Photovoltaic charger control system and method based on temperature feedback

Abstract

The invention relates to a photovoltaic charger control system and method based on temperature feedback. The control system comprises a temperature acquisition unit, a PWM adjustment amount determination unit, a PWM adjustment module, a master output current acquisition module, a reference PWM generation unit and a PWM drive unit. The control method includes the steps that temperature values of DC / DC power modules are compared with a preset state temperature value and corresponding processing is carried out; if at least one temperature value larger than a temperature adjustment threshold value exists, mean values, high-end mean values and low-end mean values of the temperature values are calculated and compared to determine the power modules which need to be adjusted and the power modules which do not need to be adjusted; PWM adjustment amount corresponding to the distinguished power modules is figured out, and reference PWM is adjusted so that all the power modules can be driven. According to the photovoltaic charger control system and method, output duty ratios driven through the corresponding DC / DC power modules are adjusted through temperature feedback, the temperatures of the power modules are balanced, and therefore charging performance of a photovoltaic charger is improved.

Description

technical field [0001] The invention relates to the field of photovoltaic charger control, in particular to a photovoltaic charger control system and method based on temperature feedback. Background technique [0002] Photovoltaic charger is an important device for connecting photovoltaic power generation equipment and energy storage devices (such as batteries, etc.), and plays the role of energy conversion and intelligent management of batteries. [0003] Usually, photovoltaic chargers are designed to be used in direct parallel or interleaved parallel connection of multiple power amplifier modules due to the consideration of structural volume, installation operation, power expansion, etc., which will have the problem of current sharing. The deviation of the power supply and the length of the driving line will cause the deviation of the current, resulting in the deviation of the temperature of the power devices in each power module, and the power devices usually have tempera...

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Problems solved by technology

[0003] Usually, photovoltaic chargers are designed to be used in direct parallel or interleaved parallel connection of multiple power amplifier modules due to the consideration of structural volume, installation operation, power expansion, etc., which will have the problem of current sharing. The deviation of the power supply and the length of the driving line will cause the deviation of the current, resulting in the deviation of the temperature of the power devices in each power module, and the power devices usually have temperature limits, such as field effect transistors, IGBTs, diodes, etc. Higher temperature will shorten the service life of the power device and affect the charging performance of the charger. If the temperature exceeds the allowable operating range, it is easy to cause the breakdown of the above power device and cause damage to the charger.

[0004] Regarding the control of the temperature of power devices in a photovoltaic charger with multiple power amplifier modules connected in parallel, the usual practice is to first collect the temperature of all power amplifier modules, and then obtain the highest temperature through the hardware circuit and output it to the DSP for power reduction or over-temperature protection. , other temperatures are not sent to the DSP for sampling; or all the sampling temperatures are input to the DSP to calculate the precise temperature value of each channel, and the highest temperature is used for power reduction or over-temperature protection through software comparison, and high temperature power reduction And the over-temperature protection is to reduce the total output power, which will cause many low-temperature power amplifier modules to derate output, or because of the over-temperature protection of a certain power amplifier module, other low-temperature power amplifier modules will also stop working, which will lead to waste of energy

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