Safety Assessment Of Electromagnetic Exposure For High Voltage Power Cables Of Electric Vehicle

With the advancement and development of related technologies such as power electronics,motor drives,and battery control,electric vehicles have become a hot spot in the automotive industry in recent years.Due to the power driven by electric power driven of electric vehicles,and the increase of motor power and driving mileage,the voltage and current value of the battery pack is also increased.The electromagnetic environment inside the car has become more and more complex.When enjoying the convenience of pure electric vehicles,people are also particularly concerned about whether the complex electromagnetic environment in the electric car compartment poses a threat to human health.Firstly,the thesis briefly expounded the development history of electric vehicles in Europe and the United States and other major developed countries,and the gratifying achievements of the domestic battery electric vehicle industry.The basic principles of the main power components of battery electric vehicles and the electric drive system were introduced.Through analysis,the main sources of electromagnetic disturbance in the electric vehicle were defined,which provided a reliable basis for simulating the electromagnetic environment inside the car.In order to effectively evaluate the influence of the electromagnetic environment in the car on the human body,the three-layer human models of the driver and the passenger suitable for finite element analysis were established using a three-dimensional CAD modeling software.Then,a simplified car was established with reference to a real car model.Secondly,the battery electric vehicles have different speed grades,and the steady-state DC current flowing through power cables is also different.In this thesis,the DC bus power cable was used as the electromagnetic excitation source.By applying the steady-state DC current and harmonic current,the steady-state magnetic field generated by the power cable in the compartment and the influence of the harmonic electromagnetic field on the human body of the driver and the passenger were respectively simulated.By changing the excitation current of the power cable of the model,the magnetic induction intensity induced by the power cable current in the human body during the three different operating phases of the low speed,high speed,and maximum operating current of the electric vehicle were simulated,then the magnetic induction intensity of the human body was calculated.Battery electric vehicles were accompanied by harmonic currents in the power cables during the driving.The distribution of electromagnetic fields in human tissues was obtained by applying harmonic currents to the power cables.Finally,by comparing the calculated distribution of electromagnetic fields in human tissue with the ICNIRP reference level,the safety assessment was performed.The results showed that the higher the current flowing through the power cable,the higher the magnetic induction intensity in the human tissue.Under the three different operating conditions,the magnetic induction intensity of the human body and head tissues in driver and passengers were all lower than the ICNIRP reference level.The electric field intensity,magnetic field strength,current density,and magnetic induction intensity generated by the harmonic current of the body and head tissues in driver and passengers were all lower than the ICNIRP reference level.The magnitude of the electromagnetic field induced in the body tissue by the current in the power cable was closely related to the spatial position of the power cable.The electromagnetic exposure generated by the steady-state DC current and harmonic current of the power cable would not pose a threat to the human health.