Control method for low-voltage power source management system of new-energy vehicle

Abstract

The invention discloses a control method for a low-voltage power source management system of a new-energy vehicle. Through DC / DC output voltage control, the braking energy recycling rate of the vehicle can be increased, and the driving comfort and safety of the vehicle can be improved; high and low voltage electric energy is reasonably distributed, and the travel mileage of the vehicle is prolonged. The method is mainly characterized in that the power source management system adjusts the DC / DC output voltage according to different work modes and the state of an accumulator SOC of the vehicle, and the purpose of whole vehicle power source management is achieved. The method includes the steps that firstly, an upper limit value SOC_TOP of the low-voltage accumulator SOC is set to be a, a ranges from 85% to 90%, a lower limit value SOC_BOTT of the low-voltage accumulator SOC is 80%, a bottom limit value SOC_DOWN of the low-voltage accumulator SOC is b, b ranges from 60% to 70%, the low-voltage accumulator is charged by increasing the DC / DC output voltage and discharged by decreasing the DC / DC output voltage through a whole vehicle control unit, and the accumulator SOC is controlled between SOC_TOP and SOC_BOTT. The method mainly comprises control methods in a static charging mode, a Key-on mode, a high-voltage electric energy lacking and braking mode and a fault mode.

Description

technical field [0001] The invention belongs to the technical field of DC / DC control for new energy vehicles, and in particular relates to a low-voltage power supply management system and a control system for new energy vehicles. Background technique [0002] With the mass application of automobiles in the world, serious environmental problems and energy crises have been caused. With the development of science and technology, energy-saving and environmentally friendly new energy vehicles are born, and their energy conversion, utilization, and management affect the energy-saving effect of the vehicle. [0003] The generator of a traditional vehicle is used as the main power supply of the vehicle, and its functions are as follows: first, it provides electrical energy for the electrical components of the vehicle; second, it provides electrical energy for charging the battery. Traditional generators convert mechanical energy into electrical energy, and the efficiency is general...

AI Technical Summary

Problems solved by technology

Traditional generators convert mechanical energy into electrical energy, and the efficiency is generally between 50% and 60%, and its low energy conversion rate results in partial energy loss

[0004] At present, the DC / DC of new energy vehicles works in a constant 14.5V voltage output mode. In this constant output voltage mode, it will cause the following problems: First, after the DC / DC works, the low-voltage battery is in a charging state for a long time, and the remaining power is high. (SOC) state of the low-voltage battery has no braking energy recovery and electric energy storage space for static charging of the vehicle; second, when the SOC of the power battery of a pure electric vehicle is close to 30%, the power battery provides power for the whole vehicle through DC / DC, which is not reasonable. Utilize the low-voltage electric energy stored in the low-voltage battery; third, there is a lack of failure strategies for the failure of the electrical components of the vehicle

For example, in the patent document with publication number CN101764512A, its DC / DC output voltage is only two voltage levels of 14.5V and 12V. If the DC / DC detects that its own output current is small, then adjust the CD / DC output voltage to 12V. When it detects that its own output current is large, adjust the DC / DC output voltage to 14.5V. This scheme does not formulate a DC / DC control scheme from the energy management of the vehicle and the performance of the low-voltage battery itself, and does not use the electrical power of the vehicle as the power motor brake. The workload during energy recovery, there is a case where the braking energy recovery rate is not high

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