Sampling rate converter with line frequency and phase locked loops for energy metering

A device connected to a power distribution network, comprising:

• sensing circuitry configured to receive an analog poly-phase signal associated with power delivered using alternating current (AC) over the power distribution network, wherein the analog poly-phase signal having at least one current component and at least one voltage component comprising a reference voltage component;
• a processor configured to execute computer-readable instructions;
• and
• a memory configured to store the computer-readable instructions that, when executed by the processor, cause the processor to perform operations comprising:
• converting, using an analog to digital converter (ADC), the analog poly-phase signal to a digital poly-phase signal sampled at a first sampling rate;
• detecting a fundamental frequency of the analog poly-phase signal based on the digital poly-phase signal;
• determining a second sampling rate, wherein the second sampling rate is based on and tracks the fundamental frequency;
• resampling the digital poly-phase signal at the second sampling rate;
• for each cycle of the resampled digital poly-phase signal:
• transforming the resampled digital poly-phase signal to a frequency-domain signal using Fast Fourier Transformation (FFT);
• calculating a phase angle of the reference voltage component based on the frequency-domain signal;
• adjusting the resampled digital poly-phase signal by compensating the calculated phase angle;
• and
• transforming the adjusted resampled digital poly-phase signal to an updated frequency-domain signal using FFT;
• and
• calculating one or more measurements based on the updated frequency-domain signal.

An electronic energy meter, comprising:

• a sensor configured to receive an analog poly-phase signal associated with power delivered using alternating current (AC) over a power distribution network, the analog poly-phase signal having at least one current component and at least one voltage component comprising a reference voltage component;
• an analog to digital converter (ADC) configured to convert the analog poly-phase signal to a digital poly-phase signal sampled at a first sampling rate;
• and
• a power signal processing unit connected to the ADC and configured to:
• detect a fundamental frequency of the analog poly-phase signal based on the digital poly-phase signal;
• determine a second sampling rate, wherein the second sampling rate is based on and tracks the fundamental frequency;
• resample the digital poly-phase signal at the second sampling rate;
• for each cycle of the resampled digital poly-phase signal:
• transform the resampled digital poly-phase signal to a frequency-domain signal using Fast Fourier Transformation (FFT);
• calculate a phase angle of the reference voltage component based on the frequency-domain signal;
• adjust the resampled digital poly-phase signal by compensating the calculated phase angle;
• and
• transform the adjusted resampled digital poly-phase signal to an updated frequency-domain signal using FFT;
• and
• calculate one or more measurements based on the updated frequency-domain signal.