seen that the voltage and current measurement range span is relatively large, which poses a great challenge to the full-range measurement of DC electric energy. The existing DC metering technology has a narrow measurement range and cannot guarantee the accuracy of small current measurement.

[0004] Patent document No. ZL 201710065112.9 discloses an electric energy data acquisition system based on wireless network transmission, involving an acquisition and detection system of a power grid line and its working method, which can be widely used for signal acquisition and detection of low-voltage lines. An electric energy data acquisition system based on wireless network transmission consists of an electric energy acquisition device, a communication power supply device and a patch voltage acquisition device; the electric energy acquisition device is connected to the communication power supply device through a communication bus; the patch voltage acquisition device transmits data to the communication power supply device through wireless transmission. The electric energy acquisition device has a housing one; a communication bus interface and a manual coding switch are arranged on the surface of the housing one; a current signal acquisition interface, a temperature signal acquisition interface, a programmable gain amplifier (PGA), a digital signal converter (second-order sigma-delta ADC), a precision reference source, a filtering module, a metering module, a precision clock and a communication module are arranged in the housing one, but the above problems are still not solved.

[0005] Therefore, the existing DC power detection method has shortcomings and needs to be improved and enhanced. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a high-precision DC power detection device and method, which can solve the problem of narrow DC power measurement range and improve the accuracy of small current measurement.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A high-precision DC electric energy detection device, comprising: a management unit, a measurement chip, an isolation voltage detection unit, a first current detection unit, a second current detection unit and a shunt; the management unit has an AD channel;

[0009] The first current detection unit and the second current detection unit are connected to the shunt respectively; the isolation voltage detection unit and the first current detection unit are connected to the measurement chip respectively; the measurement chip is connected to the management unit; and the second current detection unit is connected to the AD channel.

[0010] Preferably, the isolated voltage sampling unit comprises: a voltage division sampling circuit, an isolation chip and a back-end measurement sampling circuit connected in sequence, and the back-end measurement sampling circuit is connected to the measurement chip.

[0011] Preferably, the voltage-dividing sampling circuit comprises: a varistor, a voltage divider, a voltage sampling resistor and a filter; the filter is connected to the isolation chip; the voltage divider comprises a first voltage-dividing resistor group and a second voltage-dividing resistor group connected in parallel;

[0012] The varistor is connected between the positive voltage and the negative voltage of the detection circuit, the first voltage-dividing resistor group is connected in series to the positive voltage of the detection circuit, and the second voltage-dividing resistor group is connected in series to the negative voltage of the detection circuit; the two ends of the voltage sampling resistor are respectively connected to the output ends of the first voltage-dividing resistor group and the second voltage-dividing resistor group, and one end is grounded; the output end of the first voltage-dividing resistor group and the output end of the second voltage-dividing resistor group are respectively connected to the filter.

[0013] Preferably, the first voltage-dividing resistor group and the second voltage-dividing resistor group both use the same voltage-dividing circuit;

[0014] The voltage-dividing circuit is composed of a plurality of voltage-dividing resistors connected in series.

[0015] Preferably, the filter includes a first filter capacitor, a second filter capacitor and a third filter capacitor; one end of the first filter capacitor is connected to the output end of the first voltage-dividing resistor group, and the other end is grounded; one end of the second filter capacitor is connected to the output end of the second voltage-dividing resistor group, and the other end is grounded; two ends of the third filter capacitor are respectively connected to the output end of the first voltage-dividing resistor group and the output end of the second resistor group.

[0016] Preferably, the first current detection unit and the second current detection unit both use the same current sampling circuit;

[0017] The current sampling circuit includes a current voltage dividing resistor, a current sampling resistor, a first current filtering circuit and a second current filtering circuit; one end of the current voltage dividing resistor is respectively connected to the current sampling resistor and the first current filtering circuit, and the other end is connected to the shunt; the other end of the current sampling resistor is respectively connected to the first filtering circuit and the second filtering circuit; the output end of the first current filtering circuit and the output end of the second current filtering circuit are respectively connected to the measuring chip or the AD channel.

[0018] Preferably, it also includes a communication module and a display module, which are respectively connected to the management unit.

[0019] A high-precision DC power detection method applied to the high-precision DC power detection device comprises the following steps:

[0020] S1, the measuring chip receives the voltage data detected by the isolation voltage detection unit and the first current data detected by the first current detection unit respectively, and sends them to the management unit;

[0021] S2, the management unit receives the second current data detected by the second current detection unit through the AD channel, and amplifies it by a predetermined multiple; the management unit obtains the first electric energy data according to the first current data, and obtains the second electric energy data according to the second current data;

[0022] S3, the management unit selects the electric energy output data at this time according to the relationship between the first current data and the rated current;

[0023] S4. The management unit calculates the electric energy accumulated value according to the electric energy output data.

[0024] Preferably, in the high-precision DC power detection method, step S3 specifically comprises:

[0025] S31, the management unit determines whether the first current data is greater than or equal to the first proportional value of the rated current, and if so, takes the first electric energy data as the electric energy output data; if not, executes step S32;

[0026] S32. The management unit determines whether the first current data is greater than or equal to the second proportional value of the rated current. If so, the management unit obtains the electric energy output data according to the second electric energy data through a fuzzy precision processing formula to obtain the electric energy output data; if not, the second electric energy data is used as the electric energy output data.

[0027] Preferably, in the high-precision DC power detection method, in step S32, the fuzzy precision processing formula is obtained using the following steps:

[0028] S321, the management unit performs full-range current detection calibration on the equipment before leaving the factory to obtain several groups of discrete data; the discrete data includes electric energy

[0029] S322. The management unit performs data fitting based on the electric energy data and the current data in the plurality of groups of discrete data to obtain the fuzzy precision processing formula of the device.

[0030] Compared with the prior art, the present invention provides a high-precision DC electric energy detection device and method, which divides current sampling into two paths through the shunt, one path passes through the measurement chip, and the other path passes through the AD channel of the management unit, and performs electric energy measurement and accumulation respectively, and finally selects the measurement data in segments through the fuzzy algorithm to improve the measurement accuracy, thereby improving the detection range and accuracy of DC electric energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural block diagram of the high-precision DC electric energy detection device in the present invention;

[0032] Figure 2 is a circuit diagram of an isolation voltage detection unit in the present invention;

[0033] Figure 3 It is a circuit diagram of the current sampling circuit of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Please refer to the figure. The present invention provides a high-precision DC power detection device, including: a management unit 1, a measurement chip 2, an isolation voltage detection unit 3, a first current detection unit 4, a second current detection unit 5 and a shunt 6; the management unit 1 has an AD (analogue-to-digital conversion) channel (not shown);

[0036] The first current detection unit 4 and the second current detection unit 5 are connected to the shunt 6 respectively; the isolation voltage detection unit 3 and the first current detection unit 4 are connected to the measurement chip 2 respectively; the measurement chip 2 is connected to the management unit 1; the second current detection unit 5 is connected to the AD channel.

[0037] Specifically, the management unit 1 is an MCU (Microcontroller Unit) or a CPU (central processing unit), which is not specifically limited in the present invention. Preferably, it is an MCU of model FM33A048, which can manage the voltage, current, power and other data transmitted in the measuring chip 2, and has an AD channel to perform set processing on the second current data of the second current detection unit 5 (for example, to expand the current data by a certain multiple), and manage the electric energy of the line in combination with the voltage and current data transmitted by the measuring chip 2; the measuring chip 2 performs data exchange via an SPI link connection, and preferably has a model of RN8209G; the shunt 6 is preferably a manganese-copper shunt 6.

[0038] Accordingly, the present invention also provides a high-precision DC power detection method, comprising the steps of:

[0039] S1, the measuring chip receives the voltage data detected by the isolation voltage detection unit and the first current data detected by the first current detection unit respectively, and sends them to the management unit;

[0040] S2, the management unit receives the second current data detected by the second current detection unit through the AD channel, and amplifies it by a predetermined multiple; the management unit obtains the first electric energy data according to the first current data, and obtains the second electric energy data according to the second current data;

[0041] S3, the management unit selects the electric energy output data at this time according to the relationship between the first current data and the rated current;

[0042] S4. The management unit calculates the electric energy accumulated value according to the electric energy output data.

[0043] Specifically, the high-precision DC electric energy detection method provided by the present invention outputs electric energy data according to the relationship between the first current data and the rated current data, thereby expanding the detection accuracy. The input current is transmitted to the first current detection unit 4 and the second current detection unit 5 respectively through the shunt 6, and then the first current data and the second current data detected are sent to the measurement chip 2 and the management unit 1 respectively for processing. In the measurement chip 2, no further processing is performed, and the data is only subjected to certain basic functions such as filtering before being transmitted to the management unit 1; at the same time, the management unit 1 amplifies the second current data transmitted by the second current detection unit 5 through the AD channel. Here, the amplification process can amplify the small current data and increase the measurement width; the management unit 1 outputs the electric energy data according to the relationship between the first current data transmitted by the measurement chip 2 and the rated current. For example, when the first current data is less than a certain value, the second electric energy data will be directly used for cumulative calculation.

[0044] As a preferred solution, in this embodiment, the isolated voltage sampling unit includes: a voltage dividing sampling circuit, an isolation chip and a back-end measurement sampling circuit connected in sequence, and the back-end measurement sampling circuit is connected to the measurement chip 2. Preferably, the isolation chip U8 is an AMC1200B chip produced by TI.

[0045] As a preferred solution, in this embodiment, the voltage-dividing sampling circuit includes: a varistor RVA, a voltage divider, a voltage sampling resistor RT and a filter; the filter is connected to the isolation chip U8; the voltage divider includes a first voltage-dividing resistor group and a second voltage-dividing resistor group connected in parallel;

[0046] The varistor is connected between the positive voltage V+ and the negative voltage V- of the detection circuit, the first voltage-dividing resistor group is connected in series to the positive voltage V+ of the detection circuit, and the second voltage-dividing resistor group is connected in series to the negative voltage V- of the detection circuit; the two ends of the voltage sampling resistor are respectively connected to the output ends of the first voltage-dividing resistor group and the second voltage-dividing resistor group, and one end is grounded; the output end of the first voltage-dividing resistor group and the output end of the second voltage-dividing resistor group are respectively connected to the filter.

[0047] As a preferred solution, in this embodiment, the first voltage-dividing resistor group and the second voltage-dividing resistor group both use the same voltage-dividing circuit;

[0048] The voltage divider circuit is composed of a plurality of voltage divider resistors connected in series. Preferably, the first voltage divider resistor group and the second voltage divider resistor group each include 5 voltage divider resistors connected in series, wherein the 5 voltage divider resistors of the first voltage divider resistor group are RA1-RA5, and the 5 voltage divider resistors of the second voltage divider resistor group are RA6-RA10; the resistance value of the voltage divider resistor is not specifically limited, and is set according to the needs of the site, and whether each resistor is the same is not limited.

[0049] As a preferred solution, in this embodiment, the filter includes a first filter capacitor CA1, a second filter capacitor CA2 and a third filter capacitor CA3; one end of the first filter capacitor CA1 is connected to the output end of the first voltage-dividing resistor group, and the other end is connected to the second filter capacitor CA2 and grounded; one end of the second filter capacitor CA2 is connected to the output end of the second voltage-dividing resistor group, and the other end is connected to the first filter capacitor CA1 and grounded; both ends of the third filter capacitor CA3 are respectively connected to the output end of the first voltage-dividing resistor group and the output end of the second resistor group.

[0050] Specifically, the back-end measurement sampling circuit includes a back-end voltage-dividing resistor, a sampling resistor and a back-end filter capacitor. Preferably, the back-end voltage-dividing resistor is 4, namely, the back-end voltage-dividing resistor RA15 / RA16 / RA18 / RA19; the back-end filter capacitor is 2, namely, the back-end filter capacitor CA6 / CA7, and the connection relationship thereof is as follows: Figure 2 shown.

[0051] The working principle of the isolated voltage sampling unit is as follows: the voltage-dividing sampling circuit is connected to the voltages V+ and V-, the varistor RVA is connected between V+ and V-, the first voltage-dividing resistor group is connected in series to V-, the second voltage-dividing resistor group is connected in series to V+, the voltage sampling resistor RT is connected between the output end of the second voltage-dividing resistor group and the output end of the first voltage-dividing resistor group, and one end is grounded, the first filter capacitor CA1 and the second filter capacitor CA2 are respectively connected to the output end of the second voltage-dividing resistor group and the output end of the first voltage-dividing resistor group, and are grounded, the third filter capacitor CA3 is connected between the input ends VINP and VINN of the isolation chip U8; the isolation chip U 8, the VDD1 pin is connected to the isolation front-end system power supply VCC5, the GND1 pin is connected to the isolation system ground GND5, the VDD2 pin is connected to the isolation back-end system power supply DVCC, and the capacitor CA5 is connected between DVCC and the isolation back-end system ground GND, and the GND2 pin is connected to the isolation back-end system ground GND; the back-end voltage-dividing resistor RA15 and the back-end voltage-dividing resistor RA16 are respectively connected to the pins VOUTP and VOUTN of the isolation chip U8, and the back-end filter capacitors CA6 and CA7 are respectively connected between the sampling input signals V1+, V1- and the isolation back-end system ground GND, and the detected voltage signal is transmitted to the measurement chip 2 through the input signal V1+ and the input signal V1-.

[0052] As a preferred solution, in this embodiment, the first current detection unit 4 and the second current detection unit 5 both use the same current sampling circuit;

[0053] The current sampling circuit includes a current voltage dividing resistor RB1, a current sampling resistor RB3, a first current filtering circuit ( Figure 3 The middle current filter circuit is composed of the current filter resistor RB2 and the current filter capacitor CB1) and the second current filter circuit ( Figure 3The first current filter circuit and the second current filter resistor both use the same RC (Resistor-Capacitance circuit) filter circuit, which is the conventional use of the RC circuit and is not specifically limited; one end of the current voltage divider resistor RB1 is connected to the current sampling resistor and the first current filter circuit respectively, and the other end is connected to the shunt 6; the other end of the current sampling resistor RB3 is connected to the first current filter circuit and the second filter circuit respectively; the output end of the first current filter circuit and the output end of the second filter circuit are connected to the measurement chip 2 or the AD channel respectively. The output points of the first current filter circuit and the second current filter circuit output current signals I1P+ and I1N- to the outside respectively, and output them to the AD channel of the measurement chip 2 or the management unit 1.

[0054] Specifically, the input signal of the current sampling circuit is a 75mV signal passing through the manganese copper shunt 6. The 75mV signal is input into the current sampling channel of the measuring chip 2 and the AD channel of the management unit 1 after being divided by the current voltage divider RB1; taking the connection between the second current detection unit 5 and the AD channel as an example, since the resistance of the current filter resistor RB2 / RB5 is small, the impedance between I1P+ and I1N- in the AD channel is large, so the signal input into the AD channel is actually equivalent to the voltage difference between I1P+ and I1N-, which is equivalent to the voltage difference between the current sampling resistor and the ground GND, so the performance of the current sampling resistor will directly affect the accuracy of the sampling measurement. Therefore, it is only necessary to accurately control the performance of the current sampling resistor, and the resistance and capacitance values ​​of the resistors and capacitors mentioned above are not specifically limited, and shall be subject to on-site implementation.

[0055] As a preferred solution, in this embodiment, a communication module 8 and a display module 7 are also included, and are connected to the management unit 1 respectively. Preferably, the communication module 8 is an RS485 communication device, which can be short-circuited with the management unit 1 through a solder joint, and the communication rate supports 4800bps, 9600bps and 19200bps. The display module 7 is a liquid crystal display, which adopts a large screen, wide viewing angle and multi-line display, with a white backlight, and can display clearly even in dim light; the screen size of the display module 7 is set according to the on-site situation, and the present invention does not make a specific limitation.

[0056] As a preferred solution, in this embodiment, step S3 specifically includes:

[0057] S31, the management unit determines whether the first current data is greater than or equal to the first proportional value of the rated current, and if so, takes the first electric energy data as the electric energy output data; if not, executes step S32;

[0058] S32, the management unit determines whether the first current data is greater than or equal to the second proportional value of the rated current, if so, the management unit obtains the power output data according to the second power data through the fuzzy precision processing formula, and obtains the power output data; if not, the second power data is used as the power output data. Preferably, the first proportional value is 10%, and the first proportional value is 10% of the rated current; the second proportional value is 0.5%, and the second proportional value is 0.5% of the rated current.

[0059] As a preferred solution, in this embodiment, in step S32, the fuzzy fine processing formula is obtained using the following steps:

[0060] S321, the management unit performs full-range calibration of current detection on the equipment before leaving the factory to obtain several groups of discrete data; the discrete data includes electric energy and current data; here, the full-range calibration includes a common calibration method in this field, calibrates several representative current points, and calculates the electric energy data at this time; of course, in the present invention, the discrete points are measured in two ways and calculated separately, and the specific operation process is not repeated here;

[0061] S322, the management unit performs data fitting based on the power data and the current data in the plurality of groups of discrete data to obtain the fuzzy precision processing formula of the device. Here, the data fitting is a calculation method commonly used in this field or mathematics field, and is not specifically limited; the fuzzy precision processing formula is obtained by using data fitting of a plurality of discrete data, and is not specifically limited.

[0062] In summary, the wide range high-precision DC power detection device provided by the present invention supports 100V-1000V, and the DC power measurement accuracy in the full range of 1A-600A meets the standard requirement of 0.2%. It is an important part of photovoltaic direct-drive air-conditioning power generation, electric vehicle charging piles, and tower base station DC distribution operation and settlement. It can improve the DC power measurement accuracy level and improve the defect of poor measurement accuracy under the condition of small DC power current (≤5%In, In is the rated current). In addition, the DC voltage sampling adopts an isolation method to prevent the voltage from being connected in reverse and burning the device.

[0063] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. A high-precision DC power detection device, characterized in that: include: A management unit, a measuring chip, an isolation voltage detection unit, a first current detection unit, a second current detection unit and a shunt; The management unit has an AD channel; The first current detection unit and the second current detection unit are connected to the shunt respectively; the isolation voltage detection unit and the first current detection unit are connected to the measurement chip respectively; the measurement chip is connected to the management unit; the second current detection unit is connected to the AD channel; Wherein, the high-precision DC power detection method of the high-precision DC power detection device is: S1, the measuring chip receives the voltage data detected by the isolation voltage detection unit and the first current data detected by the first current detection unit respectively, and sends them to the management unit; S2, the management unit receives the second current data detected by the second current detection unit through the AD channel, and amplifies it by a predetermined multiple; the management unit obtains the first electric energy data according to the first current data, and obtains the second electric energy data according to the second current data; S3, the management unit selects the electric energy output data at this time according to the relationship between the first current data and the rated current; the step S3 specifically includes: S31, the management unit determines whether the first current data is greater than or equal to the first proportional value of the rated current, and if so, takes the first electric energy data as the electric energy output data; if not, executes step S32; S32, the management unit determines whether the first current data is greater than or equal to the second proportional value of the rated current. If so, the management unit obtains the electric energy output data according to the second electric energy data through a fuzzy precision processing formula to obtain the electric energy output data; if not, the second electric energy data is used as the electric energy output data; in step S32, the fuzzy precision processing formula is obtained using the following steps: S321, the management unit performs full-range current detection calibration on the equipment before leaving the factory to obtain several groups of discrete data; the discrete data includes electric energy data and current data; S322, the management unit performs data fitting according to the electric energy data and the current data in the plurality of groups of discrete data to obtain the fuzzy precise processing formula of the device; S4. The management unit calculates the electric energy accumulated value according to the electric energy output data.

2. The high-precision DC electric energy detection device according to claim 1 is characterized in that: The isolation voltage detection unit comprises: a voltage division sampling circuit, an isolation chip and a back-end measurement sampling circuit which are connected in sequence, and the back-end measurement sampling circuit is connected to the measurement chip.

3. The high-precision DC electric energy detection device according to claim 2 is characterized in that: The voltage-dividing sampling circuit comprises: a varistor, a voltage divider, a voltage sampling resistor and a filter; the filter is connected to the isolation chip; the voltage divider comprises a first voltage-dividing resistor group and a second voltage-dividing resistor group connected in parallel; The varistor is connected between the positive voltage and the negative voltage of the detection circuit, the first voltage-dividing resistor group is connected in series to the positive voltage of the detection circuit, and the second voltage-dividing resistor group is connected in series to the negative voltage of the detection circuit; the two ends of the voltage sampling resistor are respectively connected to the output ends of the first voltage-dividing resistor group and the second voltage-dividing resistor group, and one end is grounded; the output end of the first voltage-dividing resistor group and the output end of the second voltage-dividing resistor group are respectively connected to the filter.

4. The high-precision DC electric energy detection device according to claim 3 is characterized in that: The first voltage-dividing resistor group and the second voltage-dividing resistor group both use the same voltage-dividing circuit; The voltage-dividing circuit is composed of a plurality of voltage-dividing resistors connected in series.

5. The high-precision DC electric energy detection device according to claim 3 is characterized in that: The filter includes a first filter capacitor, a second filter capacitor and a third filter capacitor; one end of the first filter capacitor is connected to the output end of the first voltage-dividing resistor group, and the other end is grounded; one end of the second filter capacitor is connected to the output end of the second voltage-dividing resistor group, and the other end is grounded; two ends of the third filter capacitor are respectively connected to the output end of the first voltage-dividing resistor group and the output end of the second voltage-dividing resistor group.

6. The high-precision DC electric energy detection device according to claim 1, characterized in that: The first current detection unit and the second current detection unit both use the same current sampling circuit; The current sampling circuit comprises a current voltage dividing resistor, a current sampling resistor, a first current filtering circuit and a second current filtering circuit; one end of the current voltage dividing resistor is connected to the current sampling resistor and the first current filtering circuit respectively, and the other end is connected to the shunt; the other end of the current sampling resistor is connected to the first current filtering circuit and the second current filtering circuit respectively; The output end of the first current filter circuit and the output end of the second current filter circuit are connected to the measurement chip or the AD channel respectively.

7. The high-precision DC electric energy detection device according to claim 1, characterized in that: It also includes a communication module and a display module, which are respectively connected to the management unit.

8. A high-precision DC power detection method applied to the high-precision DC power detection device according to any one of claims 1 to 7, characterized in that: Includes steps: S1, the measuring chip receives the voltage data detected by the isolation voltage detection unit and the first current data detected by the first current detection unit respectively, and sends them to the management unit; S2, the management unit receives the second current data detected by the second current detection unit through the AD channel, and amplifies it by a predetermined multiple; the management unit obtains the first electric energy data according to the first current data, and obtains the second electric energy data according to the second current data; S3, the management unit selects the electric energy output data at this time according to the relationship between the first current data and the rated current; The step S3 specifically includes: S31, the management unit determines whether the first current data is greater than or equal to the first proportional value of the rated current, and if so, takes the first electric energy data as the electric energy output data; if not, executes step S32; S32, the management unit determines whether the first current data is greater than or equal to the second proportional value of the rated current. If so, the management unit obtains the electric energy output data according to the second electric energy data through a fuzzy precision processing formula to obtain the electric energy output data; if not, the second electric energy data is used as the electric energy output data; in step S32, the fuzzy precision processing formula is obtained using the following steps: S321, the management unit performs full-range current detection calibration on the equipment before leaving the factory to obtain several groups of discrete data; the discrete data includes electric energy data and current data; S322, the management unit performs data fitting according to the electric energy data and the current data in the plurality of groups of discrete data to obtain the fuzzy precise processing formula of the device; S4. The management unit calculates the electric energy accumulated value according to the electric energy output data.

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