DC Distribution Systems and Microgrids

Cover
Contents
Preface
1 DC microgrid control principles – hierarchical control diagram
1.1 Introduction
1.2 The hierarchical control for DC MGs
1.3 Primary control
1.3.1 Basics of droop control
1.3.2 Power sharing errors
1.3.3 Droop strategies
1.3.4 Dynamic power sharing
1.3.5 Interfaces to upper levels
1.4 Secondary control
1.4.1 Centralized approach
1.4.2 Distributed approach
1.4.2.1 Communication through dedicated communication channels
1.4.2.2 Communication through power lines
1.5 Tertiary control
1.6 Summary
References
2 Distributed and decentralized control of dc microgrids
2.1 Introduction
2.2 Decentralized approaches
2.2.1 Mode-adaptive (autonomous) droop control
2.2.2 Nonlinear droop control
2.2.3 Frequency droop control
2.3 Distributed approaches
2.3.1 Fully communicated control
2.3.2 Sparse communicated (consensus-based) control
2.3.3 Sparse communicated control using current information
2.3.3.1 Current regulator
2.3.3.2 Voltage regulator
2.4 Conclusion and future study
References
3 Stability analysis and stabilization of DC microgrids
3.1 Dynamic characteristics of DC microgrids
3.2 DC microgrids stability analysis
3.3 Passive approaches for stabilization of DC microgrids
3.4 Control strategies for stable DC microgrids operation
3.5 Operation of rectifiers with instantaneous constant power loads
3.6 Summary
References
4 Coordinated protection of DC microgrids
4.1 Introduction
4.2 Faults in DC power systems
4.2.1 Fault types and behavior
4.2.2 Fault current analysis
4.2.3 Faults in various bus configurations
4.2.3.1 Point-to-point
4.2.3.2 Multiterminal
4.3 Coordinated protection techniques
4.3.1 AC side protection
4.3.1.1 Fault detection
4.3.1.2 Protection by AC circuit breakers
4.3.2 DC side protection
4.3.2.1 Fault detection
4.3.2.2 Postfault processes
4.3.3 Applications
4.3.3.1 High-voltage DC transmission
4.3.3.2 Shipboard power system
4.3.3.3 Traction power systems
4.3.3.4 Photovoltaic park
4.3.3.5 Data centers
4.3.3.6 Aircraft power systems
4.4 Summary
Acknowledgment
References
5 Energy management systems for dc microgrids
5.1 Introduction
5.2 DC microgrid operation and control fundamentals
5.2.1 Power/energy management schemes
5.2.1.1 Interactive power/energy management strategies
5.2.1.2 Passive power/energy management strategies
5.2.2 Control schemes
5.2.2.1 Local control functionalities
5.2.2.2 Coordinated control
5.3 Interfacing converter control strategies for power/energy management purposes
5.3.1 Voltage control/grid-forming mode
5.3.2 Current control/grid-following mode
5.4 Illustrative example
5.5 Conclusions
References
6 Control of solid-state transformer-enabled DC microgrids
6.1 Introduction
6.2 Solid-state transformer-based microgrid: architecture and benefits
6.3 Centralized power management of solid-state transformer-based DC microgrid
6.3.1 Power management strategy
6.3.2 Case study
6.3.2.1 Passive grid interaction (Mode 3)
6.3.2.2 Transition from passive grid interaction mode to active grid interaction mode (Mode 2 to Mode 3)
6.3.2.3 Islanding mode (Mode 8)
6.3.2.4 Islanding mode transition (Mode 8 to Mode 9)
6.3.3 Summary
6.4 Hierarchical power management of solid-state transformer-enabled DC microgrid
6.4.1 Power management strategy
6.4.1.1 Primary control algorithm
6.4.1.2 Secondary control algorithm
6.4.1.3 Tertiary control algorithm
6.4.2 Case study of a small-scale DC microgrid
6.4.2.1 Case I: Primary control of the SST-enabled DC microgrid system
6.4.2.2 Case II: Secondary control of the SST-enabled DC microgrid system
6.4.2.3 Case III: First tertiary control
6.4.2.4 Case IV: Second tertiary control
6.4.2.5 Comparison of the two tertiary control methods
6.4.3 Summary
6.5 Control of SST-enabled DC microgrid as a solid-state synchronous machine (SSSM)
6.5.1 Concept of the SSSM
6.5.2 Frequency regulation
6.5.3 Power up/down reserve support
6.5.4 Voltage regulation
6.5.5 Case study
6.5.5.1 Case I: Load change
6.5.5.2 Case II: Source change
6.5.5.3 Case III: Power up/down reserve
6.5.5.4 Case IV: Islanding and reconnection
6.5.6 Summary
6.6 Conclusion
References
7 The load as a controllable energy asset in dc microgrids
7.1 Introduction
7.1.1 Local area power and energy system
7.2 Why control the load?
7.2.1 Benefit of load control
7.2.2 Is load modulation practical?
7.3 Time-scale of energy requirements
7.3.1 Short-term transients
7.3.2 Long-term transients
7.4 Autonomous load control
7.4.1 Control
7.4.2 Architecture
7.4.3 Strategy for controlling the load to be an energy asset
7.5 Droop control for stability and information communication
7.5.1 Constant power load and its deleterious effect on dc systems
7.5.2 Steady state stabilization
7.5.3 Dynamic stabilization
7.6 Voltage-based load interruption
7.6.1 Power flow analysis
7.6.2 Contingency analysis
7.6.3 Search algorithm
7.7 dv/dt-Based dynamic load interruptions
7.8 Load prioritization and scheduling
7.9 Summary
Acknowledgments
References
8 Electric vehicle charging infrastructure and dc microgrids
8.1 Overview of EV and EVSE markets and trends
8.2 dc Fast charging systems and requirements
8.2.1 dc Fast charging systems and standards
8.2.2 State-of-the-art EV dc fast chargers
8.2.3 dc Fast charger power converter topologies
8.3 Microgrid topologies for EV charging
8.3.1 State-of-the-art dc fast charger installation
8.3.2 Medium-voltage dc fast chargers: a new approach to high-power EV fast charging
8.4 Conclusions and future trends
References
9 Overview and design of solid-state transformers
9.1 Solid-state transformer: concept
9.2 SST in electric distribution grid application
9.3 ST architecture classification
9.3.1 Power conversion stages
9.3.2 Modularity
9.3.3 Modularity level
9.3.4 dc Link voltage availability
9.4 Solid-state transformer and smart transformer architectures overview
9.5 dc–dc Stage: power converter topologies
9.5.1 Requirements
9.5.2 Basic module topologies
9.6 Series resonant converter
9.6.1 Current stress
9.6.2 Efficiency expectation
9.7 Dual active bridge (DAB) converter
9.7.1 Modulation strategy
9.7.2 Analysis of the DAB using the PSM
9.7.3 Current stresses on the DAB
9.7.4 Efficiency calculation
9.8 Active-bridge converter: control description and tuning
9.9 Summary
References
10 Bipolar-type DC microgrids for high-quality power distribution
10.1 Introduction
10.2 Bipolar-type DC distribution systems
10.3 Topologies and operational aspects of bipolar LVDC grids
10.3.1 Distribution converter topologies
10.3.1.1 Two-level voltage source converter
10.3.1.2 Three-level neutral point clamped converter
10.4 Balancing topologies
10.4.1 Bidirectional buck-boost topologies
10.4.2 Coupled inductor current redistributor
10.4.3 Three-level DC–DC current redistributors
10.5 Control schemes
10.5.1 Cascade control
10.5.2 AC–DC converter control
10.5.2.1 Single-phase AC–DC converter control
10.5.2.2 Voltage-oriented control
10.5.2.3 Direct power control
10.5.2.4 Balancing leg control
10.5.2.5 Symmetrical component control-based methods
10.6 Summary
Acknowledgement
References
11 Aircraft DC microgrids
11.1 Introduction
11.2 Aircraft electrical power system
11.2.1 Power generation
11.2.2 Power distribution
11.2.3 Power utilization
11.2.4 Energy storage system
11.3 Power quality requirements in aircrafts
11.4 Aircraft starter/generator control
11.5 Control strategies in aircraft DC microgrids
11.5.1 Primary control
11.5.2 Secondary control
11.6 Stability analysis
11.7 Chapter summary
Acknowledgement
References
12 Shipboard MVDC microgrids
12.1 Introduction
12.2 Architecture of shipboard MVDC power systems
12.2.1 Structure of DC bus
12.2.2 Prime movers
12.2.3 Components of shipboard MVDC power systems
12.2.3.1 AC generators
12.2.3.2 Energy storage systems
12.2.3.3 Ship loads
12.2.3.4 Power converters
12.3 Control of shipboard MVDC power systems
12.3.1 Gen-sets
12.3.2 Energy storage systems
12.3.3 Power management control
12.3.3.1 Local control
12.3.3.2 Central control
12.3.3.3 Case study
12.4 Stability analysis
12.5 Faults and protection
12.5.1 Architecture of protection schemes
12.5.2 Fault detection and location
12.6 Summary
References
13 DC-based EVs and hybrid EVs
13.1 Introduction
13.1.1 Power electronic system in electrified vehicles
13.1.2 DC auxiliary loads in electrified vehicles
13.2 Converter topologies in electrified vehicles
13.2.1 Conductive HV battery chargers
13.2.2 Active power filters in HV battery chargers
13.2.3 LV auxiliary power modules
13.3 Practical design considerations
13.3.1 Selections of switching devices
13.3.2 Selections of DC-link capacitors
13.3.3 Design considerations of DC bus bars
13.4 Topological reconfigurations of DC systems in electrified vehicles
13.4.1 Topological reconfigurations in HV charging and propulsion systems
13.4.2 Topological reconfigurations in dual-voltage charging systems
13.5 Conclusions
References
14 DC data centers
14.1 Introduction
14.2 Development of DC power distribution in data centers
14.3 Efficiency
14.4 Reliability
14.4.1 Fault tolerance
14.4.2 Back-up power
14.5 Integration with other DC sources and loads
14.5.1 Renewable and distributed energy sources
14.5.2 Cooling
14.5.3 Lighting
14.6 Installation
14.6.1 Isolation
14.6.2 Grounding
14.6.3 Wiring
14.6.4 Connectors
14.6.5 Total cost of ownership
14.7 Protection
14.8 Power quality
14.9 Stability
14.10 Existing high voltage DC data centers
14.11 Key obstacles to widespread adoption of DC data centers
14.11.1 Overly optimistic claims
14.11.2 Emergence of rack-level UPS
14.11.3 Protection and DC circuit breakers
14.11.4 Incumbent cost and familiarity advantages
14.12 Conclusion
References
15 DC microgrid in residential buildings
15.1 Introduction
15.2 Conceptualisation: DC microgrids in buildings
15.3 Classification of microgrids
15.3.1 AC microgrid system
15.3.2 Hybrid AC–DC microgrid system
15.3.3 DC microgrid system
15.4 Topologies for DC microgrid for residential applications
15.4.1 Unipolar LVDC system
15.4.2 Bipolar LVDC system
15.5 Mathematical analysis of AC vs DC microgrid system
15.5.1 Total daily load
15.5.2 Voltage, current and power losses in DC supply
15.6 Comparison between AC and DC residential buildings
15.7 AC residential buildings
15.8 DC residential buildings
15.9 Automation architecture for smart DC residential buildings
15.9.1 Field level
15.9.2 Field network
15.9.3 Automation level
15.9.4 Primary and secondary network
15.9.5 Management level
15.10 Advantages, challenges and barriers of smart DC residential buildings
15.11 Comparison AC and DC residential buildings: an illustrative example
15.12 Conclusions
References
16 DC microgrids for photovoltaic powered systems
16.1 Introduction
16.2 Architecture of dc microgrids
16.2.1 MVDC and LVDC microgrid for dc distribution systems
16.2.2 LVDC microgrid for space applications
16.2.3 MVDC microgrid for marine applications
16.2.4 LVDC microgrid for data centers
16.2.5 LVDC microgrid for homes
16.2.6 MVDC microgrid for oil-drilling applications
16.3 dc Microgrids for photovoltaic power plants
16.4 PV system modeling
16.4.1 Ideal model of a PV cell
16.4.2 Single diode with series resistance model
16.4.3 Single-diode with shunt resistance model
16.4.4 Double-diode model
16.5 Power converter technologies
16.5.1 Transformerless topologies
16.5.2 dc Converters with high-frequency transformers
16.5.3 Next generation PV converters
16.6 Control of dc microgrids for PV collection plants
16.7 Simulation of a droop-controlled PV microgrid
16.8 Summary
References
17 Demonstration sites of dc microgrids
17.1 Introduction
17.2 Off-grid dc microgrids
17.2.1 Architecture
17.2.2 Components
17.2.3 Control and operational safety
17.2.4 Socioeconomic impact
17.2.5 Discussion
17.3 Transportation electrification
17.3.1 Shipboard dc microgrids
17.3.1.1 Architecture
17.3.1.2 Components
17.3.1.3 Power quality, control and protection
17.3.1.4 Economical operation
17.3.2 Railway traction with dc supply
17.3.2.1 Architecture
17.3.2.2 Components
17.3.2.3 Protection
17.3.3 Discussion
17.4 Datacenters
17.4.1 Architecture
17.4.2 Components
17.4.3 Protection and grounding system
17.4.4 Discussion
17.5 Residential and commercial dc buildings
17.5.1 dc House
17.5.1.1 Architecture
17.5.1.2 Components
17.5.1.3 Control
17.5.1.4 Protection
17.5.2 Building interiors
17.5.2.1 Architecture
17.5.2.2 Components
17.5.2.3 Control
17.5.2.4 Protection
17.5.2.5 Economics
17.5.3 dc Distribution grids
17.5.3.1 Architecture
17.5.3.2 Components
17.5.3.3 Control
17.5.4 Discussion
References
Index
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