Acquisition circuit and method for improving acquisition precision of temperature sensor

Abstract

The invention relates to an acquisition circuit and method for improving acquisition precision of a temperature sensor. The acquisition circuit comprises a thermistor Rntc, an impedance Rx of a temperature sensing acquisition line and a pull-up resistor R1 which are sequentially connected in series between a grounding end GND and a power supply voltage end VDD; the VAD end is used for acquiring an AD voltage value Vad of the CPU end, and the end part of the VAD end is connected between the impedance Rx of the temperature sensing acquisition line and the pull-up resistor R1; a resistor R2 is connected with the two ends of the thermistor Rntc in parallel; a switch S1 is used for controlling the on-off of a branch circuit where the resistor R2 is located; the resistance value of the impedance RX of the temperature sensing acquisition line is firstly obtained, and then the accurate resistance value of the thermistor Rntc can be calculated according to the impedance RX of the temperature sensing acquisition line.

Description

technical field [0001] The invention belongs to the field of battery management systems for new energy vehicles, in particular to the field of circuits and methods for improving the acquisition accuracy of temperature sensors. Background technique [0002] As one of the core components of electric vehicles, the Battery Management System (BMS) has always been the focus of electric vehicle research and development; in the BMS system, the temperature sensor is generally used to collect the temperature of the charging socket or the temperature of the coolant inlet and outlet for thermal management, but During the long-term use of the connector and wiring harness connected to the temperature sensor, factors such as vibration, aging, condensation, etc. will likely appear: cause the temperature sensor connection line to loosen and fail: when the connection line is loose and faulty, it is equivalent to the temperature sensor collection line The impedance above becomes larger, and th...

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Problems solved by technology

[0002] As one of the core components of electric vehicles, the battery management system (BMS) has always been the focus of electric vehicle research and development; in the BMS system, the temperature sensor is generally used to collect the temperature of the charging socket or the temperature of the coolant inlet and outlet for thermal management, but During the long-term use of the connector and wiring harness connected to the temperature sensor, factors such as vibration, aging, condensation, etc. will likely appear: cause the temperature sensor connection line to loosen and fail: when the connection line is loose and faulty, it is equivalent to the temperature sensor acquisition line The impedance above becomes larger, and the extra impedance will be superimposed on the calculation result of the NTC's temperature resistance value, resulting in a large error in the temperature value after the table lookup. According to the law of the RT table of temperature sense, the larger the resistance value is The smaller the temperature value of the meter, the smaller the calculated temperature value will be when the actual temperature is already high, which will make the BMS system fail to diagnose the temperature of the charging socket or the water inlet and outlet. In fact, the temperature of the charging socket It is already very high, and the charging operation needs to be disconnected but not disconnected, resulting in extreme dangers such as fire, or the actual battery is still very hot and needs to continue cooling without continuing to cause the battery to overheat and cause extreme dangers such as thermal runaway

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