| The deterioration of air quality and the appearance of the energy crisis have accelerated the development of new energy vehicles.As a member of the new energy vehicles,the extended-range electric vehicle is equipped with a range extender on the basis of a pure electric vehicle.It can be driven not only by a motor like a pure electric vehicle but also can work with a range extender when the batteries’ power is low,which has overcome the shortcoming that a pure electric vehicle can only drive a short distance.In an extended-range electric vehicle there are a large number of high-power devices,such as batteries,an ISG,and motors.The cables connecting these high-power devices are high-voltage or high-current,which makes the electromagnetic environment in the vehicle more complex.This paper focuses on the features of cable bundles in the extended-range electric vehicle.There are high-voltage and low-voltage cables,strong-current and weak-current cables and the number is huge.In this paper,firstly a transmission line model is established to calculate the exact crosstalk value.Secondly,for the problem of long calculation time and memory occupation in the simulation of the full harness model,a reduction technique is adopted..Finally,the fuzzy inference method is used to predict the crosstalk value caused by a strong current cable inside an extended-range electric vehicle.This paper introduces the working principle of the extended-range electric vehicle and the complex wiring inside.After that,two frequency-domain models are established:inductive-capacitive crosstalk model and the distributed-parameters model of multiconductor transmission line.Using the image method,the unit-length inductance matrix and the unit-length capacitance matrix are deduced.Then a simulation by CST software is used to verify the accuracy and applicable conditions of these two models.According to the characteristics of the wiring harness of the extended-range electric vehicle,the models with strong-current source and high-voltage source as the excitation source are established.Each parameter that may affect the crosstalk value is analyzed one by one,and the graph of the crosstalk value changing with each parameter is obtained through simulation.According to the conclusions obtained,some measures can be taken to reduce the crosstalk value.By grouping the conductors according to certain rules,the complexity of the harness is reduced.Compare and analyze the crosstalk values achieved by CST simulation,and record the time and memory used for the simulation.The conclusion is that the crosstalk value in the reduced model is basically the same as the crosstalk value before using the reduction technique,but the time spent in the post-equivalent model simulation is greatly shortened,and the amount of computer memory used in the simulation process is greatly reduced.When it comes to practical projects,the method of fuzzy inference is used to predict the crosstalk value in the extended-range electric vehicle.According to the analysis of the factors that may affect the crosstalk,the main factors are determined.The original data is processed by the method of mathematical statistics to obtain the fuzzy relationship.When given an input,we will get the predicted value according to the relationship.This fuzzy prediction method does not require the establishment of a complex harness model.It mainly relies on experience and the accumulation of the early data.It provides a method for predicting crosstalk caused by Strong-current wires in an extended-range electric vehicle. |
