Solid-state electricity meters measure and display power consumption in residential, industrial, and commercial dwellings, as well as sub-stations in the electric grid. They are evolving rapidly, and different solutions and architectures are required to meet varying regional utility requirements.
- The basic e-meter is a direct replacement for the traditional mechanical meter. These devices still need to be read manually, and are generally based on low-end microcontrollers with LCD drivers and low power consumption. They also use metrology AFE (analog front-end) devices which must comply with applicable ANSI and IEC specifications.
- Smart meters are part of an advanced metering infrastructure (AMI) also referred to as the “Smart Grid”. It enables two-way communications back to the utility using technologies such as power-line carrier, fixed and mesh wireless networks, as well as communications to the in-home area networked devices such as thermostat, appliances and PHEV (plug-in hybrid vehicle). They are also an essential component in enabling metering services in deregulated utility markets. These meters need to support alternative local generation methods such as wind and solar.
As implementation and architecture become more sophisticated, electricity meters demand additional processing power and larger Flash memories for software stacks. They also need to support communication standards such as PRIME, G3, IEEE 1901.2, IEEE 802.15.4g and IEEE 802.15.4.
Features and Benefits
- Platform solution includes Single- and Poly-phase Metrology AFE and SoC (System on a Chip) devices meeting global requirements up to class 0.2 accuracy
- SoC’s provide option to include OFDM PLC and/or metrology
- Dual ARM® Cortex® M4-based architecture supports independent application, metrology, and communications
- Atmel’s Metrology library allows flexibility to adapt to global requirements
- Up to 7 Sigma-Delta ADCs (analog-to-digital converters), with 20-bit resolution and 102 dB dynamic range
- Up to 6000:1 dynamic range (AFE devices)
- Support Shunt, Current Transformer and Rogowsky sensors
- Dedicated current channel for neutral current measurement used in anti-tamper detection
- Up to 2MB Embedded Flash
- Up to 256 Kbytes of Embedded SRAM (independent of metrology)
- Host of integrated peripherals including low-power RTC, LCD, USART and SPI
- AES, CPKCC, ICM (SHA) encryption with TRNG (true random number generator)
In a typical electricity meter design the measurement of active (kWH) or reactive (kVarH) energy consumption is performed by high resolution Sigma-delta ADCs with a precision voltage reference, and advanced metrology algorithms running in a dedicated DSP or hardware engine. Measurement results are displayed and processed by applications and communications processing blocks and transported over either secured wireless or power-line carrier physical layer technologies.
At the core of Atmel’s smart energy platform is SAM4C series of products starting with SAM4C16C and SAM4C8C system-on-chip solutions for smart energy applications built around two high performance 32-bit ARM®Cortex® M4-based RISC processors. These devices operate at a maximum speed of 100 MHz and feature up to 2 MB of embedded Flash, 304 KB of SRAM and on-chip cache for each core. The dual ARM Cortex M4-based architecture allows for integration of application layer, communications layers, and metrology functions in a single device. It allows options for integrated software metrology or external hardware metrology AFE as well as an integrated or external powerline carrier (PLC) physical layer solution.
With its broad microcontroller portfolio, communications, NVM and hardware security products, Atmel offers the key components of an electricity meter. The Atmel AVR and ARM® microcontroller families provide a rich array of features that electricity meters demand.
Learn more about the Atmel solution Application Notes, Devices, and Tools and Software.