Low Resolution Stochastic Flash ADC for High Precision Energy and RMS Voltage Measurements for Smart Grid

This paper describes 4-bit Stochastic Flash ADC based instrument, with its low-resolution compensated by adding dither (uniform noise) to the input signal and calculation of the output average value over a finite time period, resulting in low part count, high sampling speed and low error. Precision of this instrument is user controlled - the longer the period of measurement, higher the measurement precision. This enables measurement of electrical quantities over long time intervals, such as electrical energy and RMS voltage in a power grid. For 60-second measurement period, precision is 58 ppm, and for 180 s it is 34 ppm.