single-phase electricity meter reference design based on Kinetis
Freescale Semiconductor today announced a smart meter reference design that will be demonstrated during embedded world, March 1-3, 2011 in Nuremberg, Germany. The reference design, which will be featured as part of Freescale’s Smart Energy Wall display, provides a high-performance solution for power measurement in single-phase, two-wire installations targeted at the residential metering market.
According to a study prepared by Dr. Ahmad Faruqui of The Brattle Group for the Edison Foundation’s Institute for Electric Efficiency (IEE), this technology could save energy consumers more than a billion dollars annually for a population base the size of the US or Europe. With the growing consumption of energy worldwide, particularly in the residential market, utility providers need increasingly accurate and cost-effective energy metering solutions. Freescale’s MK30X single-phase electricity meter reference design addresses these accuracy and cost needs by providing efficient analog-to-digital converters (ADCs) combined with an embedded programmable gain amplifier (PGA) to increase the accuracy of energy measurement, along with a cost-effective shunt sensing circuit implementation and bill of materials (BOM).
The 32-bit Kinetis MK30X256 MCU at the heart of the MK30X reference design is based on the ARM Cortex-M4 core. This powerful core’s effective support of 32-bit math enables fast Fourier transform (FFT) based metering algorithms, which calculate metering quantities from elementary voltage and current harmonics. This calculation approach results in the precise accuracy of the reactive energy, as compared to other known metering algorithms.
The MK30X reference design includes a 128-bit unique identification and FlexMemory that provides every meter with an individual identifier and tamper detection. Firmware based on an MQX real-time operating system enables customers to design electricity meters based on their unique requirements and is well-suited for use in advanced markets.
Customization is available using the built-in LCD, which provides the standard metering values. The designer can choose any of the measured values by clicking on the device’s built-in buttons. The designer is also able to choose from several types of communication interfaces for remote collection of data. One option is connection to a ZigBee network via an I2C interface, meaning the meter can easily be enabled as part of a smart grid network. The meter is also able to connect outside of the home via SCI/SPI for last-mile communication.