State-Space Modeling of an Open-Loop Conversion Chain in Electric Vehicles

The development and increase in the use and reliance on electric vehicles as an alternative to vehicles that depend on fuel make us care about the basic parts that depend on their operation in a typical way. From here, one of the important elements whose task is to convert the energy stored in the battery to the engine and vice versa is the conversion chain. In view of mentioning the conversion chain, it mainly consists of two main power electronics stages: a bi-directional DC-DC converter, and DC-AC inverter. With this intention, one of the most popular types of DC-DC converters is selected for this study which is the CUK converter, alongside the most popular and reliable DC-AC inverter type which is the Voltage Source Inverter (VSI). Taking advantage of the strengths and features of the model-based method, it will be the most suitable choice for the objective to be used for improving the efficiency of the EVs by investigating the faults that impact the conversion chain and attempting to detect, identify, diagnose or prognose, and understand the cause of their occurrence. In this paper, the state-pace method is used to model the CUK converter and the VSI, to obtain a global model of the chain and the model is verified using MA TLAB script. The script code is used to elaborate a diagnosis/prognosis approach and the results are compared against the equivalent circuit that was built using MATLAB/Simulink which represents a real system.