A dual-mode and direct-access DC electric energy meter and electric energy measurement method

Abstract

The present invention discloses a dual-mode and direct-access DC energy meter and an energy measurement method, which belongs to the field of energy measurement. The energy meter: connects a dual-channel voltage sampling module with a positive DC bus, a negative DC bus and a return line, collects the positive voltage V+, the negative voltage V‑ and the positive and negative voltages V DC , the positive voltage V+, the negative voltage V‑, and the positive and negative voltages V DC Convert it into a voltage digital signal and output it to the metering module; connect the dual-channel current sampling module to the positive DC bus and the negative DC bus, collect the positive bus current I+ and the negative bus current I‑, and output the collected positive bus current I+ and negative bus current I‑ to the metering module as current digital signals; the metering module receives the voltage digital signal and the current digital signal, and measures the positive electric energy, the negative electric energy and the total electric energy according to the voltage digital signal and the current digital signal, and outputs the metering data. The present invention can be configured to measure the electric energy on the bipolar power grid and the pseudo-bipolar power grid.

Description

Technical Field

[0001] The present invention relates to the field of electric energy metering, and more specifically, to a dual-mode and direct-access direct current electric energy meter and an electric energy metering method. Background Art

[0002] With the rapid development of economy, society and technology, more and more new energy elements such as distributed power generation, energy storage and electric vehicles are connected to the distribution network. New energy supply modes of source-grid-load-storage interaction are emerging. Flexible DC distribution and AC / DC hybrid distribution have become important development directions of future distribution networks, complementing traditional AC distribution and realizing interconnection of AC / DC power grids.

[0003] The rapid development of DC distribution network has created more application environments for DC power metering. There are three types of DC distribution network wiring: asymmetric single-pole wiring, two-pole wiring (true bipolar) and symmetrical single-pole wiring (pseudo bipolar). For the two-pole wiring, since each pole can operate independently, the energy meter installed on the two-pole line needs to input two voltages and two currents respectively to measure the energy on the two transmission lines and the total energy. For the single-pole wiring, the energy meter can input one voltage and one current to calculate the energy.

[0004] The DC energy meters currently used are mainly installed on the load side. For example, in DC charging piles, the energy meter can only input one voltage and one current, and generally uses an indirect access DC energy meter. The use of indirect access DC energy meters increases the error link, brings many inconveniences to metering management, and reduces the accuracy of metering. The voltage level on the low-voltage side of the DC distribution network is mostly 750V (±375V), and the current is less than 500A. It is more convenient to use a direct access energy meter without a transformer or shunt. Summary of the invention

[0005] The present invention aims to realize the electric energy measurement of bipolar connection and pseudo bipolar connection DC distribution network connection forms by switching the metering mode, and proposes a dual-mode and direct access DC electric energy meter, comprising:

[0006] A dual-channel voltage sampling module is connected to the positive DC bus, the negative DC bus and the return line to collect the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative DC bus to the neutral point, and the positive and negative voltages V of the positive bus to the negative bus. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert it into voltage digital signal and output it to the metering module;

[0007] A dual-channel current sampling module, which is connected to the positive DC bus and the negative DC bus, collects the positive bus current I+ and the negative bus current I-, converts the collected positive bus current I+ and the negative bus current I- into current digital signals and outputs them to the metering module;

[0008] The metering module receives the voltage digital signal and the current digital signal, measures the total electric energy according to the voltage digital signal and the current digital signal, and outputs the electric energy pulse signal and the metering raw data.

[0009] Optionally, the dual-channel voltage sampling module includes a resistor voltage divider sensor and a 24-bit ADC chip;

[0010] The resistor voltage divider voltage sensor collects the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative bus to the neutral point, and the voltage V between the positive and negative buses. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert into voltage digital signal;

[0011] The 24-bit ADC chip transmits the voltage digital signal to the metering module.

[0012] Optional, dual-channel current sampling module includes 2 current sensors and 1 24-bit ADC chip;

[0013] The current sensor is a shunt, a zero flux mutual inductor or a TMR sensor. If the current sensor is a shunt, an isolation amplifier is connected.

[0014] Optionally, the metering module measures the electric energy of each bus and the total electric energy, and can be set to use a bipolar metering mode or a pseudo bipolar metering mode;

[0015] Optionally, the bipolar metering mode calculates the effective value and average value of the positive voltage and positive bus current, as well as the positive power P+ and positive electric energy W+ based on the positive bus current I+ and the positive voltage V+;

[0016] According to the negative bus current I- and the negative voltage V-, calculate the effective value and average value of the negative voltage and the negative bus current, as well as the negative power P- and the negative electric energy W-;

[0017] Sum the positive electrode energy W+ and the negative electrode energy W- to calculate the total energy W DC , according to the total electrical energy W DC Output electrical energy pulse;

[0018] Optionally, the pseudo bipolar metering mode uses the negative bus current I- as a comparison monitor for the positive bus current I+, and the positive and negative voltages V DC, calculate the effective value and average value of the positive and negative voltages and the positive bus current, and the total power P DC And total power W DC ;

[0019] Or, use the positive bus current I+ as a comparison monitor for the negative bus current I-, and according to the negative bus current I-, the positive and negative voltages V DC Calculate the effective value and average value of the positive and negative voltages and the negative bus current, and the total power P DC And total power W DC ;

[0020] According to the total electrical energy W DC Output electrical energy pulses.

[0021] Optionally, the energy meter also includes:

[0022] A management module, wherein the management module is used to manage the electric energy meter;

[0023] The management includes: communication management, display management, data storage management, clock management, key operation management, power storage management and event recording;

[0024] A communication interface module, the communication interface module is used for metering data communication and meter settings, including switching the bipolar metering mode or pseudo bipolar metering mode of the metering module;

[0025] A display and key module, which is used to switch the bipolar metering mode or pseudo-bipolar metering mode of the metering module, and to display metering data and meter parameters;

[0026] A storage unit, wherein the storage unit is used to store the metering data;

[0027] A power module, the power module is used to supply power to the electric energy meter;

[0028] A battery module, wherein the battery module is used to supply power to the clock module;

[0029] A clock module, which is used for displaying the time of the electric energy meter;

[0030] A pulse output module, wherein the pulse output module is used to output electric energy pulses of the electric energy meter.

[0031] The present invention also proposes a method for measuring electric energy, comprising:

[0032] The dual-channel voltage sampling module is connected to the positive DC bus, the negative DC bus and the return line, and the dual-channel voltage sampling module is used to collect the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative DC bus to the neutral point, and the positive and negative voltages V of the positive bus to the negative bus.DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert it into voltage digital signal and output it to the metering module;

[0033] Connect the dual-channel current sampling module to the positive DC bus and the negative DC bus, and use the dual-channel current sampling module to collect the positive bus current I+ and the negative bus current I-, and convert the collected positive bus current I+ and negative bus current I- into current digital signals and output them to the metering module;

[0034] The metering module is used to receive the voltage digital signal and the current digital signal, the total electric energy is measured according to the voltage digital signal and the current digital signal, and the electric energy pulse signal and the metering raw data are output externally.

[0035] Optionally, the dual-channel voltage sampling module includes a resistor voltage divider sensor and a 24-bit ADC chip;

[0036] The resistor voltage divider voltage sensor collects the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative bus to the neutral point, and the voltage V between the positive and negative buses. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert into voltage digital signal;

[0037] The 24-bit ADC chip transmits the voltage digital signal to the metering module.

[0038] Optional, dual-channel current sampling module includes 2 current sensors and 1 24-bit ADC chip;

[0039] The current sensor is a shunt, a zero flux mutual inductor or a TMR sensor. If the current sensor is a shunt, an isolation amplifier is connected.

[0040] Optionally, the metering module measures the electric energy of each bus and the total electric energy, and can be set to use a bipolar metering mode or a pseudo bipolar metering mode;

[0041] Optionally, the bipolar metering mode calculates the effective value and average value of the positive voltage and positive bus current, as well as the positive power P+ and positive electric energy W+ based on the positive bus current I+ and the positive voltage V+;

[0042] According to the negative bus current I- and the negative voltage V-, calculate the effective value and average value of the negative voltage and the negative bus current, as well as the negative power P- and the negative electric energy W-;

[0043] Sum the positive electrode energy W+ and the negative electrode energy W- to calculate the total energy W DC , according to the total electrical energy W DC Output electrical energy pulse;

[0044] Optionally, the pseudo bipolar metering mode uses the negative bus current I- as a comparison monitor for the positive bus current I+, and the positive and negative voltages V DC , calculate the effective value and average value of the positive and negative voltages and the positive bus current, and the total power P DC And total power W DC ;

[0045] Or, use the positive bus current I+ as a comparison monitor for the negative bus current I-, and according to the negative bus current I-, the positive and negative voltages V DC Calculate the effective value and average value of the positive and negative voltages and the negative bus current, and the total power P DC And total power W DC ;

[0046] According to the total electrical energy W DC Output electrical energy pulses.

[0047] The present invention can set the metering mode. In the bipolar metering mode, the positive electrode electric energy, the negative electrode electric energy and the total electric energy can be measured respectively. When one pole fails, the electric energy metering is not affected. In the pseudo bipolar metering mode, the total electric energy can be measured and the positive and negative electrode currents can be monitored. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a system structure diagram of a dual-mode and direct-access DC electric energy meter of the present invention;

[0049] Figure 2 It is a schematic diagram of a dual-channel voltage sampling module of the present invention;

[0050] Figure 3 It is a schematic diagram of a dual-channel current sampling module of the present invention;

[0051] Figure 4 This is a schematic diagram of bipolar metering wiring of the present invention;

[0052] Figure 5 This is a schematic diagram of the pseudo-bipolar metering wiring of the present invention;

[0053] Figure 6 The present invention is a flow chart of a method for measuring electric energy. DETAILED DESCRIPTION

[0054] Now, exemplary embodiments of the present invention are described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0055] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0056] The present invention provides a dual-mode and direct-access DC energy meter 200, such as Figure 1 As shown, including:

[0057] A dual-channel voltage sampling module is connected to the positive DC bus, the negative DC bus and the return line to collect the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative DC bus to the neutral point, and the positive and negative voltages V of the positive bus to the negative bus. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert it into voltage digital signal and output it to the metering module;

[0058] A dual-channel current sampling module, which is connected to the positive DC bus and the negative DC bus, collects the positive bus current I+ and the negative bus current I-, and converts the collected positive bus current I+ and negative bus current I- into current digital signals and outputs them to the metering module;

[0059] The metering module receives the voltage digital signal and the current digital signal, measures the total electric energy according to the voltage digital signal and the current digital signal, and outputs the electric energy pulse signal and the metering raw data.

[0060] The energy meter also includes:

[0061] A management module, wherein the management module is used to manage the electric energy meter;

[0062] The management includes: communication management, display management, data storage management, clock management, key operation management, power storage management and event recording;

[0063] A communication interface module, the communication interface module is used for metering data communication and meter settings, including switching the bipolar metering mode or pseudo bipolar metering mode of the metering module;

[0064] A display and key module, which is used to switch the bipolar metering mode or pseudo-bipolar metering mode of the metering module, and to display metering data and meter parameters;

[0065] A storage unit, wherein the storage unit is used to store the metering data;

[0066] A power module, the power module is used to supply power to the electric energy meter;

[0067] A battery module, wherein the battery module is used to supply power to the clock module;

[0068] A clock module, which is used for displaying the time of the electric energy meter;

[0069] A pulse output module, wherein the pulse output module is used to output electric energy pulses of the electric energy meter.

[0070] Among them, the dual-channel voltage sampling module includes a resistor voltage divider sensor and a 24-bit ADC chip;

[0071] The resistor voltage divider voltage sensor collects the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative bus to the neutral point, and the voltage V between the positive and negative buses. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert into voltage digital signal;

[0072] The 24-bit ADC chip transmits the voltage digital signal to the metering module.

[0073] Among them, the dual-channel current sampling module includes 2 current sensors and 1 24-bit ADC chip;

[0074] The current sensor is a shunt, a zero flux mutual inductor or a TMR sensor. If the current sensor is a shunt, an isolation amplifier is connected.

[0075] Among them, the metering module measures the electric energy of each bus and the total electric energy, and can be set to use a bipolar metering mode or a pseudo bipolar metering mode;

[0076] Among them, the bipolar metering mode calculates the effective value and average value of the positive voltage and positive bus current, as well as the positive power P+ and positive electric energy W+ based on the positive bus current I+ and positive voltage V+;

[0077] According to the negative bus current I- and the negative voltage V-, calculate the effective value and average value of the negative voltage and the negative bus current, as well as the negative power P- and the negative electric energy W-;

[0078] Sum the positive electrode energy W+ and the negative electrode energy W- to calculate the total energy W DC , according to the total electrical energy W DC Output electrical energy pulse;

[0079] Among them, the pseudo bipolar metering mode uses the negative bus current I- as the comparison monitoring of the positive bus current I+, and the positive and negative voltages V DC, calculate the effective value and average value of the positive and negative voltages and the positive bus current, and the total power P DC And total power W DC ;

[0080] Or, use the positive bus current I+ as a comparison monitor for the negative bus current I-, and according to the negative bus current I-, the positive and negative voltages V DC Calculate the effective value and average value of the positive and negative voltages and the negative bus current, and the total power P DC And total power W DC ;

[0081] According to the total electrical energy W DC Output electrical energy pulses.

[0082] Dual voltage sampling module, such as Figure 2 As shown, it includes a resistor voltage divider sensor and a 24-bit ADC chip, and uses mid-segment differential sampling to collect the positive voltage V+ (positive bus to neutral point voltage), negative voltage V- (negative bus to neutral point voltage), positive and negative voltage V DC (Positive bus to negative bus voltage).

[0083] Dual current sampling module, such as Figure 3 As shown, it includes 2 current sensors and a 24-bit ADC chip. The current sensor can be a shunt, a zero flux mutual inductor, and a TMR sensor. When a shunt is used, the output of the shunt needs to be connected to an isolation amplifier to eliminate the influence of high common-mode voltage. When a zero flux mutual inductor and a TMR sensor are used, there is no need to connect an isolation amplifier. The dual-channel current sampling module can simultaneously collect the positive bus current I+ and the negative bus current I-. The metering module 3 completes the DC power metering function, including two power metering methods: bipolar metering and pseudo-bipolar metering, and provides power and pulse output signals and metering raw data to the outside.

[0084] The two metering modes involved in the present invention are as follows:

[0085] ±375V bipolar measurement mode, wiring as Figure 4 As shown: the metering mode of the energy meter is set to the dual-stage metering mode through the button or the communication interface. The voltage sampling module of the energy meter is respectively connected to the positive DC bus, the negative DC bus, and the return line, and respectively connected to the U+, U-, and PE voltage input terminals of the energy meter. A resistor voltage divider voltage sensor is used to collect the voltage V+ between the positive pole and the neutral point and the voltage V- between the negative pole and the neutral point, and the ±375V high voltage analog signal is converted into a small voltage signal input into the ADC chip, and then the voltage digital signal is output to the metering chip.

[0086] The electric energy meter current sampling module is connected to the positive DC bus and the negative DC bus respectively. The positive current sensor terminals I1+ and I2+ are connected in series to the positive DC bus to collect the positive bus current I+. The negative current sensor terminals I1- and I2- are connected in series to the negative DC bus to collect the negative bus current I-.

[0087] When the current sensor is a shunt, the measured small voltage signal of the shunt is output to the isolation amplifier and then to the ADC chip, and the ADC chip outputs the current digital signal to the metering chip.

[0088] When the current sensor is a TMR or zero magnetic flux sensor, the small voltage signal output by the TMR or zero magnetic flux sensor is output to the ADC chip, and the ADC chip outputs the current digital signal to the metering chip.

[0089] The metering chip calculates the positive electrode voltage effective value and average value, positive electrode current effective value and average value, positive electrode power P+, and positive electrode electric energy W+ according to V+ and I+; calculates the negative electrode voltage effective value and average value, negative electrode current effective value and average value, negative electrode power P-, and negative electrode electric energy W- according to V- and I-; adds the positive electrode electric energy W+ and the negative electrode electric energy W- to obtain the total electric energy W DC .

[0090] The metering chip is based on the total DC power W DC The control pulse output module outputs electric energy pulses. The metering chip transmits data to the management module for display.

[0091] ±375V pseudo bipolar measurement mode, wiring as Figure 5 As shown, the metering mode of the energy meter is set to single-stage metering mode through buttons or communication interface. The voltage sampling module of the energy meter is connected to the positive DC bus and the negative DC bus respectively, and connected to the U+ and U- voltage input terminals of the energy meter respectively. The voltage V between the positive pole (+375V) and the negative pole (-375V) of the system is collected by resistance voltage division. DC , convert the high voltage analog signal into a low voltage signal and input it into the ADC chip, and then output the voltage digital signal to the metering chip.

[0092] The current sampling module of the energy meter is connected to the positive DC bus and the negative DC bus respectively. The positive current sensor terminals I1+ and I2+ are connected in series to the positive DC bus to collect the positive bus current I+. The negative current sensor terminals I1- and I2- are connected in series to the negative DC bus to collect the negative bus current I-. Because the positive bus current is equal to the negative bus current, the metering chip can use the positive or negative bus current to calculate the energy value. The metering chip calculates the energy value based on V DC 、I+ calculates the positive and negative voltage effective value and average value, positive current effective value and average value, DC power P DC, DC power W DC ; Calculate the negative electrode current effective value and average value based on I- for comparison and monitoring with the positive electrode current. Or the metering chip calculates the negative electrode current effective value and average value based on V DC 、I-Calculate the positive and negative voltage effective value and average value, negative current effective value and average value, DC power P DC , DC power W DC ; Calculate the effective value and average value of the positive electrode current based on I+ for comparison and monitoring with the negative electrode current.

[0093] If the current sensor is a shunt, the measured small voltage signal of the shunt is first output to the isolation amplifier and then to the ADC chip, and the ADC chip outputs the current digital signal to the metering chip. When the current sensor is a TMR or zero flux sensor, the small voltage signal output by the TMR or zero flux sensor is output to the ADC chip, and the ADC chip outputs the current digital signal to the metering chip.

[0094] The metering chip is based on the total DC power W DC Control the pulse output module to output electrical energy pulses.

[0095] The metering chip transmits the data to the management module for display.

[0096] The present invention also proposes a method for measuring electric energy, such as Figure 6 As shown, including:

[0097] The dual-channel voltage sampling module is connected to the positive DC bus, the negative DC bus and the return line, and the dual-channel voltage sampling module is used to collect the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative DC bus to the neutral point, and the positive and negative voltages V of the positive bus to the negative bus. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert it into voltage digital signal and output it to the metering module;

[0098] Connect the dual-channel current sampling module to the positive DC bus and the negative DC bus, and use the dual-channel current sampling module to collect the positive bus current I+ and the negative bus current I-, and output the collected positive bus current I+ and negative bus current I- as current digital signals to the metering module;

[0099] The metering module is used to receive the voltage digital signal and the current digital signal, the total electric energy is measured according to the voltage digital signal and the current digital signal, and the electric energy pulse signal and the metering raw data are output externally.

[0100] Among them, the dual-channel voltage sampling module includes a resistor voltage divider sensor and a 24-bit ADC chip;

[0101] The resistor voltage divider voltage sensor collects the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative bus to the neutral point, and the voltage V between the positive and negative buses. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert into voltage digital signal;

[0102] The 24-bit ADC chip transmits the voltage digital signal to the metering module.

[0103] Among them, the dual-channel current sampling module includes 2 current sensors and 1 24-bit ADC chip;

[0104] The current sensor is a shunt, a zero flux mutual inductor or a TMR sensor. If the current sensor is a shunt, an isolation amplifier is connected.

[0105] Among them, the metering module measures the electric energy of each bus and the total electric energy, and can be set to use a bipolar metering mode or a pseudo bipolar metering mode;

[0106] Among them, the bipolar metering mode calculates the effective value and average value of the positive voltage and positive bus current, as well as the positive power P+ and positive electric energy W+ based on the positive bus current I+ and positive voltage V+;

[0107] According to the negative bus current I- and the negative voltage V-, calculate the effective value and average value of the negative voltage and the negative bus current, as well as the negative power P- and the negative electric energy W-;

[0108] Sum the positive electrode energy W+ and the negative electrode energy W- to calculate the total energy W DC , according to the total electrical energy W DC Output electrical energy pulse;

[0109] Among them, the pseudo bipolar metering mode uses the negative bus current I- as the comparison monitoring of the positive bus current I+, and the positive and negative voltages V DC , calculate the effective value and average value of the positive and negative voltages and the positive bus current, and the total power P DC And total power W DC ;

[0110] Or, use the positive bus current I+ as a comparison monitor for the negative bus current I-, and according to the negative bus current I-, the positive and negative voltages V DC Calculate the effective value and average value of the positive and negative voltages and the negative bus current, and the total power P DC And total power W DC ;

[0111] According to the total electrical energy W DC Output electrical energy pulses.

[0112] The present invention can set the metering mode. In the bipolar metering mode, the positive electrode electric energy, the negative electrode electric energy and the total electric energy can be measured respectively. When one pole fails, the electric energy metering is not affected. In the pseudo bipolar metering mode, the total electric energy can be measured and the positive and negative electrode currents can be monitored.

[0113] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiments of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0114] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0115] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0116] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0117] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0118] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A dual-mode and direct-access DC electric energy meter, the electric energy meter comprising: A dual-channel voltage sampling module is connected to the positive DC bus, the negative DC bus and the return line to collect the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative DC bus to the neutral point, and the positive and negative voltages V of the positive bus to the negative bus. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert it into voltage digital signal and output it to the metering module; A dual-channel current sampling module, which is connected to the positive DC bus and the negative DC bus, collects the positive bus current I+ and the negative bus current I-, and converts the collected positive bus current I+ and negative bus current I- into current digital signals and outputs them to the metering module; A metering module, wherein the metering module receives a voltage digital signal and a current digital signal, measures total electric energy according to the voltage digital signal and the current digital signal, and outputs an electric energy pulse signal and metering raw data to the outside; The metering module measures the electric energy of each bus and the total electric energy, and can be set to use a bipolar metering mode or a pseudo bipolar metering mode; The bipolar metering mode calculates the effective value and average value of the positive voltage and the positive bus current, as well as the positive power P+ and the positive electric energy W+ according to the positive bus current I+ and the positive voltage V+; According to the negative bus current I- and the negative voltage V-, calculate the effective value and average value of the negative voltage and the negative bus current, as well as the negative power P- and the negative electric energy W-; Sum the positive electrode energy W+ and the negative electrode energy W- to calculate the total energy W DC , according to the total electrical energy W DC Output electrical energy pulse; The pseudo bipolar metering mode uses the negative bus current I- as a comparison monitor for the positive bus current I+, and the positive and negative voltages V DC , calculate the effective value and average value of the positive and negative voltages and the positive bus current, and the total power P DC And total power W DC ; Or, use the positive bus current I+ as a comparison monitor for the negative bus current I-, and according to the negative bus current I-, the positive and negative voltages V DC Calculate the effective value and average value of the positive and negative voltages and the negative bus current, power P DC And total power W DC ; According to the total electrical energy W DC Output electrical energy pulse; The dual-channel voltage sampling module includes a resistor voltage divider sensor and a 24-bit ADC chip; The resistor voltage divider voltage sensor collects the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative bus to the neutral point, and the voltage V between the positive and negative buses. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert into voltage digital signal; The 24-bit ADC chip transmits the voltage digital signal to the metering module; The dual-channel current sampling module includes two current sensors and a 24-bit ADC chip; The current sensor is a shunt, a zero flux mutual inductor or a TMR sensor. If the current sensor is a shunt, an isolation amplifier is connected.

2. A method for measuring electric energy using an electric energy meter as claimed in claim 1, the method comprising: The dual-channel voltage sampling module is connected to the positive DC bus, the negative DC bus and the return line, and the dual-channel voltage sampling module is used to collect the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative DC bus to the neutral point, and the positive and negative voltages V of the positive bus to the negative bus. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert it into voltage digital signal and output it to the metering module; Connect the dual-channel current sampling module to the positive DC bus and the negative DC bus, and use the dual-channel current sampling module to collect the positive bus current I+ and the negative bus current I-, and output the collected positive bus current I+ and negative bus current I- as current digital signals to the metering module; Use the metering module to receive the voltage digital signal and the current digital signal, measure the total electric energy according to the voltage digital signal and the current digital signal, and output the electric energy pulse signal and the metering raw data to the outside; The metering module measures the electric energy of each bus and the total electric energy, and can be set to use a bipolar metering mode or a pseudo bipolar metering mode; The bipolar metering mode calculates the effective value and average value of the positive voltage and the positive bus current, as well as the positive power P+ and the positive electric energy W+ according to the positive bus current I+ and the positive voltage V+; According to the negative bus current I- and the negative voltage V-, calculate the effective value and average value of the negative voltage and the negative bus current, as well as the negative power P- and the negative electric energy W-; Sum the positive electrode energy W+ and the negative electrode energy W- to calculate the total energy W DC , according to the total electrical energy W DC Output electrical energy pulse; The pseudo bipolar metering mode uses the negative bus current I- as a comparison monitor for the positive bus current I+, and the positive and negative voltages V DC , calculate the effective value and average value of the positive and negative voltages and the positive bus current, and the total power P DC And total power W DC ; Or, use the positive bus current I+ as a comparison monitor for the negative bus current I-, and according to the negative bus current I-, the positive and negative voltages V DC Calculate the effective value and average value of the positive and negative voltages and the negative bus current, and the total power P DC And total power W DC ; According to the total electrical energy W DC Output electrical energy pulse; The dual-channel voltage sampling module includes a resistor voltage divider sensor and a 24-bit ADC chip; The resistor voltage divider voltage sensor collects the positive voltage V+ of the positive DC bus to the neutral point, the negative voltage V- of the negative bus to the neutral point, and the positive and negative voltages V between the positive and negative buses. DC , the positive voltage V+, the negative voltage V- and the positive and negative voltages V DC Convert into voltage digital signal; The 24-bit ADC chip transmits the voltage digital signal to the metering module; The dual-channel current sampling module includes two current sensors and a 24-bit ADC chip; The current sensor is a shunt, a zero flux mutual inductor or a TMR sensor. If the current sensor is a shunt, an isolation amplifier is connected.

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