Secondary Side Current Voltage Frequency Tracking Method in Isolated Grid Frequency Conversion System
A current voltage, frequency conversion system technology, applied in spectrum analysis/Fourier analysis, etc., can solve the problems of zero-crossing and fundamental wave zero-crossing deviation, frequency measurement error, affecting frequency measurement, etc., to achieve simple implementation and high anti-noise The effect of jamming ability and wide tracking frequency range
Active Publication Date: 2018-10-02
XIAN XIRE ENERGY SAVING TECH
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Problems solved by technology
The following problems will be encountered in frequency tracking: noise interference, fluctuations near the actual zero-crossing point, multiple false zero-crossing points, resulting in frequency measurement errors; the influence of high-order harmonics, the system signal often contains high-order harmonics , resulting in a deviation between the zero-crossing point and the fundamental wave zero-crossing point, which affects the frequency measurement
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Embodiment Construction
[0050] The present invention will be further described below in conjunction with the accompanying drawings.
[0051] The basic idea of the present invention is to use the fusion of wavelet packet decomposition and singular value decomposition to realize the effective extraction of partial discharge electromagnetic wave energy signals. The specific process is as follows:
[0052] 1. Initialize each variable
[0053] a) The sampling frequency of the acquisition system is fs, and the sampling interval is T s =1 / f s
[0054] b) Suppose the frequency of the fundamental component is f a , then the period is T a =1 / f a , the number of sampling points m in one cycle is m=T a / T s ;
[0055] c) The actual frequency is f;
[0056] 2. Read the time-domain waveform of the original signal and store it as an array x;
[0057] 3. Use the following formula to extract the fundamental component of the signal;
[0058]
[0059] Among them: n represents the position of the samplin...
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The invention discloses a current voltage frequency tracking method of a secondary side in an isolated grid frequency conversion system. The method comprises: (1), current voltage signals in an isolated grid frequency conversion system are collected by a sampling device at a sampling rate of 10kHz to 100kHz; (2), on the basis of Fourier transform, a fundamental component of a to-be-detected current voltage signal of a secondary side in the current voltage signals is extracted; (3), with a zero-crossing-point detection method, zero crossing points of the fundamental component of the to-be-detected current voltage signal at the secondary side are determined and the numbers of sampling points between the zero crossing points are recorded; and (4), according to the numbers of sampling points between the zero crossing points, an average sampling point number of one period is determined and the frequency of the to-be-detected signal is supposed to be 50Hz, and the frequency of the to-be-detected signal is obtained by using a frequency calculation formula. According to the invention, the method has the following advantages: firstly, the method has the high robustness and the wide frequency tracking range; and when the frequency is supposed to be 50Hz, the signal frequencies from 20Hz to 100Hz can be tracked normally; and secondly, the algorithm can be implemented simply; the measurement precision meets the standard; and the method has the excellent anti-noise interference capability.
Description
Technical field: [0001] The invention belongs to the technical field of electrical secondary system measurement, and in particular relates to a method for tracking the current, voltage, and frequency of a secondary side in an isolated grid frequency conversion system, which is used for tracking the current, voltage, and frequency of the secondary system. Background technique: [0002] In the electrical system operating in isolated grid, the system frequency will be operated with frequency conversion according to the working conditions of the electrical equipment, and the operating frequency range is between 30 and 60 Hz. Current, voltage, and frequency are still very important operating parameters, which are of great significance to system stability, safety, and efficiency, and reliable frequency measurement is a prerequisite for active power control, load protection, and system recovery. At the same time, the accuracy of the current and voltage sampling values and the cor...
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IPC IPC(8): G01R23/16
CPCG01R23/16
Inventor 赵煦兀鹏越冯仰敏
Owner XIAN XIRE ENERGY SAVING TECH