Distributed photovoltaic power supply PV configuration and power limit value setting method based on life estimation

Abstract

The invention discloses a distributed photovoltaic power supply PV configuration and power limit value setting method based on life estimation, and belongs to the technical field of power electronic application. The method comprises the following steps: S1, establishing a mathematical model of a photovoltaic system; s2, changing photovoltaic array configuration and a power limit value; s3, calculating power loss considering PV configuration and a power limit value; s4, calculating the junction temperature of the IGBT and the capacitor; s5, calculating the service lives of the IGBT and the capacitor considering PV configuration and a power limit value; s6, comparing the service life of the IGBT and the service life of the capacitor, and selecting the smaller one of the two as the service life of the photovoltaic inverter; and S7, comparing the calculated service life with a system service life requirement, outputting Ks and Rs if the calculated service life meets the system service life requirement, returning to S2 if the calculated service life does not meet the system service life requirement, and recalculating after changing the Ks and Rs values to finally obtain a group of Ks and Rs values. According to the method, a group of PV configuration and power limit values meeting the service life requirement can be selected according to the system requirement, the PV configuration and the power limit values are set, and the reliability of system operation is ensured.

Description

technical field [0001] The invention belongs to the technical field of power electronics applications, and in particular relates to a distributed photovoltaic power supply PV configuration and power limit setting method based on life estimation. Background technique [0002] Photovoltaic systems have accounted for the largest share of all renewable energy investment for nearly a decade, and as PV module and installation costs fall, a greater proportion will be connected. Photovoltaic inverter is a key component of photovoltaic system. In order to reduce the cost of photovoltaic power generation and improve the competitiveness of solar power generation, higher requirements are put forward for the reliability of photovoltaic inverter. However, as an indicator for evaluating the cost of a photovoltaic system, the two goals of maximum power generation and the actual life of the inverter are mutually restrictive. In this case, special consideration needs to be given to the design...

AI Technical Summary

Problems solved by technology

However, with the continuous growth of photovoltaic grid-connected systems, the power grid is facing many challenges. Even if the MPPT mode is maintained within the rated power range, system overvoltage, serious degradation of switching devices, high light rejection rate and load fluctuations will occur. Therefore, the traditional MPPT can no longer meet the requirements. For this reason, a variable power point tracking (Variable Power Point Tracking, VPPT) control method with a variable tracking direction of the photovoltaic operating point is proposed. By adopting a variable power limit The method solves the problem that the inverter design is too large or insufficient, and improves the reliability of the inverter, but it will cause a decrease in the utilization rate of the photovoltaic inverter

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