Final Project Done by Students of UQU College of Engineering and Islamic Architecture.

1. Study and Design of a
Grid Tie Photovoltaic
System By
Nasser Mansour Alblhi , I.D.: 434006515
Tammam Ali Ba’ashn , I.D.: 433013312
Ahmed Shafi , I.D.: 433013343
Abdullah Ahmed Alslim , I.D.: 433013558
Project Advisor: Prof. Anis Ammous
Department Affiliation: Electrical Engineering Department,
College of Engineering and Islamic Architecture, Umm Al-Qura
University, Makkah Al-Mukarramah

2. 1- introduction
2- state of the art about PV systems
3- description of the designed system
4- Realization of the PV system
5- conclusion

3. 1-Introduction
The increase in electricity demand along with population
makes it hard for electricity Company to satisfy all customer
needs. Therefore, there must be support electricity
generation the most famous way Fossil fuels are non-
renewable, will eventually dwindle, becoming too
expensive or too environmentally damaging to retrieve.

4. Solar energy is an effective alternative,
mostly it is not connected to the grid (Off-
Grid System). It has some problems that
reduce its effectiveness; one of these
problems is its limitation to provide power to
all loads since volume of batteries would be
prohibitive .

5. Our Project aims to study and design an Inverter
that connect the DC part of the system with the
grid including all the control and the margin of
losses and THD levels
We have two objectives:
(1) Designing a grid tie PV system with injected
current good quality
(2) Realization DC/AC converter with modern
control methods.

6. 1- introduction
2- state of the art about PV systems
3- description of the designed system
4- Realization of the PV system
5- conclusion

7. 2-State of The Art about PV System
 Photovoltaic (PV) Solar cells convert sunlight directly into electricity.
 Operating Characteristics of PV panels:
Fig 1: IV Curve of photovoltaic module

8.  Behavior of PV panels at different irradiance
 behavior of PV panels at different temperature
Fig 2:IV Curve of PV panels with different irradiance
Fig 3:IV Curve of PV panels with different temperature

9. Off Grid System
Fig 4: Off grid system

10. 
Benefits:
 Provides power for critical loads when the power grid is down.
 Off-grid solar systems can be cheaper than extending power lines
in certain remote areas.
Downside:
 Limitation of batteries.
 Batteries are expensive; require ongoing maintenance and periodic
replacement.
 There are dangerous to deal with high current batteries so caution
needs to be exercise

11. On Grid System
Fig 5: On Grid System

12. Benefits:
 Always there is access to power.
 Save more money
 Reliable and stable energy
Downside:
 No power during grid outage.
Types of pure On-Grid Solar PV systems
 1- String Inverter
Fig 6: String Inverter

13.  Micro Inverter
 Power Optimizers
Fig 7:Micro Inverter Type
Fig 8:Power Optimize

14. 1- introduction
2- state of the art about PV systems
3- description of the designed system
4- Realization of the PV system
5- conclusion

15. Proposed System
Fig 9: proposed system diagram

17. DC/DC Converters
 A DC-to-DC converter is an electronic circuit or
electromechanical device that converts a source of direct
current DC from one voltage level to another
 In our project we used Boost converter producing a
voltage higher than the input voltage
Fig 10: circuit diagram of dc/dc boost converter

18. Maximum power point tracking
technique:
 Since the output of converter is variable, we will control
the switching IGBT of the DC boost converter such that
the output power will be maximum
Fig 11: PV characteristic

19. Fig12: P&O method
We used Perturb and observe method as shown

20. Fig 13: MPPT controller implemented in
Fig 14: PV power output controlled by P&O MPPT controller

22. 1- Voltage regulation loop using PI
controller
 it's important to protect DC bus from high voltage
levels during transient state and even during
operation. Best controller to do such function is PI
controller .
Fig 15: PI controller diagram

23. Fig 16: PI controller circuit diagram

24. 2-Inverter circuit and Hysteresis
controller:
 In order to design a grid tie solar system, there must be
an inverter to synchronize PV panel's voltage to the grid
voltage along with optimization of system performance
 Inverter can't operate without control deriving signal.
 Therefore, we designed this system with hysteresis
band controller.
 Hysteresis controller controls the load current by forcing
it to operate in a band in the shape of reference signal.
 Hysteresis controller takes the PI control signal in
sinusoidal form as an input .
 the band affect the shape of the sinusoidal output signal
in which affect the THD levels of the signal.

25. Fig 17: Hysteresis band
Fig 18:Hysteresis block diagram

26. Inverter
 inverter is an electronic device that converts direct
current (DC) to alternating current (AC), the converted
Ac can be at any required voltage and frequency.
 In our project we used single phase full wave inverter
Fig 19: single phase full wave
inverter
Fig 20: Output of inverter

27. Results
 We used MATLAB/SIMULINK to simulate the proposed system
 In the following slides, the output of the controllers and the final
circuit are shown.

28. Fig 21: Output of PI controller
Fig 22: voltage of protected
DC bus

29. Fig 23: hysteresis controller as SIMULINK function

30. Fig 24: output signals from hysteresis

31. Final circuit of the proposed system
 we connected all the subsystems to one circuit of this
proposed system. Many parameters will change due to
this connection as well as the initial transient state needs
to be taken in consecration
Fig 25: circuit of the proposed system of solar system inverter

32.  Output for different values of hysteresis band (Delta I)
Fig 26: output THD% with Delta I=0.5A, fixed inductance at 2mH
Fig 27: output current with Delta
I=0.5A, fixed inductance at 2mH

33. Fig 19: output with Delta I= 0.1 ,
fixed inductance at 10mHFig 28: output THD% with Delta I=0.1A, fixed inductance at 10mH
Fig 29: output current with Delta
I=0.1A, fixed inductance at 10mH

34. Fig 30: output of the system

35. 1- introduction
2- state of the art about PV systems
3- description of the designed system
4- Realization of the PV system
5- conclusion

36. Realization of the proposed system and Testing
 After designing completed the team started
implementing the Inverter circuit.
 In Proteus program we designed the PCB layout and
printed the inverter circuit.
 Devices were installed on the PCB
 Modification on the design was made to fix the errors.
 Testing was done to make sure that the circuit operates
well.

37. Components
 1- Voltage Sensor:
 A voltage sensor can in fact determine, monitor and can measure the
supply of voltage. It can measure AC level or/and DC voltage level.
 In our system we used 12V transformer as voltage sensor to get an
image of the grid
 We used the resistive type as shown:
So Vout = 2.5 V
Fig 31 : Resistive Voltage sensor using 12V transformer

38. Fig 32: output of the image of the grid

39. 2- Current Sensor:
 A current sensor is a device that detects electric current in a wire, and
generates a signal proportional to that current
 In our system we used current sensor to detect system current and
send it to the microcontroller.
 There are three Pins connected to the connector as following:
 •An image of the system current (Out)
 •+5V input
 •0V GND
Fig 33: current sensor diagram

40. 3-IGBT
 An IGBT, or insulated gate bipolar transistor, is a solid state device (with
no moving parts). It is a switch that is used in order to allow power flow
in the On state and to stop power flow when it is in the Off state. An
IGBT works by applying voltage to a semiconductor component,
therefore changing its properties to block or create an electrical path.
Features of IGBT:
 • Voltage driven (easy to drive)
 •Continuous gate signal requirement
 •Unidirectional current capability
 •Low conduction losses
 •Fast switching
Fig 34: IGBT circuit

41. 4-Heat sink
Rsa<
𝑇jmax −𝑇𝑎
𝑅
− 𝑅𝑗𝑐 − 𝑅𝑐𝑠
From IGBT datasheet:
T jmax= 125°C
Rj-c=0.43 °C/W
The thermal resistance Rcs is
assumed to be 0.2 °C/W
Ta is assumed equal to 50 °C
The dissipated power in each IGBT is
assumed to be 30W
From the above equation, we can deduce:
Rsa= 0.19 °C/W
Fig 35: Thermal resistance of heat sink
Heat sinks are devices that enhance heat dissipation from a hot
surface, usually the case of a heat generating component, to a
cooler ambient, usually air

42. Inverter Circuit
Connector
Inductor
Current Sensor
Voltage Sensor
Fig 36: Inverter Circuit

43. 1- introduction
2- state of the art about PV systems
3- description of the designed system
4- Realization of the PV system
5- conclusion

44. CONCLUSION
 This project accomplished a grid tie solar system with
desired performance and quality.
 The major topic of this project was the DC/AC converter
or Inverter and all its peripheral circuits and controllers.
 The team planned to work on improving this project in
the future and convert it into a product.