A dc/dc conversion circuit control method, device and photovoltaic inverter

Abstract

The application discloses a DC / DC conversion circuit control method, device and photovoltaic inverter. This method is applicable to each DC / DC conversion circuit in a photovoltaic inverter with multiple MPPT inputs, including: when the sum of the output power of all DC / DC conversion circuits does not reach the power limit value of the inverter circuit, obtain the The wafer junction temperature of the power switch tube inside the DC / DC conversion circuit; determine the power limit value corresponding to the interval of the wafer junction temperature; divide the variation range of the wafer junction temperature into multiple intervals in advance, and assign a power to each interval Limit value, the larger the value of the interval, the higher the corresponding power limit value; control the DC / DC conversion circuit of this channel to perform MPPT control without exceeding the currently determined power limit value. This application avoids the situation that when the sum of all DC / DC output powers does not reach the power limit value of the inverter circuit, some DC / DCs limit the power in advance, resulting in the loss of power generation.

Description

technical field [0001] The present invention relates to the technical field of power electronics, and more specifically, to a DC / DC conversion circuit control method, device and photovoltaic inverter. Background technique [0002] figure 1 It shows a photovoltaic inverter with multi-channel MPPT (Maximum Power Point Tracking, maximum power point tracking) input, which adopts a two-stage structure: the front stage is a multi-channel DC / DC conversion circuit (such as a boost circuit), and the rear The stage is an inverter circuit; the input end of each DC / DC conversion circuit is individually connected to several photovoltaic panels, and the output ends of all DC / DC conversion circuits are connected in parallel to the inverter circuit. [0003] In the above-mentioned photovoltaic inverter, each DC / DC conversion circuit independently performs MPPT control to maximize the output power of the photovoltaic panel connected to itself. At the same time, in order to ensure that the ...

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Problems solved by technology

[0004] However, since the orientation, position, and shading conditions of different photovoltaic panels may be different, and the number of photovoltaic panels connected to each DC / DC conversion circuit may also be different, this may lead to each DC / DC conversion circuit. If the output power of the inverter circuit is not the same, then it is possible that when the sum of the output power of all DC / DC conversion circuits has not reached the power limit value of the inverter circuit, some of the DC / DC conversion circuits have already started to operate with limited power. , resulting in loss of power generation

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