Research On Electromagnetic Compatibility Of Speed Sensor Of Electric Locomotive

With the development of science and technology,China has entered a new area of high-speed railways,However,in view of the high-speed rail in the coexistence of high-power and weak electricity system,it was a severe test to achieve electromagnetic compatibility between the vehicle equipment,and to achieve the anti-interference of vehicle equipment.In the thesis I studied electromagnetic compatibility problem of speed sensor,especially speed sensor's cable shielding grounding and signal filtering anti-interference technique.Firstly I introduced the research background and then introduces the speed sensor of electric locomotive speed,electromagnetic interference theory,Focusing on the vehicle over-voltage disturbance and conducting a theoretical analysis,I measured the over-voltage of the motor train when it raised and lowered the bow at the scene,and I summarized the corresponding distribution law.In addition,I measured the differential mode disturbance pulses of the speed sensor on the EMU.Secondly,I introduced the basic theory of shielded cable grounding based on electric field shielding,magnetic field shielding and ground loop analysis.And on this basis,I conducted a simulation test based on the GB 17624.4 standard in the laboratory,and The grounding problem of the shielding layer of the speed sensor is studied.In the test pulsar disturbance source was used to simulate the overvoltage impulse group disturbance on the vehicle,and I measured differential mode disturbance pulses in different grounding modes of the shielding layer of the speed sensor.Then I calculated the corresponding cable time-domain shielding effectiveness,and analyzed the frequency domain characteristics of disturbance pulse.Moreover,considering engineering practice,I gave engineering recommendations.Then,I simulated the train speed signal and produced simulation signals of burst-pulse of speed sensor.Afterwards,I focused on the digital filter anti-interference technique of the speed sensor.I introduced the principle of minimum mean square error(LMS)filtering,and carried out the simulation of speed sensor LMS filtering.The simulation results showed that the LMS filter was not suitable for the filtering process of complex speed conditions due to the lack of expected response data of the LMS filter.In addition,I introduced the basic principle of Kalman filter,and established the Kalman filter model of the speed sensor.In order to improve the performance of one-dimensional(speed)Kalman filter,I proposed a method of estimating acceleration and acceleration rate of change based on least-squares curve fitting principle,then I applied the method to complex velocity conditions.In order to verify the performance of Kalman filter,I carried on the simulation research and studied the anti-inference performance of Kalman filter under different speed conditions.Then the laboratory simulation test data was used.All results have achieved good signal anti-interference effect.Finally,I summarized the whole thesis,and pointed out the existing problems,achievements,and future research directions.