Wide-frequency detection circuit and frequency tracking method thereof

Abstract

The invention provides a wide-frequency detection circuit and a frequency tracking method thereof. The circuit comprises a wide-frequency signal source, a high-frequency filter circuit, a voltage conversion circuit, a comparison circuit and a programmable processor, wherein the wide-frequency signal source is used for inputting an alternating-current voltage signal and applying the alternating-current voltage signal to the input side of the high-frequency filter circuit; the high-frequency filter circuit is used for filtering high-frequency interference of the alternating-current voltage signal and outputting the filtered alternating-current voltage signal to the voltage conversion circuit through the output side; the voltage conversion circuit outputs a low-voltage signal to the comparison circuit and the programmable processor, the comparison circuit compares the input low-voltage signal and generates a comparison pulse signal, and the comparison circuit outputs the comparison pulsesignal to the programmable processor so as to control a timer in the programmable processor to work. The method provided by the invention adopts the circuit to track the signal frequency. According tothe invention, the power grid frequency can be monitored on line in real time, and target tracking feedback control is carried out by taking the power grid frequency as a reference standard.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a wide frequency detection circuit and a frequency tracking method applied to the circuit. Background technique [0002] Due to the uncertainty of access to the grid load and the access of a large number of distributed energy sources, the grid frequency will fluctuate, which is a great challenge for power electronic equipment that relies on grid frequency for control. Therefore, a technology that adapts to wide voltage frequency is particularly important for the use of power electronic equipment. [0003] In the prior art, for example, a zero-crossing detection circuit whose patent application number is CN201821470201 mainly includes a sampling circuit and an amplifying circuit. A sampling circuit for sampling the power supply voltage to obtain a zero-crossing signal at the same frequency as the power supply; the input terminal is connected to the sampling circuit, and...

AI Technical Summary

Problems solved by technology

Especially when the frequency is switched from 45Hz to 65Hz, the frequency change rate reaches 44.4%, it is difficult to have a set of coefficients that can satisfy the control stability at various frequencies

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