Electromagnetic Pulse Effects And Suppression Technology Of Vehicle Sensors

As the integration of vehicle electronic information increases,fuel economy and mobility are improved,and electromagnetic interference risks also follow.In addition to natural sources of electromagnetic hazards such as lightning and static electricity,there are also man-made sources of electromagnetic hazards such as communications,radar,and electromagnetic pulse weapons.This also makes the electromagnetic pulse environment of vehicles increasingly complex.As a key component of the vehicle’s electronic control system,the sensor will be subject to consequences such as signal disturbances and device damage in the complex external electromagnetic environment,which will have a huge impact on the safety and reliability of the vehicle,especially on the battlefield.The harm of electromagnetic pulse weapons is even greater.Tactical vehicles that perform various special tasks need to improve their adaptability in the harsh electromagnetic pulse environment.Therefore,it is of great significance for the research of electromagnetic pulse effect and suppression technology of vehicle sensors.In this paper,a certain type of high-pressure common rail diesel engine bench is used as the test object,and the high-power microwave effect test of each sensor of the engine is carried out,and the Hall speed sensor such as crankshaft and camshaft is determined as the key research object.Combining the working principle and test data analysis,the electromagnetic pulse effect of the Hall speed sensor is studied from the sensor induction and transmission processes.Based on the test results,the vehicle sensor electromagnetic pulse protection circuit design and the suppression material performance verification test are carried out.The main research contents are as follows:(1)Test and analysis of electromagnetic pulse effect of vehicle sensors.Set up a highpressure common rail diesel engine electromagnetic pulse irradiation environment.Based on the disturbance of each sensor and the time-frequency domain characteristics of the interference signal under the engine sensitivity threshold,it is determined that the Hall speed sensor is the key research object,and the device selection for the subsequent protection circuit Provide data support.(2)Research on electromagnetic pulse effect of Hall-type speed sensor.Starting from the induction process,set up the electromagnetic pulse irradiation environment of the AH3503 Hall element and the conditioning circuit,and compare and analyze the disturbance of the AH3503 analog signal and the conditioned digital signal under the electromagnetic pulse.The result shows that the root cause of the output disorder is induction.In the process,the analog signal is disturbed and deformed to produce convex pulses.Starting from the transmission process,build a group pulse injection test platform to obtain sensor sensitivity thresholds and fault signal waveforms,and study the influence of electromagnetic pulses on the output waveform during transmission,as well as the relationship between pulse repetition frequency and sensitivity thresholds and transient mutation thresholds.The results show that when the electromagnetic pulse acts on the transmission process,the sensor output waveform will be disturbed,and the sensitivity threshold will decrease as the pulse repetition frequency increases and is at the lowest value at 400 k Hz.(3)Vehicle sensor electromagnetic pulse suppression technology.Starting from the radiation coupling approach,based on the shielding principle of the absorbing material,a sensor absorbing suppression scheme is proposed,and the absorbing suppression ability is verified through the electromagnetic pulse irradiation test.Starting from the conduction coupling approach,the protective performance test of the protective device and its combination is carried out.Based on the test results,the electromagnetic pulse protection circuit of the active sensor of the vehicle is designed.The attenuation value of electromagnetic pulse interference signal reaches 16 d B.The main contributions and innovations of this paper include:(1)An electromagnetic pulse effect analysis method based on the two processes of sensor induction and transmission is proposed.By analyzing the influence of the broadband and high-power microwave environment on the AH3503 Hall element and the conditioning circuit,it is determined that the sensor output disorder is caused by the electromagnetic pulse acting on the induction process,which leads to the deformation of the analog signal.Through EFT pulse injection into the signal line and power line of the Hall speed sensor,the relationship between the electromagnetic pulse parameters and the sensor sensitivity threshold during the transmission process is analyzed,and the results show that the sensitivity threshold will decrease with the increase of pulse repetition and finally stabilize.(2)This paper proposes a sensor electromagnetic pulse suppression scheme that takes the two interference coupling paths of radiation and conduction as the breakthrough point.The conduction coupling suppression scheme combines the characteristics of the sensor’s working signal and interference signal to design an active sensor electromagnetic pulse protection circuit that combines power limiting,pulse absorption and filtering,and attenuates the electromagnetic pulse interference of the wiring harness by 16 d B.The radiation coupling suppression scheme shields the sensor harness and connectors with shielding materials,and at the same time arranges absorbing materials on the surrounding metal surface to absorb the reflected energy of electromagnetic pulses.The test results show that this scheme can increase the engine sensitivity threshold by 8k V/m.