A detection circuit and method for detection line disconnection

Abstract

The invention discloses a detection line drop detection circuit and method. The detection line drop detection circuit comprises a voltage-dividing insulation circuit, an upper bridge arm circuit, a lower bridge arm circuit, a first detection line, a second detection line, a switch circuit, the first voltage sampling circuit and a second voltage sampling circuit. Through connecting a first end of the switch circuit to a voltage division end of the upper bridge arm circuit, connecting a second end of the switch circuit to a first end of the voltage sampling circuit, connecting a second end of the voltage sampling circuit to a cathode of a high voltage bus, connecting a first end of the newly added first detection line to a voltage dividing end of the voltage-dividing insulation circuit and connecting a second end of the first detection line to a second end of the switch circuit, the on and off of different circuits can be controlled, the real-time detection of detection line drop is achieved according to a detected voltage value of the first voltage sampling circuit, and the effectiveness and safety of unbalanced bridge insulation detection are improved.

Description

technical field [0001] The invention relates to the technical field of insulation detection, in particular to a circuit and method for detection of disconnection of a detection line. Background technique [0002] At present, many vehicles use DC high-voltage equipment as the power source, such as the power battery of pure electric vehicles. The working voltage of these DC high-voltage equipment is as high as several hundred volts, and its voltage level has far exceeded the safe voltage level of the human body, which is safe for the human body. Therefore, the safety of high-voltage electricity must be considered first, and the insulation performance of the high-voltage electricity of the whole vehicle is one of the main problems of high-voltage electricity safety. If the insulation of the whole vehicle fails, one of the body will be electrified, which will cause hidden dangers to the personal safety of the drivers and passengers; the other will be a leakage current if the ins...

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Problems solved by technology

If the insulation of the whole vehicle fails, one of the body will be electrified, which will cause hidden dangers to the personal safety of the drivers and passengers; the other will be a leakage current if the insulation fails. Hazards of car spontaneous combustion and battery explosion

[0003] At present, the detection of the leakage of these DC high-voltage equipment is mainly realized by the unbalanced bridge insulation detection method. On the one hand, the existing unbalanced bridge insulation detection circuit cannot detect the disconnection of the insulation detection line. ; On the other hand, the method of using pulse width modulation (Pulse Width Modulation, PWM) to inject feedback to the insulation detection line needs to add circuit devices such as isolated power supply isolation sampler, the design is complicated, and the cost is relatively high

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