How to use KM34 to meet class 0.2% active energy accuracy?

[geem-guanmian_x]

We are using KM34Z256 MCU in the product to measure the energy. 24-bit sigma-delta ADC is used for 3-phase current sampling and 16-bit SAR is used for 3-phase voltage sampling. Now the product meet class 0.2% current /0.2% voltage /0.5% active energy accuracy with default FW function blocks and basic calibration.

Is it possible to meet 0.2% active energy in this setup? What are the critical issues should be considered?

[geem-guanmian_x]

Hi,

Thank you for the reply.

We have already meet 0.5% active energy accuracy. I wonder to know if 0.2% accuracy is required, is it possible to meet for KM34, and what is the critical issue we should consider?

Best regards

GuanMian Xu

[Sebastian_Del_Rio]

Hi Xu, I hope you're doing well!

Could you please take a look at the documentation for the One-Phase and Two-Phase Power meter Reference Designs which support 0.2% accuracy? These also implement the KM34 MCU.

These are FFT based around the information in AN4255, FFT-Based Algorithm for Metering Applications, which can support Three-Phase Power Meters as well.

Please let me know if you need any more information.

Take care, best regards,

Sebastian

[Sebastian_Del_Rio]

Hi Xu, I hope you're doing well!

Could you please take a look at the KM3x Three-Phase Power Meter Reference Design found on our website?

It's pre-certified according to European EN50470- 1, EN50470-3, class B and C, as well as to IEC 62053-21 and IEC 62052-11 international standards for electronic meters of active energy classes 2 and 1.

As such, it is capable of achieving a Class C accuracy, which relates to a 0.5% accuracy.

It comes with a Software Package containing drivers and example code to configure and run the application, as well the configurations for ADC used in an IAR Embedded Workbench example project.

Please let me know if you need any more information.

Take care, best regards,

Sebastian