SusTEM Special Sessions
on
Thermal Energy Management
Technical Analysis of a Stand-Alone PVWind System with Hybrid Storage for
Households
Xiaonan Han, Yaodong Wang, Tony Roskilly
Sir Joseph Swan Centre for Energy Research
Newcastle Institute for Research on Sustainability
Newcastle University, UK
Contents
Introduction
Electricity Consumption of Household
Design of a Stand-Alone Hybrid Renewable Energy System
Modelling of the System
Control Strategy
Results and Discussion
Conclusions
Introduction
Background
Electricity
Energy Storage
Energy and
Pollution
Battery, flywheel,
supercapacitor and FC
•
3 major fossil fuels
trend to dry up
•
•
Renewable
Energy
Serious CO2 emission
Global warming and
Climate change
Hybrid Electricity
Energy Storage
(HEES) consisting of
battery and
supercapacitor
•
•
The stand-alone PV
system
•
The stand-alone
wind-energy system
•
The wind-PV hybrid
renewable energy
system (HRES)
•
Introduction (2)
Background (2)
(1)As much as 40% of the population in the whole
world is still living in isolated households (without
power supply).
(2)The electricity consumption in households
accounted for 29% of the total energy
consumption in the UK.
Introduction (2)
Background (3)
UK solar resource
Introduction (2)
Background (4)
UK wind source
Introduction (3)
Aims and Objectives
Previous
1. Electricity Energy Storage has
already been considered in a
PV or wind-turbine system.
2. Specific weather conditions
without frequency changes
are used.
3. Constant load or special load
is the base of the simulation.
4. Simulation period is short.
This Study
1. To propose a system which is
the wind-PV HRES with the
battery-supercapacitor HEES.
2. To use real weather data as
input.
3. To chose a 24-hour typical
load
profile
in
a
UK
household for the proposed
system.
4. To obtain the performance of
a whole day under proposed
control strategy.
A Typical 24-Hour Electricity Consumption of
a UK household in Winter
Design of a Stand-Alone Hybrid Renewable
Energy System for the Household
VPV
MPPT
IPV
VDC IAC
DC/DC
PV
Array
PWM
PMSG
Wind
turbine
VWT
IWT
AC/DC
240V DC
Bus
DC/DC
DC/AC
LOAD
MPPT
DC/DC
DC/DC
Battery
SOC
Super
capacitor
Energy
Management
System
VDC PPV PWT Pload
MPPT – Maximum Power
Point Tracking
PMSG – Permanent magnet
synchronous generator
PWM – pulse-width
modulation
Modelling of the System – Control Strategy
(1) Incremental Conductance (INCond) MPPT of PV Array
P V  I
dP
dI
 I V
0
dV
dV
dI
I

dV
V
Modelling of the System – Control Strategy (2)
(1) Incremental Conductance (INCond) MPPT of PV Array
Start
Monitor
V（k）and
I（k）
Y
V（k）-V(k-1)>0
N
Y
Y
dI/dV=-I/V
I(k)-I(k-1)=0
N
N
dI/dV>-I/V
N
Decrease
Vref
I(k)-I(k-1)>0
Y
Increase
Vref
Return
N
Decrease
Vref
Y
Increase
Vref
Modelling of the System – Control Strategy (3)
(2) PSF (power signal feedback) MPPT of Wind Turbine
Start
Initialization
L=1; M=1; D0=0.1
Monitor
V(k) and I(k)
Pb : Reference value of
increased power
L : Constant
M : Step lenghth
D0 : Initial duty
D : Duty for the DC/DC
converter
P(k)=V(k)I(k)
M=D0[P(k)-P(k-1)]/Pb
Y
P(k)-P(k-1)=0
N
D(k+1)=D(k)+L*M
Return
Modelling of the System – Control Strategy (4)
(3) Control Strategy of Hybrid Electricity Energy Storage (HEES)
Pd=PPV+PWT-Pload
Monitor
SOC of Battery and VDC
Monitor
Pd and VDC
N
SOC>20%
N
Pd>0
Y
Y
VDC>V*DC
-2%<(VDC-V*DC)/V*DC<2%
N
Constant-Voltage
Charging
-2%<(VDC-V*DC)/V*DC<2%
Y
Constant-Current
Charging
N
Constant-Voltage
Discharging
Y
Constant-Current
Discharging
N
Constant-Current
Charging
Y
Constant-Current
Discharging
Buck/Boost Bi-directional Converter
Buck/Boost Bi-directional Converter
Battery
Supercapacitor
Constant-Voltage
Discharging
Typical Weather Data used for simulation in
a Sunny Winter Day
Solar
Time
Irradiation
(W/ m2)
Ambient
Temperature (℃)
Wind
Speed
Solar
Time
Irradiation
(W/ m2)
(m/s)
Ambient
Temperature (℃)
Wind
Speed
(m/s)
00:00
0
6
11
12:00
641
5
19
01:00
0
5
11
13:00
642
5
18
02:00
0
5
12
14:00
440
4
19
03:00
0
5
18
15:00
389
4
18
04:00
0
4
17
16:00
234
4
18
05:00
0
5
16
17:00
15
4
20
06:00
0
5
19
18:00
0
4
18
07:00
4
5
18
19:00
0
3
19
08:00
54
4
15
20:00
0
3
15
09:00
283
4
15
21:00
0
3
14
10:00
451
4
16
22:00
0
2
15
11:00
572
5
17
23:00
0
2
15
Sizing
PV Array
Determine
the Capacity
Wind
Turbine
Supercapacitor
Battery
Sizing
Two WT6000 Wind Turbines
Model
Manufacturer
Cut-in Wind Speed (mph)
Rated Wind Speed (mph)
Cut-out Wind Speed (mph)
Rated Output Power (W)
Battery System Available Voltage
(V)
WT6000
Proven Engineering
6
22
145
6000
48,120,or 240
A 3.3kW PV Roof System
Power
Type of Cell
Number of Cells
Cell Efficiency
Maximum Voltage at Maximum
Power Point (V)
Maximum Current at Maximum
Power Point (A)
Dimensions (mm)
Weight (kg)
190W +/-3%
Monocristallin
72
17.7%
37.3
5.1
1580×808×40
14.8
Sizing
(1) Battery
Model
Voltage (V)
Capacity (Ah)
Dimensions (mm)
Weight (kg)
NPL100-12
12
100
407×172.5×240
39
Model
Rated Capacitance (F)
Rated Voltage (V)
Rated Current (A)
Gravimetric Specific Energy
(Wh/kg)
Volumetric Specific Energy (Wh/l)
Dimensions (mm)
Weight (kg)
EMHSP-0094C0-045R0
94
45
340
(2) Supercapacitor
2.8
3.7
212×193×201
11
Simulation Results and Discussion
PV
Power
output
Load
Wind
turbine
Battery
Supercapacitor
Simulation Results and Discussion (2)
(1) Output of the Generation Units
Output of the PV System
Output of the Wind-Turbine System
Simulation Results and Discussion (3)
(1) Output of the Generation Units
Difference between Supply and Household Load
(Pd=PPV+PWT - Pload)
Simulation Results and Discussion (4)
(2) HEES Implement
The state of charge (SOC) of the Battery over the Whole Typical Day
Simulation Results and Discussion (5)
(3) Voltage of the Junction Point
Voltage of DC Link in the
Proposed System
Voltage of DC Link in the
System without Supercapacitor
Conclusions
A stand-alone wind-PV system with a HEES
consisting of a battery and supercapacitor is
proposed with an optimised control strategy.
Real typical data is used as the base of
simulation after analysis.
The proposed system can supply sufficient
and stable electrical energy to an isolated
00 the correspondingly bad
household during
weather condition for 24 hours.
The output of the PV array and the wind turbine
were always retained at the MPP with the fast
changing weather conditions due to the use of
MPPT. The DC voltage at the junction can be
maintained within an acceptable fluctuation range
in the whole day.
Performance of
the proposed
system
Conclusions (2)
…
Other
Alternative
Energy
Converter
DC/DC
Optimal
Sizing
PV
Array
PMSG
Wind
turbine
AC/DC
DC/DC
DC Bus
DC/AC
DC/DC
EES
Consider
about
CCHP
Combined
with
Biofuel
Technology
Further
Research
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