Solar system

Department of Electrical Power and Machine Engineering
Graduation Project (2015/2016)
Entitled:
Performance Analysis and Enhancement of
Microcontroller-Based PV Pumping Systems
Supervisor : Dr. Said M. Allam
Faculty of Engineering Tanta University

Prepared by:
1) Ibrahim Samir Ahmed El-Nagar
2) Ahmed Azab Ahmed Atef
3) Ahmed Kadry Ahmed Ali
4) Ahmed Mohamed Abd El-Kareem Omara
5) Ismail Abd El-Aziz Ismail Soliman
6) Abd El-Kader Ali Abd El-Kader Lashin
7) Abdalla Ramadan Iraqi Shalabi
8) Ali Hussein Ashraf Abu El-Fotoh
9) Hani Mohamed Abd El-Fattah El-Touni

Renewable Energy Sources and Conventional Sources
Overview
Conventional energy
Gas power station
Steam power station
Nuclear power station
Coal power station
Harmful
effects on
environment
are
exhaustible Run out fastly
emit carbon dioxide when burnt, adding to
the greenhouse gases in the atmosphere and
pushing us faster towards global warming
1

Renewable Energy Sources and Conventional Sources
Overview
Renewable energy
Solar energy sources
Wind energy sources
Geothermal Energy
Hydroelectricity
Ocean Energy
Bio-Energy
Sustainable and
so will never run
out
Less maintenance
than traditional
generators
Their fuel being
derived from
natural
Produces little or
no waste products
2

Renewable Energy
Overview
Solar energy sources
Photovoltaic Cells Concentrated Solar Power (CSP)
3

Renewable Energy
Overview
Photovoltaic applications
Power pump
Solar lighting
Domestic applications
Ventilation system
Power plants
Solar cars
4

 Solar photovoltaic water pumping system
Pump running on electricity generated by photovoltaic panels or
the radiated thermal energy available from collected sunlight as opposed
to grid electricity or diesel run water pumps
 Advantages
 More economical
 Lower operation and maintenance costs
 Have less environmental impact
 Useful where grid electricity is unavailable or alternative sources (in
particular wind) do not provide sufficient energy
Photovoltaic applications
Overview
PV pumping systems
5

 Obtain a full survey about PV pumping system and numerating its advantage over
conventional pumping system.
 Present a full system description for different schemes of operation.
 Study process and conditions of different radiations for PV pumping system.
 Study the dynamic behavior and steady-state Analysis of PV pumping system.
 Study the performance analysis and performance enhancement for the system.
 Present the simulation and the experimental results.
 Provide Feasibility study for specific space of land.
Objectives:
Overview
The study aims to:
6

General System Description and Modeling
DC Motor-Based Pumping System
Single-phase IM-Based Pumping System
Experimental Work
PV Pumping System Feasibility Study
Conclusions and Future Work
Outlines:
Overview

 In order to investigate the performance of a PV pumping system, its components
and their characteristics must first be studied
System Components
System Description
7

System Description
PV Cell
 PV cell is a p-n junction element that
converts solar energy into direct current
electricity by the photovoltaic effect
 A single PV cell usually produces voltages
and currents in the order of millivolts and
milliamperes
Construction and Operation
8

 To produce higher voltages, currents and power levels, PV cells
are connected electrically in series and/or parallel combinations
System Description
PV Cell
Construction and Operation
9

System Description
PV Cell
PV Characteristics
10

System Description
PV Cell
PV Characteristics
11

System Description
PV Cell
PV Characteristics
12

System Description
PV Cell
PV Characteristics
13

Two relations are of significant importance, the I-V
and P-V characteristic curves
𝐼𝑠𝑐 on the I-V curve is the maximum current of the
solar cell and occurs when the voltage across device is
zero
𝑉𝑜𝑐on the I-V curve is the maximum voltage of the
solar cell and occurs when the current through the
device is zero
Between these two points on the I-V curve lie many
points with different values of voltage and current and
the point of operation is determined by load
Maximum power is obtained at the knee point of I-V
curve
System Description
PV Cell
PV Characteristics
14

 Decreasing irradiation reduces the PV module’s output current significantly with
slight decrease in voltage and also decrease the PV power
System Description
PV Cell
PV Characteristics - Effect of changing irradiation on the I-V curve
15

Cell photo current :
Iph = [ISCr + Ki (T - 298)]*λ /1000
Cell reverse saturation current:
Irs = ISCr / [e
(
q VOC
Ns k A T
)
-1]
Cell saturation current Io :
Io=Irs
T
Tr
3
exp
q∗Ego
A k
1
Tr
−
1
T
Output current of PV cell :
I = Np *Iph – Np*Io* e
q∗ V+I∗Rs
Ns K A T −1 –
V+I∗Rs
Rp
System Description
PV Cell
Equivalent Circuit of a Single Diode Model
16

Power modulators are power electronic circuits used in the circuit between the
source and the load with the goal of adapting the characteristics of the source to the
requirements of the load such as DC/DC converter and DC/AC inverter
System Description
Power Modulator
Power modulator type will vary depending on the type of motor and PV design
17

 Different type of electric motor can be employed for driving the
pump
System Description
Driving Motor
Driving motors
DC motors AC motors
18

Among different types of pumps centrifugal pump was chosen due to :
Its simplicity, low cost and low maintenance
 The availability of large selection of designs for wide range of flow rates and heads
System Description
Centrifugal Pump
Load type:
The centrifugal pump application in the system is to store water in tank for
further use in agriculture purposes so the main application isn’t affected by changing
motor speed and hence flow of water when the irradiation is decreased or when night
comes
19

The two main parts of the pump are the impeller and the
volute .
Impeller is immersed in water so when impeller rotate it
makes the fluid surrounding it also rotate
This imparts centrifugal force to water and water moves
radially out
Since rotational mechanical energy transferred to fluid , at
the volute both pressure and kinetic energy of water will
increase
At suction eye water is being displaced so low pressure
will be induced at the eye, this helps sucking fresh water
stream into the pump again
The impeller is fitted inside a casing so the water moving
out will be collected inside it and will move in the same
direction of the rotation of impeller to discharge nozzle
System Description
Centrifugal Pump
Principle of Operation
20

If Water at the eye of impeller isn’t present
initially, the low pressure developed by the rotating
air at the eye will be negligibly small to suck fresh
water
So to make pump work perfectly priming is to be
applied in which the eye of impeller is fully
submerged in liquid without any air trap
System Description
Centrifugal Pump
Principle of Operation
21

The characteristics of a centrifugal pump
is the relation between the flow rate (Q )
and total head (H)at a given speed.
System Description
Centrifugal Pump
Pump Characteristics
22

The total system head curve describes the total head
required by the system which consists of
Static component
• Difference in height between source and
destination.
• Independent of flow
Dynamic component
• Resistance to flow in pipe and fittings.
• Depends on size, pipes, pipe fittings, flow rate,
nature of liquid
• Proportional to square of flow rate
System Description
Centrifugal Pump
23

The operating point is the intersection between
pump curve and system curve
System Description
Centrifugal Pump
24

The centrifugal pump relations are: volumetric flow rate
Q = A1V1 = A2V2
Load torque of the driving motor
TL = A w2
Input mechanical power required by the driving motor
Pin = TL w = A w3
Pump hydraulic power
Pin =
r g Q TDH
h
Total dynamic head
TDH= h +
0.025 L Q2
12 d5
System Description
Centrifugal Pump
Pump mathematical model
25

System Description
System Setup
26

Experimental Work
Outlines:

DC-Motor-Based PV Pumping System
System Description
27
Boost Converter

DC-DC Boost Converter
L
Diode
IGBT C𝑉𝑖𝑛 𝑉𝑜𝑢𝑡
𝐷 =
𝑡 𝑜𝑛
𝑇
𝑉𝑜𝑢𝑡=
𝑉𝑖𝑛
1−D
28
Rin=Ro 1 − D 2
R3
MPP

29
PV Design Considerations
 Normally, as knowing the load power and efficiency, motor output power can be determined
 The rated current and rated voltage are known from the nameplate of this driving motor
There are two methods of designing PV dimensions (𝑁𝑠, 𝑁𝑝)
1-According to rated power of driving motor.
2- According to starting current.

30
Selected irradiation:
The irradiation at which the PV
maximum power is equal to the
motor rated power.
𝑃𝑚𝑎𝑥 = 𝑃𝑟𝑎𝑡𝑒𝑑
𝑃𝑚𝑎𝑥 = 𝑃𝑟𝑎𝑡𝑒𝑑

31
𝑁𝑠 = 𝐾1 ∗
𝑉𝑑𝑐 ∗ (1 − 𝐷)
𝑉𝑐𝑒𝑙𝑙
𝑁𝑠 Number of series cells
𝑉𝑑𝑐 The load terminal voltage
𝑉𝑐𝑒𝑙𝑙 PV cell voltage
𝐾1 For estimating the open circuit
voltage of PV array (𝐾1 ≥ 1)
𝑁𝑝 = 𝐾2 ∗
𝐼 𝑑𝑐
𝐼𝑠𝑐,𝑐𝑒𝑙𝑙 ∗ (1 − 𝐷)
𝑁𝑝 Number of parallel cells
𝐼 𝑑𝑐 Current required by the load
𝐼𝑠𝑐,𝑐𝑒𝑙𝑙 Short circuit current of cell
𝐾2 for estimating the short circuit
current of PV (𝐾2 ≥1)
D Duty cycle of the boost converter

32
System Parameters:
PV Cell
At 1000 W/m2 and 25°C
Open Circuit Voltage (Voc) 0.54 V
Short Circuit Current (Isc) 0.8 A
Series Resistance (Rs) 0.05 Ω
Shunt Resistance (Rp) 95 Ω
Maximum Power (Pmpp) 0.245 W
Voltage at Maximum Power (Vmpp) 0.38 V
Current at Maximum Power (Impp) 0.65 A
PV Module
At 1000 W/m2 and 25°C
Open Circuit Voltage (Voc) 419.58V
Short Circuit Current (Isc) 30.38A
Maximum Power (Pmpp) 7210W
Voltage at Maximum Power (Vmpp) 291.5V
Current at Maximum Power (Impp) 24.73A
𝑁𝑠 =777
𝑁𝑝 =38

Separately Excited DC Motor
Terminal Voltage (Va) 500V
Input Current (Ia) 10A
Input Power (Pin) 5000W
Output Power (Po) 5 hp (3730W)
Speed (Nm) 1750 r/min
Field Voltage(Vf) 300 V
Centrifugal Pump
Input Power (P) 5 hp (3730W)
Rotation Speed (n) 1750 r/min
Flow Rate (Q) 24.42 liter/s
Head (H) 10 m
Efficiency (h) 69%
Pump Constant (A) 58.5*10-5N.m.s2/rad2
33
System Parameters:
DC/DC Boost Converter
3000 HZ𝑓𝑐
78.5 mHL
1.4 mFC

34
0 100 200 300 400 500 600
0
5000
10000
15000
VPV
(V)
P(Watt)
Direct Connection
UsingBoost Converter
𝑃𝑟𝑎𝑡𝑒𝑑
0 100 200 300 400 500 600
0
10
20
30
40
50
VPV
(V)
IPV
(A)
Direct connection
Using Boost Converter
Irradiation of 1000 𝑊/𝑚2
Designed Duty=44 %
𝑁𝑠 =777
𝑁𝑝 =38
𝑁𝑠 =980
𝑁𝑝 =60

35
Dynamic Response under Open-Loop Operation
725 W/𝑚2

36
Dynamic Response under Open-Loop Operation
Duty Cycle =0.5

37
Steady-State Characteristics under Open-Loop Operation
Duty Cycle =0.5

38
Duty Cycle =0.5

39
Duty Cycle =0.5

40
Duty Cycle = 0.44

41
Duty Cycle = 0.3

Direct Connection
42

43
 The operating point is uncontrolled
 Duty cycle is an effective element in changing the system performance
 Power generated from the PV source is not completely used
Performance Analysis under Open-Loop Operation
Conclusions

44
Recommendations
It is recommended to use a controller to enhance the
system efficiency to exploit the solar power

It is desired to enhance system performance and optimize the produced power
from the PV system
Objectives:
 Maximizing the produced power from PV under the irradiation (725 W/m2
) by
using maximum power point tracking (MPPT) techniques
 Limiting the produced power from PV above the irradiation (725 W/m2) to the DC
motor rated power
Performance Enhancement under Closed-loop Operation
DC Motor-Based PV Pumping System
45

At the irradiation ( 725 W/𝑚2 ) the
maximum power produced from the PV is
equal to the rated input power of the DC
motor ( 5000 W )
Above the irradiation ( 725 W/𝑚2 ) the
produced power will be limited at the DC
motor input rated power
Under the irradiation ( 725 W/𝑚2 ) the
produced power will be maximized
Performance Enhancement
Prated = 5000 W
46

Perturbation and Observation (P&O)
Incremental conductance (IC)
Constant voltage method
Open circuit voltage method
Short circuit current method
Temperature method
Cost
Convergence
speed
Sensors
required
Range of
effectiveness
Analogue or
digital
implementation
Simplicity
MPPT Techniques
47

Maximum power is tracked under the
irradiation ( 725 W/𝑚2 )
P&O MPPT Technique
∆P = P(k) – P(k-1)
∆V = V(k) – V(k-1)
Start
Read I(k) & V(k)
NO
P(k) = I(k) X V(k)
Delay V(k) and P(k) by k-1 instant V(k-1), P(k-1)
Yes NO
D = D - ∆D D = D + ∆D
∆P X ∆V> 0
Return
∆V ∆P ∆V X ∆P ∆D
+ + + -
- - + -
- + - +
+ - - +
48

Power is limited at the rated value
above the irradiation ( 725 W/𝑚2 )
∆P = P(K) – P(k-1)
∆V = V(k) – V(K-1)
Start
Read I(K) & V(k) & Pref
Yes
NO
P(k) = I(k) X V(k)
P(k) > Pref
Delay V(k) and P(K) by K-1 instant V(k-1), P(k-1)
Yes NO
D = D - ∆D D = D + ∆D
∆P X ∆V> 0
Return
∆V ∆P ∆V X ∆P ∆D
+ + + -
- - + -
- + - +
+ - - +
Modified P&O Technique
49

Modified P&O
50

Simulation Results - Dynamic Response
51

3232 W
1744 W
5000 W
52

53

Simulation Results – Steady-state characteristics
54

Simulation Results – Steady-state characteristics
55

Outlines
Single-Phase IM-Based Pumping System
Experimental Work

Single-Phase Induction Motor-Based PV Pumping System
System Description
56

57
 In case of direct connection, a PV with a large
rating is required to operate the motor at suitable
values
 Using a DC/DC boost converter allows for good
operation with lower PV ratings as well as provides
a control variable for the control technique
 The PV was designed taking in consideration the
use of a boost converter
System Description

58
Motor
(Capacitor-Run)
Terminal Voltage (Vm) 110 V
Input Current (Im) 2.5 A
Input Power (Pin) 246 W
Output Power (Po) 0.25 hp (186.5 W)
Speed (Nm) 1731 r/min
Capacitor (C) 21.5 mF
Input Power Factor (PFin) 0.89
Centrifugal Pump
Input Power (P) 0.25 hp (186.5 W)
Rotation Speed (n) 1725 r/min
Flow Rate (Q) 1.5 liter/s
Head (H) 8.5 m
Efficiency (h) 69%
Pump Constant (A) 3.1 * 10-5 N.m.s2/rad2
System Description
Motor and Pump Parameters

59
 The PV was designed to have a maximum power equal to the rated input power of the motor at an
irradiation level of 725 W/m2
PV Cell
At 1000 W/m2 and 25°C
Series Resistance (Rs) 0.05 W
Parallel Resistance (Rp) 95 W
Maximum Power (Pmpp) 0.245 W
Voltage at Maximum Power
(Vmpp)
0.38 V
PV Module
At 1000 W/m2 and 25°C
Maximum Power (Pmpp) 330 W
Voltage at Maximum Power (Vmpp) 46.2 V
123
series
cells
11
parallel
cells
System Description
PV Parameters

60
The PV was designed to have a maximum power equal to the rated input power of the motor at an
irradiation level of 725 W/m2
Pin rated
= 228 W
System Description
PV Characteristics

61
 Convert power from DC to AC
 Control magnitude of output voltage through PWM
 SPWM is used in industrial applications
 With SPWM, distortion factor and lower-order
harmonics are reduced significantly
 Two types of generating pulses in SPWM:
 Bipolar
 Unipolar
System Description
Single-Phase Inverter

62
ON
ON
OFF
OFF
Bipolar SPWM
System Description

63
ON
ON
OFF
OFF
OFF
OFF
Unipolar SPWM
𝑓𝑜 = 𝑓𝑚 𝑉𝑜=
𝑚 𝑉𝑑𝑐
2
𝑚 =
𝐴 𝑚
𝐴 𝑐
System Description

64
Dynamic
Response
Steady-State
Characteristics
 DC/DC Boost Converter duty-cycle (D) = 0.42
 Single-Phase Inverter Modulation Index (m) = 0.9

65
Simulation Results- Dynamic Response
Arbitrary
irradiations levels
600, 725 and 1000
W/m2 were
selected

66
Simulation Results- Dynamic Response

67
reflected load
shifted
operating power
below maximum power of PV
and rated motor input power
Simulation Results- Steady-State Characteristics

68
Simulation Results- Steady-State Characteristics

69
 Varying irradiation leads to varying
voltages and changes the Torque-speed
curves
 At certain low voltages, the operating
point falls in the unstable region
 For the used system parameters, selected
duty cycle and modulation index, the
stability region is in the irradiation range
higher than 567 W/m2
0 50 100 150
0
0.5
1
1.5
2
2.5
Motor Speed (rad/s)
MotorTorque(N.m)
92.5 V
40V
47V
66 V
stable
region
Stability Limit

70
 The PV panels full capabilities are not utilized
 The motor is derated due to lower voltages and input power.
Consequently, motor speed and output mechanical power are reduced and
the pump flowrate degrades
 Higher currents at lower voltages due to increased slip
 The motor is liable to go out of stability at lower voltages/irradiations
 Performance Enhancement is needed
Conclusions

Performance Enhancement under Closed-Loop Operation
Prated
P&O is used to track the max
power under the irradiation 725
W/𝑚2 through control on duty
Forcing the MPPT Controller
to obtain the input rated power
of the motor above the
irradiation 725 W/𝑚2
71

P&O MPPT Technique
∆P = P(k) – P(k-1)
∆V = V(k) – V(k-1)
Start
Read I(k) & V(k)
NO
P(k) = I(k) X V(k)
Yes NO
D = D - ∆D D = D + ∆D
∆P X ∆V> 0
Return
∆V ∆P ∆V X ∆P ∆D
+ + + -
- - + -
- + - +
+ - - +
72

Forcing the MPPT Controller to obtain the input
rated power
Duty cycle Modulation index
 The two systems behavior will be the same in the part of maximizing at lower irradiations
 The difference between the two system is in the part of upper irradiations
73

Closed Loop System Limited by Duty-Cycle Control
∆P = P(k) – P(k-1)
∆V = V(k) – V(k-1)
Start
Read I(K) & V(k) & Pref
Yes
NO
P(k)=I(k)X V(k)
P(k) > Pref
Delay V(k) and P(K) by K-1 instant V(k-1), P(k-1)
Yes NO
D = D - ∆D D = D + ∆D
∆P X ∆V> 0
Return
At the irradiation 725 W/𝑚2 the maximum
power of the PV equals the rated input power
of the motor
Under the 725 W/ 𝑚2 the P&O MPPT
technique is applied using the duty cycle of the
boost converter
Above the irradiation 725 W/𝑚2 The MPPT is
limited to the input rated power of the motor
by a control on the duty cycle of the boost
converter
The PV power is used to indicate the
irradiation
The power is maximized if the PV power less
than the rated input power of the motor
Else the PV power will be referenced to the
rated input power of the motor
74

Simulatuion Results – Dynamic Response
Arbitrary
irradiations levels
600, 725 and 1000
W/m2 were selected
75

76

Simulation Results – Dynamic Response
77

Simulation Results – Steady-State Characteristics
78

Closed Loop System Limited by Modulation-Index Control
∆P = P(k) – P(k-1)
∆V = V(k) – V(k-1)
M = Mc
Start
Read I(k) & V(k) &Vref &Mc &Dc
Yes
NO
P(k) = I(k) X V(k)
V(k) > Vref
Yes NO
D = D - ∆D D = D + ∆D
∆P X ∆V >
0
M = M - ∆M
Return
D = Dc
 At the irradiation 725 W/𝑚2
the maximum power
of the PV equals the rated input power of the
motor
 Under the 725 W/𝑚2 the P&O MPPT technique is
applied using the duty cycle of the boost converter
and Modulation index remains constant at the
selected value in design
 Above the irradiation 725 W/𝑚2 The MPPT is
limited to the input rated power of the motor
by a control on the modulation index of the
inverter and the duty cycle remains constant at the
selected value in design
The total motor voltage is used to indicate the
irradiation
The power is maximized if the total motor
voltage less than the rated total motor voltage
Else the total motor voltage will be referenced
to the rated total motor voltage
RMS of Vtotal=110 V
M=0.9 V1=92.4 V
M=0.662 V1=79.5 V
M=0.547 V1=72.3 V
79

Arbitrary
irradiations levels
600, 725 and 1000
W/m2 were selected
80

81

82

83

Forcing the MPPT Controller to obtain the input
rated power
Duty Cycle Modulation index
 As a result of the increase of the harmonic content in the limitation using
modulation-index control the limitation using duty-cycle control is
preferred
 The drawback of the motor unstable operation at lower irradiations was unsolved in
both control systems and the system is incapable of operating at these irradiations
84

Closed Loop System Limited by Duty-Cycle Control Aided with V/F Control
Objectives :
1- Stability operation for lower irradiations
2- Improving the system efficiency (internal eff (1-s))
 Use of frequency control is Implemented
85

Start
Yes
NO
Read VBoost &F/V& Fr &Mc
Read I(k) & V(k) & Pref
Frequency= (VBoost × M × (F/V)) / √2
Frequency> Fr
Frequency=Fr
∆P=P(k) – P(k-1)
∆V=V(k) – V(k-1)
P(k)=I(k)X V(k)
P(k) > Pref
Yes NO
D = D - ∆D D = D + ∆D
∆P X ∆V> 0
Return
Yes
NO
86

Arbitrary irradiations
levels 200, 600, 725 and
1000 W/m2 were
selected
87

88

89

90

 The use of frequency control improved the system stability at lower irradiations
providing a wider range of operation
91

Outlines
Experimental Work

Experimental work
PV terminal
panel
Tanks and
piping system
Single phase IM
Cupped to pump
Microcontroller
Single phase inverter
Experimental set up
92

PV array
Experimental set up
93

PV array
 PV was resistance loaded to draw its I-V characteristics
Experimental set up
94

PV array
PV I-V characteristics
Experimental set up
95

Tanks and Piping system
Experimental set up
 This tank setup is used to get raid of
source and destination of water problem
Destination
Source
96

Digital controller
Digital controllers are preferred than analog due to its flexibility and
programmable capabilities
 DSP and Microcontroller are varies ways to implement the controller
 Microcontroller abilities are sufficient to this application
Microcontroller has advantages of low cost ,isolated from PC
operation.
Microcontroller is preferred to be used in this application
Experimental set up
97

Microcontroller (Arduino UNO board)
 A microcontroller is used to generate the
gating signals for the inverter
 An AVR atmega328p microcontroller is used
 Arduino UNO board is used to get raid of
power, supply ,programming ,PC , and
oscillator interface problems
Experimental set up
98

SPWM gating signals generation
Direct Digital Synthesis (DDS) can generate any periodic signal form
a look up table of it’s samples.
The sinusoidal wave reference signal is generated using a DDS
technique .
Output
Reference sin
wave sample
Pre-scaler
8-bit index
accumulatorf clock
DDS
frequency
index
sinusoidal
look up
table
Experimental set up
99

SPWM gating generation
The atmega328p timers have two important modes of operation Fast
PWM and Clear Timer on Compare Match (CTC)
Two timers are used timer2 (Fast PWM) and timer1 (CTC)
Fast PWM allows generating carrier signal and outputs pulses
according to reference – carrier comparison
 Clear Timer on Compare Match (CTC) allows generating variable
frequency compare match interrupt which is used as DDS clock
Experimental set up
100

Output
Reference sin
wave sample
8-bit index
accumulator
Sin wav look up
table
DDS
clock
index
Pre-scaler Timer 2
Timer
frequency
Output
pulses
Pre-scaler Timer1
f clock
Compare match
interrupt
Required frequency
Modulation
index
f clock
Experimental set up
101

 SPWM gating signals
at
𝑓𝑜=50
𝑓𝑐=1KHz
M=0.9
at
𝑓𝑜=50
𝑓𝑐=1KHz
M=0.5
Experimental set up
102

SPWM gating generation
SPWM gating signals
at
𝑓𝑜=50
𝑓𝑐=2KHz
M=0.5
at
𝑓𝑜=50
𝑓𝑐=2KHz
M=.9
Experimental set up
103

Inverter depend on H-Bridge
technique.
Bipolar gating is used.
Switches need a pulse of 18V to
operate but controller output voltage
is just 5V so another level of switches
is used to control in 18V by 5V pulse
(Opto coupler).
Experimental set up
104

NOT IC
Used to
Invert
Controller
pulses
Input
Pulses
From
controller
(Opto- coupler)
Gated from
NOT IC
(Opto- coupler)
Gated from
Controller
Transforms
Used to
isolate
firing
signals for
switches
Experimental set up
105

 Current at R load
at
R=R1 ,195V
M=0.9
at
R<R1 ,195V
M=0.9
Experimental set up
106

 Current at inductive load
at
R=R1 ,L =L1 ,100V
M=0.9
at
R=R1 ,L <L1 ,100V
M=0.9
Experimental set up
107

Total system operation
DC fed Pump
No Load
Loaded
PV fed Pump
No Load
Loaded
Experimental results
108

Pump fed from DC supply
 NO Load
Starting current Speed run-up
109

 NO Load
Steady-state current Run speed
110

 NO Load
Speed Deceleration
111

 Loaded
112

 Loaded
Speed run up Run speed
113

 Loaded
Steady-state current
114

Pump fed from PV supply
 NO Load
115

 NO Load
Steady-state speed Speed deceleration
116

 Loaded
117

 Loaded
118

 Loaded
Steady-state current
119

Practical System
120

Electrical Supply
1- Grid Connected 2-Diesel Generator 3- PV System
Common Methods Used for Supplying Pumping Systems
121

 It is not suitable for remote areas.
 Outage is widespread specially in Summer.
It costs the consumer 200 LE/month/acre.
Power supplied from the grid represents a burden, as pumps consume form 25:50 KW for
every 5 acres.
1-Main Features of Pump Fed by Grid
122

123

 Diesel fuel is not easily to transport to areas of use
 Its cost is high and in a continuous increasing
 It is not easily available in times of increased demand
 Impurities and dust in diesel fuel cause damage to the pump and thus
require maintenance and there for additional cost.
 Pollute the environment and noisy.
2- Main Features of Pump fed by Diesel Generator
124

 Can be used in remote areas.
 Do not pollute the environment.
 It is not noisy.
 It does not require any maintenance just inverter maintenance every 5 years.
 It has a long life time 25 years.
3- Main Features of Pump fed by PV System
125

For 20 HP Pump
20-25 acres
20 𝑚3 water
50 m depth
7 hours/day
Case Study
 [1] Using Grid
200 LE/month/acre
4000 LE/month
4000*12 = 48000 LE/year
126

 [2] Diesel Generator Running cost
Requires 35 liter diesel fuel per day
35*30 = 1050 Liter/month
1050*12 = 12600 Liter/year.
for average cost 2 LE/Liter
So 12600*2 = 25200 LE/year
Diesel generators require oil exchange
every year with a cost 6000 LE/year
Total cost 25200+6000= 31200 LE/year
 [3] Using PV pumping`s cost
with cost 9000 LE/HP
for 20 HP
20*9000 = 180000 LE
Case Study
127

Grid Diesel Generator PV
Initial cost (LE/year) ---- 90,000 180,000
Running cost (LE/year) 48,000 31,200 ----
Maintenance cost
(LE/year)
----
10,000
Generator’s maintenance
every 5 years
1,500
inverter’s
maintenance every
5 years
Total cost for 25 years
(LE)
1,200,000 920,000 187,500
Financial Comparison between the 3 Sources
128

Grid Diesel Generator PV
Initial cost (LE/year) ---- 90,000 180,000
Running cost (LE/year) 48,000 31,200 ----
Maintenance cost
(LE/year)
----
10,000
Generator’s maintenance
every 5 years
1,500
inverter’s
maintenance every
5 years
Total cost for 25 years
(LE)
1,200,000 920,000 187,500
Financial Comparison between the 3 Sources
129

Practical Systems for PV Pumping Systems
130

Conclusions
 The project presented a simple PV water pumping system with the aim of studying its
performance analysis and possibilities for enhancement
 System different components; PV cells, centrifugal pumps, driving motors, DC/DC boost
converters, DC/AC inverters, were described and modelled
 Two systems were studied; one based on a separately-excited DC motor and the other on a
single-phase induction motor, and each was studied under-open loop and closed-loop conditions
 For the DC motor-Based PV pumping system, design considerations guaranteed the maximum
power of the PV array to equal the rated input power of the motor at certain selected irradiation
with a DC/DC boost converter taken into consideration
131

Conclusions
 Under open-loop operation:
 With lower irradiations, the PV was not utilized to its maximum power, the motor was
derated and the pump’s flow rate reduced
 With higher irradiations, the motor was exposed to over voltages and over currents
 Control objectives were to:
 Obtain the maximum PV power at lower irradiations
 Limit the PV power to the rated input power of the motor at higher irradiations
 P&O MPPT Technique with power limitation modification was employed to achieve these
objectives
132

Conclusions
 Under closed-loop control operation, at lower irradiations the MPPT algorithm successfully
operated the PV at its maximum power point while at higher irradiations, the motor and
consequently the pump were operated at its rated value
 The control algorithm proposed was proven effective in performance enhancement
 Single-Phase Induction Motor-Based had the same design considerations with different motor
and pump ratings and the addition of an inverter taken into consideration
 Under open-loop operation:
 For all irradiations, PV power not utilized to its maximum, motor was derated with
increased currents due to increased slip and pump flow rate reduced
 Motor was unstable at lower irradiations with lower voltages
133

Conclusions
 For performance enhancement, there systems were proposed:
 Closed-loop system limited by duty-cycle control
 Closed-loop system limited by modulation index control
 Closed-loop system limited by duty-cycle control aided with V/f control
134

Future Work
 Operation of the experimental system under closed loop conditions as tested in simulation by
providing voltage and current transducers
 Using a three phase induction motor with the control algorithms obtained in the study
 Using batteries to make use of the wasted power at higher irradiations. As at higher irradiations
the power is limited to operate at rated conditions. Implementing batteries in the system will
need an energy management study
 Implementation of AC filters to eliminate the harmonic content produced by the inverter to
prevent derating of the machine and reduce losses
 Implementation of a sun tracker system to maintain maximum possible irradiation falling on the
PV with position control and irradiation sensors. Thus, adding sun tracker to MPPT tracking will
significantly enhance the total system efficiency and operate at high efficiency for longer periods
of time
135

Solar system

More Related Content

What's hot

Similar to Solar system

More from Ahmed M. Elkholy

Recently uploaded

Solar system

Editor's Notes