Load on-off control system and its control method, electric vehicle

Abstract

The invention discloses a load on-off control system and its control method, and an electric vehicle, wherein the load on-off control system includes a high-voltage battery pack, a contactor circuit, a first voltage acquisition circuit, a second voltage acquisition circuit and a control circuit. A voltage acquisition circuit and a second voltage acquisition circuit respectively acquire the ground voltage of the input end of the contactor circuit and the voltage across the high-voltage battery pack, when the voltage change of the input end of the contactor circuit to the ground voltage relative to the voltage across the high-voltage battery pack When the amount exceeds the first preset voltage threshold, it is determined that the contactor circuit successfully performs the switch switching action; when the input terminal of the contactor circuit to the ground voltage is within the first preset voltage threshold relative to the voltage change at both ends of the high-voltage battery pack, It is determined that the contactor circuit does not successfully perform the switch switching action, thereby improving the accuracy and reliability of detecting the contactor switch state.

Description

technical field [0001] The invention relates to the technical field of electric vehicles, in particular to a load on-off control system and a control method thereof, and an electric vehicle. Background technique [0002] With the country's strong support for new energy vehicles, the development of electric vehicles is becoming more and more rapid. The main source of power for electric vehicles is electricity, and the working voltage of the entire high-voltage circuit reaches several hundred volts. Whether the high-voltage contactor is properly engaged and disconnected will affect the safety of electric vehicles and drivers. [0003] The existing electric vehicle contactor state detection schemes include: [0004] (1) There is a small mechanical switch inside the contactor. When the main contact is closed, the auxiliary insulator squeezes the small switch to make it conduct. The external circuit detects the disconnection and pull-in state of the small switch to judge the mai...

AI Technical Summary

Problems solved by technology

[0008] (1) The detection method of the built-in auxiliary switch of the contactor: the circuit is complicated, the power consumption is large, the cost of the components used is high, and the reliability of long-term use is low

[0009] (2) The detection method of the voltage sampling at the back end of the contactor: When the positive and negative bus contactors fail to pick up during the high-voltage power-on process, it is impossible to accurately detect whether the positive bus contactor is not closed or the negative bus contactor Not sucked

[0010] (3) The external injection signal and the high-voltage signal are on the same road, which requires high safety distance and electrical isolation, and the cost of the isolation circuit is high. The contact impedance of the main contact has a great influence on the reliability of the judgment result, and the overall reliability is low.

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