The Research On Signal Detecting And Output Control Method Of Power Conditioner For Railway Power Supply System

With the rapid development of China's high-speed railway,the power quality problems of electrified railway power supply system are more and more attention.However,most of the railway lines in our country are in the situation of two kinds of locomotive(AC-DC locomotive and AC-DC-AC locomotive)mixed run,the problems such as negative sequence,harmonic and reactive are particularly prominent,seriously affect power system security.Hence,taking effective control measures against the problems of electrified power supply system has very important significance for security and stability development of China's railway in the direction of high-speed and heavy-duty.This paper studies the research status of traction power quality compensation device,and the RPC(Railway Static Power Conditioner),which can implement active power two-way flow between the two power supply arms,is chosen as the research object.Then based on Scott transformer traction power supply system,the topology,working principle,voltage,current and power flow relationship of the RPC comprehensive compensation system is introduced.A new sign command current detection method based on FBD(Fryze-Buchholz-M.Dpenbrock,FBD)theory is proposed,to active the negative,harmonic and reactive components isolated from the total signal,and improve the flexibility of the RPC compensation target.At the same time,the tradition lower-pass filter is replaced by the integral average filter to speed up the detection.In order to enhance the response speed and tracking precision of current tracking control,a compound control method composed of hysteresis loop and PR(Proportion Resonance)control is presented.Ease the contradiction between the current tracking accuracy and speed of response.It always cause the DC-link voltage in overshoot at the moment of RPC put into system,thus,a compound PI control,which composed of conventional PI controller and VAPI(PI Controller with Variable Arguments)controller,is presented.The new control method eliminate the voltage overshoot and current impact issues.Simulation results verify the effectiveness of two compound control methods.To verify the RPC comprehensive compensation effect for negative sequence,reactive and harmonics,three common operating conditions of traction powersupply system are simulated in Matlab/simulink,and the results confirm the validity of RPC.Finally,the overall structure of design of RPC is established.And IGBT module selection method,design methods of turns ration and capacity,output inductance and DC-link capacitor are presented.The hardware and software design methods of the control system is introduced,the peripheral controller circuit of DSP,the main program and interruption program design methods are introduced.It will lay the foundation for the other follow-up works.