New-Tech Magazine Europe | Dec 2015 Digital edition

to the U.S. Energy Information Administration (EIA), by 2013 (the latest year for which numbers are available) U.S. electric utilities had installed 51,924,502 smart meters of which 89 percent were in residential customer installations. Smart meters are more than just monitoring units that can be interrogated remotely. A key advantage of these intelligent devices is the supply of information that allows both utilities and consumers to manage supply and demand. Utilities are able to use the information to precisely determine peaks in demand and reserve generating capacity for similar future peaks. The utility can also set “dynamic” tariffs, reflecting the costs (and carbon content) of generation and distribution at any particular time, or rewarding consumers for using electricity at times when renewable sources are producing a lot of power. Consumers could even opt for packages that allow appliances to be turned on and off automatically by the grid operator to help maintain virtually a second-by-second balance between supply and demand. A downside of smart meters is the requirement for them to be “always on.” Each unit draws relatively little current, but the combined effect of millions is significant. The silicon vendors have responded by cutting the quiescent current of their high-voltage power solutions for these always-on, non-isolated systems for applications such as smart meters. Several manufacturers offer AC-to- DC voltage regulators that meet the tough demands of smart metering. For example, STMicroelectronicssupplies a power supply module, the VIPER06, that can operate froman 85V to 265VAC input and features an 800V power metal-oxide semiconductor field-effect transistor (MOSFET). The chip can output up to 8W yet consumes just a few hundred microamps quiescent current. For its part, TI has recently introduced the UCC28880, an AC-to-DC switching regulator for smart-meter applications. The UCC28880 integrates the controller

and communications technology in the U.S. and the rest of the developed world is a huge task. The cost of the exercise will run into billions of dollars without even factoring in disruption to customers as sections of the grid are upgraded. However, the rewards are great. A smart grid will dramatically improve the efficiency of the electricity system by reducing system losses, make it easier to switch in renewable energy sources (thus reducing the requirement for “base load” - fossil- fuel generating capacity that must be kept running permanently to cope with anticipated peaks), and enable utilities to encourage consumers to reduce consumption through flexible tariffs. Higher efficiency and greater contributions from renewable sources also helps authorities meet their commitments to reduce carbon emissions. Smart grids also limit disruption caused by outages by allowing operators to quickly isolate faults and re-route power to as many consumers as possible while the problem is rectified. The success of smart grids will rely heavily on novel silicon and innovative design engineers; and those products will in turn rely on specialized power modules that meet the particular requirements of smart- grid application such as wide-input voltage ranges and low-quiescent currents. The good news is that there are already many integrated solutions commercially available for engineers looking to take a slice of this lucrative market sector. For more information about the parts discussed in this article, use the links provided to access product pages on the Digi-Key website. References: 1. “Carbon Emission Reductions by the Implementation of a Smart Grid,” Steven Keeping, NOJA Power, 2013. 2. “Smart Grid & Energy Solutions Guide,” Texas Instruments, 2015.

and a 700V power MOSFET into one device. The chip also integrates a high-voltage current source, enabling start-up and operation directly from the rectified mains voltage. The quiescent current of the device is less than 100µA, improving the efficiency of the solution. TI says that by using the UCC28880 engineers can design most common regulator topologies using a minimum number of external components. Utilities have also implemented “concentrators” as part of their smart- metering systems. Concentrators gather information from a group of smart meters (for example, those in a single apartment block) and aggregate and analyze the data before transmitting it wirelessly or via a power line modem to the utility. Concentrators can also be used to send information from the central control facility back to the smart-meter group and facilitate maintenance functions such as software updates. In addition to supplying power modules for smart meters, STMicroelectronics also caters for the power requirements of concentrators. The power requirements for concentrators are similar to those for smart meters, although a little more demanding due the additional computation performed by the unit. STMicroelectronics promotes the Altair 04-900 AC-to-DC switching voltage regulator for concentrator applications. It is based on a quasi- resonant flyback topology and is capable of operating from a mains input and features a 900V breakdown power stage. The Altair features low-standby consumption (around 1mA) and overcurrent protection to safeguard against transformer saturation and secondary diode short circuiting. The company also provides a power supply reference design for smart-metering applications, under the part number STEVAL-ISA105V1 (Figure 4). Huge rewards Modernizing decades-old electricity infrastructure with computerization

Contributed By Electronic Products, DigiKey Electronics

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