Adaptive online filter for DC offset elimination

摘要

A phase angle detector with a PLL, a power converter, and a method for reducing offsets in an input signal, in which an adaptive offset processor selectively removes a DC offset component from the input signal to generate a modified signal including a fundamental frequency component and higher order harmonics of the input signal with the DC offset component removed, and the PLL provides a phase angle signal at least partially according to the modified signal.

主权项

1. An adaptive offset processing apparatus, comprising:
an adaptive tracking filter having an adaptive passband defined by a frequency signal, the tracking filter being operative to remove substantially all frequency components of an input signal that are outside the passband to generate a fundamental frequency signal; a first summer operatively coupled with the adaptive tracking filter to subtract the fundamental frequency signal from the input signal to generate a first modified signal with a fundamental frequency component substantially removed; a low pass filter having a cutoff frequency, the low pass filter being operatively coupled with the first summer to remove substantially all high frequency components above the cutoff frequency from the first modified signal to generate a second modified signal including a DC offset component with the fundamental frequency component and higher order harmonics substantially removed; and a second summer operatively coupled with the low pass filter to subtract the second modified signal from the input signal to generate a third modified signal substantially including the fundamental frequency component and higher order harmonics of the input signal with the DC offset component substantially removed.