CENTRALIZED MPPT EXITING AND SWITCHING METHOD AND APPLICATION THEREOF

摘要

A method for exiting a MPPT centralized mode of a photovoltaic inverter including a plurality of DC chopper circuits and an inverting circuit is provided in the present disclosure. The method includes: performing a MPPT control individually on each of photovoltaic strings to obtain a maximum power point for each of the photovoltaic strings, when the photovoltaic inverter is operating in the MPPT centralized mode, wherein the photovoltaic strings are connected in parallel to the DC bus via DC chopper circuits which stop operating; determining a standard value for the maximum power points of the photovoltaic strings according to the type of the plurality of DC chopper circuits; and determining whether voltage differences between the voltages of the maximum power points and the standard value exceed a preset voltage difference, and restarting DC chopper circuits connected to photovoltaic strings with voltage differences exceeding the preset voltage difference, to achieve both a high conversion efficiency of the whole system and a high MPPT efficiency. A method for switching MPPT centralized modes and related applications are further provided.