A grid-connected inverter and its dead zone phase shift compensation method

Abstract

The invention provides a grid-connected inverter and its dead zone phase shift compensation method. The calculation of the phase shift caused by the beat: determine the switching cycle of the grid-connected inverter; determine the dead zone time of the grid-connected inverter; determine the grid-connected inverter The number of delayed switching cycles required for the generation of the inverter PWM drive signal; the calculation of the lag phase shift caused by the switching cycle beat; the calculation of the phase shift caused by the dead zone: determine the expected output voltage frequency of the grid-connected inverter; determine the modulation degree of the grid-connected inverter ; Obtain the leading phase shift of the expected output voltage fundamental caused by the dead zone; calculate the total phase shift of the expected output voltage fundamental; fundamental phase shift compensation: obtain the phase of the target phase voltage component in the αβ coordinate system; rewrite the target phase voltage in the αβ coordinate system Component phase: call the SVPWM or SPWM program in the grid-connected inverter control program to generate the grid-connected inverter drive signal for grid-connected. The invention is beneficial to the accurate phase control of the grid-connected inverter, and has the advantages of simplified method, clear logic, improved 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...

AI Technical Summary

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

Images