WO2023065452A1 - 一种电能表直流计量电压采样装置 - Google Patents

一种电能表直流计量电压采样装置 Download PDF

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WO2023065452A1
WO2023065452A1 PCT/CN2021/131781 CN2021131781W WO2023065452A1 WO 2023065452 A1 WO2023065452 A1 WO 2023065452A1 CN 2021131781 W CN2021131781 W CN 2021131781W WO 2023065452 A1 WO2023065452 A1 WO 2023065452A1
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resistor
voltage
module
signal
sampling
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PCT/CN2021/131781
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English (en)
French (fr)
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黄亚娟
都正周
张永利
李想
郭权
孙应军
钱波
纪建设
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河南许继仪表有限公司
许继集团有限公司
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques

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  • the invention relates to the technical field of smart electric meters, in particular to a DC metering voltage sampling device for electric energy meters.
  • DC energy meter As technology develops, there is an increasing need for DC metering.
  • the place of use of DC energy meter is suitable for DC charging piles, batteries, photovoltaic power generation and other DC signal equipment power measurement and energy metering devices, and can also be used in modern supply and distribution DC systems such as industrial and mining enterprises, civil buildings, and building automation.
  • the voltage level of the power supply to be metered in DC metering is higher.
  • the rated voltage value of metering is generally required to be DC700V or DC750V, and the current specification can reach DC300A or even 600A; in photovoltaic power generation
  • the voltage level in the system is as high as DC1000V, and the current specification is also around DC200A.
  • Such high voltage and current specifications require a higher level of safety and fool-proofing in the DC metering system.
  • the current sampling In DC metering, the current sampling generally adopts the shunt sampling method to convert the measured current into the corresponding measured voltage signal; the voltage sampling generally adopts the resistance divider sampling method to convert the measured voltage into the corresponding measured voltage signal Input to the DC electric energy meter for direct measurement, and the specific circuit form of voltage sampling is shown in Figure 1 below.
  • a DC signal switching circuit can be used to switch the DC signal into a 50Hz pulse wave signal and then turn on the high-pass filter inside the metering chip. Filter out the DC component in the DC signal. This measure can effectively improve the accuracy of DC metering and is widely used in DC energy meter products.
  • FIG. 2 The specific circuit form is shown in Figure 2 below.
  • the voltage sampling and current sampling in this scheme share the same ground (GND).
  • GND ground
  • terminal 2 in the current sampling wiring corresponding to GND in Figure 2
  • the voltage sampling Terminal 3 in the wiring corresponding to VIN2 in Figure 1
  • terminal 1 in Figure 3 is connected to IIN1+ in Figure 2
  • terminal 2 and terminal 3 are connected to GND in Figure 2 as metering commons
  • terminal 4 is connected to VIN1 in Figure 1.
  • an embodiment of the present invention provides a DC metering voltage sampling device for electric energy meters, including: a first voltage divider module, an optocoupler processing module, a signal amplification module, a second voltage divider module and a sampling Signal switching module;
  • the input terminals of the first voltage dividing module are respectively connected to the positive pole and the negative pole of the voltage sampling terminal of the electric energy meter to be tested;
  • the optocoupler processing module linearly amplifies and isolates the sampling signal after being divided by the first voltage dividing module, and its output terminal automatically adjusts the output according to the connection between the positive pole and the negative pole of the voltage sampling terminal of the electric energy meter to be measured. the reference point of the voltage;
  • the signal amplification module amplifies the sampling signal output by the optocoupler processing module, and outputs the amplified sampling signal to the sampling signal switching module after passing through the second voltage divider module;
  • the sampling signal switching module performs differential processing on the single-channel voltage signal output by the second voltage dividing module according to the preset frequency value to obtain a differential signal of equal amplitude and input it to the voltage channel of the metering chip for metering.
  • the first voltage dividing module includes: a first resistor, a second resistor, a third resistor and a fourth resistor connected in series;
  • the first input terminal and the second input terminal of the optocoupler processing module are respectively connected to two ends of the fourth resistor.
  • the input signals of the optocoupler processing module are respectively VIP and VIN, and the output signals are respectively VOP and VON;
  • VOP-VON n ⁇ (VIP-VIN);
  • n is the linear amplification factor of the optocoupler processing module.
  • the signal amplification module includes: an operational amplifier, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a second capacitor, and a third capacitor;
  • the fifth resistor is connected in series with the positive input terminal of the operational amplifier
  • the seventh resistor is connected in series with the negative input terminal of the operational amplifier
  • the eighth resistor and the third capacitor are connected in parallel with the operational amplifier respectively.
  • the negative input end is connected to the output end
  • the sixth resistor and the second capacitor are connected in parallel, one end is connected to the positive input end of the operational amplifier and the other end is grounded.
  • the signal amplification module further includes: a ninth resistor, a tenth resistor and an adjustable resistor;
  • the adjustable resistor is connected in series between the positive input terminal of the operational amplifier and the sixth resistor;
  • the ninth resistor and the tenth resistor are connected in parallel with the adjustable resistor after being connected in series;
  • connection end of the ninth resistor and the tenth resistor is also connected to the third end of the adjustable resistor.
  • the resistance values of the fifth resistor, the sixth resistor, the seventh resistor and the eighth resistor are equal;
  • the output voltage value of the operational amplifier is:
  • VIP and VIN are input signals of the optocoupler processing module
  • VOP and VON are output signals of the optocoupler processing module
  • n is a linear amplification factor of the optocoupler processing module.
  • the second voltage dividing module includes: an eleventh resistor, a twelfth resistor and a sixth capacitor;
  • the eleventh resistor is arranged in series at the output end of the signal amplification module
  • the twelfth resistor is connected in parallel with the sixth capacitor
  • One end of the sixth capacitor is connected to the negative electrode of the eleventh resistor, and the other end is grounded.
  • the output voltage value of the second voltage divider module is:
  • VIP and VIN are input signals of the optocoupler processing module
  • VOP and VON are output signals of the optocoupler processing module
  • n is a linear amplification factor of the optocoupler processing module.
  • the preset frequency value is 50Hz.
  • the input signal of the voltage sampling loop is allowed to be a positive signal or a negative signal, and the isolation characteristics of the linear optocoupler are used to avoid the short circuit between the voltage sampling loop and the current sampling loop, so as to Compatible with two situations where the current sampling of the DC energy meter is connected to the positive or negative pole of the power supply under test.
  • FIG. 1 is a schematic diagram of a DC voltage sampling circuit in the prior art
  • FIG. 2 is a schematic diagram of a switching circuit for voltage sampling and current sampling signals in the prior art
  • Fig. 3 is a schematic diagram of the connection mode of terminal 3 and terminal 4 when the shunt sampling in the prior art is connected to the positive pole of the power supply;
  • Fig. 4 is a schematic diagram of the connection mode of terminal 3 and terminal 4 when the shunt sampling in the prior art is connected to the negative pole of the power supply;
  • Fig. 5 is a schematic diagram of the main modules of the DC metering voltage sampling device of the electric energy meter provided by the embodiment of the present invention.
  • Fig. 6 is a schematic diagram of a sampling signal switching module in the DC metering voltage sampling device for an electric energy meter provided by an embodiment of the present invention.
  • the embodiment of the present invention provides a DC measuring voltage sampling device for an electric energy meter, including: a first voltage divider module, an optocoupler processing module, a signal amplification module, and a second voltage divider module connected in series in sequence and the sampling signal switching module; the input end of the first voltage dividing module is respectively connected to the positive pole and the negative pole of the voltage sampling terminal of the electric energy meter to be measured; the optocoupler processing module performs linear amplification and Isolation, the output end automatically adjusts the reference point of the output voltage according to the connection of the positive and negative terminals of the voltage sampling terminal of the electric energy meter to be tested; the signal amplification module amplifies the sampling signal output by the optocoupler processing module, and amplifies the processed The sampling signal is output to the sampling signal switching module after passing through the second voltage dividing module; the sampling signal switching module performs differential processing on the single-channel voltage signal output by the second voltage dividing module according to the preset frequency value to obtain
  • the first voltage dividing module includes: a first resistor R1 , a second resistor R2 , a third resistor R3 and a fourth resistor R4 connected in series.
  • the optocoupler processing module includes: a linear optocoupler U2 and a first capacitor C1; the first input terminal VIP and the second input terminal VIN of the optocoupler processing module U2 are respectively connected to both ends of the fourth resistor R4, and VCC1/ GND1 is the power supply for the input terminal of the optocoupler processing module, and VCC2/GND2 is the power supply for the output terminal of the optocoupler processing module.
  • the input signals of the optocoupler processing module are respectively VIP and VIN, and the output signals are respectively VOP and VON;
  • VOP-VON n ⁇ (VIP-VIN);
  • n is the linear amplification factor of the optocoupler processing module.
  • the signal amplification module includes: an operational amplifier U1, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a second capacitor C2, and a third capacitor C3; the fifth resistor R5 is connected in series with the operational amplifier The positive input terminal of U1, the seventh resistor R7 is connected in series with the negative input terminal of the operational amplifier U1, the eighth resistor R8 and the third capacitor C3 are connected in parallel with the negative input terminal and the output terminal of the operational amplifier U1 respectively, and the sixth resistor R6 and After the second capacitor C2 is connected in parallel, one end is connected to the positive input end of the operational amplifier U1 and the other end is grounded.
  • the signal amplification module further includes: a ninth resistor R9, a tenth resistor R10, and an adjustable resistor RT1;
  • the adjustable resistor RT1 is connected in series between the positive input terminal of the operational amplifier U1 and the sixth resistor R6; the ninth resistor R9 and the tenth resistor R10 are connected in parallel with the adjustable resistor RT1 after being connected in series; the connection between the ninth resistor R9 and the tenth resistor R10 terminal is also connected to the third terminal of the adjustable resistor RT1.
  • the resistance values of the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 are equal; the output voltage value of the operational amplifier U1 is:
  • VIP and VIN are input signals of the optocoupler processing module
  • VOP and VON are output signals of the optocoupler processing module
  • n is a linear amplification factor of the optocoupler processing module.
  • the second voltage dividing module includes: the eleventh resistor R11, the twelfth resistor R12 and the sixth capacitor C6; the eleventh resistor R11 is set in series at the output end of the signal amplification module; the twelfth resistor R12 and the sixth The capacitor C6 is connected in parallel; one end of the sixth capacitor C6 is connected to the negative electrode of the eleventh resistor R11, and the other end is grounded.
  • the output voltage value of the second voltage divider module is:
  • VIP and VIN are input signals of the optocoupler processing module
  • VOP and VON are output signals of the optocoupler processing module
  • n is a linear amplification factor of the optocoupler processing module.
  • the sampling signal switching module includes: the sixth MOS transistor Q6, the seventh MOS transistor Q7, the eighth MOS transistor Q8, the ninth MOS transistor Q9, the tenth MOS transistor Q10, the twenty-first resistor R21, the twenty-second Resistor R22, twenty-third resistor R23, twenty-fourth resistor R24, twenty-fifth resistor R25, fifty-fifth resistor R55, fifty-sixth resistor R56, fifty-seventh resistor R57.
  • the 50Hz signal is the electric energy
  • VIN1 and VIN2 are connected incorrectly during the wiring process, since the voltage sampling wiring of the power supply under test is not in the same ground as the current sampling circuit at the front end of the optocoupler, the output of VOP and VON at the rear end of the optocoupler will automatically adjust the output according to the input situation. Reference point for voltage. Therefore, the reverse connection of the voltage line will not cause a short circuit of the power supply under test, and based on the output characteristics of the linear optocoupler, the corresponding relationship between VO_2, VIP and VIN is:
  • VO_2 VIN-VIP
  • the equal-amplitude differential signals (Vo+ and Vo-) obtained by the VO_2 voltage through the switching circuit are the same as the differential signals (Vo+ and Vo-) obtained by normal wiring, and the phase difference is 180° , the obtained display voltage value remains unchanged, and the direction display voltage is negative, indicating that the voltage line is reversed.
  • the self-adaptation of the voltage sampling common terminal is realized, so as to be compatible with the two situations in which the DC electric energy meter is connected to the positive pole or the negative pole of the power supply under test.
  • the preset frequency value is 50Hz.
  • the embodiment of the present invention aims to protect a DC metering voltage sampling device of an electric energy meter, which includes: a first voltage dividing module, an optocoupler processing module, a signal amplification module, a second voltage dividing module and a sampling signal switching module connected in series in sequence;
  • the input terminal of a voltage dividing module is respectively connected with the positive pole and the negative pole of the voltage sampling terminal of the electric energy meter to be tested;
  • the signal amplification module amplifies the sampling signal output by the optocoupler processing module, and passes the amplified sampling signal through the second voltage divider After the module is output to the sampling signal switching module;
  • the sampling signal switching module performs differential processing on the single-channel voltage signal output by the second voltage divider module according to the preset frequency value, and obtains a differential signal of equal amplitude and inputs it to the voltage channel of the metering
  • the input signal of the voltage sampling loop is allowed to be a positive signal or a negative signal, and the isolation characteristics of the linear optocoupler are used to avoid the short circuit between the voltage sampling loop and the current sampling loop, so as to Compatible with the current sampling of the DC electric energy meter connected to the positive pole or the negative pole of the power supply under test, which improves the foolproofness of the product and ensures the safety of on-site wiring.

Abstract

一种电能表直流计量电压采样装置，包括：依次串联连接的第一分压模块、光耦处理模块、信号放大模块、第二分压模块和采样信号切换模块；第一分压模块的输入端分别与待测电能表电压采样端子的正极和负极连接；光耦处理模块对经第一分压模块分压后的采样信号进行线性放大及隔离，其输出端依据待测电能表电压采样端子的正极和负极的连接情况自动调整输出电压的参考点；信号放大模块对光耦处理模块输出的采样信号进行放大处理，并将放大处理后的采样信号经第二分压模块后输出至采样信号切换模块；采样信号切换模块依据预设频率值对第二分压模块输出的单路电压信号进行差分处理，得到等幅值的差分信号并输入至计量芯片电压通道进行计量。该装置可以允许电压采样回路的输入信号可为正信号，也可为负信号，并利用线性光耦的隔离特性，避免电压采样回路与电流采样回路短路，以兼容直流电能表电流采样接在被测电源的正极或负极两种情况。

Description

一种电能表直流计量电压采样装置 技术领域
本发明涉及智能电表技术领域，特别涉及一种电能表直流计量电压采样装置。
背景技术
随着技术的发展，对直流计量的需求越来越大。目前直流电能表的使用场所适用于直流充电桩、电池、光伏发电等直流信号设备电量测量和电能计量装置，亦可用于工矿企业、民用建筑、楼宇自动化等现代供配直流电系统。相比较于交流计量场所，直流计量中的待计量电源的电压等级更高，比如在直流充电桩中，计量的额定电压值要求一般为DC700V或DC750V，电流规格可达到DC300A甚至600A；在光伏发电系统中电压等级高达DC1000V，电流规格也在DC200A左右。如此高的电压电流规格，就要求直流计量系统中的安全性和防呆性级别更高。
在直流计量中，电流采样一般采用分流器采样方式将被测电流转换成对应的被测电压信号；电压采样一般采用的是电阻分压采样方式，将被测电压转换成对应的被测电压信号输入到直流电能表中直接进行计量，电压采样具体的电路形式如下图1所示。另外为提高直流电能表在-40℃～70℃全温度范围内的计量精度，可采用一种直流信号切换电路，将直流信号切换成50Hz的脉冲波信号后打开计量芯片内部的高通滤波器，滤除直流信号中的直流分量成分。此项措施能有效地提高直流计量精度，在直流电能表产品中应用广泛，具体的电路形式如下图2所示。此种方案中的电压采样和电流采样共地(GND)，在直流电能表接线过程中，参考示意图如下图3，会将电流采样接线中的端子2(对应图2中的GND)和电压采样接线中的端子3(对应图1中的VIN2)作为公共端(采样参考点)使用。实际接 线中图3中的端子1接入图2中的IIN1+，端子2和端子3作为计量公共端接入图2中的GND，端子4接入图1中的VIN1。
随着直流电能表应用场所越来越广泛，受安装位置布局的影响，在不同的场所直流表安装的位置也有所不同，部分厂家将直流电能表分流器采样(电流回路采样)安装在待计量高压电源的正极，一些厂家直流表分流器采样安装在待计量高压电源负极。甚至同一厂家的不同型号产品上直流表分流器采样安装方式也会有所不同，采样分流器被接在被测电源的正极或负极上。原设计方案中直流电能表的端子2和端子3为电流采样回路和电压采样回路的的公共端(参考点)，端子3受电流采样回路(端子2)安装方式的影响，需要对应的接在被计量电源的正极或负极上，如下图3和图4所示。
在实际批量安装过程中，电压采样端子3和电流采样端子4极易被接反，接反会造成被测电源正负极短路，出现直流电表损坏现象，甚至损坏被测电源。对上述问题，亟需找到兼容两种接法的电压采样方案。
发明内容
本发明实施例的目的是提供一种电能表直流计量电压采样装置，在不改变原有总体计量方案的基础上，允许电压采样回路的输入信号可为正信号，也可为负信号，并利用线性光耦的隔离特性，避免电压采样回路与电流采样回路短路，以兼容直流电能表电流采样接在被测电源的正极或负极两种情况。
为解决上述技术问题，本发明实施例提供了一种电能表直流计量电压采样装置，包括：依次串联连接的第一分压模块、光耦处理模块、信号放大模块、第二分压模块和采样信号切换模块；
所述第一分压模块的输入端分别与待测电能表电压采样端子的正极和负极连接；
所述光耦处理模块对经所述第一分压模块分压后的采样信号进行线 性放大及隔离，其输出端依据所述待测电能表电压采样端子的正极和负极的连接情况自动调整输出电压的参考点；
所述信号放大模块对所述光耦处理模块输出的采样信号进行放大处理，并将放大处理后的所述采样信号经所述第二分压模块后输出至所述采样信号切换模块；
所述采样信号切换模块依据预设频率值对所述第二分压模块输出的单路电压信号进行差分处理，得到等幅值的差分信号并输入至计量芯片电压通道进行计量。
进一步地，所述第一分压模块包括：串联连接的第一电阻、第二电阻、第三电阻和第四电阻；
所述光耦处理模块的第一输入端和第二输入端分别与所述第四电阻的两端连接。
进一步地，所述光耦处理模块的输入信号分别为VIP和VIN，其输出信号分别为VOP和VON；
VOP-VON＝n×(VIP-VIN)；
其中，n为所述光耦处理模块的线性放大倍数。
进一步地，所述信号放大模块包括：运算放大器、第五电阻、第六电阻、第七电阻、第八电阻、第二电容和第三电容；
所述第五电阻串联于所述运算放大器的正极输入端，所述第七电阻串联于所述运算放大器的负极输入端，所述第八电阻和第三电容并联后分别与所述运算放大器的负极输入端和输出端连接，所述第六电阻和所述第二电容并联后一端与所述运算放大器的正极输入端连接且另一端接地。
进一步地，所述信号放大模块还包括：第九电阻、第十电阻和可调电阻；
所述可调电阻串联于所述运算放大器正极输入端和所述第六电阻之间；
所述第九电阻和第十电阻串联后与所述可调电阻并联连接；
所述第九电阻与所述第十电阻的连接端还与所述可调电阻的第三端连接。
进一步地，所述第五电阻、所述第六电阻、所述第七电阻和所述第八电阻的电阻值相等；
所述运算放大器的输出电压值为：
VO_1＝VOP-VON＝n×(VIP-VIN)；
其中，VIP和VIN为所述光耦处理模块的输入信号，VOP和VON为所述光耦处理模块的输出信号，n为所述光耦处理模块的线性放大倍数。
进一步地，所述第二分压模块包括：第十一电阻、第十二电阻和第六电容；
所述第十一电阻串联设置于信号放大模块的输出端；
所述第十二电阻与所述第六电容并联连接；
所述第六电容的一端与所述第十一电阻的负极连接，其另一端接地。
进一步地，所述第十一电阻和第十二电阻的阻值关系为：
Figure PCTCN2021131781-appb-000001
所述第二分压模块的输出电压值为：
Figure PCTCN2021131781-appb-000002
其中，VIP和VIN为所述光耦处理模块的输入信号，VOP和VON为所述光耦处理模块的输出信号，n为所述光耦处理模块的线性放大倍数。
进一步地，所述预设频率值为50Hz。
本发明实施例的上述技术方案具有如下有益的技术效果：
在不改变原有总体计量方案的基础上，允许电压采样回路的输入信号可为正信号，也可为负信号，并利用线性光耦的隔离特性，避免电压采样回路与电流采样回路短路，以兼容直流电能表电流采样接在被测电源的正极或负极两种情况。
附图说明
图1是现有技术中的直流电压采样电路示意图；
图2是现有技术中的电压采样和电流采样信号切换电路示意图；
图3是现有技术中的分流器采样接在电源正极时端子3和端子4的接线方式示意图；
图4是现有技术中的分流器采样接在电源负极时端子3和端子4的接线方式示意图；
图5是本发明实施例提供的电能表直流计量电压采样装置主要模块示意图；
图6是本发明实施例提供的电能表直流计量电压采样装置中采样信号切换模块示意图。
具体实施方式
为使本发明的目的、技术方案和优点更加清楚明了，下面结合具体实施方式并参照附图，对本发明进一步详细说明。应该理解，这些描述只是示例性的，而并非要限制本发明的范围。此外，在以下说明中，省略了对公知结构和技术的描述，以避免不必要地混淆本发明的概念。
请参照图5和图6，本发明实施例提供了一种电能表直流计量电压采样装置，包括：依次串联连接的第一分压模块、光耦处理模块、信号放大模块、第二分压模块和采样信号切换模块；第一分压模块的输入端分别与待测电能表电压采样端子的正极和负极连接；光耦处理模块对经第一分压模块分压后的采样信号进行线性放大及隔离，其输出端依据待测电能表电压采样端子的正极和负极的连接情况自动调整输出电压的参考点；信号放大模块对光耦处理模块输出的采样信号进行放大处理，并将放大处理后的采样信号经第二分压模块后输出至采样信号切换模块；采样信号切换模块依据预设频率值对第二分压模块输出的单路电压信号进行差分处理，得到等幅值的差分信号并输入至计量芯片电压通道进行计量。
具体的，第一分压模块包括：串联连接的第一电阻R1、第二电阻R2、 第三电阻R3和第四电阻R4。
具体的，光耦处理模块包括：线性光耦U2、第一电容C1；光耦处理模块U2的第一输入端VIP和第二输入端VIN分别与第四电阻R4的两端连接,另外VCC1/GND1是光耦处理模块输入端的供电电源，VCC2/GND2是光耦处理模块输出端的供电电源。光耦处理模块的输入信号分别为VIP和VIN，其输出信号分别为VOP和VON；
VOP-VON＝n×(VIP-VIN)；
其中，n为光耦处理模块的线性放大倍数。
具体的，信号放大模块包括：运算放大器U1、第五电阻R5、第六电阻R6、第七电阻R7、第八电阻R8、第二电容C2和第三电容C3；第五电阻R5串联于运算放大器U1的正极输入端，第七电阻R7串联于运算放大器U1的负极输入端，第八电阻R8和第三电容C3并联后分别与运算放大器U1的负极输入端和输出端连接，第六电阻R6和第二电容C2并联后一端与运算放大器U1的正极输入端连接且另一端接地。
具体的，信号放大模块还包括：第九电阻R9、第十电阻R10和可调电阻RT1；
可调电阻RT1串联于运算放大器U1正极输入端和第六电阻R6之间；第九电阻R9和第十电阻R10串联后与可调电阻RT1并联连接；第九电阻R9与第十电阻R10的连接端还与可调电阻RT1的第三端连接。
具体的，第五电阻R5、第六电阻R6、第七电阻R7和第八电阻R8的电阻值相等；运算放大器U1的输出电压值为：
VO_1＝VOP-VON＝n×(VIP-VIN)；
其中，VIP和VIN为光耦处理模块的输入信号，VOP和VON为光耦处理模块的输出信号，n为光耦处理模块的线性放大倍数。
进一步地，第二分压模块包括：第十一电阻R11、第十二电阻R12和第六电容C6；第十一电阻R11串联设置于信号放大模块的输出端；第十二电阻R12与第六电容C6并联连接；第六电容C6的一端与第十一电阻R11 的负极连接，其另一端接地。
进一步地，第十一电阻R11和第十二电阻R12的阻值关系为：
Figure PCTCN2021131781-appb-000003
第二分压模块的输出电压值为：
Figure PCTCN2021131781-appb-000004
其中，VIP和VIN为光耦处理模块的输入信号，VOP和VON为光耦处理模块的输出信号，n为光耦处理模块的线性放大倍数。
具体的，采样信号切换模块包括：第六MOS管Q6、第七MOS管Q7、第八MOS管Q8、第九MOS管Q9、第十MOS管Q10、第二十一电阻R21、第二十二电阻R22、第二十三电阻R23、第二十四电阻R24、第二十五电阻R25、第五十五电阻R55、第五十六电阻R56、第五十七电阻R57。50Hz信号为由电能表内部MCU产生的脉冲波信号，当50Hz信号为高电平时，第六MOS管Q6、第七MOS管Q7和第九MOS管Q9导通，使得Vo+与GND2连通，Io+与GND2连通，即Vo+＝0V,Io+＝OV；第八MOS管Q8和第十MOS管Q10关断,使得VO_2上的信号通过第二十三电阻R23、第二十五电阻R25输出到Vo-，IIN1+上的信号通过第五十七电阻R57输出到Io-,即Vo-＝VO_2,Io-＝IIN1+；当50Hz信号为低电平时，第八MOS管Q8和第十MOS管Q10导通，使得Vo-与GND2连通，Io-与GND2连通，即Vo-＝0V,Io-＝OV；第六MOS管Q6、第七MOS管Q7和第九MOS管Q9关断,使得VO_2上的信号通过第二十二电阻R22、第二十四电阻R24输出到Vo+，IIN1+上的信号通过第五十六电阻R56输出到Io+,即Vo+＝VO_2,Io+＝IIN1+；故在50Hz脉冲整个周期内VO_2电压经过采样信号切换模块后被切换成等幅值的差分信号(Vo+和Vo-)输入到计量芯片电压通道进行计量，因为VO_2电压值与原始采样端的采样信号VIP-VIN值相等且与原方案中的采样值相等，在计量校表过程中不需要再处理信号值。
具体的，假使在接线过程中VIN1和VIN2接错线，由于被测电源的电 压采样接线在光耦前端与电流采样回路不共地，光耦后端的VOP和VON输出根据输入的情况自动调整输出电压的参考点。故电压线接反不会造成被测电源短路，且基于线性光耦的输出特性，VO_2与VIP和VIN的对应关系为：
VO_2＝VIN-VIP；
如图6所示，此种条件下VO_2电压经过切换电路得到的等幅值的差分信号(Vo+和Vo-)与正常接线得到的差分信号(Vo+和Vo-)幅值一样，相位差180°，得到的显示电压值不变，方向显示电压负向提示电压线接反。从而实现电压采样公共端的自适应，以兼容直流电能表接在被测电源的正极或负极两种情况。
进一步地，预设频率值为50Hz。
本发明实施例旨在保护一种电能表直流计量电压采样装置，包括：依次串联连接的第一分压模块、光耦处理模块、信号放大模块、第二分压模块和采样信号切换模块；第一分压模块的输入端分别与待测电能表电压采样端子的正极和负极连接；光耦处理模块对经第一分压模块分压后的采样信号进行线性放大及隔离，其输出端依据待测电能表电压采样端子的正极和负极的连接情况自动调整输出电压的参考点；信号放大模块对光耦处理模块输出的采样信号进行放大处理，并将放大处理后的采样信号经第二分压模块后输出至采样信号切换模块；采样信号切换模块依据预设频率值对第二分压模块输出的单路电压信号进行差分处理，得到等幅值的差分信号并输入至计量芯片电压通道进行计量。上述技术方案具备如下效果：
在不改变原有总体计量方案的基础上，允许电压采样回路的输入信号可为正信号，也可为负信号，并利用线性光耦的隔离特性，避免电压采样回路与电流采样回路短路，以兼容直流电能表电流采样接在被测电源的正极或负极两种情况，提高产品的防呆性，保证现场接线的安全。
应当理解的是，本发明的上述具体实施方式仅仅用于示例性说明或解释本发明的原理，而不构成对本发明的限制。因此，在不偏离本发明的精 神和范围的情况下所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。此外，本发明所附权利要求旨在涵盖落入所附权利要求范围和边界、或者这种范围和边界的等同形式内的全部变化和修改例。

Claims (9)

  1. 一种电能表直流计量电压采样装置，其特征在于，包括：依次串联连接的第一分压模块、光耦处理模块、信号放大模块、第二分压模块和采样信号切换模块；
    所述第一分压模块的输入端分别与待测电能表电压采样端子的正极和负极连接；
    所述光耦处理模块对经所述第一分压模块分压后的采样信号进行线性放大及隔离，其输出端依据所述待测电能表电压采样端子的正极和负极的连接情况自动调整输出电压的参考点；
    所述信号放大模块对所述光耦处理模块输出的采样信号进行放大处理，并将放大处理后的所述采样信号经所述第二分压模块后输出至所述采样信号切换模块；
    所述采样信号切换模块依据预设频率值对所述第二分压模块输出的单路电压信号进行差分处理，得到等幅值的差分信号并输入至计量芯片电压通道进行计量。
  2. 根据权利要求1所述的电能表直流计量电压采样装置，其特征在于，
    所述第一分压模块包括：串联连接的第一电阻、第二电阻、第三电阻和第四电阻；
    所述光耦处理模块的第一输入端和第二输入端分别与所述第四电阻的两端连接。
  3. 根据权利要求1所述的电能表直流计量电压采样装置，其特征在于，
    所述光耦处理模块的输入信号分别为VIP和VIN，其输出信号分别为VOP和VON；
    VOP-VON＝n×(VIP-VIN)；
    其中，n为所述光耦处理模块的线性放大倍数。
  4. 根据权利要求1所述的电能表直流计量电压采样装置，其特征在于，所述信号放大模块包括：运算放大器、第五电阻、第六电阻、第七电阻、第八电阻、第二电容和第三电容；
    所述第五电阻串联于所述运算放大器的正极输入端，所述第七电阻串联于所述运算放大器的负极输入端，所述第八电阻和第三电容并联后分别与所述运算放大器的负极输入端和输出端连接，所述第六电阻和所述第二电容并联后一端与所述运算放大器的正极输入端连接且另一端接地。
  5. 根据权利要求4所述的电能表直流计量电压采样装置，其特征在于，所述信号放大模块还包括：第九电阻、第十电阻和可调电阻；
    所述可调电阻串联于所述运算放大器正极输入端和所述第六电阻之间；
    所述第九电阻和第十电阻串联后与所述可调电阻并联连接；
    所述第九电阻与所述第十电阻的连接端还与所述可调电阻的第三端连接。
  6. 根据权利要求4所述的电能表直流计量电压采样装置，其特征在于，
    所述第五电阻、所述第六电阻、所述第七电阻和所述第八电阻的电阻值相等；
    所述运算放大器的输出电压值为：
    VO_1＝VOP-VON＝n×(VIP-VIN)；
    其中，VIP和VIN为所述光耦处理模块的输入信号，VOP和VON为所述光耦处理模块的输出信号，n为所述光耦处理模块的线性放大倍数。
  7. 根据权利要求1所述的电能表直流计量电压采样装置，其特征在于，
    所述第二分压模块包括：第十一电阻、第十二电阻和第六电容；
    所述第十一电阻串联设置于信号放大模块的输出端；
    所述第十二电阻与所述第六电容并联连接；
    所述第六电容的一端与所述第十一电阻的负极连接，其另一端接地。
  8. 根据权利要求7所述的电能表直流计量电压采样装置，其特征在于，
    所述第十一电阻和第十二电阻的阻值关系为：
    Figure PCTCN2021131781-appb-100001
    所述第二分压模块的输出电压值为：
    Figure PCTCN2021131781-appb-100002
    其中，VIP和VIN为所述光耦处理模块的输入信号，VOP和VON为所述光耦处理模块的输出信号，n为所述光耦处理模块的线性放大倍数。
  9. 根据权利要求1所述的电能表直流计量电压采样装置，其特征在于，
    所述预设频率值为50Hz。
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