Research On Harmonic Suppression Of Electrified Railway Based On Hamiltonian System

Due to the rapid development of electrified railways,electric locomotives are constantly evolving.In addition to the traditional DC drive electric locomotives in the used,there are many AC drive electric locomotives that become the main models.The working principle and control method of the AC drive locomotive are quite different from those of the traditional DC drive locomotive,and the corresponding current harmonic characteristics are also very different,but they also have bad effects to on the power quality.Due to the two different types of electric locomotive existing at the same time,the harmonic current analysis and treatment of the electrified railway become more complicated.Therefore,the harmonic current of the electrified railway is obtained from the modeling of the electric locomotive,and then the active filter based on the Hamiltonian system theory is designed to solve the harmonic problem of the electrified railway.The main work carried out in this paper is as follows:1)Establish the MATLAB/Simulink locomotive simulation model with analyzing the working principle of the AC-station electric locomotive SS9 and the AC-DC-AC electric locomotive CRH2.For the SS9 electric locomotive,the harmonic current characteristics of different voltage regulation stages are analyzed according to the change of the rectification voltage regulating circuit.The model of CRH2 electric locomotive made with three-level PWM rectifier,three-level inverter and three-phase asynchronous motor,while using instantaneous current direct control,SVPWM modulation,and rotor fixed magnetic field control.And the harmonic current characteristics of the traction side are analyzed.2)Introduced the Hamiltonian system theory,analyzed the Hamiltonian system control theory and the controller's method.According to the circuit structure of the active filter to control the electrified railway harmonics,the port-controlled Hamiltonian system model of the active filter is obtained,and the closed-loop control of the active filter is realized by using the port-controlled Hamiltonian control principle.The control mode of the source filter.Combined with the single-phase detection method based on instantaneous reactive power theory,the MATLAB/Simulink simulation model of the active filter is designed.3)For the first time,the active filter based on Hamiltonian system control theory is used to control the harmonics of electrified railways,and the MATLAB/Simulink simulation model for harmonic suppression of electrified railways is established.The SS9 electric locomotive model,the CRH2 electric locomotive model and the locomotive mixed running model are respectively used for harmonic suppression by the filter.According to the simulation experiment results,the detected harmonic current characteristics are analyzed and the effects of electrified railway harmonic suppression are examined.