A three-voltage power supply system for automobiles and its control method

Abstract

The invention relates to a power supply for an automobile, in particular to a three-voltage power supply system for the automobile and a control method thereof. The system comprises a 12 V power supply unit, a 48 V power supply unit, a 300 V power supply unit, a DC / DC convertor Z1 and a DC / DC convertor Z2; the low-voltage end of the DC / DC convertor Z1 is in electric connection with a 12 V power supply of the 12 V power supply unit, and the high-voltage end of the DC / DC convertor Z1 is in electric connection with a 48 V power supply of the 48 V power supply unit; the low-voltage end of the DC / DC convertor Z2 is in electric connection with the 48 V power supply, and the high-voltage end of the DC / DC convertor Z2 is in electric connection with a 300 V power supply of the 300 V power supply unit; the three-voltage power supply system control method comprises the steps of power supply step-by-step preheating at a low temperature and power supply charging and discharging control based on SOC. By means of the three-voltage power supply system for the automobile and the control method thereof, the problems that the current in a low-voltage power supply circuit inside the automobile is overlarge, the specific fuel consumption is too high due to the fact that engine matching is too large and discharging of vehicle-mounted lithium ion batteries are difficult in a cold area are solved.

Description

technical field [0001] The invention relates to a power supply used in automobiles, in particular to a three-voltage power supply system for automobiles and a control method thereof. Background technique [0002] At present, the development of automobiles is facing four problems: first, due to the severe situation of energy consumption and environment, new energy vehicles have become an important direction for future transportation development; second, lithium-ion batteries have poor low-temperature characteristics and are not suitable for discharging at low temperatures; The third is that in order to meet the power requirements when the vehicle is matched with the engine, the engine displacement is often selected too large, causing the engine to often not work in the high-efficiency working area, and the fuel consumption rate is high at this time; the fourth is that the degree of electrification of automobiles continues to increase Correspondingly, the electric power demand...

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Problems solved by technology

[0003] Aiming at the above problems, the present invention provides a three-voltage power supply system for automobiles and its control method, which overcomes the excessive current in the low-voltage power supply circuit in the automobile, the high fuel consumption rate of the engine due to matching problems, and the on-board lithium-ion battery in cold regions. Difficult to discharge, contribute to the development of new energy vehicles

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