Three-phase two-level photovoltaic inverter DC overvoltage fault cause positioning method

• Main Authors: MENG XUESONG, MA MINGYAO, ZHANG XING, XU SHUIQING, XIONG PENGBO
• Format: Patent
• Language: Chinese; English
• Published: 08.06.2021
• Subjects: CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION; MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; SYSTEMS FOR STORING ELECTRIC ENERGY; TESTING

The invention discloses a three-phase two-level photovoltaic inverter direct current overvoltage fault cause positioning method, and belongs to the field of photovoltaic inverter fault diagnosis. The method comprises the following steps: sampling voltage and current signals before and after a fault of the photovoltaic inverter; obtaining an output voltage d-axis component and a grid-connected point three-phase line current q-axis component through calculation; and carrying out discrete wavelet decomposition reconstruction on the d-axis component of the output voltage to obtain a singularity judgment logic value, carrying out filtering and primary linear fitting on the q-axis component of the three-phase line current of the grid-connected point to obtain a curve trend judgment logic value, and finally, outputting a corresponding fault cause result according to fault judgment logic. The method can accurately judge the reason of the DC overvoltage fault of the photovoltaic inverter, and has the advantages of sim