Smart meters for smart grids

Pursuant to the “EnWG”, the law on renewable energies, “intelligent energy meters” are to be fitted to all new buildings since 2010. According to §21d, they are to indicate “the actual energy consumption and utilisation time to the end user”.

Although this only refers to the minimum requirements, the paradigm change from classic Ferraris meters to processor-based electronics has begun, since existing electromechanical meters are unable to measure utilization periods. Smart counters also provide more demanding features such as logging actual utilization for load profiles or readings via internet.

However, the precise and efficient measuring of power & voltage values on-site remains the basic requirement. IDT, manufacturers of semiconductors, have recognized this increasing demand and have developed an entire range of single phase & polyphase metering ICs.

Overview Metering-ICs from IDT

Single phase and polyphase metering ICs

The new IDT range of polyphase metering ICs offers the largest dynamic range and the lowest temperature coefficient on the market. This enables manufacturers of smart energy meters to increase equipment performance while at the same time reducing costs by consolidating product variants and simplifying their calibration.

The polyphase energy meter ICs 90E32 and 90E36 are an addition to IDT’s 90E2x range of single phase meter ICs, extending the portfolio of solutions for all meter types. Their dynamic range is 5000:1 (90E32) and 6000:1 (90E36) respectively. Thanks to IDT’s proprietary temperature compensation technology, they achieve excellent temperature tracking (reference voltage < +/-5 ppm/°C) and exceptional performance across a wide range of applications and environmental conditions. Overall precision is ±0.2% within the temperature range from -40 ºC to +85 ºC.

The modules comply with all aspects of international (IEC, ANSI) and Chinese (GB, DL) standards and can be used for triphase meters with 4 lines (3P4W) or with 3 lines (3P3W) to measure effective power and apparent power.

The IDT90E36 also comprises an integrated calculation engine for discreet Fourier transformations (DFT), to recognize harmonic distortion (THD = Total Harmonic Distortion), for accessing raw a/D converter data (ADC) via direct memory access port (DMA) and versatile parameter measuring functions.

These characteristics offer additional flexibility during the development process and enhance the application possibilities for the module on data acquisition terminals (DAT) and other electric equipment for monitoring electric parameters.

Product brochure 90E21 (single phase)
Product brochure 90E22 (single phase)
Product brochure 90E23 (single phase)
Product brochure 90E24 (single phase)
Product brochure 90E32 (poly phase)
Product brochure 90E36 (poly phase)

The concept of the analogue frontend

Electronic meters basically consist of a data acquisition unit, a unit for storing and processing the voltage and power readings and communication interfaces for exchanging data.

Practice has shown that it is useful to separate data acquisition and processing into two separate ICs, as this provides manufacturers with better flexibility when it comes to choosing preferred CPU architectures and allows the further use processing algorithms which have been developed for years.

IDT’s metering ICs therefore integrate all required functions for acquiring analogue values and for conditioning and filtering, and offer a powerful serial interface (SPI) for transferring the values to a host-CPU. As an analogue frontend, they hence fulfil all tasks required for acquiring physical values such as voltage, power, phase position, effective and apparent power, distortion (or, as the case may be, harmonics) with the statutory precision and repeatability, and leave communication and storage tasks to the downstream CPU.

IDT offers reference circuits and development systems for single phase and polyphase metering ICs, incl. layout data and operating & calibration software to permit swift and easy implementation of these modules into smart meters.

Article about Metering Ics from IDT