Plug-in hybrid electric vehicle battery system high-voltage precharging control method

Abstract

The invention discloses a plug-in hybrid electric vehicle battery system high-voltage precharging control method. The method includes the steps that S1, a main negative relay and a precharge relay arecontrolled to be closed, a main positive relay is controlled to be opened, and a load is powered on; and S2, after high-voltage precharging is finished, the precharge relay is controlled to be opened, the main positive relay is controlled to be closed, and high-voltage power-on is finished. By the adoption of the plug-in hybrid electric vehicle battery system high-voltage precharging control method, a precharging circuit is additionally arranged in a plug-in hybrid electric vehicle battery system, precharging diagnostic strategies are added to a BMS according to the precharging circuit designrequirements, the safety of the whole vehicle power-on process is more effectively controlled, the situation that the relays are damaged due to the too large current in the power-on process is prevented, the safety of the high-voltage precharging circuit is achieved, it is guaranteed that a plug-in hybrid electric vehicle is powered on normally, and safety and reliability are improved.

Description

technical field [0001] The invention belongs to the technical field of new energy vehicle power batteries, in particular, the invention relates to a high-voltage pre-charging control method for a plug-in hybrid vehicle battery system. Background technique [0002] Energy crisis and environmental development have become increasingly prominent social contradictions, and the development of new energy vehicles can effectively alleviate this contradiction; with the introduction of a series of policies and standards for new energy vehicles, the requirements for new energy vehicles are becoming more and more stringent , At the same time, the safety requirements of new energy vehicles are very strict. As the core part of new energy vehicles, the safety performance of batteries determines the performance and user reliability of new energy vehicles. [0003] According to the content requirements of electric vehicle and human body safety standards, under the condition that the maximum...

AI Technical Summary

Problems solved by technology

[0008] If there is no pre-charging circuit in the high-voltage pre-charged battery system, when the high-voltage power is turned on, the main positive and negative relays are directly closed with the capacitor C. At this time, the battery voltage is more than 300 volts, and the voltage at both ends of the capacitor C is close to OV, which is quite an instant short circuit. According to the ohm Law, bus current I=V / R1, R1 is megohm level, at this time I has exceeded the relay capacity, in this case, after power-on, the main positive and main negative relays are extremely easy to damage

[0009] The current commonly used technology is to add a buffer unit inside the motor controller, that is, add a buffer resistor inside the motor controller to realize the buffering effect at the moment of power-on; but this structure has many disadvantages and is easy to fail; when this buffer resistor When it fails, the main positive and main negative relays are directly connected, and a large inrush current is generated on the circuit at this time, and the main positive and main negative relays are easily damaged

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