The invention discloses a method for improving the
electric energy measuring and sampling precision. The method comprises the following steps that multi-periodic-wave sampling is conducted on alternating-
current voltage and current signals, sampling values are accumulated to acquire an average value,
fast Fourier transform (FFT) is conducted according to the sampling average value, a real part value and an imaginary part value of a
voltage phasor and a real part value and an imaginary part value of a current
phasor are calculated, the square of the real part value of the
voltage phasor and the square of the imaginary part value of the
voltage phasor are added, the square of the real part value of the current phasor and the square of the imaginary part value of the current phasor are added,
software gain multiple amplification and extraction are conducted to obtain a Um value and an Im value, 4<n+2> Um values and 4<n+2> Im values are continuously sampled and then subjected to bubble sorting from large to small to acquire 4<n> values, the 4<n> values are accumulated and then shifted rightwards by n bits, a M-bit
oversampling value is obtained, and then the ADC sampling resolution ratio precision is improved. According to the method, an expensive ADC does not need to be adopted, the hardware cost is low, and the ADC sampling resolution ratio bit number can be increased; the anti-disturbance performance of the
system is high, and the measuring precision is high; the method is easy to achieve, accurate and reliable in data and capable of meeting the requirements of an industrial
electric energy meter.