Method and device for obtaining AC signal parameters

Abstract

This specification provides a method and device for obtaining parameters of an AC signal; the parameters include the frequency f of the fundamental signal; the method includes: processing the AC signal with a hysteresis comparison circuit to obtain the first fundamental frequency f p ; Sampling the AC signal to generate a sampling data set {AD m}; and, for the sample data set {AD m} Perform discrete Fourier transform to generate the second fundamental frequency f s ; According to the first fundamental frequency f p , the second fundamental frequency f s and the frequency difference between the two determine the fundamental signal frequency f. This manual takes into account the inherent characteristics of using hysteresis comparator circuit processing and discrete Fourier transform processing to calculate the fundamental frequency, and through two methods of verification processing, the actual fundamental signal frequency f can be determined more accurately.

Description

technical field [0001] The present invention relates to the technical field of electrical signal detection, in particular to a method and device for acquiring AC signal parameters. Background technique [0002] For power supply systems such as diesel generator sets, in order to ensure that the output power meets the load requirements, a closed-loop control system needs to be formed between the power source and the generator. Taking the diesel generator set as an example, it detects the AC signal of the generator through the detection sensor, and uses the unit controller to analyze the AC signal and determine the AC electrical parameters of the generator (including the effective value of voltage or current, frequency and phase), And adjust the output characteristics of the diesel engine accordingly. The core parameters of the AC electrical parameters include the frequency of the fundamental wave signal; the accuracy of the detection frequency has an important impact on the su...

AI Technical Summary

Problems solved by technology

[0004] However, both of the aforementioned two methods have disadvantages: (1) the Fourier transform method has a fence effect; in order to make the calculation result meet a certain accuracy requirement, it is necessary to ensure a sufficiently high sampling frequency and a sufficient number of sampling points; and the sampling frequency and The increase in the number of sampling points will significantly increase the data processing time of the unit controller, which is difficult to meet the real-time requirements; in practical applications, the Fourier transform method will have errors; (2) by comparing the AC signal into a square wave for frequency The calculation method has high requirements on the voltage signal. When the amplitude of the AC signal is low, an effective square wave signal cannot be generated. big error

Images