ADI 公司的ADE7878是高精度三相电能测量IC,集成了串行接口和三个灵活的脉冲输出,包括有二阶Delta-Sigma ADC,数字积分器,基准电路,以及进行总的有功,无功和表观能量测量以RMS计算所需要的所有信号处理.采用固定功能的DSP来实现这些信号处理. ADE7878具有精度高,支持EN 50470-1, EN 50470-3, IEC 62053-21, IEC 62053-22 and IEC 62053-23,和三相三线或四线制兼容,测量误差小于0.1%, 工作电压在2.4 到 3.7V.本文介绍ADE7878主要特性,功能方框图, 总的有功和无功与表观电量累加框图,以及评估板EVAL-ADE7878EB主要特性,方框图, 电路图和材料清单BOM.
is a high accuracy, 3-phase electrical energy measurement IC with serial interfaces and three flexible pulse outputs. The ADE7878 incorporates second-order Σ-Δ ADCs, a digital integrator, reference circuitry, and all the signal processing required to perform total (fundamental and harmonic) active, reactive and apparent energy measurement, fundamental only active and reactive energy measurement and rms calculations. A fixed function digital signal processor (DSP) executes this signal processing.
TheADE7878 is suitable to measure active, reactive, and apparent energy in various 3-phase configurations, such as WYE or DELTA services, with both three and four wires. The ADE7878 provides system calibration features for each phase, that is, rms offset correction, phase calibration, and gain calibration. The CF1, CF2 and CF3 logic outputs provide a wide choice of power information: total/fundamental active/reactive power, total apparent power or sum of current rms values.
The ADE7878 has waveform sample registers that allow access to all ADC outputs. The device also incorporates power quality measurements such as short duration low or high voltage detections, short duration high current variations, line voltage period measurement and angles between phase voltages and currents. Two serial interfaces can be used to communicate with the ADE7878: SPI or I2
C while a dedicated high speed interface, HSDC (High Speed Data Capture) port, can be used in conjunction with I2
C to provide access to the ADC outputs and real time power information. The ADE7878 has also two
interrupt request pins, IRQ0 and IRQ1 , to indicate that an enabled interrupt event has occurred.
Three specially designed low power modes ensure the continuity of the energy accumulation when the ADE7878 is in tampering situation.
The ADE7878 is available in 40-lead LFCSP lead free package.
Highly accurate; supports EN 50470-1, EN 50470-3, IEC 62053-21, IEC 62053-22 and IEC 62053-23
Compatible with 3-phase, 3 or 4 wire (delta or wye) and other 3-phase services
Supplies total (fundamental and harmonic) active/reactive/ apparent energy and fundamental active/reactive energy on each phase and on the overall system
Less than 0.1% error in active and reactive energy over a dynamic range of 1000 to 1 at 25℃
Less than 0.2% error in active and reactive energy over a dynamic range of 3000 to 1 at 25℃
Supports current transformer and di/dt current sensors
Dedicated ADC channel for the neutral current input
Less than 0.1% error in voltage and current rms over a dynamic range of 1000 to 1 at 25℃
Supplies sampled waveform data on all 3 phases and neutral current
Selectable No-load threshold level for total and fundamental active and reactive powers and for apparent powers
Low power battery mode monitors phase currents for anti-tampering detection
Phase angle measurements in both current and voltage channels with max 0.3° error
Wide supply voltage operation 2.4 to 3.7V
Battery supply input for missing neutral operation
Reference 1.2 V (drift 10 ppm/°C typ) with external overdrive capability
Single 3.3 V supply
40-Lead Frame Chip Scale (LFCSP) Lead Free Package
Operating temperature -40° to 85℃
C, SPI®, HSDC serial interfaces
Evaluation Board Documentation ADE7878 Energy Metering IC EVAL-ADE7878EB
This documentation describes the ADE7878 evaluation kit hardware, firmware and software functionality. The evaluation board contains an ADE7878 and a LPC2368 microcontroller.
The ADE7878 and its associated metering components are optically isolated from the microcontroller. The microcontroller communicates with the PC using a USB interface. Firmware updates can be loaded using one PC com port and a regular serial cable.
The ADE7878 evaluation board and this documentation, together with the ADE7878 data sheet provide a complete evaluation platform for the ADE7878.
The evaluation board has been designed so that ADE7878 can be evaluated in an energy meter. Using appropriate current transducers, the evaluation board can be connected to a test bench or high voltage (240Vrms) test circuit. On-board resistor dividers networks provide the attenuation for the line voltages.
This application note describes how the current transducers should be connected for the best performance. The evaluation board requires two external 3.3V power supplies and the appropriate current transducers.
Evaluation board designed to be used together with accompanying software to implement a fully functional three-phase energy meter
Easy connection of various external transducers via screw terminals
Easy modification of signal conditioning components using PCB sockets
LED indicators on logic outputs CF1, CF2, CF3, IRQ0, and IRQ1
Optically isolated metering components and USB based communication with PC
External voltage reference option available for on-chip reference evaluation
PC COM port-based firmware updates