Grid-connected inverter and dead zone phase shift compensation method thereof

Abstract

The invention provides a grid-connected inverter and a dead zone phase shift compensation method thereof. The dead zone phase shift compensation method comprises the steps of calculation of phase shaft cased by lagging by determining a switching period of the grid-connected inverter, determining dead time of the grid-connected inverter, determining the number of delay switching periods required for generating a PWM driving signal of the grid-connected inverter, and calculating the lagging phase shift caused by switching period beat; calculation of phase shift caused by dead zone by determiningthe expected output voltage frequency of the grid-connected inverter, determining the modulation degree of the grid-connected inverter, obtaining expected output voltage fundamental wave leading phase shift caused by a dead zone and calculating an expected output voltage fundamental wave total phase shift; and fundamental wave phase shift compensation by obtaining a target phase voltage componentphase under an alpha beta coordinate system, rewriting a target phase voltage component phase under an alpha-beta coordinate system, and calling an SVPWM or SPWM program in the grid-connected inverter control program to generate a grid-connected inverter driving signal for grid connection. The method is beneficial to accurate phase control of the grid-connected inverter and has the advantages ofbeing simple, clear in logic, capable of improving grid-connected control precision and the like.

Description

technical field [0001] The invention relates to the technical field of grid-connected inverters, in particular to a grid-connected inverter and a dead zone phase shift compensation method thereof, which are used for high-precision phase grid-connected grid-connected inverters. Background technique [0002] Grid-connected inverters are widely used in photovoltaic power generation, wind power generation and other application fields. As a grid-connected inverter (VSI) powered by DC voltage, when the working state of the upper and lower power switches of the same bridge arm is switched, it is necessary to set a sufficiently long dead Zone time, in order to prevent the bridge arm direct current short circuit caused by the power switch overcurrent damage. [0003] The addition of dead time will cause some problems that deviate from the ideal modulation. So far, the main concerns of people are: (1) Under the same modulation degree, the effective value of the fundamental wave of the...

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Problems solved by technology

[0003] The addition of dead time will cause some problems that deviate from the ideal modulation. So far, the main concerns of people are: (1) Under the same modulation degree, the effective value of the fundamental wave of the output phase voltage (or line voltage) drops, that is, the maximum voltage Utilization rate decreases; (2) The output phase voltage (line voltage) is distorted according to the average value of the switching cycle, that is, the actual output fundamental phase voltage (or line voltage) is distorted, causing distortion and phase shift of the grid-connected current ;

But up to the present, also do not appear above-mentioned corresponding compensation method, also do not find explanation or report with similar technology of the present invention, and similar data both at home and abroad

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