Front Cover
Grid Connected Converters
Grid Connected Converters: Modeling, Stability and Control
Copyright
Dedication
Contents
Foreword
Preface
Acknowledgments
I - Concepts, fundamentals, modeling, and dynamics analysis
1 - An introduction to renewable integrated power grids
1.1 Modern power grids
1.2 Renewable energy sources and distributed generators
1.3 Grid connected converters
1.4 Renewable integrated power grids: characteristics and challenges
1.5 Current trends and future directions
1.5.1 Dynamic impact of GCCs
1.5.2 GCC-based demand response
1.5.3 GCC-based virtual inertia
1.5.4 Future research needs
1.6 Summary
References
2 - Grid connected converters: fundamentals and configurations
2.1 General structure and essentials
2.1.1 General structure and classification
2.1.2 Reference frames
2.1.2.1 The Ξ±Ξ²-frame
2.1.2.2 The dq-frame
2.2 Configurations and applications
2.3 Basic control loops
2.3.1 Control system for grid-following GCC
2.3.2 Control system for grid-forming GCC
2.4 Dynamic characteristics emulation
2.4.1 Review and applications
2.4.2 An example: virtual resistor
2.5 Relevant grid codes and standards
2.5.1 Grid code and standards requirements
2.5.2 Protection, power quality and synchronization
2.5.3 Grid voltage support
2.5.4 Grid frequency support
2.6 Summary
References
3 - Modeling and dynamic performance of grid connected converters
3.1 A background and overview
3.1.1 Active power and frequency response modeling
3.1.2 Reactive power and voltage response modeling
3.2 Active power and frequency response model
3.2.1 Typical GCC and relevant control system
3.2.2 Modeling methodology
3.2.3 Step-response analysis and evaluation
3.2.3.1 Response to active power reference change
3.2.3.2 Ripple attenuation ability
3.2.3.3 Experimental verification
3.3 Reactive power and voltage response model
3.3.1 Typical GCC and relevant control system
3.3.1.1 Inner VI-based control
3.3.1.2 Inner Q-based control
3.3.1.3 Output impedance models
3.3.2 Modeling methodology
3.3.3 Step-response analysis and evaluation
3.4 Comprehensive and reduced GCC models
3.4.1 A comprehensive model
3.4.2 Reduced dynamic models
3.4.2.1 Example 1: focusing on LFC filter dynamics
3.4.2.2 Example 2: LFC filter and a virtual resistor
3.4.2.3 Example 3: LFC filter and three virtual resistors
3.4.2.4 Example 4: using dq-frame
3.5 Summary
References
4 - Grid connected converters: stability assessment and sensitivity analysis
4.1 Stability analysis methods: an overview
4.1.1 Frequency domain
4.1.2 Time domain
4.1.3 Impedance-based stability analysis methods
4.1.3.1 Analytical analysis method
4.1.3.2 Frequency-analysis simulator
4.1.3.3 Time-domain simulation-based frequency-scan method
4.1.3.4 Passivity-based stability analysis
4.1.4 PoincarΓ© map-based stability analysis method
4.2 Stability analysis using closed-loop eigenvalues/poles graph
4.2.1 Stability analysis of P-Ο model
4.2.2 Stability analysis of Q-V model
4.3 A frequency characteristics-based stability assessment
4.3.1 Impedance matrix-based formulation
4.3.2 Computation of frequency characteristics
4.3.2.1 Preliminaries
4.3.2.2 Proposed method
4.3.2.3 Application example
4.3.2.3.1 Stability analysis
4.3.2.3.2 Perturbation impact analysis
4.3.3 Extension of method for nonlinear function blocks
4.3.3.1 Stamps of nonlinear function blocks
4.3.3.2 Application example
4.4 PoincarΓ© map-based stability assessment
4.4.1 Stability analysis methodology
4.4.1.1 Averaged analysis of a linear GCC with state feedback controller
4.4.1.2 Principle of the shooting method
4.4.1.3 Computation of sensitivity matrix
4.4.1.4 Generalized sensitivity matrix computation for analog control
4.4.1.5 Generalized sensitivity matrix computation for digital control
4.4.2 Application example
4.4.2.1 State-space equations of the GCC system
4.4.2.2 Control principle of the GCC with sinusoidal compensator
4.4.2.3 Dedicated simulator in the MATLAB environment
4.4.2.4 Stability analysis results
4.5 Sensitivity analysis
4.6 Summary
References
5 - Dynamic impacts modeling and evaluation of grid connected converters
5.1 Dynamic timescales and stability classification
5.1.1 Dynamic timescales and stability in renewable integrated power grids
5.1.2 Impact of GCCs on power grid stability
5.1.3 GCC stability
5.2 A dynamic model for the GCCs integration evaluation
5.2.1 Multi-generator power grid description
5.2.2 Unified GCC-based DGs integrated power grid model
5.2.3 Model simplification
5.2.4 Simulation study
5.3 An updated frequency response model for a GCC-based DGs integrated power system
5.4 Summary
References
II - Control synthesis for stabilizing and performance enhancement
6 - Control structure of grid connected converters
6.1 Overall control structure
6.1.1 Grid-following-based GCC
6.1.2 Grid-forming-based GCC
6.2 Main control loops and objectives
6.2.1 P-Ο droop and relevant control loops
6.2.2 Q-V droop and relevant control loops
6.2.2.1 VI-based control and Q-based control
6.2.2.2 Comparison of VI-based control and Q based control
6.3 Feedforward and feedback control schemes
6.3.1 A GCC example
6.3.2 Feedforward and feedback control loops
6.4 Virtual synchronous generator
6.4.1 Rotational inertia reduction in modern power grids
6.4.2 Virtual synchronous generator concept and structure
6.5 Summary
References
7 - Stability and performance improvement of grid connected converters
7.1 Oscillation damping enhancement methods
7.1.1 Discrete state-space model of GCC
7.1.2 Digital control scheme
7.1.3 Damping improvement using virtual impedance
7.1.4 Simulation and experimental results
7.2 Time delay compensation
7.2.1 Proposed method
7.2.2 State estimation enhancement
7.2.3 Experimental results for damping control with delay compensation
7.2.4 Extension to a three-phase GCC
7.3 Passivity-based stabilization
7.3.1 Passivity-based stabilizing
7.3.2 Design examples
7.3.2.1 A single-phase GCC example
7.3.2.2 A 3-phase GCC example
7.4 Summary
References
8 - Advanced control synthesis methods for grid connected converters
8.1 Optimal control design
8.1.1 Case study and dynamic modeling
8.1.2 Optimal voltage controller design
8.1.3 Application example
8.2 Digital optimal control design
8.2.1 Case study and discrete dynamic model
8.2.2 Design of sinusoidal compensator and state-feedback gains
8.2.3 Optimal tuning of control system parameters
8.2.4 Estimation of state variables by the minimum-order observer
8.3 Lyapunov-based digital control design
8.3.1 Lyapunov-based control synthesis methodology
8.3.2 Reference generator
8.3.3 Simulation and experimental results
8.3.4 Stability analysis
8.4 Model predictive control-based controller design
8.4.1 An overview
8.4.2 Finite control set model predictive control
8.4.2.1 Types of cost function
8.4.2.2 Weighting factor design
8.4.3 The proposed FCS-MPC-based VSG control
8.4.3.1 Overall framework
8.4.3.2 VSG control
8.4.3.3 Current command generation for the FCS-MPC
8.4.3.4 FCS-MPC synthesis
8.4.4 Analysis of PLL impact on the system stability and performance
8.4.5 Simulation and experimental results
8.5 Robust damping control
8.5.1 Case study and dynamic modeling
8.5.2 Design methodology
8.5.2.1 Theoretical background
8.5.2.2 Synthesis framework
8.5.3 Simulation and experimental results
8.5.3.1 Simulation result
8.5.3.2 Experimental verification
8.6 Summary
References
9 - Grid connected converters for grid dynamics shaping
9.1 Flexible grid connected converters for dynamics emulations
9.2 Virtual dynamic shaping
9.2.1 Virtual impedance loop
9.2.2 Experimental verification
9.2.3 Virtual Q-droop and voltage estimator
9.2.4 Virtual governor and inertia
9.2.5 Virtual dynamics for power quality enhancement
9.2.5.1 Control methodology
9.2.5.2 Simulation results
9.3 Grid ancillary service support
9.3.1 Frequency regulation support from a motor drive system
9.3.1.1 Overall control scheme
9.3.1.2 VSG-based GCC control
9.3.1.3 Experimental results
9.3.2 PV-based PβΟ control support
9.4 Dynamic shaping in power grids with HVDC and low-frequency transmission systems
9.4.1 Dynamic shaping in power grids with HVDC
9.4.2 Dynamic shaping in power grids with low-frequency transmission systems
9.4.2.1 LFAC system
9.4.2.2 Addressed control scheme
9.4.2.3 Simulation results
9.5 Summary
References
Index
A
C
D
E
F
G
H
I
J
L
M
N
O
P
Q
R
S
T
V
W
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