Research On The State Detection Circuit Of Electric Vehicle Power Battery Pack

In the present,automobile industry,the level of electric vehicle development has been further improved.One of the core technologies in the development of electric vehicles is to detect the status of the internal battery pack.However,due to the slow development of domestic technology and few studies on such problems,the battery status detection circuit should be developed independently at the request of the manufacturer.Based on the research status in China,a circuit which can detect the status of the power battery of electric vehicles is designed.The detection of current,temperature and voltage can be realized to ensure that the electric vehicle will not cause serious safety accidents due to inaccurate estimation of battery status during normal operation.Based on the ASMC 0.5 m 60 V BCD process design for automotive electronics,the battery status detection circuit mainly includes four parts: state acquisition front end,multiple selector,power management circuit and ADC.The current and temperature of the battery are detected by hall sensor and temperature sensor respectively,and the corresponding interface circuit is designed for the two sensors to complete the conversion of two physical quantities,current and temperature,to analog voltage signals.In order to select the high voltage information of the battery and the analog low voltage signal of temperature and current conversion,the multiplexer designs the high voltage switch and low voltage switch respectively,and selects the battery state information into the ADC by closing and disconnecting the switch.The power management circuit is based on the structure of linear voltage stabilizer,and the combination of pre-stabilizer circuit and negative feedback loop is adopted to improve the power supply voltage suppression ratio of the circuit,and the soft start circuit is designed to ensure the power supply safety of the power management circuit.The incremental Sigma Delta ADC modulator is designed and simulated on a transistor-level circuit in order to convert analog signals from the multiplexer.Simulation results of multiplexer show that the multiplexer can switch between high and low voltage channels.The simulation results of power management circuit show that the circuit can achieve the conversion of voltage from 40 V to 5V,and the effect of power voltage suppression ratio enhancement circuit is good.Incremental Sigma Delta ADC simulation results show that when the sampling rate is 256 SPS,the signal noise ratio of the modulator is about 103.5dB,and the effective digit is 16.90bit...