Electromagnetic Compatibility Research On Electric Drive System Of New Energy Vehicles

With the continuous development of new energy vehicles,their on-board electrical equipment is also increasing.Electromagnetic disturbance formed by electromagnetic coupling between electrical and electronic systems will lead to serious failures and functional degradation of new energy vehicles,and their electromagnetic compatibility has become an important issue affecting the functional safety of new energy vehicles.It is of great significance to ensure the safe driving of new energy vehicles and reduce or avoid faults.In this thesis,the electromagnetic compatibility performance of new energy vehicles is comprehensively analyzed and studied through theoretical analysis,simulation research and experimental verification.The main work is as follows:Firstly,based on the theory of three elements of electromagnetic compatibility,the motor drive system of new energy vehicles is determined as its main electromagnetic disturbance source.The Sinusoidal Pulse Width Modulation(SPWM)inverter circuit is established with Ansys electromagnetic simulation software Simplorer.Based on the actual new energy vehicle driving parameters,the parameters of the permanent magnet synchronous motor are designed and calculated,then the finite element model of the motor is established with Ansys electromagnetic simulation software Maxwell.The simulation results meet technical specification requirements for motor design.Then,the field circuit Co-simulation model of the motor drive system of new energy vehicles is established,focusing on the voltage and current output by the three-phase cable of the drive system.The current and voltage output are analyzed in time domain and frequency domain,and the harmonic component of the output current is calculated as 6.11%.According to the analysis of the simulation results,the three-phase current output by the drive system of new energy vehicles is the main disturbance source of the vehicle,and the SPWM inverter circuit is an important factor to generate harmonics in the drive system.Secondly,in order to study the vehicle radiation of new energy vehicles,this thesis builds a simplified model of three-phase cable and vehicle on the Maxwell software.The three-phase current output by the inverter is used as the excitation source to simulate and analyze the magnetic field distribution characteristics in the vehicle.Then,considering that harmonics also affect the magnetic field distribution in the car,different harmonic currents are also simulated as excitation sources.Finally,considering that the length of three-phase cable has different effects on the simulation results,1m and 2m cables are set for comparison.The simulation results show that the electromagnetic disturbance of the new energy vehicle drive system has a great impact on the electromagnetic environment in the form of electromagnetic radiation.Finally,in view of the large number of cables inside new energy vehicles,in order to solve the crosstalk coupling problem between drive cables and signal cables,theoretical analysis and test methods are adopted to focus on the shielded cable grounding method.In the time domain,a surge simulator is used to inject the impulse disturbance to simulate the influence of the impulse disturbance current of the vehicle strong electric equipment.In the frequency domain,the signal line test method of immunity to conducted disturbance induced by radio-frequency field is used to simulate the frequency domain disturbance of vehicle strong electric equipment.Finally,the basic principle of new energy vehicle wiring is obtained based on the test,which provides a certain reference for the new energy vehicle industry in cable wiring.