This application note describes the fast digital calibration procedure for STPMC1 energy meters, which is more effective and innovative than the traditional calibration procedure.
This document outlines a fast digital calibration procedure specifically designed for energy meters based on the STPMC1 device. The STPMC1 functions as an energy calculator and is an ASSP designed for effective energy measurement in power line systems utilizing Rogowski coils, current transformers, and shunt or Hall current sensors. When used in combination with one or more STPMx ICs, it implements all functions needed in 1, 2, or 3-phase energy meters.
The procedure allows for reduced calibration time and enables calibration parameters to be written permanently, eliminating the need for re-calibration. The document integrates information from application note AN2299 and provides specific calibration calculations for the STPMC1 device, covering working point settings, algorithm choices, offline parameter calculations, online procedures, and coherency checks.
| Voltage nominal value (Vn) | 230 V |
|---|---|
| Current nominal value (In) | SA |
| Voltage calibrator ideal value (PM=0) | 0.875 |
| Voltage calibrator ideal value (PM=1) | 0.9375 |
| Current calibrator ideal value (PM=0) | 0.875 |
| Current calibrator ideal value (PM=1) | 0.9375 |
| Internal voltage reference (Vref) | 1.23 |
| Gain of decimation filter (Kint_comp) | 1.004 |
| Gain of integrator (50 Hz) | 0.815 |
| Gain of integrator (60 Hz) | 0.679 |
The advantages include reduced calibration time and no need for re-calibration as the calibration parameter can be written in a permanent way.
This application note integrates the AN2299 application note for the STPMC1 metering chip.
The STPMC1 is designed for effective energy measurement in power line systems utilizing Rogowski coil, current transformer, and Shunt or Hall current sensors.