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Research On Three-Phase Voltage PWM Rectifier And Control Strategies

Posted on:2012-06-15Degree:MasterType:Thesis
Country:ChinaCandidate:W J XuFull Text:PDF
GTID:2212330338966543Subject:Power electronics and electric drive
Abstract/Summary:PDF Full Text Request
The circuits of traditional diode rectifier and phase controlled rectifier are simple reliable,low cost, but a lot of harmonics and reactive power are injected into the system,and cause serious power pollution, or even damage the electrical equipment. But as a new generation of rectifier devices, the PWM rectifier has a lot of advantages such as high power factor operation,the grid current approach to sine wave,stable voltage output on the DC side, low current harmonic pollution and energy feedback, thus, the application of PWM rectifier becomes more and more extensive, and it becomes the one of the hotspots in the area of power electronics.The object of study of the paper is three-phase PWM rectifier. Three-phase voltage source rectifier (VSR) is usually controlled by dual closed-loop control scheme, and the key to achieve the high performance is the current control. This paper mainly researches on several current control methods through simulation, and gives analysis and comparison results. Firstly, the thesis introduces the principle of PWM rectifier and the topology of VSR, then derives the mathematic models in three-phase stationary coordinate, two-phase stationary coordinate and two-phase synchronously rotating coordinate of the three-phase PWM rectifier under balanced supply conditions.Secondly, three control methods of three-phase VSR under balanced supply conditions, include current hysteretic control, voltage space vector control and variable frequency hysteretic SVPWM control are introduced in this dissertation, include the principle,the simulation model and simulation results analysis.Finally, the thesis introduces the principle and the topology of three-phase VSR, and then derives the mathematic model under unbalanced supply conditions. Meanwhile, two kinds of controlling scheme for PWM rectifier under unbalanced conditions, including:the AC current control method aiming to inhibit the AC side negative sequence current, and dual current control scheme aiming to eliminate the harmonics of the dc link voltage are analyzed .In addition, the paper presents the principle, the simulation model and simulation analysis in the condition of Matlab/Simulink of these two methods.Simulation results show that, the three-phase voltage style PWM rectifier in this paper can run with a high power factor, achieve two-way power transmission and realize the stable control of direct current voltage. Practical theoretical and control method can be obtained through simulation analysis and research to PWM rectifier under balanced and unbalanced conditions.
Keywords/Search Tags:PWM rectifier, hysteretic loop, SVPWM, negative sequence current, dual current control
PDF Full Text Request
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