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Study On The Engineering Problems Of Grid-connected Converters For Wind Power Generation

Posted on:2007-03-08Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q ZhangFull Text:PDF
GTID:1102360182486700Subject:Power electronics and electric drive
Abstract/Summary:PDF Full Text Request
It is a focus of attention of the world energy industry for improving the energy structure, utilization of renewable energy, reducing environmental pollution and improving power quality. Wind energy is one of the new and renewable resources that have the most favorable development prospect and exploitation technologies are most advanced at the present time. With the development of the exploitation and utilization of wind energy, wind energy technology also have marked progress, and become an embranchment of energy technology. This paper mainly study the voltage source grid-connected inverter and relative technology used in wind power generation system. The main contents of this paper are as follows:1. The characteristics and construct of three-phases voltage source grid-connected inverter is analyzed. A mathematical model for the inverter used in wind power grid-connected systems is established by using Matlab/Simulink.2. According to different out-filter used in grid-connected inverter, different current control strategy by using different variable is compared. This paper proposes a robust strategy for regulating the grid current entering grid from a three-phase VSI system connected via a T-filter. The control strategy integrates a loop bridge current regulator with grid current and voltage feed forward to stabilize the system. Theoretical results of the analysis and simulation are experimentally verified.3. To make the harmonic elimination PWM control inverter be of a good sine wave output by taking the converter characteristic of instantaneous and stability into consideration. The low-pass filter network is used to the inverter circuit. The filter, typically a series inductance, acts to reduce the switching harmonics entering the distribution network. An alternative filter is a T-filter, which can achieve reduced levels of harmonic distortion at lower switching frequencies. But it make instability is bring to system by using a T-filter. This paper proposes a step-by-step procedure for designing the T-filter of a front-end three-phase inverter. Anemulation model for T-filter design is built and tested using different values of parameter from this design. The experimental results demonstrate the performance of the design procedure both for the T-filter and for the inverter controller4. The main circuit of high power inverters used in wind power grid-connected system is studied in the paper. According to the characteristics of 1GBT, the driver circuit of IGBT is designed. The Engineering method ,by which the power, current and resistance of driver circuit is calculated, is given. For Based on the analysis of the snubber-circuit, the paper investigates the protect problem of IGBT inverter. The Engineering design procedure of suitable parameter for snubber-circuit is discussed in the paper.6. The experimental variable speed constant frequency wind power generation system of110KVA has been put into use. The design including hardware and software is discussed inthe paper. Final the performance of filter and the control strategy was verified by experimentalresults.
Keywords/Search Tags:grid-connected inverter, current control, T-filter, subber-circuit, Current harmonic
PDF Full Text Request
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