IEC class 0.5 electronic watthour meter implemented with first-order sigmadelta converters
This paper presents a design of a precise electronic watthour meter implemented with first-order sigmadelta analog-to-digital converters. An efficient digital signal-processing circuit is introduced into the design where the whole signal processing is performed directly on an oversampled signal, eliminating the necessity for a decimation filter. It is shown that Gaussian noise, added to the input signal of sigmadelta modulators, decorrelates quantization error of first-order sigmadelta modulators and thus substantially reduces measurement error at low-signal amplitudes. The effect of added noise is analyzed by extensive behavioral simulations for various input signal amplitudes and for various input noise levels. The results show that IEC accuracy class 0.5 can be achieved with first-order sigmadelta converters and digital signal processing in the sigmadelta domain.
sigmadelta modulation digital signal processing digital filters electrical energy measurement mixed-mode simulation noise analysis