The Study Of Diesel Multiple Unit600V Power Excitation System

In the modern transport system, diesel locomotive is the main force of the rail transport for un-electrified railway lines. In terms of running flexibility and comfort, the contemporary Diesel Multiple Unit (DMUs) have made great progress in operating performance, ride comfort and environmental protection. DMUs can run on non-electrified lines, as well as on the electrified railway lines. Stable operation of power supply systems of DMUs ensures operating performance and comfort. Among the measures those improve stable operation of the generators. The use of modern control theory for excitation control system has been recognized as an economic and effective way.The excitation control system of DMUs power supply systems’plays a significant role in keeping stable output voltage of the generators. In this thesis, the600V power supply and the correspondent excitation system of DMUs are investigated. Hereby the power supply system possesses a TPZ25constant-voltage exciter which delivers exciting current to the generator, such that a600V,200～400KW power source is ensured despite the variant load. This is vital to the safe operation for the air-conditioning system of the train.Major work accomplished in this thesis include:Firstly, a detailed analysis is represented regarding the control mode and features of the TPZ25excitation systems. The phase-controlled rectifier excitation for constant voltage regulation is applied and realized in order to overcome the drawbacks of the current excitation systems. This scheme is a direct excitation. It’s faster in response than the original indirect excitation. By comparing with excitation control used in commerce, we can get advantages of the control scheme applied in this thesis.Secondly, to further improve the performance of the excitation system, nonlinear control methodologies are studied and utilized in this thesis. The direct feedback linearization method is applied to the DMUs excitation control system. With this method, the nonlinear dynamics of the excitation systems can be cancelled and the entire system appears a linear unit, such that the well-developed linear control strategies, e.g. pole placement, can be applied. Simulative studies verify the feasibility and superiority of the applied control scheme.