Monitoring isolation in at least one High Voltage (HV) system present in an Electric Vehicle (EV) by calculating a leakage ratio as Vpack/Vi, wherein Vpack is the voltage of a vehicle battery and Vi is input voltage to a differential amplifier. A leakage resistance is determined using the calculated leakage ratio, and the leakage current as Vpack/leakage resistance. At least one action is performed if the leakage current has crossed pre-defined thresholds. The system comprises a series resistor chain having two high value resistances and two low value resistances, a power supply 602, a differential amplifier 603, an ADC (Analog to Digital Converter) 604, an isolator 605, and a controller 606. The high value resistances are connected to the positive and negative terminals of a battery 601. The low value resistances are connected across inverting and non-inverting inputs of the differential amplifier and a junction of the low value resistances is connected to chassis of the EV. The differential amplifier monitors voltage difference between the inverting and non-inverting inputs. The ADC 604 converts the voltage difference into digital form and the isolator isolates digital data from output of the ADC.
Systems and methods for monitoring isolation in high voltage systems
2018-05-23
Patent
Electronic Resource
English
Isolation resistance monitoring for high voltage systems
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