Research On The Comprehensive Compensation Of Power Supply System Based On Scott Transformer

Along with our country economy unceasing enhancement,people's travel demand growing,promoted the rapid development of railway in our country,the study of traction power supply system has become the focus,and phase-out of existing railway traction power supply mode,the three-phase unbalanced load of power grid caused by the serious negative sequence problem,although the railway traction substation adopts three-phase ac phase in sequence mode connection,still can't good to eliminate the negative sequence current impact on power grid side,at the same time,because our country most railway electric locomotive is used-straight and pay-direct-type mixed run mode,the use of power electronic equipment will produce a large amount of harmonic current and reactive power problem,at the same time,the conventional existing electric railway traction power supply system of the split phase problem,in the process of the electric locomotive running in case of phase splitting zone there will be a power outage this serious impact on the development of railway in the direction of high speed and overloaded,Therefore,it is very important to suppress harmonics in the same phase and compensate the reactive power,and maintain the three-phase balance of the power grid side.Paper firstly introduces two kinds of different ways of traction power supply,one is the conventional way of traction power supply,another is in phase traction power supply mode,compared the advantages and disadvantages and disadvantages of the two,considering the combined average filter rapid response performance and characteristic of the Scott transformer vice edge on both sides differ 90 the advantages of capacity utilization to 100%,and selection based on Scott traction transformer in phase of traction power supply mode,combined with the control of railway power regulator,the lateral load current researches on the reactive power and harmonic current compensation is given based on RPC Scott traction transformer topology structure and working principle of comprehensive compensation system,Scott traction transformer is expounded briefly from the perspective of compensation and the grid side voltage current relationship,and combined with the mean filter rapid response ability,replace single-phase PLL with average filter to obtain the measured voltage source unit is cosine signal source,thereby eliminating the early phase lock caused by phase deviation,improve the load side base wave active and fundamental reactive current and real-time performance,dynamic performance of RPC compensation goal provides accurate quick detection signal.Simulink simulation is verified,the results confirmed the two control methods and rational,at the same time the RPC compensation device in under the action of the above two kinds of control method,constructed the cophase traction power supply system for the traction of the analysis,the results show that the constructed based on RPC in phase of the control system of traction power supply technology is feasible and can be a very good finish of in-phase railway load side of the fundamental wave reactive current and harmonic current compensation,the output side only active current of three-phase power supply,greatly eliminates the single-phase three-phase unbalance and harmonic problems caused by the load,the RPC comprehensive compensation effect is good.Paper finally studies the RPC in the parameter design of main circuit components,and the design of the control system,especially the IGBT module selection,strain ratio and the output transformer capacity and the capacity of the dc side capacitor and the reference voltage for the parameters design.In addition,the hardware and software design of RPC system are briefly described in the last part.It is mainly the design of the peripheral circuit of DSP chip and the general situation of related procedures,which provides a reliable reference for future engineering applications.