Apparatus and methods for power quality measurement

摘要

A method for measuring characteristics of a power line signal having a fundamental frequency is provided. The method includes estimating the fundamental frequency of the power line signal, and generating a sampling clock that is substantially synchronized to the estimated fundamental power line frequency. The power line signal is sampled with the substantially synchronized sampling clock to generate data samples that include one or more substantially complete cycles of the power line signal. The data samples are processed to detect zero crossings of the power line signal, and the detected zero crossings are used to calculate an r.m.s. voltage of the power line signal measured over one full cycle, commencing at a zero crossing, and refreshed each half-cycle. Other aspects are also provided.

主权项

1. A method for measuring characteristics of a power line signal having a fundamental frequency, the method comprising:
estimating the fundamental frequency of the power line signal using a digital signal processor coupled to an analog-to-digital converter sampling the power line signal; generating a sampling clock based on the estimated fundamental power line frequency using a clock generator coupled to an output of the digital signal processor to receive a control signal from the digital signal processor representative of the estimated fundamental frequency of the power line signal; sampling the power line signal with the sampling clock using the analog-to-digital converter after generating the sampling clock with the clock generator, to generate data samples that include one or more complete cycles of the power line signal; using the digital signal processor to process the data samples to detect zero crossings of the power line signal; and using the detected zero crossings to calculate a U_rms(½) value, the r.m.s. voltage of the power line signal measured over one full cycle, commencing at a zero crossing, and refreshed each half-cycle.