Configurable AFEs change the future of power line communications


When I was a kid, someone from the power company regularly came to our house to read our electric meter so that we could be billed for our home's power consumption. Not only was this time consuming, but it also meant sending people into remote areas, and I'm sure everyone has heard stories of technicians being chased by the family dog. But with the advent of the smart grid, manually reading meters is becoming a thing of the past.

Over the past few years, a revolution has been happening for the power grid. It is becoming “smart.” What does this mean? The primary purpose of the power grid is to transport power from a power plant to your house through electrical wires. Your house has an electrical meter that shows how much power you have used, and you get billed for it. Since your house is already connected by a network of wires to the power plant, why not use that connection to transfer information in addition to power? This is where the smart grid comes into place.

By using a noise-resilient modulation scheme (such as OFDM), managing the physical layer protocol with a microcontroller (MCU) such as a TI C2000™ MCU and broadcasting onto the power line with a dedicated transmitter such as an AFE032 analog front end (AFE), electrical meter companies are now able to build e-meters that will communicate from your home back to the power plant in real time, allowing not only power utility companies to automatically measure your power consumption, but also to adjust in real time their power production depending on the demands of the users.

However, some of the real challenges with e-meters are to meet specific standards of emissions to avoid interference with other means of communication (such as wireless or High-Frequency). Those standards are different depending on the region of the world you live in, making the process of manufacturing e-meters very complex. Moreover, designing a power amplifier capable of delivering in excess of 1.5A at 21Vpp can prove itself a difficult engineering task. No other single monolithic IC in the market can claim to have such capabilities while maintaining a THD + Noise below 0.003%. Admittedly, a good discrete design could meet this requirement, but it would require careful design, over 20 discrete components and would take more than 10 times the number of components required by a single IC. This is where a fully integrated analog front end could save the day.

Designed to be deployed anywhere in the world, the AFE032 integrates a power amplifier capable of transmitting a signal onto the power line via a dedicated electrical network. The power amplifier is the unique component that can either break or make the solution. Transmitting an analog OFDM signal into a low impedance power line requires a special, well-designed power amplifier that can broadcast the signal over a long distance.

This is where key specifications of the AFE032 come into play such as:

  • Large output swing, up to 21Vpp
  • Large output current up to 1.5A typical
  • Large bandwidth in a gain of 6.5V/V or more (3.82MHz for the AFE032)
  • High slew rate in a gain of 6.5V/V (75V/us for the AFE032)

Moreover, the AFE032 also incorporates several adaptable on-the-fly filters to clean up the output signal to prevent interference with other modes of communication and comply with the standards of the country the e-meter is being deployed.

The capabilities of the power amplifier coupled with the adaptable filters is what make the AFE032 a flexible solution, that can be deployed anywhere in the world with very minimal changes and time.Coupled with a C2000 MCU, the AFE032 can be configured to transmit information on the grid in Japan, France, or the U.S., with minimum changes to the e-meter and electrical configuration. This allows the e-meter manufacturer to have one design fits all approach for the smart grid.

At this point, the future of power line communications is no longer constrained to the smart grid, but a new whole new world of building automation, lighting control and smart appliances, which are flourishing all around us to make the use of the electrical network in every house and every building a new mean of communication and control. With its highly configurable approach, this is where integrated analog front end products can respond to the needs of the future of power line communication.

Discover TI’s vision for the smart grid and energy markets in this new industrial video and read our new white paper about technologies that will allow smart cities on the grid to embrace renewable forms of energy generation.

Learn more about TI’s smart grid capabilities in these blog posts featured during #OntheGrid week: