Metering & Energy Monitoring

The ADE9000 is a highly accurate, fully integrated, multiphase energy and power quality monitoring device. Superior analog performance and a digital signal processing (DSP) core enable accurate energy monitoring over a wide dynamic range. An integrated high end reference ensures low drift over temperature with a combined drift of less than ±25 ppm/°C maximum for the entire channel including a programmable gain amplifier (PGA) and an analog-to-digital converter (ADC).

The ADE9000 offers complete power monitoring capability by providing total as well as fundamental measurements on rms, active, reactive, and apparent powers and energies. Advanced features such as dip and swell monitoring, frequency, phase angle, voltage total harmonic distortion (VTHD), current total harmonic distortion (ITHD), and power factor measurements enable implementation of power quality measurements. The ½ cycle rms and 10 cycle rms/12 cycle rms, calculated according to IEC 61000-4-30 Class S, provide instantaneous rms measurements for real-time monitoring.

The ADE9000 offers an integrated flexible waveform buffer that stores samples at a fixed data rate of 32 kSPS or 8 kSPS, or a sampling rate that varies based on line frequency to ensure 128 points per line cycle. Resampling simplifies fast Fourier transform (FFT) calculation of at least 50 harmonics in an external processor.

The ADE9000 simplifies the implementation of energy and power quality monitoring systems by providing tight integration of acquisition and calculation engines. The integrated ADCs and DSP engine calculate various parameters and provide data through user accessible registers or indicate events through interrupt pins. With seven dedicated ADC channels, the ADE9000 can be used on a 3-phase system or up to three single-phase systems. It supports current transformers (CTs) or Rogowski coils for current measurements. A digital integrator eliminates a discrete integrator required for Rogowski coils.

The ADE9000 absorbs most complexity in calculations for a power monitoring system. With a simple host microcontroller, the ADE9000 enables the design of standalone monitoring or protection systems, or low cost nodes uploading data into the cloud.

Note that throughout this data sheet, multifunction pins, such as CF4/EVENT/DREADY, are referred to either by the entire pin name or by a single function of the pin, for example, EVENT, when only that function is relevant.

Applications

• Energy and power monitoring
• Power quality monitoring
• Protective devices
• Machine health
• Smart power distribution units
• Polyphase energy meters

The ADE9078 is a highly accurate, fully integrated energy metering device. Interfacing with both current transformer (CT) and Rogowski coil sensors, the ADE9078 enables users to develop a 3-phase metrology platform, which achieves high performance for Class 1 up to Class 0.2 meters.

The ADE9078 integrates seven high performances ADCs and a flexible DSP core. An integrated high end reference ensures low drift over temperature with a combined drift of less than ±25 ppm/°C maximum per channel, each of which includes a programmable gain amplifier (PGA) and ADC.

The ADE9078 offers an integrated flexible waveform buffer that stores samples at a fixed data rate or a sampling rate that varies based on line frequency to ensure 64 points per line cycle. These two options make it easy to implement harmonic analysis in an external processor according to IEC 61000-4-7.

Two power modes are provided to enable detection of meter tampering: PSM2 uses a low power comparator to compare current channels to a threshold and indicates whether it is exceeded on the IRQ0 and IRQ1 outputs; PSM1 enables fast measurement of current and voltage rms (xVRMS and xIRMS), active power, and VAR during a tamper.

The ADE9078 allows advanced and highly accurate energy measurements, enabling one platform to cover a wide range of meters, through a combination of various high end metrology features and superior analog performance.

Applications

• Polyphase meters
• Power quality monitoring
• Protective device

The ADE7880 is high accuracy, 3-phase electrical energy measurement IC with serial interfaces and three flexible pulse outputs. The ADE7880 device incorporates second-order sigma-delta (Σ-Δ) analog-to-digital converters (ADCs), a digital integrator, reference circuitry, and all of the signal processing required to perform the total (fundamental and harmonic) active, and apparent energy measurements, rms calculations, as well as fundamental-only active and reactive energy measurements. In addition, the ADE7880 computes the rms of harmonics on the phase and neutral currents and on the phase voltages, together with the active, reactive, and apparent power, and the power factor and harmonic distortion on each harmonic for all phases. Total harmonic distortion plus noise (THD + N) is computed for all currents and voltages. A fixed function digital signal processor (DSP) executes this signal processing. The DSP program is stored in the internal ROM memory.

The ADE7880 is suitable for measuring active, reactive, and apparent energy in various 3-phase configurations, such as wye or delta services with both three and four wires. The ADE7880 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 active powers, apparent powers, or the sum of the current rms values, and fundamental active and reactive powers.

Figure 1: High Common-Mode Voltage Current Monitor (All Connections and Decoupling Not Shown)

Lithium ion (Li-Ion) battery stacks contain a large number of individual cells that must be monitored correctly in order to enhance the battery efficiency and prolong the battery life. The 6-channel AD7280A devices in the circuit shown in Figure 1 act as the primary monitor providing accurate measurement data to the Battery Management Controller (BMC).

The AD7280A contains an internal ±3 ppm reference that allows a cell voltage measurement accuracy of ±1.6 mV. The ADC resolution is 12 bits and allows conversion of up to 48 cells within 7 μs.

The AD7280A, which resides on the high voltage side of the Battery Management System (BMS) has a daisy-chain interface, which allows up to eight AD7280A’s to be stacked together and allows for 48 Li-Ion cell voltages to be monitored. Adjacent AD7280A's in the stack can communicate directly, passing data up and down the stack without the need for isolation. The AD7280A master device on the bottom of the stack uses the SPI interface to communicate with the BMC, and it is only at this point that high voltage galvanic isolation is required in order to protect the low-voltage side of the BMS. The ADuM1201 digital isolator and the ADuM5401 isolator with integrated dc-to-dc converter combine to provide the required six channels of isolation in a compact and cost effective solution.

Figure 1. AD7280A Daisy-Chain Configuration Circuit with Isolation (Simplified Schematic: All Connections and Decoupling Not Shown)

High-side current monitors are likely to encounter overvoltage conditions from transients or when the monitoring circuits are connected, disconnected, or powered down. This circuit, shown in Figure 1, uses the overvoltage protected ADA4096-2 op amp connected as a difference amplifier to monitor the high-side current. The ADA4096-2 has input overvoltage protection, without phase reversal or latch-up, for voltages of 32 V higher than and lower than the supply rails.

The circuit is powered by the ADP3336 adjustable low dropout 500 mA linear regulator, which can also be used to supply power to other parts of the system, if desired. Its input voltage can range from 5.2 V to 12 V when set for a 5 V output. To save power, the current sensing circuit can be powered down by removing power to the ADP3336; however, the power source, such as a solar panel, can still operate.

This applies voltage to the inputs of the unpowered ADA4096-2; however, no latch-up or damage occurs for input voltages up to 32 V. If slower throughput rates are required, the AD7920 can also be powered down between samples. The AD7920 draws a maximum of 5 μW when powered down and 15 mW when powered up. The ADA4096-2 requires only 120 μA under operational conditions. When operating at 5 V, this is only 0.6 mW. The ADP3336 draws only 1 μA in the shutdown mode.

Lithium ion (Li-Ion) battery stacks contain a large number of individual cells that must be monitored correctly in order to enhance the battery efficiency, prolong the battery life, and ensure safety. The 6-channel AD7280A devices in the circuit shown in Figure 1 act as the primary monitor providing accurate voltage measurement data to the System Demonstration Platform (SDP-B) evaluation board, and the 6-channel AD8280 devices act as the secondary monitor and protection system. Both devices can operate from a single wide supply range of 8 V to 30 V and operate over the industrial temperature range of −40°C to +105°C.

The AD7280A contains an internal ±3 ppm reference that allows a cell voltage measurement accuracy of ±1.6 mV. The ADC resolution is 12 bits and allows conversion of up to 48 cells within 7 μs.

The AD7280A has cell balancing interface outputs designed to control external FET transistors to allow discharging of individual cells and forcing all the cells in the stack to have identical voltages.

The AD8280 functions independently of the primary monitor and provides alarm functions indicating out of tolerance conditions. It contains its own reference and LDO, both of which are powered completely from the battery cell stack. The reference, in conjunction with external resistor dividers, is used to establish trip points for the over/undervoltages. Each cell channel contains programmable deglitching (D/G) circuitry to avoid alarming from transient input levels.

The AD7280A and AD8280, which reside on the high voltage side of the battery management system (BMS) have a daisychain interface, which allows up to eight AD7280A’s and eight AD8280’s to be stacked together and allows for 48 Li-Ion cell voltages to be monitored. Adjacent AD7280A's and AD8280’s in the stack can communicate directly, passing data up and down the stack without the need for isolation.

The master devices on the bottom of the stack use the SPI interface and GPIOs to communicate with the SDP-B evaluation board, and it is only at this point that high voltage galvanic isolation is required to protect the low voltage side of the SDP-B board. The ADuM1400, ADuM1401 digital isolator, and the ADuM5404 isolator with integrated dc-to-dc converter combine to provide the required eleven channels of isolation in a compact and cost effective solution. The ADuM5404 also provides isolated 5 V to the VDRIVE input of the lower AD7280A and the VDD2 supply voltage for the ADuM1400 and ADuM1401 isolators.