Hybrid AC/DC microgrid and Electric Vehicles

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© Md Shamiur Rahman

Email: [email protected]

Power Management and Control of a Hybrid AC/DC Microgrid Integrated with Renewable Energy

Resources and Electric Vehicles

Md Shamiur Rahman

(S2925282)

Supervisors:

Professor Junwei Lu

&

Dr. Jahangir Hossain

Griffith School of Engineering •1


Contents

1. Introduction

2. Literature Review

3. Research Objectives

4. Methodology

5. Preliminary Results

6. Project Timeline

7. Conclusion

* Details and bibliographies are provided in the Confirmation of PhD Candidature report

•2


Introduction Hybrid AC/DC microgrid: Building blocks of ‘Smart Grid’

Renewable Energy Resources

Utility Grid

Compressed Air System

Electric Vehicles

PCC

Batteries

Household appliances and electronics

Electric Vehicles Flywheel

WT

Intellegent Bypass Switch

DC Coupled Subsystem

AC Bus

DC Bus

Interfacing Converter

•3 Source: Aalborg University

Communication


Introduction Hybrid AC/DC microgrid:


Utility Grid


Electric Vehicles

PCC

Batteries



WT




Island Mode


AC Bus

DC Bus

Communication


Introduction Hybrid AC/DC microgrid:


Utility Grid


Electric Vehicles

PCC

Batteries



WT




Grid-tied Mode


AC Bus

DC Bus

Communication


Introduction What is the Difference Between

a ‘Microgrid’ and a ‘Smart Grid’ ??

Smart Grid

•6


Introduction

•7


Introduction Microgrids: Australia Perspective

Source: Commonwealth Scientific and Industrial Research Organization (CSIRO)

•8


Introduction Microgrids: Pilot Projects in Australia

Source: CSIRO

Microgrid detail States Primary Energy

Resource

Capacity (kW)

Purpose

CSIRO, Newcastle New South Wales PV 110 Research

King Island Tasmania PV

110 Remote Community

Kings Canyon Northern Territory PV

225 Tourism

Coral Bay Western Australia Wind 825 Remote Community

Bremer Bay Western Australia Wind 660 Remote Community

Denham Western Australia Wind 920 Remote Community

Esperence Western Australia Wind 3600 Remote Community

Hopetoun Western Australia Wind 1200 Remote Community

Rottnest Island Western Australia Wind 600 Remote Community

In Queensland, GU, QUT and UQ have microgrid

research test bed

•9


Introduction Renewable Electricity Generation:

Challenges

• High Capital Cost

• Intermittency

• Storage Requirements

• Low Efficiency

• Unable to Produce in Large Quantities of Energy

• Large Area Requirement

• Low Inertia

Advantages

• Abundant Source of

Energy

• Low Greenhouse Gas Emissions

• Low Operational Cost

• Stable Energy Prices

• Microgrid Operation

Resources

• Wind power

• Hydropower

• Solar Energy

• Biomass

• Biofuel

• Geothermal Energy

•10


Introduction Global New Investments in Renewable Energy:

•11


Introduction Global Cumulative PV Capacity:

•12


Introduction Global Cumulative Wind Power Capacity:

•13


Introduction Renewable Policies: In Europe, the UK is targeting for 15% by the end of 2015/16 and

Germany is directing towards 25-30% within 2020 and aiming for 50% by 2030 of their total electricity generation to be generated

In Australia, renewable energy target (RET) is set for 20% by the end of 2020 which is presently 9.6%

In New Zealand, 72% of total electricity is generated through renewable sources and they are targeting towards 90% by the end of 2025.

100% or all renewable electricity generation is considered in countries like Costa Rica (by 2021), Fiji (by 2030), Denmark (by 2050), Scotland (by 2020)

•14


Introduction Renewable Policies: Feed-in-tariff policies have been enacted in total 98

countries/states around the world In Australia, South Australia, Queensland, Canberra, New South

Wales and Victoria have their feed-in-tariff policies. Regulation standards like Renewable Portfolio Standards

(RPS)/Quota policies have been introduced in Australia in 2001

•15


Introduction Electric Vehicles: Australia Perspective

Model 2014 2013 2012 2011 2010

Mitsubishi Outlander P-HEV 895 0 0 0 0

Nissan Leaf 173 188 77 19 0

Mitsubishi i MiEV 0 15 95 30 112

Holden Volt 58 101 80 0 0

BMW i3 33 0 0 0 0

Tesla Model S 22 0 0 0 0

Tesla Roadster 0 0 5 6 0

Registration of highway-capable plug-in electric cars by model

•16


Introduction Electric Vehicles: Australia Perspective

Mitsubishi Outlander

P-HEV

Nissan Leaf

Mitsubishi i-MiEV Chevrolet/Holden Volt BMW i3 Tesla Model S

Tesla Roadster

•17


Introduction Electric Vehicles (EV): Vehicle-to-Grid (V2G)

Challenges

• Stochastic charging pattern

• Storage lifecycle degradation

• Fast charging

• Smart coordinated charging

• Voltage fluctuation

• Harmonic distortion

• Peak demand management

• Additional infrastructure requirements

Advantages

• Active power regulation

• Reactive power support

• Load balancing

• Load shifting via valley filling

• Tracking of renewable energy sources

• Peak load shaving

• Current harmonics filtering

• Voltage regulation

• Frequency regulation

•18

Charging Power Level for Electric Vehicles

Level Voltage Rating

Charger Location

Power Level

Level - 1 Opportunity

120 V/230 V On-board 1-phase

Up to 2 kW

Level - 2 Primary

240 V/400 V On-board

1 or 3 phase

4 - 20 kW

Level - 3 Commercial

Fast Charging

480 V - 600 V (DC Fast

Charging)

Off-board 3-phase

50- 100 kW


Introduction Statement of the Problems Unpredictable impacts of renewable resources like PV and

wind as distributed generator (DG) units and EV as loads in microgrid operation

Extracting the advantages of V2G operation by utilizing EV-energy storage systems (EV-ESS)

Dynamic load management through proper control and power sharing of DG units and EV-ESS

Seamless transition of microgrid operational modes Fault fortification Quality power (low harmonics)

•19


Literature Review Impact Analysis: PV, Wind and EV

Representative Literatures

Year Identified Issues

PV M. Thomson et al.

2007

• High capital cost • Intermittency • Storage requirements • Low efficiency • Low inertia • Voltage and frequency fluctuation • Reliable forecasting • Distorted power

Wind

Wei Li et al. 2006

J. Charles Smith et al. 2007

By Le Xie et al. 2011

EV

Murat Yilmaz et al. 2013 • Increased peak load demand • Negative effects on power system components i.e. transformers,

distribution cables etc. • Increased system losses • Voltage deviation at EV interconnection points • Unbalanced phase condition due to single phase AC charging or slow

charging • Harmonics injection due to power electronics based charging interface • Stability issue

Jia Ying Yong et al. 2015

•20


Literature Review Vehicle-to-Grid: V2G


Year Purpose

Tan Ma et al. 2014

Active Power Management Luc´ıa Igualada et al. 2014

Fabian Kennel et al. 2013

Mithat C. Kisacikoglu et al. 2015 Reactive Power Operation

Jia Ying Yong et al 2015

M. Kesler et al. 2014

Sekyung Han et al. 2010 Frequency Regulation

Hui Liu et al. 2013

Chenye Wu et al. 2012 Voltage Regulation

Baosen Zhang et al. 2015

F. R. Islam et al. 2014 Filter Operation

•21


Literature Review Hybrid AC/DC Microgrid


Year Contribution Inadequacies

Xiong Liu et al. 2011 Coordination control of a hybrid AC/DC microgrid with PV, WT and storage is proposed

V2G facility has not been explored

A. A. A. Radwan et al.

2012 Interaction dynamics in hybrid ac/dc has been analysed to asses stability

Impacts of large capacity storages like EV's have not been explored

A. Mohamed et al. 2012 An energy management scheme is proposed based on • a nonlinear regression based PV and load

data forecasting • Fuzzy based control of storages • Pulse load mitigation

Other renewable sources like wind has not been considered and EV fast charging and scheduling is not considered

J. M. Guerrero et al. 2013 Unbalanced condition has been considered Large number of EV penetration can affect the control algorithm

P.C. Loh et al. 2013 Droop based power sharing is proposed in presence of storage system

Dynamic power sharing capability of energy storages like EV-ESS is not properly explained

•22


Literature Review Hybrid AC/DC Microgrid


Year Contribution Inadequacies

R Majumder 2014 Back to back interfacing converter with droop control strategy has been proposed

No V2G application is considered

Xiaonan Lu and J. M. Guerrero et al.

2014 A hierarchical control structure is developed for hybrid AC/DC microgrid


N. Eghtedarpour et al. 2014 Droop based power sharing is proposed including overloaded condition

No storage and unbalanced condition is considered

Teimourzadeh Baboli et al.

2014 Mixed integer linear model based energy management scheme is proposed


Peng Wang et al. 2015 Distributed control strategies have been proposed for hybrid AC/DC/DS structure

• A complicated structure • The DS bus can be extended for

multiple EV penetration

•23


Literature Review

1. Level 3 (Tertiary Control)

2. Level 2 (Secondary Control)

3. Level 1 (Primary Control)

4. Level 0 (Inner Control Loops)

Hierarchical Microgrid Control

•24


Literature Review Primary Control: Local Control (LC) Objectives:

Droop Based Method

•Conventional Droop Control

•Adjustable Load Sharing Control

•VPD/FQB Droop Control

•Virtual Frame Transformation Method

•Virtual Output Impedance Method

•Adaptive Voltage Droop Control

•Signal Injection Method

•Non-linear Load Sharing

Non-Droop Based Method

•Centralized control

•Master-slave control

•Average load sharing control

•Circular chain control (3C)

•25

• Parallel power sharing among multiple DG units

• Bus voltages and system frequency stabilization


Literature Review Secondary Control: Microgrid EMS Objectives:

Methods

• Genetic Algorithms (GA)

• Particle Swarm Optimization (PSO)

• Model Predictive Control (MPC)

• Ant Colony Optimization (ACO)

• Potential Function Based Control

• Voltage Unbalance Compensator Technique

• Multi-Agent (MAS) Concept

• Gossip-Based Technique

• Distributed Cooperative Control

•26

• Microgrid Energy Management System (EMS)

• Maintaining all electrical levels within acceptable range

• Synchronization or restoration of microgrid with grid


Literature Review Secondary Control

•27 Centralized EMS Operation

N-Period Forecasting of Non-Dispatchable

Generation

N-Period Forecasting of Electrical/Thermal Load

• SOC of EV-ESS

• Operational Limits

• Security and Reliability Constraints

• Main Grid interconnection Status

• Energy Price Forecasting

Microgrid Centralized EMS

Microgrid Model, Settings

and Policies

Command to Controllable Loads (DSM)

On/Off/Shift

Set Points for dispatchable DER for Next

Period

Inputs

Outputs


Literature Review Secondary Control

•28 Multi-Agent Based EMS Operation

Microgrid Central Controller

Primary/Local Controller



Service

Agents

Service

Agents

Database

Forecasting


Literature Review Tertiary Control: Host Grid Objectives:

Methods

• Equal Marginal Cost Based Approach

• Gossiping Algorithm

• Game Theory Based Approach

•29

• Sets ‘Optimal’ set points as per requirements of the host grid

• Coordinates the operation of multiple microgrids

• Import and export power to/from the grid


Literature Review Inner Loop Control: Objectives:

Methods

• Proportional-Integral-Derivative (PID) Control

• Proportional-Resonant (PR) Control

• Predictive Control

• Dead-Beat (DB) Control

• Hysteresis Control

• LQG/LQR Control

•30

• Handling stability and regulation issues

• Maintaining performance parameters which includes rise time, settling time, steady-state error, damping etc.

• Sliding Mode (SM) Control

• 𝑯∞ Control

• Repetitive Control

• Artificial Neural Networks (ANN) Control

• Fuzzy Logic (FL) Control


Literature Review Standards: IEEE-1547 Series

System response to abnormal

voltage condition

System response to abnormal

frequency condition

•31


Literature Review Standards: IEEE-1547 Series

Maximum harmonic distortion of PCC voltage and current

•32


Literature Review Standards: Australia

Islanding condition within Australia

•33


Research Objectives

Impact analysis of EV penetration considering hybrid AC/DC microgrid paradigm

Grid-connected power control and management algorithm for interfacing converter/STATCOM and EV-ESS

Islanded power control and management algorithm for interfacing converter/STATCOM and EV-ESS

Simulation of the developed algorithms in a hybrid AC/DC microgrid model for validation

Performing technical and economical optimization •34


Methodology

Impact Analysis

Literature Review

Impacts on load profile, voltage profile, phase

unbalance, harmonics and stability

Grid-connected

Power Control and Management

Islanded

Power Control and Management

Input and Output Identification

Constraints determination

Theoretical Model

Development

Mathematical Validation

Technique Selection

Simulation and Microgrid Modelling

Data collection of Griffith Microgrid Model

System Operation and

Testing

Model Development

Optimization

Technical

Economical

Experimental Validation

Article - 1

Article - 2

Article - 3

Article - 4


Preliminary Results

Hybrid AC/DC Microgrid: Schematics

•36

40 kW 50 kW

50 kW


Preliminary Results

Hybrid AC/DC Microgrid: Simulink Model

•37


Preliminary Results

Developed Grid-tied Control Strategies

•38


Preliminary Results Proposed Energy Storage Charge/Discharge Algorithm:

•39


Preliminary Results

Case Studies: Variable Loading

•40


Preliminary Results


Active Power Profile Reactive Power Profile

Balanced by the Grid

•41


Preliminary Results


AC and DC Bus Voltage EV-ESS State-of-Charge (SOC)

•42


Preliminary Results


PCC Voltage Harmonics PCC Current Harmonics

•43


Preliminary Results


System Frequency in Hz

•44


Preliminary Results


Inverter Output Voltage

Before 𝑳𝑪𝑳 Filter

Inverter Output Voltage

After 𝑳𝑪𝑳 Filter

•45


Preliminary Results

Case Studies: Real life Irradiation Variance

Irradiation Profile and PV output power

•46


Preliminary Results


Active Power Profile

•47

Reactive Power Profile


Preliminary Results


•48

AC and DC Bus Voltage


Future Aims

•49

Future Microgrid Model in Griffith University

Nathan Campus

Challenges and Design Requirements

N44: Highly unbalanced load profile

N05: DC fast charging of Evs

N74: Contains critical loads and requires UPS Operation

Four-legged STATCOM operation


Future Aims

•50

Grid-tied Mode Island Mode


Project Timeline

•51


List of Publications Book Chapter: 1. Md Shamiur Rahman, F. H. M. Rafi , M. J. Hossain and J. Lu, “Power Control and Monitoring

of Smart Grid with EVs”, in Vehicle-to-Grid: Linking Electric Vehicles to the Smart Grid, IET Publication. (Published)

Conference Papers: 1. Md Shamiur Rahman, M. J. Hossain and J. Lu, “Utilization of Parked EV-ESS for Power

Management in a Grid-Tied Hybrid AC/DC Microgrid”, Australasian Universities Power Engineering Conference(AUPEC), 2015. (Submitted)

2. Md Shamiur Rahman, M. J. Hossain and J. Lu, “Frequency Regulation and Power Balancing in an Islanded Hybrid AC/DC Microgrid with EV-ESS”, IEEE PES Asia-Pacific Power and Energy Engineering Conference(IEEE PES APPEEC), 2015. (Writing in progress)

3. F. H. M. Rafi, Md Shamiur Rahman, M. J. Hossain and J. Lu, “Implementation of Smart Inverter for Real Time Radiation and Temperature Variation Effects on AC/DC Microgrid with PV System”, IEEE International Conference on Power Electronics and Drive Systems (PEDS), 2015. (Accepted)

•52


Conclusions

This presentation presents:

• The concept of multi bus hybrid AC/DC microgrid

• Impacts and challenges of EV penetration and features of V2G

• A generalized hybrid AC/DC microgrid has been designed in MATLAB/SIMULINK

• A reactive power controller and an EV-ESS charge/discharge controller has been proposed

• Both controllers have been exposed to variable scenarios

• In future the model will be extended to Griffith University microgrid model for practical validation

•53


Conclusions

Expected Contributions of the Research

• Impact analysis of renewable resources and emerging EV loads in microgrid paradigm

• A novel power sharing technique for microgrid in all operational mode utilizing V2G operation with fault tolerance and unbalanced condition handling capability

• A novel energy management scheme for hybrid AC/DC microgrid to ensure economic and reliable operation

• Experimental validation

•54


Thank You

•55