WO2014032388A1 - Current sampling method for shock load electric energy meter - Google Patents

Current sampling method for shock load electric energy meter Download PDF

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Publication number
WO2014032388A1
WO2014032388A1 PCT/CN2013/000765 CN2013000765W WO2014032388A1 WO 2014032388 A1 WO2014032388 A1 WO 2014032388A1 CN 2013000765 W CN2013000765 W CN 2013000765W WO 2014032388 A1 WO2014032388 A1 WO 2014032388A1
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Prior art keywords
current
sampling
branch
conditioning
converter
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PCT/CN2013/000765
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French (fr)
Chinese (zh)
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马建
陈克旭
张春强
王爱民
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国家电网公司
江西省电力科学研究院
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Publication of WO2014032388A1 publication Critical patent/WO2014032388A1/en

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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
    • G01R19/2506—Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values ; Details concerning sampling, digitizing or waveform capturing
    • G01R19/2509—Details concerning sampling, digitizing or waveform capturing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R21/00—Arrangements for measuring electric power or power factor
    • G01R21/133—Arrangements for measuring electric power or power factor by using digital technique

Definitions

  • the invention relates to a current sampling method for an impact load electric energy meter, belonging to the technical field of electric power measurement.
  • a wide-range electric energy meter is generally used to measure electric energy.
  • the current sampling process of an input channel of a wide-range energy meter is generally implemented as follows: The input current is first passed through a current transformer to convert a large current into a small voltage signal, and the small voltage signal is processed by a process control amplifier and other signal conditioning circuits, and An A/D function block performs analog to digital conversion.
  • the referred A/D function block can be a separate analog-to-digital conversion chip or an analog-to-digital conversion section for current loop signal sampling in the energy metering chip.
  • the wide-range energy meter can control the range of the input current by switching the sampling loop of the current transformer or the gain of the programmable amplifier.
  • the wide-range energy meter sampling and range control feature is that each current sampling channel has only one A/D function block, and various range switching is set before this A/D function block.
  • the disadvantage of this method is that the measurement error increases as the input current amplitude changes rapidly. The reasons are as follows: The wide-range energy meter continuously monitors the input and output currents while continuously collecting the voltage and current signals of each channel for energy measurement. Determine whether the current input current exceeds the set range. If it is exceeded, adjust the range setting. Monitoring the input current size Each time a result data is obtained, a test time period is required before, which is hereinafter referred to as Trj, and T rj theoretically requires at least a quarter of the cycle time.
  • the current range setting needs to be adjusted at a certain time, it indicates that the current range setting before the time is not suitable for the input current, and the current sampled current data error for the energy metering is naturally large. If the current amplitude changes slowly, compared with the time interval of the secondary current range adjustment before and after, the error of the sampled data in TVj before adjustment is also small; if the current amplitude changes faster, T rj and the secondary current range before and after Adjusted time If the interval is large, the error of the sampled data before adjustment will be relatively large.
  • the object of the present invention is to solve the problem that the current data for electric energy metering of the wide-range electric energy meter is sampled before each span adjustment is large, and the present invention proposes to apply to an impact load or have a current amplitude.
  • the energy meter current sampling method for the load of the fast fluctuation characteristic the method can ensure that the current data for the energy measurement before the current range adjustment is sampled under the range setting state suitable for the input current in the period.
  • each current sampling channel is composed of a current transformer and N ( ⁇ l ) conditioning sampling branches
  • each of the conditioning sampling branches is composed of a buffer, an amplifier, a limiting protection circuit, Low-pass filter, A/D drive circuit and A/D converter.
  • N conditioning sampling branches are distributed.
  • the small voltage signal enters the conditioning sampling branch, it first removes the influence of the input impedance of the branch on the output of the current converter through a buffer, and then sends the amplifier to signal amplification, and then limits the signal amplitude to A/ through the limiting protection circuit.
  • the D converter inputs the allowable range, and then sends a low-pass filter for anti-aliasing filtering. Finally, it is driven by the A/D driver circuit and then sent to the A/D converter.
  • each of the current sampling channels is provided with N conditioning sampling branches, and the amplifiers of the respective branches are respectively set with different amplification factors, so that the input current signal ranges suitable for sampling of each branch are in different positions, and then Connecting the input of each conditioning sampling branch in parallel to the current converter is equivalent to superimposing the signal range suitable for sampling in each branch, so that any input current signal can always fall within a wide range.
  • the strips of the sampling branch are suitable for sampling.
  • the output of the current sampling channel is the A/D conversion data of each conditioning sampling branch of the channel.
  • one of the branches A/D conversion data is correct, and other branches
  • the circuit either over-amplifies the input current to cause the amplifier to saturate, or the amplification is insufficient to make the A/D input signal too small to affect the A/D conversion accuracy. In short, the data error of A/D conversion is large.
  • the A/D conversion data of each conditioning sampling branch is taken out by the MCU that calculates the electric energy by the measuring unit, and then calculated according to the effective value formula, and the calculation results are separately predicted.
  • the A/D conversion data of the upper limit is the data when the amplifier is saturated
  • the A/D conversion data of the lower limit is the data when the amplification is insufficient
  • the data is discarded.
  • the A/D conversion data between the upper and lower limits is the correct data and can be used to calculate the electrical energy.
  • the beneficial effects of the present invention are that, by adopting a multi-conditioning sampling branch in parallel operation, instead of performing the range switching in front of the A/D function block, the sampling in the Tj before each range adjustment in the current mode is avoided.
  • the invention is suitable for current sampling of an impact load electric energy meter.
  • Figure 1 is a block diagram of a current sampling channel and its connection diagram in an electric energy meter
  • Figure 2 is a schematic diagram of the functions and external interfaces of the programmable logic device CPLD;
  • Figure 3 is a circuit diagram of the conditioning sampling branch.
  • the current sampling channel of the embodiment of the present invention is composed of a current transformer and an N (N l ) conditioning sampling branch.
  • the current transformer can be either a precision sampling resistor or a wide current transformer.
  • the output of the current transformer is connected to the input V it of the N conditioning sampling branches.
  • the three-phase electric energy meter requires three current sampling channels, and the current converter inputs of the three current sampling channels are respectively connected to the a-phase input current, the b-phase input current, and the c-phase input current.
  • the outputs of the respective conditioning sampling branches of the three current sampling channels are connected to the microprocessor MCU of the meter metering unit via a programmable logic device CPLD.
  • the CPLD in this embodiment can be programmed to have a data buffer, a decoder, an inverter, a multi-input NAND gate function, a CPLD implementation function and an external interface diagram as shown in FIG. 2, CPLD and each The output of the conditioning sampling branch and the connection between the microprocessor MCUs of the meter metering unit are specifically: the data lines of each conditioning sampling branch are connected to the input of the data buffer via the data bus DB, the data buffer The output is connected to the data bus Dbus of the MCU; the address bus Abus of the MCU is connected to the input of the decoder, and the decoder outputs a plurality of chip select signals. , CSa2 ' - CSaN , CSbi , CS b 2 "' CS bN , CScl ,
  • the conditioning sampling branch circuit is shown in Figure 3.
  • the integrated circuit IC1 and the resistor R1 form a buffer;
  • the integrated circuit IC2, the resistor R2, the resistor R3, and the resistor R4 form an amplifier;
  • the integrated circuit IC3, the resistor R5, the resistor R6, the resistor R7, and the resistor R8, capacitor Cl, capacitor C2 constitute a low-pass filter;
  • integrated circuit IC4, resistor R9 constitutes A / D drive circuit;
  • integrated circuit IC5 and its surrounding RC components include resistor R10, resistor Rl l, resistor R12, resistor R13,
  • the resistor R14, the resistor R15, the resistor R16, the resistor R17, the capacitor C3, the capacitor C4, the capacitor C5, the capacitor C6, and the capacitor C7 constitute an A/D converter.
  • the integrated circuit IC5 uses the low-power analog-to-digital conversion device AD976 chip, and their inputs have differential mode overvoltage protection, so the circuit No special limiting protection circuit has been designed.
  • the current sampling channel needs to accurately sample the input current in the range of 0.25A ⁇ 6A as the design requirement, and the N-conditioning sampling branch is described, and the range of the input current signal range suitable for sampling is determined by each branch:
  • the A/D conversion chip used in this embodiment is AD976, and the maximum range of acceptable input signals is -10V ⁇ +10V, so the AC signal with the effective value in the range of 2V ⁇ 6V can be used as the A/D for AD976.
  • An AC signal whose RMS value exceeds the preset upper limit may have a peak value of ⁇ 10V when the signal is a distortion wave with a certain peak, and an A/D with an RMS value lower than the preset lower limit. Conversion will affect the conversion accuracy.
  • the range of the input current signal that can be sampled in the conditioning sampling branch 1 can be set at 2A to 6A ; the range of the input current signal suitable for sampling in the conditioning sample branch 2 can be set at 0. 7A ⁇ 2. 1A; The range of the input current signal is set to 0. 25A ⁇ 0. 75A;
  • the transform coefficient k of the current transformer is defined as: the output small voltage of the current transformer ( )
  • the A/D conversion data of each conditioning sampling branch is taken out by the MCU that calculates the power by the measuring unit, and each time the wave data is filled,
  • the effective data of the input signals of the three conditioning sampling branches A/D converters are respectively calculated by using the cycle data.
  • the effective value of the input signal of the A/D converter of a conditioning sampling branch is greater than the preset upper limit - 6V, indicating that the amplification factor of the amplifier in the conditioning sampling branch is When the input current signal is over-amplified, the amplifier may be saturated, so the A/D conversion data has a large error and cannot be used to calculate the power;
  • a conditioning sampling branch A/D converter input signal The effective value is less than the preset lower limit - 2V, indicating that the amplification factor of the amplifier in the conditioning sampling branch is insufficient for the input current signal at this time, and the A/D conversion data error is also large.
  • the effective value of the input signal of a conditioning sampling branch A/D converter is between the preset upper limit and the preset lower limit, that is, between 2V and 6V, indicating that The input current signal is within the range of the input current signal suitable for sampling by the conditioning sampling branch, and the data sampled by the conditioning sampling branch is correct data and can be used to calculate electrical energy.

Abstract

A current sampling method for a shock load electric energy meter. Each current sampling channel consists of a current converter and N conditioning sampling branch circuits. Each conditioning sampling branch circuit consists of a buffer, an amplifier, an amplitude limiting protection circuit, a low-pass filter, an A/D drive circuit and an A/D converter. When a current sampling channel is working, an input current is first converted into a small-voltage signal by the current converter, and then distributed to the N conditioning sampling branch circuits; after entering the conditioning sampling branch circuits, the small-voltage signal first passes through the buffer, then is sent to the amplifier for signal amplification, then passes through the amplitude limiting protection circuit to limit the signal amplitude to a range which is allowed to be input into the A/D converter, then is sent to the low-pass filter, and finally is sent to the A/D converter after passing through the A/D drive circuit. By adopting the mode of parallel operation of a plurality of conditioning sampling branch circuits, the problem of relatively large errors in current data sampled within a period prior to measurement range switching is avoided. It is suitable for a shock load electric energy meter to sample a current.

Description

冲击负荷电能表电流采样方法 技术领域  Impact load electric energy meter current sampling method
本发明涉及一种冲击负荷电能表电流采样方法， 属电力计量技术领域。  The invention relates to a current sampling method for an impact load electric energy meter, belonging to the technical field of electric power measurement.
背景技术 Background technique
目前， 在输入电流幅度变化较大的场合， 普遍采用宽量程电能表计量电能。 宽量程电能表一个输入通道的电流采样过程一般是这样实现的： 输入电流首先 经过一个电流变换器， 将大电流转换成小电压信号， 小电压信号经过程控放大 器和其他信号调理电路处理， 送给一个 A/D功能块进行模数转换。 所指的 A/D功 能块可以是独立的模数转换芯片， 也可以是电能计量芯片内用于电流回路信号 采样的模数转换部分。 宽量程电能表可以通过切换电流变换器的取样回路， 或 程控放大器的增益， 实现量程的控制， 从而适应输入电流幅度的大小变化。  At present, in the case where the input current amplitude varies greatly, a wide-range electric energy meter is generally used to measure electric energy. The current sampling process of an input channel of a wide-range energy meter is generally implemented as follows: The input current is first passed through a current transformer to convert a large current into a small voltage signal, and the small voltage signal is processed by a process control amplifier and other signal conditioning circuits, and An A/D function block performs analog to digital conversion. The referred A/D function block can be a separate analog-to-digital conversion chip or an analog-to-digital conversion section for current loop signal sampling in the energy metering chip. The wide-range energy meter can control the range of the input current by switching the sampling loop of the current transformer or the gain of the programmable amplifier.
宽量程电能表采样及量程控制的特点是每个电流采样通道只有一个 A/D功 能块， 各种量程切换均设置在这个 A/D功能块之前。 这种方式的缺点是在输入电 流幅度变化较快时计量误差随之增加， 原因如下： 宽量程电能表在连续采集各 通道电压电流信号用于电能计量的同时， 还要连续监测输入电流大小， 判断当 前输入电流是否超出所设量程范围， 超出了则调整量程设置。 监测输入电流大 小每得出一次结果数据， 之前都需要一个测试时间段， 该时间段下文称 Trj， Trj 从理论上讲至少需要四分之一周波的时间。 假定某时刻判出需调整电流量程设 置， 那么说明在该时刻之前的 内的电流量程设置对输入电流来说是不适合的， 内采样的用于电能计量的电流数据误差自然就比较大。 如果电流幅度变化较 慢， 与前后二次电流量程调整的时间间隔相比较小， 则调整前 TVj内采样数据 的误差影响也较小； 如果电流幅度变化较快， Trj与前后二次电流量程调整的时 间间隔相比较大， 则调整前 内采样数据的误差影响就会比较大。 The wide-range energy meter sampling and range control feature is that each current sampling channel has only one A/D function block, and various range switching is set before this A/D function block. The disadvantage of this method is that the measurement error increases as the input current amplitude changes rapidly. The reasons are as follows: The wide-range energy meter continuously monitors the input and output currents while continuously collecting the voltage and current signals of each channel for energy measurement. Determine whether the current input current exceeds the set range. If it is exceeded, adjust the range setting. Monitoring the input current size Each time a result data is obtained, a test time period is required before, which is hereinafter referred to as Trj, and T rj theoretically requires at least a quarter of the cycle time. Assuming that the current range setting needs to be adjusted at a certain time, it indicates that the current range setting before the time is not suitable for the input current, and the current sampled current data error for the energy metering is naturally large. If the current amplitude changes slowly, compared with the time interval of the secondary current range adjustment before and after, the error of the sampled data in TVj before adjustment is also small; if the current amplitude changes faster, T rj and the secondary current range before and after Adjusted time If the interval is large, the error of the sampled data before adjustment will be relatively large.
发明内容 Summary of the invention
本发明的目的是， 为克服宽量程电能表在每次量程调整前的 内采样的用 于电能计量的电流数据误差较大的问题， 本发明提出一种应用于冲击负荷或具 有电流幅值较快速波动特征之负荷的电能表电流采样方法， 该方法可保证每次 电流量程调整前 内采样的用于电能计量的电流数据， 是在与该时段输入电流 相适应的量程设置状态下采样的。  The object of the present invention is to solve the problem that the current data for electric energy metering of the wide-range electric energy meter is sampled before each span adjustment is large, and the present invention proposes to apply to an impact load or have a current amplitude. The energy meter current sampling method for the load of the fast fluctuation characteristic, the method can ensure that the current data for the energy measurement before the current range adjustment is sampled under the range setting state suitable for the input current in the period.
实现本发明的技术方案是， 每一路电流采样通道均由一个电流变换器和 N ( ^ l ) 条调理采样支路构成， 每一条调理采样支路均由缓冲器、 放大器、 限 幅保护电路、低通滤波器、 A/D驱动电路和 A/D转换器构成。 电流采样通道工作 时， 输入电流首先经电流变换器转换成小电压信号， 再分送 N条调理采样支路。 小电压信号进入调理采样支路后， 首先经一个缓冲器， 消除本支路输入阻抗对 电流变换器输出的影响， 再送放大器做信号放大， 然后通过限幅保护电路， 将 信号幅度限制在 A/D转换器输入允许的范围， 接着送低通滤波器做抗混叠滤波， 最后经 A/D驱动电路做信号驱动后送 A/D转换器。  The technical solution of the present invention is that each current sampling channel is composed of a current transformer and N ( ^ l ) conditioning sampling branches, and each of the conditioning sampling branches is composed of a buffer, an amplifier, a limiting protection circuit, Low-pass filter, A/D drive circuit and A/D converter. When the current sampling channel is working, the input current is first converted into a small voltage signal by the current transformer, and then N conditioning sampling branches are distributed. After the small voltage signal enters the conditioning sampling branch, it first removes the influence of the input impedance of the branch on the output of the current converter through a buffer, and then sends the amplifier to signal amplification, and then limits the signal amplitude to A/ through the limiting protection circuit. The D converter inputs the allowable range, and then sends a low-pass filter for anti-aliasing filtering. Finally, it is driven by the A/D driver circuit and then sent to the A/D converter.
本发明的原理是， 每一路电流采样通道设置 N条调理采样支路， 各条支路 的放大器分别设置不同的放大倍数， 使各支路所适于采样的输入电流信号范围 处于不同位置， 再将各调理采样支路的输入并联接入电流变换器， 相当于将各 支路所适于采样的信号范围叠加， 这样就可以在很宽的范围内实现任一输入电 流信号总能落在某条调理采样支路所适于采样的范围内。 电流采样通道的输出 是该通道各调理采样支路的 A/D转换数据， 如前所述， 对某一输入电流来说， 其中有一条支路 A/D转换的数据是正确的， 其他支路对该输入电流来说要么过 度放大导致放大器饱和， 要么放大不足使 A/D输入信号太小影响 A/D转换精度， 总之 A/D转换的数据误差均较大。 The principle of the invention is that each of the current sampling channels is provided with N conditioning sampling branches, and the amplifiers of the respective branches are respectively set with different amplification factors, so that the input current signal ranges suitable for sampling of each branch are in different positions, and then Connecting the input of each conditioning sampling branch in parallel to the current converter is equivalent to superimposing the signal range suitable for sampling in each branch, so that any input current signal can always fall within a wide range. The strips of the sampling branch are suitable for sampling. The output of the current sampling channel is the A/D conversion data of each conditioning sampling branch of the channel. As mentioned above, for one input current, one of the branches A/D conversion data is correct, and other branches The circuit either over-amplifies the input current to cause the amplifier to saturate, or the amplification is insufficient to make the A/D input signal too small to affect the A/D conversion accuracy. In short, the data error of A/D conversion is large.
本发明方法的电流采样通道实际接入电能表时， 各调理采样支路的 A/D转 换数据均由计量单元负责计算电能的 MCU取出， 然后按有效值公式计算， 各计 算结果再分别与预设的上下限比较， 超上限的其 A/D转换数据为所述放大器饱 和时的数据， 超下限的其 A/D转换数据为所述放大不足时的数据， 均为弃用数 据， 而处于上下限之间的其 A/D转换数据则为正确数据， 可用于计算电能。  When the current sampling channel of the method of the present invention is actually connected to the electric energy meter, the A/D conversion data of each conditioning sampling branch is taken out by the MCU that calculates the electric energy by the measuring unit, and then calculated according to the effective value formula, and the calculation results are separately predicted. Compared with the upper and lower limits, the A/D conversion data of the upper limit is the data when the amplifier is saturated, and the A/D conversion data of the lower limit is the data when the amplification is insufficient, and the data is discarded. The A/D conversion data between the upper and lower limits is the correct data and can be used to calculate the electrical energy.
本发明的有益效果是， 通过采用多调理采样支路并列运行的方式， 取代目 前在 A/D功能块前进行量程切换的方式， 避免了目前方式下每次量程调整前的 T j内采样的用于电能计量的电流数据误差较大的问题。  The beneficial effects of the present invention are that, by adopting a multi-conditioning sampling branch in parallel operation, instead of performing the range switching in front of the A/D function block, the sampling in the Tj before each range adjustment in the current mode is avoided. The problem of large current data error for electric energy metering.
本发明适用于冲击负荷电能表电流采样。  The invention is suitable for current sampling of an impact load electric energy meter.
附图说明 DRAWINGS
图 1为电流采样通道框图及其在电能表中的连接图；  Figure 1 is a block diagram of a current sampling channel and its connection diagram in an electric energy meter;
图 2为可编程逻辑器件 CPLD实现的功能及对外接口示意图；  Figure 2 is a schematic diagram of the functions and external interfaces of the programmable logic device CPLD;
图 3为调理采样支路电路图。  Figure 3 is a circuit diagram of the conditioning sampling branch.
具体实施方式 detailed description
以下结合实施例并对照附图对本发明进行详细说明。  The invention will be described in detail below with reference to the embodiments and with reference to the accompanying drawings.
如图 1所示， 本发明实施例的电流采样通道由电流变换器和 N (N l )条调 理采样支路构成。 电流变换器可以采用精密取样电阻， 也可以采用宽量限电流 互感器。 电流变换器的输出接 N条调理采样支路的输入 Vit。 这里以三相电能表 为例， 三相电能表需要三个电流采样通道， 三个电流采样通道的电流变换器输 入分别连接 a相输入电流、 b相输入电流和 c相输入电流。三个电流采样通道的 各调理采样支路的输出均通过一片可编程逻辑器件 CPLD与电能表计量单元的微 处理器 MCU相连。 本实施例中的 CPLD可编程具有一个数据缓冲器、一个译码器、一个反相器、 一个多输入与非门的功能， CPLD实现的功能及对外接口示意图如图 2所示， CPLD 与各调理采样支路的输出， 以及电能表计量单元的微处理器 MCU之间的连接具 体为：各调理采样支路的数据线均经数据总线 DB连接所述的数据缓冲器的输入， 数据缓冲器的输出接 MCU的数据总线 Dbus ; MCU的地址总线 Abus接译码器的输 入， 译码器输出多路片选信号 。,、 CSa2 ' - CSaN , CSbi , CSb2 " ' CSbN , CScl ,As shown in FIG. 1, the current sampling channel of the embodiment of the present invention is composed of a current transformer and an N (N l ) conditioning sampling branch. The current transformer can be either a precision sampling resistor or a wide current transformer. The output of the current transformer is connected to the input V it of the N conditioning sampling branches. Here, taking a three-phase electric energy meter as an example, the three-phase electric energy meter requires three current sampling channels, and the current converter inputs of the three current sampling channels are respectively connected to the a-phase input current, the b-phase input current, and the c-phase input current. The outputs of the respective conditioning sampling branches of the three current sampling channels are connected to the microprocessor MCU of the meter metering unit via a programmable logic device CPLD. The CPLD in this embodiment can be programmed to have a data buffer, a decoder, an inverter, a multi-input NAND gate function, a CPLD implementation function and an external interface diagram as shown in FIG. 2, CPLD and each The output of the conditioning sampling branch and the connection between the microprocessor MCUs of the meter metering unit are specifically: the data lines of each conditioning sampling branch are connected to the input of the data buffer via the data bus DB, the data buffer The output is connected to the data bus Dbus of the MCU; the address bus Abus of the MCU is connected to the input of the decoder, and the decoder outputs a plurality of chip select signals. , CSa2 ' - CSaN , CSbi , CS b 2 "' CS bN , CScl ,
CSC2 - CSCN , 分别连接各调理采样支路的片选线"^ ； 所有调理采样支路的 A/D 转换线 R/ΐ 相连， 全部受控于 MCU的一个输入输出口 ΙΟχ , ΙΟχ输出的控 制信号经所说的反相器驱动后， 接各 A/D转换线 R/ ； 各调理采样支路的采 样状态线 ϋ 分别接多输入与非门的一个输入口， 所接输入口分别是 BUSYax、 BUSY o2 " ' BUSY aN ^ BUSYb\、 BUSY b2 '" BUSY bN、 BUSYC\、 BUSY c2… BUSY cN， 当与非门输出低电平， 此时与非门的各输入均为高电平， 表示各支路的本次采 样均完成， 与非门输出连接 MCU的一个中断口 ， 与非门输出低电平将使 MCU产生中断。 CSC2 - CSCN, respectively connected to the chip selection line of each conditioning sampling branch "^; all the A/D conversion lines R/ΐ of the conditioning sampling branch are connected, all controlled by one input and output port of the MCU, and the output control After the signal is driven by the inverter, it is connected to each A/D conversion line R/; the sampling state line of each conditioning sampling branch is connected to one input port of the multiple input NAND gate, and the input port is BUSYax respectively. , BUSY o2 "' BUSY aN ^ BUSY b \, BUSY b2 '" BUSY bN , BUSY C \, BUSY c2 ... BUSY cN , when the NAND gate outputs a low level, the input of the NAND gate is high. Ping, indicating that the sampling of each branch is completed, the NAND gate output is connected to an interrupt port of the MCU, and the NAND gate output low level will cause the MCU to generate an interrupt.
调理采样支路电路如图 3所示， 集成电路 IC1与电阻 R1组成缓冲器； 集成 电路 IC2、 电阻 R2、 电阻 R3、 电阻 R4组成放大器； 集成电路 IC3、 电阻 R5、 电 阻 R6、 电阻 R7、 电阻 R8、 电容 Cl、 电容 C2组成低通滤波器； 集成电路 IC4、 电阻 R9组成 A/D驱动电路； 集成电路 IC5及其周边的阻容元件包括电阻 R10、 电阻 Rl l、 电阻 R12、 电阻 R13、 电阻 R14、 电阻 R15、 电阻 R16、 电阻 R17、 电 容 C3、电容 C4、电容 C5、电容 C6、电容 C7组成 A/D转换器。由于集成电路 IC1、 集成电路 IC2、 集成电路 IC3、 集成电路 IC4采用运算放大器 OP07芯片， 集成 电路 IC5采用低功耗模数转换器件 AD976芯片， 它们的输入均有差模过压保护， 因此电路中没有再设计专门的限幅保护电路。 下面以电流采样通道需准确采样范围在 0. 25A〜6A的输入电流为设计需求， 说明所说的 N条调理采样支路， 各支路所适于采样的输入电流信号范围的确定 过程： The conditioning sampling branch circuit is shown in Figure 3. The integrated circuit IC1 and the resistor R1 form a buffer; the integrated circuit IC2, the resistor R2, the resistor R3, and the resistor R4 form an amplifier; the integrated circuit IC3, the resistor R5, the resistor R6, the resistor R7, and the resistor R8, capacitor Cl, capacitor C2 constitute a low-pass filter; integrated circuit IC4, resistor R9 constitutes A / D drive circuit; integrated circuit IC5 and its surrounding RC components include resistor R10, resistor Rl l, resistor R12, resistor R13, The resistor R14, the resistor R15, the resistor R16, the resistor R17, the capacitor C3, the capacitor C4, the capacitor C5, the capacitor C6, and the capacitor C7 constitute an A/D converter. Since the integrated circuit IC1, the integrated circuit IC2, the integrated circuit IC3, and the integrated circuit IC4 use the operational amplifier OP07 chip, the integrated circuit IC5 uses the low-power analog-to-digital conversion device AD976 chip, and their inputs have differential mode overvoltage protection, so the circuit No special limiting protection circuit has been designed. In the following, the current sampling channel needs to accurately sample the input current in the range of 0.25A~6A as the design requirement, and the N-conditioning sampling branch is described, and the range of the input current signal range suitable for sampling is determined by each branch:
1、 确定 A/D转换器输入信号的有效范围。 本实施例采用的 A/D转换芯片为 AD976,其可接受的输入信号的最大范围为 -10V〜+10V， 因此可将有效值在 2V〜 6V范围的交流信号作为适于 AD976进行 A/D转换的信号， 6V作为预设上限， 2V 作为预设下限。 有效值超过预设上限的交流信号， 其峰值在信号为带一定尖状 波峰的畸变波时， 可能达到或超过 ± 10V; 而有效值低于预设下限的交流信号， 对其做 A/D转换则转换精度会受到一定影响。 1. Determine the effective range of the A/D converter input signal. The A/D conversion chip used in this embodiment is AD976, and the maximum range of acceptable input signals is -10V~+10V, so the AC signal with the effective value in the range of 2V~6V can be used as the A/D for AD976. The converted signal, 6V as the preset upper limit, 2V as the preset lower limit. An AC signal whose RMS value exceeds the preset upper limit may have a peak value of ±10V when the signal is a distortion wave with a certain peak, and an A/D with an RMS value lower than the preset lower limit. Conversion will affect the conversion accuracy.
2、 确定调理采样支路数， 确定各支路适于采样的输入电流信号范围。 由于 要求准确采样的输入电流范围在 0. 25A〜6A，故可采用 3条调理采样支路。调理 采样支路 1适于采样的输入电流信号范围可定在 2A〜6A; 调理釆样支路 2适于 采样的输入电流信号范围可定在 0. 7A〜2. 1A; 调理采样支路 3适于采样的输入 电流信号范围可定在 0. 25A〜0. 75A; 2. Determine the number of conditioning sampling branches and determine the range of input current signals that each branch is suitable for sampling. Since the input current range required for accurate sampling is from 0.25A to 6A, three conditioning sampling branches can be used. The range of the input current signal that can be sampled in the conditioning sampling branch 1 can be set at 2A to 6A ; the range of the input current signal suitable for sampling in the conditioning sample branch 2 can be set at 0. 7A~2. 1A; The range of the input current signal is set to 0. 25A~0. 75A;
3、 确定所说的电流变换器的变换系数 k、 调理采样支路 1中放大器的放大 倍数《1、 调理采样支路 2中放大器的放大倍数《2和调理采样支路 3中放大器的 放大倍数《3。 其中电流变换器的变换系数 k定义为： 电流变换器的输出小电压（ ) 3. Determine the conversion coefficient k of the current transformer, the amplification factor of the amplifier in the conditioning sampling branch 1 "1, the amplification factor of the amplifier in the conditioning sampling branch 2" 2 and the amplification factor of the amplifier in the conditioning sampling branch 3. "3. The transform coefficient k of the current transformer is defined as: the output small voltage of the current transformer ( )
~ 电流变换器的输入电流 ) 这里定 k=0. 166667V/A、 "1 =6、 "2 =17. 1429、 «3=48, 如此可实现： （1)适于调理 采样支路 1采样的， 范围在 2A〜6A的输入电流， 经电流变换器和调理采样支路  ~ Current input current of the current transformer) Here, k=0. 166667V/A, "1 =6, "2 =17. 1429, «3=48, this can be achieved: (1) Suitable for conditioning sampling branch 1 sampling Input current in the range of 2A to 6A, via current transformer and conditioning sampling branch
1 ,至调理采样支路 1中所述的 A/D转换器输入端时，信号有效值范围将在 2V〜 1. When the A/D converter input terminal described in the sampling branch 1 is conditioned, the signal valid value range will be 2V~
6V; (2)适于调理采样支路 2采样的， 范围在 0. 7A〜2. 1A的输入电流， 经电流变 换器和调理采样支路 2， 至调理采样支路 2中所述的 A/D转换器输入端时，信号 有效值范围将在 2V〜6V; (3)适于调理采样支路 3采样的， 范围在 0. 25A〜0. 75A 的输入电流， 经电流变换器和调理采样支路 3, 至调理采样支路 3中所述的 A/D 转换器输入端时， 信号有效值范围将在 2V〜6V。 6V; (2) Suitable for conditioning the sampling branch 2 sample, the range is 0. 7A~2. 1A input current, through the current transformer and conditioning sampling branch 2, to the A described in the conditioning sampling branch 2 Signal at the /D converter input The effective value range will be 2V~6V; (3) Suitable for conditioning the sampling branch 3 sampling, the range is 0. 25A~0. 75A input current, through the current converter and conditioning sampling branch 3, to the conditioning sampling branch When the input of the A/D converter is described in the way 3, the effective value of the signal will range from 2V to 6V.
包含了上述 3条调理采样支路的电流采样通道实际接入电能表时， 各调理 采样支路的 A/D转换数据均由计量单元负责计算电能的 MCU取出， 每取满一周 波数据， 则利用该周波数据分别计算 3条调理采样支路 A/D转换器输入信号的 有效值。 经计算， 若： （1)某条调理采样支路 A/D转换器输入信号的有效值大于 所说的预设上限—— 6V, 说明该调理采样支路中所述放大器的放大倍数对于此 时的输入电流信号来说是过度放大而可能导致放大器出现饱和， 因此 A/D转换 数据误差较大， 不能用于计算电能； （2)某条调理采样支路 A/D转换器输入信号 的有效值小于所说的预设下限—— 2V, 说明该调理采样支路中所述放大器的放 大倍数对于此时的输入电流信号来说是放大不足， 此时 A/D转换数据误差也较 大， 不能用于计算电能； （3)某条调理采样支路 A/D转换器输入信号的有效值处 于所说的预设上限和预设下限之间， 即 2V〜6V之间， 说明此时的输入电流信号 处于该调理采样支路适于采样的输入电流信号范围之内， 该调理采样支路采样 的数据为正确数据， 可用于计算电能。  When the current sampling channel including the above three conditioning sampling branches is actually connected to the energy meter, the A/D conversion data of each conditioning sampling branch is taken out by the MCU that calculates the power by the measuring unit, and each time the wave data is filled, The effective data of the input signals of the three conditioning sampling branches A/D converters are respectively calculated by using the cycle data. After calculation, if: (1) the effective value of the input signal of the A/D converter of a conditioning sampling branch is greater than the preset upper limit - 6V, indicating that the amplification factor of the amplifier in the conditioning sampling branch is When the input current signal is over-amplified, the amplifier may be saturated, so the A/D conversion data has a large error and cannot be used to calculate the power; (2) A conditioning sampling branch A/D converter input signal The effective value is less than the preset lower limit - 2V, indicating that the amplification factor of the amplifier in the conditioning sampling branch is insufficient for the input current signal at this time, and the A/D conversion data error is also large. , can not be used to calculate electrical energy; (3) the effective value of the input signal of a conditioning sampling branch A/D converter is between the preset upper limit and the preset lower limit, that is, between 2V and 6V, indicating that The input current signal is within the range of the input current signal suitable for sampling by the conditioning sampling branch, and the data sampled by the conditioning sampling branch is correct data and can be used to calculate electrical energy.

Claims

权 利 要 求 书 claims
1、 一种冲击负荷电能表电流采样方法， 其特征在于， 所述方法为， 每一路 电流采样通道均由一个电流变换器和 N条调理采样支路构成， 每一条调理采样 支路均由缓冲器、 放大器、 限幅保护电路、 低通滤波器、 A/D驱动电路和 A/D转 换器构成； 电流采样通道工作时， 输入电流首先经电流变换器转换成小电压信 号， 再分送 N条调理采样支路； 小电压信号进入调理采样支路后， 首先经一个 缓冲器， 消除本支路输入阻抗对电流变换器输出的影响， 再送放大器做信号放 大， 然后通过限幅保护电路， 将信号幅度限制在 A/D转换器输入允许的范围， 接着送低通滤波器做抗混叠滤波， 最后经 A/D驱动电路做信号驱动后送 A/D转 换器。 1. An impact load electric energy meter current sampling method, characterized in that, each current sampling channel is composed of a current converter and N conditioning sampling branches, and each conditioning sampling branch is composed of a buffer It is composed of converter, amplifier, limiting protection circuit, low-pass filter, A/D drive circuit and A/D converter; when the current sampling channel works, the input current is first converted into a small voltage signal by the current converter, and then distributed to N A conditioning sampling branch; after the small voltage signal enters the conditioning sampling branch, it first passes through a buffer to eliminate the influence of the input impedance of this branch on the output of the current converter, and then is sent to an amplifier for signal amplification, and then passes through the limiting protection circuit. The signal amplitude is limited to the allowable range of the A/D converter input, and then sent to a low-pass filter for anti-aliasing filtering. Finally, the signal is driven by the A/D drive circuit and sent to the A/D converter.
2、根据权利要求 1所述的一种冲击负荷电能表电流采样方法，其特征在于， 所述每一路电流采样通道设置 N条调理采样支路， 各条支路的放大器分别设置 不同的放大倍数， 使各支路所适于采样的输入电流信号范围处于不同位置， 再 将各调理采样支路的输入并联接入电流变换器， 相当于将各支路所适于采样的 信号范围叠加， 这样就可以在很宽的范围内实现任一输入电流信号总能落在某 条调理采样支路所适于采样的范围内； 电流采样通道的输出是该通道各调理采 样支路的 A/D转换数据， 对某一输入电流来说， 其中有一条支路 A/D转换的数 据是正确的， 其他支路对该输入电流来说要么过度放大导致放大器饱和， 要么 放大不足使 A/D输入信号太小影响 A/D转换精度。 2. An impact load electric energy meter current sampling method according to claim 1, characterized in that each of the current sampling channels is provided with N conditioning sampling branches, and the amplifiers of each branch are respectively set with different amplification factors. , so that the input current signal ranges suitable for sampling of each branch are at different positions, and then the inputs of each conditioning sampling branch are connected in parallel to the current converter, which is equivalent to superimposing the signal ranges suitable for sampling of each branch, so It can be realized in a wide range that any input current signal can always fall within the range suitable for sampling by a certain conditioning sampling branch; the output of the current sampling channel is the A/D conversion of each conditioning sampling branch of the channel Data, for a certain input current, the A/D conversion data of one branch is correct, and the other branches are either over-amplified for the input current, causing the amplifier to saturate, or under-amplified, causing the A/D input signal to Too small affects the A/D conversion accuracy.
3、根据权利要求 1所述的一种冲击负荷电能表电流采样方法，其特征在于， 所述电流采样通道实际接入电能表时， 各调理采样支路的 A/D转换数据均由计 量单元负责计算电能的微处理器 MCU取出， 然后按有效值公式计算， 各计算结 果再分别与预设的上下限比较， 超上限的其 A/D转换数据为所述放大器饱和时 的数据， 超下限的其 A/D转换数据为所述放大不足时的数据， 均为弃用数据， 而处于上下限之间的其 A/D转换数据则为正确数据， 可用于计算电能。 3. An impact load electric energy meter current sampling method according to claim 1, characterized in that when the current sampling channel is actually connected to the electric energy meter, the A/D conversion data of each conditioning sampling branch is obtained by the metering unit The microprocessor MCU responsible for calculating electric energy is taken out, and then calculated according to the effective value formula. Each calculation result is compared with the preset upper and lower limits respectively. The A/D conversion data exceeding the upper limit is the data when the amplifier is saturated, and the A/D conversion data exceeding the lower limit is the data when the amplifier is saturated. The A/D conversion data are the data when the amplification is insufficient, and are discarded data, while the A/D conversion data between the upper and lower limits are correct data and can be used to calculate electric energy.
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105319434A (en) * 2014-07-28 2016-02-10 国家电网公司 Method and device applied to current measurement of electric energy meter
CN107991529A (en) * 2017-12-27 2018-05-04 广东东方电讯科技有限公司 Non-linear power measures analysis recorder
CN110702976A (en) * 2019-11-01 2020-01-17 湖南银河电气有限公司 Wide-range high-precision current sensor/ammeter
CN112379162A (en) * 2020-08-21 2021-02-19 中国电力科学研究院有限公司 Differential-to-single-ended sampling device and method for station area topology identification
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CN116840544A (en) * 2023-06-12 2023-10-03 北京科荣达航空科技股份有限公司 Method and device for acquiring effective value of alternating current signal

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102830276B (en) * 2012-08-27 2015-05-13 江西省电力科学研究院 Current sampling method of shock load watt-hour meter
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CN116593769B (en) * 2023-07-17 2023-10-27 烟台东方威思顿电气有限公司 High-precision electric energy calculation method with wide dynamic range

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6397155B1 (en) * 1999-08-09 2002-05-28 Power Measurement Ltd. Method and apparatus for automatically controlled gain switching of monitors
US6735535B1 (en) * 2000-05-05 2004-05-11 Electro Industries/Gauge Tech. Power meter having an auto-calibration feature and data acquisition capabilities
CN1818682A (en) * 2006-04-03 2006-08-16 杭州华隆电子技术有限公司 High-precision electric energy meter by fractional sampler
CN101902223A (en) * 2010-08-19 2010-12-01 河南科技大学 Channel presetting method for analog-digital joint data acquisition device
CN201886064U (en) * 2010-12-21 2011-06-29 深圳市佳华利道新技术开发有限公司 Battery management system and battery pack current sampling circuit in controller thereof
CN102830276A (en) * 2012-08-27 2012-12-19 江西省电力科学研究院 Current sampling method of shock load watt-hour meter

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61292067A (en) * 1985-06-19 1986-12-22 Mitsubishi Electric Corp Method for measuring electric energy
JP2539170B2 (en) * 1993-12-10 1996-10-02 株式会社日立製作所 Current detection method and device
US6018700A (en) * 1998-02-19 2000-01-25 Edel; Thomas G. Self-powered current monitor
KR100515078B1 (en) * 2003-09-03 2005-09-14 삼성전기주식회사 Current-voltage transforming circuit employing limiter circuit by means of current sensing
CN101055299A (en) * 2007-01-31 2007-10-17 湖南大学 Impact load electric energy metering method
CN202275121U (en) * 2011-09-22 2012-06-13 绍兴电力局 Electric energy quality monitoring device with harmonic wave electric energy metering function

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6397155B1 (en) * 1999-08-09 2002-05-28 Power Measurement Ltd. Method and apparatus for automatically controlled gain switching of monitors
US6735535B1 (en) * 2000-05-05 2004-05-11 Electro Industries/Gauge Tech. Power meter having an auto-calibration feature and data acquisition capabilities
CN1818682A (en) * 2006-04-03 2006-08-16 杭州华隆电子技术有限公司 High-precision electric energy meter by fractional sampler
CN101902223A (en) * 2010-08-19 2010-12-01 河南科技大学 Channel presetting method for analog-digital joint data acquisition device
CN201886064U (en) * 2010-12-21 2011-06-29 深圳市佳华利道新技术开发有限公司 Battery management system and battery pack current sampling circuit in controller thereof
CN102830276A (en) * 2012-08-27 2012-12-19 江西省电力科学研究院 Current sampling method of shock load watt-hour meter

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105319434A (en) * 2014-07-28 2016-02-10 国家电网公司 Method and device applied to current measurement of electric energy meter
CN107991529A (en) * 2017-12-27 2018-05-04 广东东方电讯科技有限公司 Non-linear power measures analysis recorder
CN110702976A (en) * 2019-11-01 2020-01-17 湖南银河电气有限公司 Wide-range high-precision current sensor/ammeter
CN112379162A (en) * 2020-08-21 2021-02-19 中国电力科学研究院有限公司 Differential-to-single-ended sampling device and method for station area topology identification
CN112835515A (en) * 2020-12-14 2021-05-25 联芸科技（杭州）有限公司 Method for expanding number of flash memory particles mounted on storage device and storage device
CN116840544A (en) * 2023-06-12 2023-10-03 北京科荣达航空科技股份有限公司 Method and device for acquiring effective value of alternating current signal

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