Research And Design Of Hybrid Active Power Filter For The Electrified Railway

Along with the rapid development of the electrified railway, manyAC-DC electric locomotives have been used widely. The traction loadspollute the power quality and getting worse. So the reactive current andharmonic content was high in the loads, which is asymmetry andvolatility, caused adverse effects on the power grids and communicationlines, even lead to accidents or damage to equipments. Therefore, it’snecessary to deal with the electric power system harmonics, which is notonly an important guarantee for the safety operation of power grid, butalso a great means to enhance the efficiency in use of energy.This paper firstly studies the causes and characteristics of tractionpower system harmonics, and then compares the topological structures ofAPF, and gives a suitable scheme of using sigle-phase parallel hybridactive power filter to compensate the harmonics. It will overcome thepoor performance on compensation and real-time shortcomings. Beforethe design, a HAPF simulation model has been builded to verify the filterbased on Matlab/Simulink. Secondly, this paper analysis of the d-q harmonic detection algorithmand its application in single-phase circuit, based on the three-phaseinstantaneous reactive power theory, and then proposes an algorithmcalled sliding window iterative FFT-Pruning. It based on the Fourieranalysis method and its fast algorithm, and combines the characteristicsof harmonic analysis on electric power supply system, which willimprove the efficiency of DSP processing.Then this paper take high performance DSP chips TMS320F2812andMCU chips dsPIC30F4012as the control of the core to complete thehardware circuit design of the APF, including power signal acquisitioncircuit, conditioning circuits, the inverter drive and protection, and CANcommunication circuit. It also completes the selection and matching ofmain circuit components parameters. Then it analyses the control strategyof APF，especially the control method of the current tracking and DCcapacitor voltage, and gives a suitable control strategies. This paperprogramming on the CCS3.3and MPLABC30platform, including DSPinterrupt response mechanism, AD sampling, data communication anddrive signal generation.Finally, an experimental prototype is introduced, and through testingand on-site high-voltage hanging experiment, the results and signal wavesare analyzed. The HAPF is proved to have a good performance onimproving power quality of the traction power system. At the last part of the paper, it gives the summary of the system and the direction of furtherstudy.