Power Line Communication (PLC) Modem Chips Streamline Smart Meter Design

An overview of two PLC design solutions shows the progress in the realization of smart grid infrastructure.

Smart grid hardware—smart meter, smart streetlamps, and home and building automation—is getting a significant boost from the availability of power line communication (PLC, not to be confused with programmable logic controllers) modems—also known as mains communication—that support multiple communication standards and specific regulatory requirements. As the name suggests, power line communication is a form of data transmission that utilizes conductors for electric power delivery. 

Accompanying these PLC modem chips are evaluation boards and reference designs that help streamline PLC interface for smart grid applications while establishing point-to-point communications. Then there are firmware packages and PLC protocol stacks that come alongside these modem chips.

The PLC systems allow utilities to simplify the deployment of smart meters and other devices part of the grid infrastructure by delivering information for monitoring and other applications across power distribution lines. 

Take the case of Microchip's new PLC modem chip, the PL360B modem, which allows manufacturers to develop multi-protocol and field-upgradable metering infrastructure devices. The modem comes along with a reference designs for adding a PLC interface to any smart-grid device serving a PLC node.

The PL360B chip claims to facilitate power efficiency of up to 25 percent over Microchip's previous-generation PLC modem ICs. Image courtesy of Microchip Technology Inc.

The modem chip supports PLC protocols like G3-PLC or ITU G.9903 and PRIME or ITUG.9904 and is compliant with CENELEC, FCC and ARIB applications. It complies with multiple standards and proprietary protocols in the frequency band of up to 500 kHz.

Another PLC modem solution comes from STMicroelectronics. It's a modem chipset comprising of a programmable PLC engine and a line driver. Interfacing with either new or existing metering and controlling devices, STMicro's chipset acts as an external communication module.

PLC is becoming a popular connectivity vehicle in smart-grid infrastructure. Image courtesy of STMicroelectronics.

The ST8500 processor transporting information over power wires contains quad-core DSP for real-time protocol processing and an ARM ® Cortex ® -M4F core for upper-layer processing and system management. The processor has its own code and features on-chip SRAM, AES cryptographic engine, and a dedicated set of peripherals focused on smart-energy applications. It also boasts an analog front-end (AFE) for connection with the line driver.

The other part of the PLC modem chipset—STLD1 line driver—communicates reliably even across noisy cables with low impedance. The line driver chip ensures high linearity over a wide output range of 18 V in single-ended or 36 V in differential mode.

These PLC modem solutions serving the second-generation smart meter designs claim to have incorporated the design lessons learned from the first-generation digital meters. They are cost-effective and flexible, and they seem ready to serve the Internet of Things (IoT) era.