The leading semiconductor components distributor dedicated to the Asia-Pacific market, Dalianda Holdings, announced that its subsidiary Youshang has launched a three-phase parallel meter solution based on STMicroelectronics (ST) STPMS2, STISO621 and STM32F413RH chips.
As one of the key end products of smart grid construction, electricity meter undertakes the task of raw electric energy data acquisition, measurement and transmission. Today, with the rapid development of Internet of Things technology and the strong support of national policies, electricity meters are widely used in various scenarios, bringing great convenience to the accurate collection of electricity. In this context, Dalian Dayou has launched a three-phase parallel smart meter solution based on ST STPMS2 metering front-end IC, STISO621 digital isolator and STM32F413RH MCU, which complies with EN 50470-x, IEC 62053-2x, ANSI12.2x AC meter standards, It can provide customers with accurate measurement performance while providing extremely high cost performance.
STPMS2 is a dual-channel 24-bit second-order sigma-delta regulator. It measures the voltage and current of each phase of AC power through on-board voltage divider and shunt sensors, and then uses a 4MHz synchronous clock pulse distributed by the microcontroller to pair the signal. Sampled and multiplexed to deliver a sigma-delta bitstream of voltage and current through one output pin. In this scheme, three STPMS2s need to be used to collect the voltage and current data of each phase.
STISO621 is a dual-channel digital isolator based on thick oxide galvanic isolation technology. The device provides two independent channels (in opposite directions, with Schmitt trigger inputs), which provide high noise immunity and fast input/output switching times. And the maximum data transfer rate of STISO621 is 100Mbit/s, the pulse withstand voltage (VIOTM) is up to 6000V, and the maximum repetitive isolation voltage (VIORM) is 1200V. Compared to traditional opto-isolators, STISO621 ensures faster data transfer, longer lifetime, and higher reliability.
The STPM32F413RH microcontroller integrates a sigma-delta modulation digital filter (DFSDM) that converts the six bit streams into 24-bit voltage and current values and calculates all metering data in real time every 200µs. The firmware also implements a virtual communication port for accessing internal parameters, reading metering data, modifying internal configuration and calibrating board functions.
Thanks to the excellent performance of the device, this solution can achieve extremely high reliability and robustness, and the optimally designed sensing circuit and PCB configuration can ensure the solution has excellent EMI immunity and excellent signal-to-noise ratio. , enabling high-precision measurement and post-processing operations. With this solution, customers can speed up the design of three-phase AC energy meters and meet the most stringent international energy meter quality and accuracy standards.
