A method and device for controlling the output voltage of a dc/dc converter

Abstract

The invention provides a method and a device for controlling output voltage of a DC (direct current) / DC converter. The control method comprises steps as follows: a corresponding first judgment value of output voltage and a corresponding second judgment value of output voltage are acquired respectively according to a real-time temperature value of a low-voltage storage battery and a real-time SOC (state of charge) value of a high-voltage power battery; whether the real-time SOC value of the high-voltage power battery is larger than a set threshold is judged, if yes, the first judgment value of the output voltage is taken as a set instruction value of the output voltage, and otherwise, a smaller one of the first judgment value of the output voltage and the second judgment value of the output voltage is taken as the set instruction value of the output voltage; whether the set instruction value of the output voltage is in a voltage regulating range of the DC / DC converter, if yes, the set instruction value of the output voltage is taken as the output voltage of the DC / DC converter, and otherwise, an upper limit value or a lower limit value of the voltage regulating range of the DC / DC converter is taken as the output voltage of the DC / DC converter. The output voltage of the DC / DC converter can be intelligently adjusted according to the characteristics of the high-voltage power battery and the low-voltage storage battery.

Description

technical field [0001] The invention relates to the technical field of new energy vehicles, in particular to a method and device for controlling the output voltage of a DC / DC converter. Background technique [0002] The DC / DC converter is the core component of the application in the field of new energy vehicles, and is used to replace the traditional generator to provide 12V low-voltage system power supply. The DC / DC converter is the link connecting the high-voltage power battery and the low-voltage battery. To control the DC / DC converter, it is necessary to comprehensively consider the characteristics of the high-voltage power battery and the low-voltage battery. [0003] Currently, the control method of the DC / DC converter is relatively simple, and a common control method is to set a constant voltage output. Since the chemical properties of low-voltage batteries, such as lead-acid batteries, are significantly affected by the ambient temperature, the charging characteristi...

AI Technical Summary

Problems solved by technology

Since the chemical properties of low-voltage batteries, such as lead-acid batteries, are significantly affected by the ambient temperature, the charging characteristics have different requirements under different ambient temperature conditions. The constant output voltage of the DC / DC converter charges the low-voltage battery without consideration of the ambient temperature. It is easy to have a great impact on the service life of the battery

Similarly, when the SOC (State of Charge, state of charge) of the high-voltage power battery is insufficient, its chemical characteristics will deteriorate, and the power performance of the vehicle will be affected, while the DC / DC converter is always working, and power reduction cannot be achieved under constant voltage output mode, it will further accelerate the decline of the SOC of the high-voltage power battery, which will affect the service life of the high-voltage power battery

[0004] At present, there is a lack of a control strategy that takes into account both the high-voltage power battery and the low-voltage battery, and comprehensively considers their use characteristics.

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