Direct current meter and power equipment

Abstract

The utility model relates to the technical field of electric energy metering, and discloses a direct current meter and power equipment, and the direct current meter comprises a current sampling module, a voltage sampling module, a processing module and a communication module. The first ends of the current sampling module and the voltage sampling module are respectively connected with a load, and the second ends of the current sampling module and the voltage sampling module are respectively connected with the first end of the processing module; the current sampling module and the voltage sampling module are respectively used for collecting a current signal and a voltage signal and transmitting the current signal and the voltage signal to the processing module; the second end of the processing module is connected with the communication module, and the processing module is used for metering according to the current signal and the voltage signal to obtain power data; and the communication module is used for transmitting the read power data. The DC ammeter can effectively suppress transient overvoltage and overcurrent, improves measurement precision, anti-interference capability, communication stability, integration level, production efficiency and system safety, and reduces production cost.

Description

Technical Field

[0001] The present application relates to the technical field of electric energy metering, and in particular to a direct current meter and electric power equipment. Background Art

[0002] DC meters are widely used in DC charging stations to measure DC power. In existing technologies, DC meters are prone to zero drift and range drift when the ambient temperature changes, affecting measurement accuracy. DC meters lack isolation protection, making the measurement system susceptible to external electromagnetic interference, such as common-mode interference and differential-mode interference. This interference is superimposed on the measurement signal, affecting the accuracy of voltage sampling. DC meters are unable to respond quickly and accurately to rapidly changing DC signals, thus affecting measurement results. DC meters are susceptible to external electromagnetic interference, especially in the strong electromagnetic environment of charging stations, resulting in inaccurate measurement data. During the measurement process, DC meters are affected by DC ripple (the AC component superimposed on the DC stable quantity), resulting in inaccurate measurement results. These issues seriously affect the measurement accuracy and stability of DC meters. Utility Model Content

[0003] In view of this, embodiments of the present application provide a DC meter and an electric power device to improve the measurement accuracy and stability of the DC meter.

[0004] In a first aspect, an embodiment of the present application provides a DC meter, comprising: a current sampling module, a voltage sampling module, a processing module, and a communication module;

[0005] The first ends of the current sampling module and the voltage sampling module are respectively connected to the load, and the second ends of the current sampling module and the voltage sampling module are respectively connected to the first end of the processing module;

[0006] The current sampling module and the voltage sampling module are used to collect current signals and voltage signals respectively, and transmit the current signals and the voltage signals to the processing module;

[0007] The second end of the processing module is connected to the communication module, and the processing module is used to measure according to the current signal and the voltage signal to obtain power data;

[0008] The communication module is used to transmit the received power data.

[0009] In a first possible embodiment of the first aspect, the DC meter further includes a three-way switching power supply module, wherein the three-way switching power supply module is respectively connected to power supply terminals of the voltage sampling module, the processing module, and the communication module;

[0010] The three-way switching power supply module is used to provide independent power supplies for the voltage sampling module, the processing module and the communication module respectively.

[0011] In a second possible embodiment of the first aspect, the current sampling module is further configured to protect and filter the input of the current signal, and the current sampling module includes a protection unit and a filtering unit, wherein a first end of the protection unit is connected to the load, and a second end of the protection unit is connected to the filtering unit;

[0012] The protection unit is used to protect the DC meter from overvoltage and overcurrent, and the filtering unit is used to filter out high-frequency interference signals.

[0013] In a third possible embodiment of the first aspect, the protection unit includes a varistor, a first bipolar transistor, and a second bipolar transistor, and the filtering unit includes a first RC filtering network;

[0014] The first end of the varistor is connected to the positive electrode of the load, the first end and the second end of the first bipolar transistor respectively, the second end of the varistor is connected to the negative electrode of the load, the third end of the first bipolar transistor and the first end of the second bipolar transistor respectively, and the second end and the third end of the second bipolar transistor are both grounded;

[0015] A first end of the first RC filter network is connected to a first end and a second end of the first bipolar transistor, a second end of the first RC filter network is connected to a series node of the first bipolar transistor and the second bipolar transistor, a third end and a fourth end of the first RC filter network are respectively connected to the processing module, and a fifth end of the first RC filter network is grounded.

[0016] In a fourth possible embodiment of the first aspect, the voltage sampling module includes a first voltage divider network unit, a second voltage divider network unit, and an isolation amplification unit;

[0017] The first ends of the first voltage divider network unit and the second voltage divider network unit are respectively connected to the positive electrode and the negative electrode of the load, the second ends of the first voltage divider network unit and the second voltage divider network unit are respectively connected to the input end of the isolation amplification unit, the parallel node of the first voltage divider network unit and the second voltage divider network unit is grounded, and the output end of the isolation amplification unit is connected to the processing module.

[0018] In a fifth possible embodiment of the first aspect, the first voltage divider network unit and the second voltage divider network unit each include a plurality of voltage divider resistors with the same resistance value and quantity, and the isolation amplification unit includes an isolation amplifier and a second RC filter network;

[0019] Each voltage-dividing resistor in the first voltage-dividing network unit and the second voltage-dividing network unit is connected in series, and the non-inverting input terminal and the inverting input terminal of the isolation amplifier are respectively connected to one of the series nodes of the voltage-dividing resistors;

[0020] The first output end of the isolation amplifier is connected to the first end of the second RC filter network, the second output end of the isolation amplifier is connected to the second end of the second RC filter network, the third end and the fourth end of the second RC filter network are respectively connected to the processing module, and the fifth end of the second RC filter network is grounded.

[0021] In a sixth possible embodiment of the first aspect, the processing module includes a microcontroller, a metering unit, a temperature compensation unit, an LCD controller, and a memory integrated in an integrated design;

[0022] The microcontroller is respectively connected to the metering unit, the temperature compensation unit, the LCD controller and the memory, and the metering unit is also respectively connected to the current sampling module and the voltage sampling module.

[0023] In a seventh possible embodiment of the first aspect, the processing module is a SOC microprocessor.

[0024] In an eighth possible embodiment of the first aspect, the DC meter further includes: a printed circuit board and a housing, and the printed circuit board and the housing are connected by a snap-fit ​​assembly method.

[0025] In a second aspect, an embodiment of the present application provides an electric power device, including the DC meter described above.

[0026] The embodiments of the present application have the following beneficial effects:

[0027] A DC meter in this embodiment includes: a current sampling module, a voltage sampling module, a processing module, and a communication module; the first ends of the current sampling module and the voltage sampling module are respectively connected to the load, and the second ends of the current sampling module and the voltage sampling module are respectively connected to the first end of the processing module; the current sampling module and the voltage sampling module are respectively used to collect current signals and voltage signals, and transmit the current signals and voltage signals to the processing module; the second end of the processing module is connected to the communication module, and the processing module is used to measure according to the current signal and voltage signal to obtain power data; the communication module is used to transmit the received power data. Based on the above scheme, the DC meter can effectively suppress transient overvoltage and overcurrent, improve measurement accuracy, anti-interference ability, communication stability, integration, production efficiency and system safety, and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 A schematic structural diagram of a DC ammeter according to an embodiment of the present application is shown;

[0030] Figure 2 A circuit diagram of a current sampling module according to an embodiment of the present application is shown;

[0031] Figure 3 A circuit diagram of a voltage sampling module according to an embodiment of the present application is shown;

[0032] Figure 4 A circuit diagram of a processing module according to an embodiment of the present application is shown;

[0033] Figure 5 A circuit diagram of a communication module according to an embodiment of the present application is shown;

[0034] Figure 6 A circuit diagram of a three-way switching power supply module according to an embodiment of the present application is shown;

[0035] Figure 7 A schematic structural diagram of a housing according to the present invention is shown;

[0036] Figure 8 A structural schematic diagram of a printed circuit board according to an embodiment of the present application is shown.

[0037] Description of main component symbols:

[0038] 100-DC meter; 110-current sampling module; 111-protection unit; 112-filtering unit; 120-voltage sampling module; 121-first voltage divider network unit; 122-second voltage divider network unit; 123-isolation amplifier unit; 130-processing module; 131-microcontroller; 132-metering unit; 133-temperature compensation unit; 134-LCD controller; 135-memory; 140-communication module; 150-three-way switching power supply module. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0040] The components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but rather merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0041] Hereinafter, the terms "including", "having" and their cognates used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the aforementioned items, and should not be understood as excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the aforementioned items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the aforementioned items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and should not be understood as indicating or implying relative importance.

[0042] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present application.

[0043] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0044] Typically, DC meters suffer from issues such as temperature drift, signal interference, slow dynamic response, weak anti-interference capabilities, and the effects of DC ripple. The DC meter of the present application effectively suppresses transient overvoltage and overcurrent by protecting the input current signal. The DC meter also improves the measurement accuracy and anti-interference capabilities of the voltage signal through the symmetrical configuration of the positive and negative voltage divider resistor networks and the use of an isolated amplifier. The DC meter also reduces cost and size through a highly integrated design, improving communication stability and production efficiency.

[0045] The DC meter is described below with reference to some specific embodiments.

[0046] Figure 1A schematic diagram of the structure of a DC meter 100 according to an embodiment of the present application is shown. Exemplarily, the DC meter 100 includes a current sampling module 110, a voltage sampling module 120, a processing module 130, a communication module 140, and a three-way switching power supply module 150. Specifically, the current sampling module 110 and the voltage sampling module 120 are respectively connected to the power output bus of the load to collect current and voltage signals, respectively. The current sampling module 110 and the voltage sampling module 120 are also respectively connected to the processing module 130, so that the processing module 130 can obtain power data based on the current and voltage signals.

[0047] For example, the power data may include voltage, current, power, and energy consumption, etc. The DC meter 100 supports a wide range of DC and AC input voltages, achieves AC / DC adaptation, and can adapt to different power supply environments without the need for additional voltage conversion equipment, thereby improving the versatility and adaptability of the power supply.

[0048] In this embodiment, the first ends of the current sampling module 110 and the voltage sampling module 120 are respectively connected to the load, and the second ends of the current sampling module 110 and the voltage sampling module 120 are respectively connected to the first end of the processing module 130. The current sampling module 110 and the voltage sampling module 120 are respectively used to collect current signals and voltage signals and transmit the current signals and voltage signals to the processing module 130. The second end of the processing module 130 is connected to the communication module 140, which is used to measure the current and voltage signals to obtain power data. The communication module 140 is used to transmit the received power data. The three-way switching power supply module 150 is respectively connected to the power supply ends of the voltage sampling module 120, the processing module 130, and the communication module 140. The three-way switching power supply module 150 is used to provide independent power supplies to the voltage sampling module 120, the processing module 130, and the communication module 140.

[0049] In order to better understand the DC meter 100 , each component of the DC meter 100 is described in detail below.

[0050] In this embodiment, the current sampling module 110 is also used to protect and filter the input of the current signal. The current sampling module 110 includes a protection unit 111 and a filter unit 112. The first end of the protection unit 111 is connected to the load, and the second end of the protection unit 111 is connected to the filter unit 112. The protection unit 111 is used to protect the DC meter 100 from overvoltage and overcurrent, and the filter unit 112 is used to filter out high-frequency interference signals. For example, Figure 2As shown, the protection unit 111 includes a varistor YM1, a first bipolar transistor T1, and a second bipolar transistor T2, and the filtering unit 112 includes a first RC filtering network; the first end of the varistor YM1 is respectively connected to the positive electrode of the load, the first end and the second end of the first bipolar transistor T1, the second end of the varistor YM1 is respectively connected to the negative electrode of the load, the third end of the first bipolar transistor T1, and the first end of the second bipolar transistor T2, and the second end and the third end of the second bipolar transistor T2 are both grounded; the first end of the first RC filtering network is connected to the first end and the second end of the first bipolar transistor T1, the second end of the first RC filtering network is connected to the series node of the first bipolar transistor T1 and the second bipolar transistor T2, the third end and the fourth end of the first RC filtering network are respectively connected to the processing module 130, and the fifth end of the first RC filtering network is grounded.

[0051] It is understandable that during the sampling process of the current signal, transient overvoltage or overcurrent may be encountered due to power grid fluctuations, sudden load changes, etc., which may damage the electronic components inside the meter. The DC meter 100 connects a bipolar transistor in series at the input end of the current signal through the current sampling module 110 to suppress transient overvoltage and overcurrent and perform clamping protection. Since external electromagnetic interference may affect the accuracy of the current signal, the current sampling module 110 can also reduce the influence of high-frequency interference signals through the filtering unit 112 to protect the input of the current signal of the meter. The current sampling module 110 also includes a varistor YM1 to avoid damage to the DC meter 100 due to abnormal input signals and extend the service life of the DC meter 100.

[0052] In this embodiment, the voltage sampling module 120 includes a first voltage divider network unit 121, a second voltage divider network unit 122 and an isolation amplifier unit 123. The first ends of the first voltage divider network unit 121 and the second voltage divider network unit 122 are respectively connected to the positive and negative electrodes of the load, the second ends of the first voltage divider network unit 121 and the second voltage divider network unit 122 are respectively connected to the input end of the isolation amplifier unit 123, the parallel node of the first voltage divider network unit 121 and the second voltage divider network unit 122 is grounded, and the output end of the isolation amplifier unit 123 is connected to the processing module 130. For example, Figure 3As shown, the first voltage divider network unit 121 and the second voltage divider network unit 122 each include multiple voltage divider resistors of the same resistance value and quantity, and the isolation amplifier unit 123 includes an isolation amplifier U3 and a second RC filter network; each voltage divider resistor in the first voltage divider network unit 121 and the second voltage divider network unit 122 is connected in series, and the non-inverting input terminal and the reverse input terminal of the isolation amplifier U3 are respectively connected to one of the series nodes of the voltage divider resistors; the first output terminal of the isolation amplifier U3 is connected to the first terminal of the second RC filter network, the second output terminal of the isolation amplifier U3 is connected to the second terminal of the second RC filter network, the third terminal and the fourth terminal of the second RC filter network are respectively connected to the processing module 130, and the fifth terminal of the second RC filter network is grounded. It can be understood that Figure 3 The number of voltage-dividing resistors shown is only an example, and the voltage-dividing network unit is not limited to including only 7 voltage-dividing resistors.

[0053] Furthermore, the voltage sampling module 120 also includes a plurality of first filter capacitors, each of which has a first end connected to the voltage divider network unit or the isolation amplifier unit 123, and a second end connected to ground. The voltage sampling module 120 also includes a second filter capacitor, each of which has a first end connected to the series node of the first voltage divider network unit 121 and the isolation amplifier unit 123, and a second end connected to the series node of the second voltage divider network unit 122 and the isolation amplifier unit 123.

[0054] It will be appreciated that the voltage sampling module 120, by configuring a voltage divider network unit with the same number and resistance of voltage divider resistors, can, on the one hand, eliminate the influence of common-mode voltage and form a differential signal, helping to improve the anti-interference capability of voltage signal sampling in common-mode noise environments. On the other hand, the symmetry of the voltage divider network unit can reduce resistance drift caused by temperature changes. Therefore, the voltage sampling module 120 can reduce voltage signal measurement errors, improve the accuracy of voltage signal measurement and system reliability, and enhance the anti-interference capability and stability of voltage sampling. The voltage sampling module 120 also provides electrical isolation through the isolation amplifier U3, effectively isolating the input and output of the voltage signal, preventing noise or interference on the high-voltage side from propagating through the circuit to the low-voltage side, thereby protecting the safety of the measurement system and operators. The isolation amplifier U3 can be used to reduce errors caused by factors such as line impedance mismatch and temperature changes, thereby improving the accuracy of voltage sampling. During the voltage sampling process, if a circuit fault or abnormality occurs, the isolation amplifier U3 also prevents the fault from spreading, protecting the entire system from damage.

[0055] In this embodiment, the processing module 130 includes an integrated microcontroller 131, a metering unit 132, a temperature compensation unit 133, an LCD controller 134, and a memory 135. Exemplarily, the microcontroller 131 is connected to the metering unit 132, the temperature compensation unit 133, the LCD controller 134, and the memory 135, respectively. The metering unit 132 is also connected to the current sampling module 110 and the voltage sampling module 120, respectively. Specifically, the microcontroller 131 is used to control and process various operations and functions in the DC meter 100; the metering unit 132 is used to measure and calculate the power data in the DC meter 100; the temperature compensation unit 133 is used to record the usage time of the DC meter 100 and calibrate the temperature contrast of the meter to ensure the measurement accuracy of the power data; the LCD controller 134 is used to control the LCD display screen and intuitively display the power data on the screen; and the memory 135 is used to store the power data.

[0056] Alternatively, as Figure 4 As shown, processing module 130 is a SOC microprocessor that integrates a microcontroller 131, a metering unit 132, a temperature compensation unit 133, an LCD controller 134, and memory 135, providing a highly integrated and powerful solution. It can be appreciated that compared to conventional designs with a microcontroller 131 and a standalone metering chip, this SOC microprocessor eliminates a significant amount of peripheral circuitry and sampling signal isolation and communication circuitry, saving on memory circuitry. This enables DC meter 100 to meet DC energy metering requirements with lower cost, smaller size, and higher performance.

[0057] Alternatively, as Figure 5 As shown, the communication module 140 uses three optocouplers D5, D6, and D3, a transceiver U4, and other electronic components to design an RS485 communication circuit. This RS485 communication circuit uses three optocouplers D5, D6, and D3 and a transistor V6 to replace a high-speed optocoupler, achieving a communication baud rate of 115,200 bps. This RS485 communication circuit can include a receive port RX and multiple transmit ports TX to connect the processing module 130 and multiple external devices, enabling communication between the processing module 130 and multiple external devices.

[0058] In this embodiment, Figure 6 As shown, the three-way switching power supply module 150 uses electronic components such as the switching power supply chip U5, two power management chips U8 and U6, the rectifier bridge DB1, and the transformer TN1 to design a three-way output switching power supply circuit, which outputs different voltages and provides independent power supplies to the voltage sampling module 120, the processing module 130, and the communication module 140, respectively, ensuring the stability of the operation of each part and the isolation of interference between each other.

[0059] It is understood that the design of the three-way switching power supply module 150 has excellent voltage regulation performance and overvoltage and overcurrent protection functions, ensuring stable power output under voltage fluctuations and load changes. Optionally, the three-way switching power supply module 150 supports a wide range of input voltages from 24V to 420V for both DC and AC.

[0060] In this embodiment, Figure 7 and 8 As shown, DC meter 100 includes a printed circuit board (PCB) and a housing, which are connected using a snap-on assembly. Exemplarily, the PCB's auxiliary power terminals, pulse output, pulse-per-second terminals, communication terminals, and auxiliary terminals on the terminal box are secured with screws, eliminating the need for wire bonding. This snap-on assembly of the PCB and housing improves assembly efficiency.

[0061] The present application also provides an electric power device, which may be a charging pile, a charging station, an electric power transmission and distribution system, an emergency device, etc. Exemplarily, the electric power device includes the DC meter 100 as described in the above embodiment.

[0062] The above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the protection scope of the present application.

Claims

1. A DC electric meter, characterized in that: include: Current sampling module, voltage sampling module, processing module and communication module; The first ends of the current sampling module and the voltage sampling module are respectively connected to the load, and the second ends of the current sampling module and the voltage sampling module are respectively connected to the first end of the processing module; The current sampling module and the voltage sampling module are used to collect current signals and voltage signals respectively, and transmit the current signals and the voltage signals to the processing module; The second end of the processing module is connected to the communication module, and the processing module is used to measure according to the current signal and the voltage signal to obtain power data; The communication module is used to transmit the received power data.

2. The DC ammeter according to claim 1, wherein: It also includes a three-way switching power supply module, which is respectively connected to the power supply ends of the voltage sampling module, the processing module and the communication module; The three-way switching power supply module is used to provide independent power supplies for the voltage sampling module, the processing module and the communication module respectively.

3. The DC ammeter according to claim 1, wherein: The current sampling module is further used to protect and filter the input of the current signal. The current sampling module includes a protection unit and a filtering unit. The first end of the protection unit is connected to the load, and the second end of the protection unit is connected to the filtering unit. The protection unit is used to protect the DC meter from overvoltage and overcurrent, and the filtering unit is used to filter out high-frequency interference signals.

4. The DC ammeter according to claim 3, wherein: The protection unit includes a varistor, a first bipolar transistor, and a second bipolar transistor, and the filtering unit includes a first RC filtering network; The first end of the varistor is connected to the positive electrode of the load, the first end and the second end of the first bipolar transistor respectively, the second end of the varistor is connected to the negative electrode of the load, the third end of the first bipolar transistor and the first end of the second bipolar transistor respectively, and the second end and the third end of the second bipolar transistor are both grounded; A first end of the first RC filter network is connected to a first end and a second end of the first bipolar transistor, a second end of the first RC filter network is connected to a series node of the first bipolar transistor and the second bipolar transistor, a third end and a fourth end of the first RC filter network are respectively connected to the processing module, and a fifth end of the first RC filter network is grounded.

5. The DC ammeter according to claim 1, wherein: The voltage sampling module includes a first voltage dividing network unit, a second voltage dividing network unit and an isolation amplification unit; The first ends of the first voltage divider network unit and the second voltage divider network unit are respectively connected to the positive electrode and the negative electrode of the load, the second ends of the first voltage divider network unit and the second voltage divider network unit are respectively connected to the input end of the isolation amplification unit, the parallel node of the first voltage divider network unit and the second voltage divider network unit is grounded, and the output end of the isolation amplification unit is connected to the processing module.

6. The DC ammeter according to claim 5, characterized in that: The first voltage-dividing network unit and the second voltage-dividing network unit each include a plurality of voltage-dividing resistors with the same resistance value and quantity, and the isolation amplification unit includes an isolation amplifier and a second RC filter network; Each voltage-dividing resistor in the first voltage-dividing network unit and the second voltage-dividing network unit is connected in series, and the non-inverting input terminal and the inverting input terminal of the isolation amplifier are respectively connected to one of the series nodes of the voltage-dividing resistors; The first output end of the isolation amplifier is connected to the first end of the second RC filter network, the second output end of the isolation amplifier is connected to the second end of the second RC filter network, the third end and the fourth end of the second RC filter network are respectively connected to the processing module, and the fifth end of the second RC filter network is grounded.

7. The DC ammeter according to claim 1, wherein: The processing module includes a microcontroller, a metering unit, a temperature compensation unit, an LCD controller and a memory in an integrated design; The microcontroller is respectively connected to the metering unit, the temperature compensation unit, the LCD controller and the memory, and the metering unit is also respectively connected to the current sampling module and the voltage sampling module.

8. The DC electric meter according to claim 7, characterized in that: The processing module is a SOC microprocessor.

9. The DC ammeter according to claim 1, wherein: Also includes: The printed circuit board and the housing are connected by a snap-fit ​​assembly method.

10. An electric power device, characterized in that: The invention comprises a DC electric meter as claimed in any one of claims 1 to 9.

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