Dissertation > Excellent graduate degree dissertation topics show

Research on Grid-connected and Seamless Transfer Techniques of Distributed Generation Systems

Author: ZhouYan
Tutor: DuanShanXu
School: Huazhong University of Science and Technology
Course: Power Electronics and Power Drives
Keywords: Distributed generation systems And network control The dual current closed-loop control Dual-mode operation control Seamless switching Proportional Resonant Controller delta operator
CLC: TM619
Type: Master's thesis
Year: 2009
Downloads: 397
Quote: 2
Read: Download Dissertation

Abstract

As people become increasingly prominent on the continuous improvement of the quality of power supply requirements and fossil energy crisis, distributed generation systems into the 21st century one of the most important direction of development of the power sector. As the interface between the distributed power grid and load power electronic devices have become an integral part of distributed generation technologies. This article is based on the three-phase grid system, focusing on analysis and power electronics-based network and switching control technology. Firstly, LCL-based three-phase grid-connected system of state space model, pointed out that the complex coupling relationship between the d-axis and q-axis in the rotating coordinate system, no coupling between the the alpha shaft and beta axis stationary coordinate system relationship. Filter characteristics and the resonance characteristics of the LCL filter, the difference in comparison with the L filter from the control angle, and on this basis the LCL filter is equivalent to low-frequency pole and a combination of high frequency pole helps a clearer understanding and analysis of the system. Based on the principle of damped harmonic peak based The LCL filter grid control strategy divided into three categories, which adds damping resistor to increase the filter impedance inhibition of resonance excitation source, the compensation filter resonant component. Stability margin, the controller robustness, the number of sensors, compared the advantages and disadvantages of the three types of methods. Different strategies stability margin analysis is verified by experiments. Detailed analysis of the grid current as the outer loop control, the capacitor current as the inner loop double current closed-loop control strategy, the strategy of the anti-grid disturbance, the robustness of the controller, the strength of the grid adaptation discussed. Based on incomplete pole configuration and pole-zero cancellation controller design method to obtain a set of optimal controller parameters. Experiments show that the introduction of the capacitor current inner loop filter can effectively compensate for the resonant component, and also shows the effectiveness of the controller design method. Existing dual-mode control strategy is designed and implemented based closed-loop control of dual-mode operation strategy. Only detected on the basis of three control the amount of double-loop control strategy in stand-alone mode and network operation mode to achieve both share the capacitive current inner loop to ensure that the two modes of the system has good stability , dynamic performance and anti-disturbance performance. From the process of switching to stand-alone mode and network mode by setting the current controller instruction zero, to accelerate the thyristor turn-off speed to ensure the system quickly from the continuity of the load voltage grid. In order to avoid the complexity of decoupling, select the control system in the stationary coordinate system, and the introduction of proportional-resonant (PR) controller AC signal steady-state tracking no difference. When the PR controller digital implementation difficulties, The PR controller based on the q operator and delta Operators of Two implementations, the use of the means of mathematical analysis to prove the accuracy of the digital controller based on Delta operator requirements to q operator.

Related Dissertations

CLC: > Industrial Technology > Electrotechnical > Power generation, power plants > Variety of power generation > Other energy generation
© 2012 www.DissertationTopic.Net Mobile