Drawing circuit for resistance in photovoltaic grid-connected inverter direct current side noise source and method

Abstract

The invention discloses a drawing circuit for resistance in photovoltaic grid-connected inverter direct current side noise source and a method. The drawing circuit comprises a direct current voltage source, a signal source, a current probe, a spectrum analyzer and a grid-connected inverter. A negative pole on the direct current side of the grid-connected inverter is connected with the signal source through a radio frequency cable. The signal source is connected to a negative pole of the direct current voltage source. A positive pole of the direct current voltage source is connected with a positive pole on the direct current side of the grid-connected inverter through a wire. Single current probe is arranged on the wire. The single current probe is connected to the spectrum analyzer. According to the fact that high-frequency noise signal voltage in a circuit detection circuit is drawn, resistance of the photovoltaic grid-connected inverter direct current side noise source and in a conduction electro-magnetic interference (EMI) frequency range (150KHz to 30 MHz) can be effectively drawn through the fact that high-frequency signal output frequencies of the signal power source are changed one by one. According to the drawing circuit for the resistance in the photovoltaic grid-connected inverter direct current side noise source, the conduction EMI noise characteristic analysis on the direct current side of the photovoltaic grid-connected inverter and design of an EMI filter are guided, and an effective theory solution is provided for solving of the problems of the conductive EMI on the direct current side of the photovoltaic grid-connected inverter.

Description

technical field [0001] The invention relates to a circuit and method for extracting the internal impedance of the DC side noise source of a photovoltaic grid-connected inverter, which provides theoretical support for the mechanism analysis and suppression of the conducted electromagnetic interference (EMI) noise of the DC power supply system in the power electronics application system, and belongs to New energy and electromagnetic compatibility technology field. Background technique [0002] With the increasing shortage of traditional energy and the serious environmental pollution caused by it, improving the energy structure, developing new energy, and improving the power quality of new energy have become the strategic goals of my country's energy development. At the same time, with the rapid development of power electronics technology, photovoltaic power generation and its grid-connected technology have been widely used, but the power electronic devices used in large quanti...

AI Technical Summary

Problems solved by technology

Therefore, the suppression of electromagnetic interference (EMI) noise emission is an important issue that must be considered in the design and manufacture of electrical and electronic equipment. At present, the conducted EMI noise suppression of the DC power supply system usually uses the empirical value method to design the conducted EMI filter. The empirical value method does not comprehensively consider the matching problem between the noise source impedance and the load impedance, so it is often difficult for the designed conducted EMI filter to have better filtering performance. There is no systematic and effective method for extracting the internal impedance of the noise source on the DC side of the transformer, so it is impossible to evaluate the impedance matching characteristics

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