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Research On The Control Strategy Of Three-Level PWM Rectifier

Posted on:2012-06-13Degree:MasterType:Thesis
Country:ChinaCandidate:D FangFull Text:PDF
GTID:2132330335451274Subject:Electrical engineering
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ABSTRACT:Multi-level PWM rectifier has been widely used in middle & high voltage and high power conversion field for some reasons, such as its little voltage stress afford by power devices, low harmonic components in input current, ablity to run at full power-factor and bidirectional power flow. Among many of its modulation strategies, Space Vector Pulse Width Modulation has been one of the most popular research points about multi-level PWM rectifier. Its main advantages are as follows: higher DC voltage utilization radio, larger under modulation range, significant flexibility to optimize switching waveforms and well suitable for implementation on a digital computer.The paper will study on the three-level PWM rectifier as following points:(1) We choose diode clamping three-level inverter as a study object, through the introduction of three kinds of circuits topology of multi-level inverter. We analysis the work principle of the circuit and indicate the advantages of three-level NPC inverter compared with the two-level inverter.(2) We analysis the SVPWM control method of three-level rectifier in detail. Firstly it introduces the basic principle of space voltage vector modulation. Then through detail analysis and calculation, the paper shows the method of judging the location of the reference vector and the formula of the basic vectors'action time and the action order. By this way we can get the realization way of SVPWM control method.(3) For the neutral-point balance problem of three-level clamping rectifier, we analysis the causes and propos a kind of neutral-point control method basic on distribution factor. Through simulation we prove the control method's feasibility.(4) For the requirement of LVRT by the Power Systems, we analysis the power falling on the impact of wind converter, and propose the power dissipative crowbar circuit to realize it. Through simulation we prove the circuit's feasibility.(5) This thesis simulates algorithm proposed with MATLAB. At last, I make a experimental platform for three-level inverter, complete the experiment which prove the viability of SVPWM control method.
Keywords/Search Tags:three-level PWM rectifier, space vector modulation, neutral-point balance control, low voltage ride through
PDF Full Text Request
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