STMicroelectronics EVALSTPM-3PHISO Evaluation Board

STMicroelectronics EVALSTPM-3PHISO Evaluation Board features a complete three-phase energy meter with cost-effective shunt current sensors. The solution is based on the STPMS2 double-channel, 24-bit second-order sigma-delta modulator, measuring current and voltage for each phase through a voltage divider and a shunt current sensor. The sensing circuitry and PCB layout are optimized to maximize the signal-to-noise ratio for accuracy. The STMicroelectronics STPMS2 oversamples the signal using a 4MHz clock synchronized by the microcontroller and outputs voltage and current sigma-delta bitstreams multiplexed on the same pin. The two-wire communication between the STPMS2 modulator and the MCU is isolated by STISO621W, a 6kV galvanic isolated interface, allowing up to 100Mbps rate and low pulse distortion (< 3ns) for fast and safe data transfer between isolated domains.

Features

Compliant to EN 50470-x, IEC 62053-2x, ANSI12.2x standard requirements for AC watt meters
Active wideband, active fundamental, reactive and apparent power/energy calculation for each phase and cumulative
Accuracy Class 0.5 according to IEC 62053-22 on 3-ph active/apparent power measurement
Accuracy Class 1 according to IEC 62053-21 on 3-ph reactive power measurement
6 channels voltage and current decimated samples available at 200µs
RMS and THD (optional) calculation of each voltage and current signal

5kHz measurement bandwidth
Selectable high-pass filter for DC measurement
Line period and phase shift measurement for each phase
Phase voltage delays
Full calibration (amplitude, power offset, and samples offset for DC measurement)
2x configurable LEDs for pulsed outputs
Communication through USB in virtual com port mode with shell commands
6kV galvanic isolation between phases with 8mm creepage and clearance