Dissertation > Excellent graduate degree dissertation topics show

Control Strategy for Single-Phase Grid-Connected Inverter with LCL Filter

Author: LiuShangWei
Tutor: RuanXinBo
School: Huazhong University of Science and Technology
Course: Power Electronics and Power Drives
Keywords: grid-connected inverter LCL filter active damping feed-forward seamless switching
CLC: TM464
Type: Master's thesis
Year: 2011
Downloads: 300
Quote: 3
Read: Download Dissertation

Abstract


Nowadays, the fossil fuels such as goal and oil are going to be exhausted, and meanwhile, the utilization of the fossil fuels has been seriously polluting the environment. Renewable energy including solar and wind energy has the advantages of cleanness, environment-friendliness, and it has been attracting more and more attentions. In the distributed generation (DG) system based on renewable energy, the grid connected inverter is the interface between DG and grid. This thesis is dedicated to the control strategies for single-phase grid-connected inverter with LCL filter.Compared with the single-inductor filter, the LCL filter provides better harmonic attenuation, provided that the sum of two inductors is equal to the one of the single-inductor filter. As a consequence, the size and cost of the LCL filter is smaller than the single-inductor filter. This thesis analyzes the output voltage harmonics of the single-polarity double-frequency SPWM controlled inverter, and the design guidelines for the LCL filter are presented. A 6 kW grid-connected inverter with LCL filter is taken as the example to illustrate the design of the LCL filter.The resonance of LCL filter may cause instability of system. Series- or parallel-connection of one resistor with the two filter inductors and filter capacitor, respectively, could damp the resonant peak. This thesis compares the characteristics of the six passive damp methods, and it is pointed out that the parallel-connection of one resistor with the filter capacitor can not only effectively damp the resonance peak, but also has no effect on the low-frequency and high-frequency harmonics attenuation, and the other five methods affect harmonics attenuation at low frequency or high-frequency. However, the paralleled resistor with the filter capacitor results in relatively large loss. The block diagram of the LCL grid-connected inverter with the resistor being paralleled with the filter capacitor is derived, and it is equivalently transformed to another block diagram, in which, the feedback of the filter capacitor current to the input of the SPWM modulator. It is revealed that the well-known active damping method with feedback of the filter capacitor current is equivalent to the passive damping method with one resistor in parallel with the filter capacitor. Furthermore, this active damping method has no loss.For grid-connected inverter, the grid voltage has great effect on the current injected into grid, including the steady state error and current harmonics. A full feed-forward of grid voltage is proposed for the grid-connected inverter with LCL filter to fully eliminate the effect of the grid voltage. This control strategy is simplified according to the grid voltage harmonics.Grid-connected inverter is capable of working in both grid-connected mode and stand- alone mode. This thesis proposed the method for seamless switching between the two modes and the current and voltage overshoot is avoided during the switching process.A 6 kW prototype of the grid-connected inverter with LCL filter has been built and tested in the lab. The experimental results are presented to verify the effectiveness of proposed feed-forward control strategy, seamless switching method, and the design of the LCL filters.

Related Dissertations

  1. Small photovoltaic grid-connected inverter design and simulation,TM464
  2. Research & Design of Three-Phase PV Grid-connected Inverter,TM464
  3. Linear Servo System Based on thermoacoustic engine output characteristic simulation study,TM301
  4. The Stabilization Design for Nonlinear Systems Based on the Saturation Method,TP13
  5. Research of Grid-Connected Control and Islanding Detection for Photovoltaic System,TM615
  6. Research on DSP-based Three-Phase Wind Power Grid-connected Inverter,TM614
  7. Research on Solar Photovoltaic Cell Converter,TM914.4
  8. Three-Phase High Performance Double-Conversion UPS,TN86
  9. Study of Small Wind Turbines Grid-Connected Inverter,TM464
  10. The Design and Simulation Research on Transformerless Single-Phase Photovoltaic Grid-Connected Inverter,TM464
  11. Research and Development on DSP-Based Photovoltaic Grid-connected Inverter,TM615
  12. Research on Grid-connected and Seamless Transfer Techniques of Distributed Generation Systems,TM619
  13. Grid-connected PV inverter system,TM464
  14. Research on the Energy Feedback System of Urban Rail Transit,U270.35
  15. Research on Control for Grid-connected Inverter for Direct-drive Wind System,TM464
  16. Research of Residential Photovoltaic Grid-connected Inverter Based on SOPC,TM464
  17. Low power consumption Fast Transient Response LDO design of the whole chip,TM44
  18. The Research of Monitor-control System Used in Ship Gas Turbine Electric Generating Set,U665.13
  19. Tube Furnace Optimal Control Strategy and Simulation,TP273
  20. The Reductive Technique of Feedforward Network Stream Cipher,TN918

CLC: > Industrial Technology > Electrotechnical > Transformers, converters and reactors > Converter > Inverter
© 2012 www.DissertationTopic.Net  Mobile