Precharge control circuit and control method for high-voltage system of hybrid electric vehicle

Abstract

The invention provides a precharge control circuit for a high-voltage system of a hybrid electric vehicle. The precharge control circuit for the high-voltage system of the hybrid electric vehicle comprises a power battery pack, a main positive relay, a main negative relay, a precharge relay, a capacitor and a motor; one end of the main positive relay and one end of the main negative relay are correspondingly connected to the positive electrode and the negative electrode of the power battery pack, and the other end of the main positive relay and the other end of the main negative relay are connected with the motor; the capacitor is connected to both ends of the motor in parallel; the precharge relay is connected with a precharge resistor in series and then connected to both ends of the main positive relay to form a parallel circuit; and a shunt is arranged between the parallel circuit and the positive electrode of the power battery pack. Meanwhile, a precharge control method using the precharge control circuit is provided. According to the precharge control circuit and the control method for the high voltage system of the hybrid electric vehicle, through the current value collected by the shunt and the current slope value in the interval time, whether precharging of the high voltage system is completed or not is judged, the method is simple, the high voltage part does not need to be introduced into a BMS, and the safety is high.

Description

technical field [0001] The invention relates to the control field of hybrid electric vehicles, in particular to a pre-charging control circuit and a control method of a high voltage system of a hybrid electric vehicle. Background technique [0002] With the growth of population and economy, energy and environmental issues have prompted countries to develop new energy vehicles, energy-saving and environment-friendly vehicles. Hybrid electric vehicles are energy-saving and environmentally friendly, and have a broad market space and good development prospects. [0003] A hybrid vehicle is powered by an engine that consumes petroleum fuel and controls a motor driven by electricity supplied from a power battery pack. Hybrid electric vehicle power battery packs are usually composed of multiple batteries stacked in series, and a typical power battery pack is about several hundred volts. As a power component that controls a strong electric signal with a weak electric signal, a rel...

AI Technical Summary

Problems solved by technology

The damage of the high-voltage relay, such as adhesion, has a great potential safety hazard, which will cause damage or injury to the vehicle, passengers, and vehicle maintenance personnel

The current method of judging whether the pre-charging of the high-voltage system is completed is to first close the total negative relay and the pre-charging relay, and then the BMS collects the total voltage of the battery pack and the voltage at both ends of the capacitor, and compares the difference. When the difference is less than a certain value, Determine the completion of the pre-charging process and close the high-voltage system. This method needs to collect the total voltage signal of the battery pack, and the high-voltage signal detection line for collecting voltage signals needs to be directly connected to the BMS detection circuit. During the maintenance of the battery pack, If you forget to turn off the maintenance switch (MSD) of the battery pack, it may cause maintenance personnel to touch the high-voltage signal detection line and get an electric shock, which poses a certain safety hazard

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