| With the rapid progress of science and technology,China’s high-speed rail industry is also making breakthroughs.It has been ranked first in the development of high-speed rail technology in the world,and has been admitted by many countries.At the same time,the safety requirements of EMU trains are getting higher and higher.It is particularly important to use voltage-withstanding test equipment to test the performance of track cable for EMU train.In order to detect the insulation performance of track cable more accurately and comprehensively,a variable frequency power supply with good performance can not be separated from a voltage withstand test.It is very important that a variable frequency power supply with excellent performance can detect the insulation performance of cable more accurately for the voltage withstand test equipment.This thesis studies a variable frequency withstand voltage test power supply,and provide a control core with excellent performance for detecting the series cable withstand voltage test equipment of the track cable,and realize the conversion of the power frequency three-phase 380V/50 Hz AC power into the voltage required for the withstand voltage test.Value,complete series resonance withstand voltage test.This design takes the actual project as the premise background,and studies a frequency conversion test power supply based on DSP digital processor as the control core.Based on the analysis and understanding of theoretical knowledge,this thesis firstly introduces the theoretical principle of variable frequency power supply,and mainly studies the main circuit,rectifier circuit and inverse circuit of power supply.By analyzing the principle of SPWM modulation wave,a regular sampling method suitable for this design is proposed to generate SPWM pulse signal wave.In this paper,the main circuit and driving circuit of variable frequency power supply are introduced in detail.Through analysis and calculation,the hardware components of variable frequency power supply system are selected.Finally,a set of more suitable and perfect design ideas and control strategies are put forward.In this thesis,not only the hardware circuit design is studied in detail,but also the design idea,control strategy and software of the variable frequency power supply are discussed.The mathematical model is established and the digital PID optimal control scheme is put forward.The design of this thesis mainly studies the high frequency and high voltage test power supply based on TMS320F28335 digital processor.It adopts the sinusoidal pulse-width modulation(SPWM)technology control strategy,which simplifies the main circuit of the variable frequency power supply and improves the accuracy,stability and reliability of the control circuit.It include SPWM waveform forming program,SPWM variable voltage software implementation,PID control algorithm program and AD data acquisitionprogram.Finally,the software and hardware design of the frequency conversion control system based on TMS320F28335 DSP is realized,and the language programming of the control strategy proposed in this paper is realized by CCS software tools.At the end of the thesis,the MATLAB simulation software is used to simulate the frequency conversion test power rectifier circuit,inverse circuit and SPWM waveform pulse.The reliability,practicability and theoretical analysis of the design circuit are verified by simulation.Finally,the actual verification of the experimental demonstration is carried out through the physical construction,debugging and application.It is proved that the variable frequency power supply system developed under the control strategy of this design has good steady and dynamic performance,and can well realize the insulation performance test of the EMU track cable withstand voltage test equipment. |
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