Development Of Control Unit For Pure Electric Vehicle

Vehicle control unit of pure electric vehicle was chosen to be the object of the study. Base on the analysis of the functional requirements of vehicle control unit, this paper mainly analyzed the principles and prototype development of pre-charge module, isolated power supply module, discharge module, current and voltage detection module, and insulation resistance detection module of vehicle control unit. Loop control logic of high voltage, control logic of insulation resistance detection and fault treatment logic was studied and developed.Insulation resistance detection method was the part of the paper. Base on access to national standards and relevant articles, this article deeply analyzed the various situation of insulation failure and the location of the greatest leakage current and established a high-voltage system insulation resistance detection model. A new method to realize insulation resistance detection via insulation voltage detecting was proposed.High-voltage input circuit of motor controller and other devices was in control of Pre-charge module and main contactor. The switched condition of high-voltage input circuit for motor controller was determined by developing loop control logic of high voltage. Control logic of insulation resistance detection was developed, and insulation resistance detection was launched by comparing the voltage between positive and negative bus and ground. Fault treatment logic was developed to determine the working of vehicle control unit under each fault.Commissioning of vehicle control unit was finished in laboratory. Function of each module and relevant experiment data all meet with design requirement.