Major Final Print
Major Final Print
Major Final Print
BACHELOR OF TECHNOLOGY
in
ELECTRICAL AND ELECTRONICS ENGINEERING
By
Mr. T. MANIDHAR ME
Associate Professor
CERTIFICATE
This is to certify that the project entitled “MODELING AND SIMULATION OFMICRO
CONTROLLER BASED MPPT METHOD USING FPGA” is being presented with report
by B. GAYATRI SIRISHA C. SANTHOSHKUMAR, P. PREETHAM, bearing roll
numbers, 17831A0207, 17831A0209, 17831A0235 in partial fulfillment for the award of
Degree of Bachelor of Technology in Electrical and Electronics Engineering to Jawaharlal
Nehru Technological University, Hyderabad.
EXTERNAL EXAMINER
ii
VISION OF THE INSTITUTION
M3: Maintain high academic standards and teaching quality that promotes the analytical
thinking and independent judgment.
M5: Offer collaborative industry programs in emerging areas and spirit of enterprise.
QUALITY POLICY
GNIT is committed to provide quality education through dedicated and talented Faculty,world
class infrastructure, Labs and Advanced Research center to the students.
iii
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
To be recognized as one of the best EEE departments in the region and to develop the
department to a level of par excellence that produces Electrical Engineers who can bean asset
to the country.
➢ To nurture young individual into knowledge, skillful, and ethical professionals intheir
pursuit of knowledge.
➢ To promote academic growth by offering state of the art programmers for thestudents and
faculties.
➢ To develop human potential to its fullest extent so that intellectuals capable ofbeing an asset
to the country can emerge.
➢ To nurture the faculty and expose them to world class infrastructure.
➢ To sustain high performance by excellence in teaching, research and innovations.
➢ To extensive partnership and collaborations with foreign universities fortechnology up
gradation.
iv
DEPARTMENT OF ELECTRICAL AND ELECTRONICSENGINEERING
1. The main objective of Electrical and Electronics Engineering Program is the upliftmentof
rural students through technical education. These technocrats should be able to apply basic and
contemporary science, engineering, experimentation skills to identifyElectrical/Electronic
problems in the industry and academia and be able to develop practical solutions to them and
also, gain employment as an Electrical and Electronics professional.
2. The graduates of Electrical and Electronics Engineering Program should be able to establish
themselves as practicing professionals in Electrical Transmission & Distribution, Electrical
grid, Generating Plant, or sustain a life-long career in related areas. Also, the graduates of
Electrical and Electronics Engineering Program should be able to use their skills with a strong
base to prepare them for higher education.
3. The graduates of Electrical and Electronics Engineering Program should be able to develop
an ability to analyze the requirements, understand the technical specifications, design and
provide economical & social acceptable engineering solutions and produce efficient product
designs of equipment’s by means of organized training or self-learning inareas related to
Electrical and Electronics Engineering.
4. The graduates of Electrical and Electronics Engineering Program should have an exposure
to emerging cutting edge technologies, adequate training and opportunities to work as team on
multidisciplinary projects with effective communication skills, individual, supportive and
leadership qualities and also be able to establish an understanding of professionalism, ethics,
public policy and aesthetics that allows them to become good professional engineers.
v
PROGRAM OUTCOMES (PO’S):
Engineering Graduates will be able to:
1. Engineering knowledge: Apply the knowledge of mathematics, science, engineering
fundamentals, and an engineering specialization to the solution of complex engineering
problems.
2. Problem analysis: Identify, formulate, review research literature, and analyze complex
engineering problems reaching substantiated conclusions using first principles of mathematics,
natural sciences, and engineeringsciences.
3. Design/development of solutions: Design solutions for complex engineering problems and
design system components or processes that meet the specified needs with appropriate
consideration for the public health and safety, and the cultural, societal, and environmental
considerations.
4. Conduct investigations of complex problems: Use research-based knowledge and
research methods including design of experiments, analysis and interpretationof data, and
synthesis of the information to provide valid conclusions.
5. Modern tool usage: Create, select, and apply appropriate techniques, resources, and
modern engineering and IT tools including prediction and modeling tocomplex engineering
activities with an understanding of the limitations.
6. The engineer and society: Apply reasoning informed by the contextual knowledge to
assess societal, health, safety, legal and cultural issues and the consequent responsibilities
relevant to the professional engineering practice.
7. Environment and sustainability: Understand the impact of the professional engineering
solutions in societal and environmental contexts, and demonstrate theknowledge of, and need
for sustainable development.
8. Ethics: Apply ethical principles and commit to professional ethics and responsibilities and
norms of the engineering practice.
9. Individual and team work: Function effectively as an individual, and as a member or
leader in diverse teams, and in multidisciplinary settings.
vi
10. Communication: Communicate effectively on complex engineering activities with the
engineering community and with society at large, such as, being able to comprehend and write
effective reports and design documentation, make effectivepresentations, and give and receive
clear instructions.
11. Project management and finance: Demonstrate knowledge and understanding of the
engineering and management principles and apply these to one’s own work,as a member and
leader in a team, to manage projects and in multidisciplinary environments.
12. Life-long learning: Recognize the need for, and have the preparation and ability to
engage in independent and life-long learning in the broadest context of technological change.
MAPPING OF PROGRAM EDUCATIONAL OBJECTIVES (PEO’S) AND
PROGRAM OUTCOMES (PO’S) FOR ELECTRICAL AND ELECTRONICS
ENGINEERING:
vii
DECLARTION
This is to certify that the work reported in the present report titled “MODELING
AND SIMULATION OF MICRO CONTROLLER BASED MPPT METHOD USING
FPGA” is a record of work done by us in the Department of Electrical and Electronics
Engineering, Guru Nanak Institute of Technology, Ibrahimpatnam.
No part of the thesis is copied from books / journals / internet and wherever the
portion is taken, the same has been duly referred in the text. The reported work is based on
the project work done entirely by us and not copied from any other source.
viii
ACKNOWLEDGEMENT
We extend our deep sense of gratitude to the Management and Principal Dr. S.
Sreenatha Reddy, Dean Dr. Sanjeev Shrivastava and the management of Guru Nanak
Institute of Technology for providing us the best enmities to enable us complete our project
work in the stipulated time.
We also extend our sincere thanks to Dr. Nagaraja Kumari Ch, Associate Professor &
Head of the department EEE for his valuable guidance and unstinting support which gave
us the confidence required to overcome the obstacles that we faced in the completion of
this project.
We also extend our sincere thanks to Mr. T. Manidhar, Associate Professor of Electrical
and Electronics Engineering for his valuable guidance and unstinting support which gave
us the confidence required to overcome the obstacles that we faced in the completion of
this project
Last but not least, we are very thankful to our parents, friends and other faculty of the
Department of Electrical and Electronics Engineering for their constant support for
completion of this project.
ix
ABSTRACT
Solar photovoltaic (PV) is one of the most promising renewable energy resources
that converts solar energy into electricity with environment friendly manner. However, it
has low efficiency and high relative costs. In order to overcome these drawbacks, a grid-
connected PV energy system should be required to satisfy the load demand.
The aim of this thesis is to study, design a performance analysis of grid-connected
PV system as follows Improving the efficiency of grid-connected PV system to operate at
maximum power point (MPP) with the aid of perturb and observe (P&O) tracker.
This work focuses on the design and development of FPGA-based digital
controller for the grid connected solar photo-Voltaic (PV) systems as a distributed
generation. The proposed grid connected PV system is able to deliver a sinusoidal current
to the utility grid in-phase with grid voltage. In this work, the system is operated in
discontinuous conduction mode. The advantage of this mode of conduction is that it feeds
sinusoidal current with near to unity power factor into the grid. Due to the versatility of
Field Programmable Gate Array (FPGA), it offers significant advantages in high
performance and low volume applications. The level of optimization in FPGAs is very
high in comparison to microprocessors or Digital Signal Processors (DSPs) as FPGAs
allow customizable bit-widths and massive instruction-level parallelism. The proposed
FPGA-based control scheme for single- stage grid connected photovoltaic system
generates switching pulses in such a way that sinusoidal current with unity power factor is
injected into the grid
x
LIST 0F FIGURES
xi
5.6 I-V and P-V Characteristics of one module at 25degree 32
5.7 I-V and P-V Characteristics of array at 25 degree 32
5.8 a. Grid Voltage Waveforms 33
5.8 b. Grid Current Waveforms 33
5.9 Source current and Source Voltage 34
5.10 PV Voltages at maximum power for different 34
irradiance
xii
LIST OF TABLES
Table. No Name of the Table Page. No
Xiii
LIST OF ABBREVATIONS
xiv
INDEX
I. Certificates ii
II. Declaration viii
III Acknowledgement ix
1V Abstract x
V List of Figures xi-xii
VI List of Tables xiii
VII List of Abbreviations xiv
CHAPTER-1 INTRODUCTION 1-5
1.1 Introduction 1
1.2 Classification of energy resources 2
1.3 Literature Review 2-4
1.4 Project Motivation 4
1.5 Scope of Work 5
1.6 Organization of Project 5
5.1 Introduction 30
5.2 Boost Converter based MPPT Charger Controller 30-31
5.3 Simulation and Results 31-35
CHAPTER 1
INTRODUCTION
1.1 Introduction
The present day electronics world is moving towards miniaturization and low
priced equipments. At the risk of making a trite observation, the last two decade of
advances in microcontrollers, processors, and programmable logic have opened up
tremendously exciting possibilities for enhancing performance, applicability, and
economy of power electronics appliances. Thus implementing a digital circuit in place
of analog circuit attracts all the benefits associated with digital circuits.
In modern contest the world is moving from conventional energy sources to the
renewable one. To overcome the problems associated with generation of electricity
from fossil fuels, renewable energy sources can be participated in the energy mix. One
of the renewable energy sources that can be used for this purpose is the light received
from the sun. This light can be converted to clean electricity through the photovoltaic
process. The use of photovoltaic (PV) systems for electricity generation started in the
seventies of the 20th century and is currently growing rapidly worldwide.
Power electronic devices are working as an interface between grid and solar
power output. Power electronics refers to control and conversion of electrical power
with the help of power semiconductor devices, which used as switch. Advent of silicon
controlled rectifier led to the development of new area of applications [1]. Simple
triggering circuit can be realized by R or Resistance and Capacitance network. They are
not expensive and little power required for its operation. However the control and hence
the load output voltage susceptible to device temperature variations. Moreover feedback
control incorporation is not easy.
1.2 CLASSIFICATION OF ENERGY RESOURCES
The energy resources are generally classified into two categories:
1. Non-Renewable Resources of Energy
2. Renewable Resources of Energy
1.2.1 Non-Renewable Resources of Energy
Non-Renewable Resources are those natural resources which are exhaustible and
cannot be replaced once they are used. Non renewable resources are as follows:
a) Coal
b) Petroleum
c) Natural gal
d) Uranium etc.
The islanding of a grid connected independent generator occurs when a section of the
utility system containing such a PV system is disconnected from the grid line but the
grid connected inverter continues to energize the energy to the grid line in the isolated
section [5]. There are many reasons that islanding should be prevented with
photovoltaic or any other distributed energy generation. The safety, liability and
maintaining the quality of delivered power to customers ranks high on the list of
reasons [6]. The ANF structure on its own is able to provide a smooth frequency
detection as well as magnitude estimation without introducing any delay into the
estimation loop [7]. Carrasco et al. [8] proposed Power-Electronic Systems for the Grid
Integration of Renewable Energy Sources and presented new trends in power
electronics for the integration of wind and photovoltaic (PV) power generators. A
storage system technology was introduced for the resources whose output changes.
Kazantzakis et al. [18] proposed a method to integrate the photovoltaic system into
distribution network operations. Distributed PV generator was used to improve the
stability of system by appropriate control. Power modulation should be such that power
quality remainswithin specified limit. Magureanu et al. [19] proposed a real solution for
Renewable energy sources connection into distribution. Direct current link was
proposed and simulated. A new method for load sharing and droop control was
presented. Nayar et al. [20] presented the bi-directional inverters application in the
field of PV, diesel generators and battery storage. Gonzalez-Moran et al. [21] proposed
and described a photovoltaic direct current source model. PV o/p could be supplied to
inverters, which connected to grid. Proposed model considered all the parameters that
could affect o/p of PV. Mei Shan Ngan et al. [22] discussed two categories of maximum
power point tracking algorithm algorithms. Also, the advantages and disadvantages of
each maximum power point tracking algorithm were reviewed. Also compared the
results obtained by the algorithms used.
Martina Calais et al. [23] presented an overview on different multilevel topologies
and investigated their suitability for single-phase grid connected photovoltaic systems.
Gianfranco Chicco et al [24] discussed the operation of grid connected photovoltaic
(PV) systems and provided a detailed performance comparison of different inverter
technologies for connecting the photovoltaic systems to the grid.
Massimo Aiello et al. [25] calculated total harmonic distortion theoretically and
experimentally in order to show which of the currently defined distortion factors was
best suitable to detect supply pollution. Hirotaka Koizumi et al. [26] developed a novel
microcontroller for grid-connected photovoltaic (PV) systems. A 100-W-class module-
integrated converter prototype model composed of the proposed controller and a fly
back inverter had been built and tested. Brando et al. [27] proposed an architecture that
Department of EEE 3 GNIT
Modeling and Simulation of Micro Controller Based MPPT Method Using FPGA
CHAPTER 2
SOLAR PV SYSTEMS AND SOLUTIONS
2.1 INTRODUCTION
This chapter gives an overview of grid connected inverters and the PV systems. Grid
connected technologies have been discussed. The important solar characteristics in
relations to temperature and irradiance and how the open circuit voltage is affected are
depicted in the chapter. Standards to design and installation practices of PV-grid
connected systems discussed in this chapter play the significant role at the point of
common coupling. These standards helped in the development of the proposed PV
system.
2.2 SOLAR ENERGY
Solar PV systems convert sunlight into electrical energy. Photons of light hitting the
solar panel knock electrons in the substrate material into a higher level of activity; these
electrons are then channelled off of the panel to create DC electricity. In most cases, an
inverter will be used to convert the DC power into AC power, making it more directly
usable to consumers as most modern electric appliances operate only on AC power.
2.2.1. PHOTOVOLTAIC ENERGY CONVERSION
It works on the principle of simple PN junction. PV cell converts sun energy into
direct current. To get required dc power cells are connected in series and parallel to get
required power level. When cells are connected in series increases the voltage while in
parallel connection increase the current [6]. Figures 2.1 show photovoltaic energy
conversion.
2.4.3 PVARRAY
A PV array consists of several photovoltaic cells in series and parallel connections.
Series connections are responsible for increasing the voltage of the module whereas the
parallel connection is responsible for increasing the current in the array.
V+IR
I = I ph − I01 e KT −1 − I02 e nKT −1 − s → (2.1)
q(V+IRs ) q(V+IRs )
RP
V+IR
I = I ph − I02 e nKT −1 − s
q(V+IRs )
→ (2.2)
R P
The I-V characteristics of PV cell shown in fig1.6.The double exponential model and
single exponential model eqn1.2 are used to characterize the PV cell. [1–3] A PV cell
behaves differently depending on the size/type of load connected to it. This behavior is
called the PV cell ’characteristics’. The characteristic of a PV cell is described by the
current and voltage levels when different loads are connected.
Where
V =PV cell terminal voltage (V).
I = PV cell terminal current (A).
Iph = photocurrent (A).
I01 =saturation current due to diffusion mechanism (A).
I02 = saturation current due to carrier recombination in space-charge region (A).
The module’s temperature increases, the voltage value decreases and vice versa. It is
important to put into consideration the cold and hot temperatures during PV design as
shown in PV calculations. If the temperature of the module is less than the STC value
of 25°C, the module’s open circuited voltage, Voc value will actually be greater than
the value listed on the module’s listing label.
2.5.2 Module Current and Irradiance
The amount of current produced by a PV module is directly proportional to how bright
the sun is. Higher levels of irradiance will cause more electrons to flow off the PV cells
to the load attached. However the amount of voltage produced by the PV module is
affected by the irradiance value, but the effect is very small. As demonstrated in Fig.
2.5 the PV module’s voltage changes very little with varying levels of irradiance.
disadvantage. These approaches have been effectively used in standalone and grid-
connected PV solar energy systems and work well under reasonably slow and smoothly
changing illumination conditions mainly caused by weather fluctuations, seen also in
[5] [10].
In order to utilize the maximum power produced by the PV modules, the power
conversion equipment has to be equipped with a maximum power point tracker
(MPPT). This is a device which tracks the voltage at where the maximum power is
utilized at all times. It is usually implemented in the DC-DC converter, but in systems
without a DC- DC converter the MPPT is included in the DC-AC inverter control [7].
MPPT will ensure that, PV modules operate in such away maximum voltage, Vmp an
maximum current, Imp of the modules will be attained and produce maximum power,
Pmp point. However these values together with short-circuit current, Isc and open
circuitvoltages, Voc as illustrated on the Fig.2.6 are specified in the PV module data
sheet attached to it. The values are at standard test condition (STC) and they are called
PV performance parameters.
proper installation of PV system. The 690 code explain most of the important
information in both design aspects and installation. Some of this important information
includes;
• PV system conductors and coding.
• Grounding system and Module connection
• PV source circuits, PV Inverter output circuits and circuit routing.
• Identification of equipment used and system circuit requirements i.e. Open
Circuit voltage and short-circuit current.
CHAPTER 3
DSP CONTROLLER AND FIELD PROGRAMMABLEGATE ARAY
(FPGA)
3.1 DIGITAL SIGNAL PROCESSING (DSP)
Digital signal processing (DSP) is the use of digital processing, such as by computers
or more specialized digital signal processors, to perform a wide variety of signal
processing operations. The digital signals processed in this manner are a sequence of
numbers that represent samples of a continuous variable in a domain such as time,
space, or frequency. In digital electronics, a digital signal is represented as a pulse train,
which is typically generated by the switching of a transistor.
Digital signal processing and analog signal processing are subfields of signal
processing. DSP applications include audio and speech processing, sonar, radar and
other sensor array processing, spectral density estimation, statistical signal processing,
digital image processing, data compression, video coding, audio coding, image
compression, signal processing for telecommunications, control systems, biomedical
engineering, and seismology, among others. DSP can involve linear or nonlinear
operations. Nonlinear signal processing is closely related to nonlinear system
identification and can be implemented in the time, frequency, and spatio-temporal
domains. Identification and can be implemented in the time, frequency, and spatio-
temporal domains.
3.2 PURPOSE OF DIGITAL SIGNAL PROCESSING (DSP)
The goal of a DSP is usually to measure, filter or compress continuous real-world
analog signals. Most general-purpose microprocessors can also execute digital signal
processing algorithms successfully, but may not be able to keep up with such processing
continuously in real-time.
LTE, etc. In this type of architecture, as per the latency requirements, few of the
modules are ported on FPGA and the other few on DSP.
3.2.2 MICROPROCESSOR
The microprocessor is the central unit of a computer system that performs arithmetic
andlogic operations, which generally include adding, subtracting, transferring numbers
from one area to another, and comparing two numbers. It's often known simply as a
processor, a central processing unit, or as a logic chip. It's essentially the engine or the
brain of the computer that goes into motion when the computer is switched on. It's a
programmable, multipurpose device that incorporates the functions of a CPU (central
processing unit)on a single IC.
A microprocessor accepts binary data as input, processes that data, and then
provides output based on the instructions stored in the memory. The data is processed
using the microprocessor's ALU (arithmetical and logical unit), control unit, and a
register array. The register array processes the data via a number of registers that act as
temporary fast access memory locations. The flow of instructions and data through the
system is managed by the control unit. Examples of the second-generation
microprocessors are 16-bit arithmetic 7 pipelined instruction processing, MC68000
Motorola microprocessor. These processors are introduced in the year 1979, and Intel
8080 processor is another example of the microprocessor
3.2.3 Advantages of a Microprocessor
The microprocessor is that these are general purpose electronics processing devices
which can be programmed to execute a number of tasks.
• Compact size
• High speed
• Low power consumption
• It is portable
• It is very reliable
• Less heat generation
• The microprocessor is very versatile.
3.3 FIELD-PROGRAMMABLEGATEARRAY (FPGA)
A field-programmable gate array (FPGA) is an integrated circuit designed to be
configured by a customer or a designer after manufacturing – hence the term “field-
programmable”. The FPGA configuration is generally specified using a hardware
description language (HDL), similar to that used for an application-specific integrated
circuit (ASIC). Circuit diagrams were previously used to specify the configuration but
this is increasingly rare due to the advent of electronic design automation tools.
CHAPTER 4
PROJECT DESCRIPTION
4.1 ELECTRICAL GRID
An electrical grid is an interconnected network for electricity delivery from producers
toconsumers. Electrical grids vary in size and can cover whole countries or continents.
It consists of:
• Power stations: often located near energy and away from heavily populated areas
• Electrical substations to step voltage up or down.
• Electric power transmission to carry power long distances.
• Electric power distribution to individual customers, where voltage is stepped
down again to the required service voltage(s).
Although electrical grids are widespread, as of 2016 1.4 billion people worldwide were
not connected to an electricity grid.[2]. As electrification increases, the number of
people with access to grid electricity is growing. About 840 million people (mostly in
Africa) had no access to grid electricity in 2017, down from 1.2 billion in
2010.[3]Electrical grids can be prone to malicious intrusion or attack; thus, there is a
need for electric grid security. Also as electric grids modernize and introduce computers,
cyber threats also start to become a security risk.[4].
Particular concerns relate to the more complex computer systems needed to
manage grids.[5]Grids are nearly always synchronous, meaning all distribution areas all
operate with three phase alternating current (AC) frequencies synchronized (so that
peaks occur at virtually the same time). This allows transmission of AC power
throughout the area, connecting a large number of electricity generators and consumers
and potentially enabling more efficient electricity markets and redundant generation.
The combined transmission and distribution network is part of electricity
delivery, known as the "power grid" in North America, or just "the grid". In the United
Kingdom, India, Tanzania, Myanmar, Malaysia and New Zealand, the network is known
as the National Grid. Electric utility companies established central stations to take
advantage of economies of scale and moved to centralized power generation,
distribution, and system management.[6] After the war of the currents was settled in
favor of AC power, with long-distance power transmission it became possible to
interconnect stations to balance load and improve load factors.
4.2 Power Electronics Consideration
As described earlier, a variety of PFC circuit topologies [26] can be used which include
the boost converter and the buck converter. Though soft switched Zero-Voltage-
Department of EEE 20 GNIT
Modeling and Simulation of Micro Controller Based MPPT Method Using FPGA
Transition (ZVT) techniques can be used for switching all the above topologies, the hard
switched boost converter PFC circuit [4] is more popular due to its simplicity and ability
to achieve a low distortion input current waveform. The Continuous Conduction Mode
(CCM) and Critical Conduction Mode (CRM) PFC circuit topologies are the most
popular. However, both have their advantages and disadvantages. In the following
section, the CCM boost converter is discussed.
4.2.1 The CCM Boost Converter
Since the remaining part of the work is now based on a CCM PFC circuit, a detailed
discussion on the boost converter is presented below. A CCM boost converter
schematic is shown in the Fig. 4.1. Now, from the above equations, the inductor voltage
and capacitor current waveforms are plotted in Fig. 4.2, D is the on-time duty cycle of
the Q1and TS is the switching period.
The total volt-seconds applied to the inductor over one switching period is given by,
Ts
From the above, it is apparent that the output voltage increases as D increases.
However, when component non-idealizes are included, there is a limit to the maximum
possible output voltage of a boost converter.
The DC component of the inductor current (I) is derived from the fact that the
total charge on the output capacitor is always balanced. When the Q1 turns on, the load
current depletes the charge from the output capacitor while the capacitor recharges once
the Q1 turns off.
The net charge in the capacitor is found by integrating the above capacitor
current waveform
Ts V V
i (t)dt = − R DT + 1− R (1− D)T
c S s →(4.4)
0
Equating this equation to zero and collecting terms we get
−V
( D +1− D) − I (1− D) = 0 →(4.5)
R
V
I= →(4.6)
(1− D)R
Vg
I= →(4.7)
(1− D)2 R
From the plot of this equation shown in Fig. 4.3, it is apparent that the inductor
current’s DC component increases as the duty cycle increases.
The inductor current’s DC component is greater than the load current The inductor
current’s DC component is greater than the load current since the boost converter’s
output voltage is greater than the input voltage. The inductor winding resistance and
semiconductor voltage drops, through which the inductor current flows, are sources of
power loss. Thus, as the inductor current increases with increasing duty cycle, the
efficiency also decreases.
When the Q1 turns off the inductor current slops is given by,
Fig. 4.3 shows the inductor current waveform with l il representing the total inductor ripple
current
Vg
di = DT →(4.10)
l s
L
From the above expression, it is apparent that the inductor ripples current increases with
lower inductance. The increase in ripple increases the RMS inductor current and this
4.2.2 HYSTERESIS CONTROL
Figure 4.5 shows this type of control in which two sinusoidal current references IPref,
IVref are generated, one for the peak and the other for the valley of the inductor current.
According to this control technique, the switch is turned on when the inductor current
goes below the lower reference IVref and is turned off when the inductor current goes
above the upper reference IPref, giving rise to a variable frequency control. Also with this
control technique the converter works in CICM.
high level. In particular, at the first stage, relay, or “on-off’ regulators, ranked highly
for design of feedback systems. The reason was twofold: ease of implementation and
high efficiency of hardware. A number of processes in mechanics, electrical
engineering, and other areas, are characterized by the fact that the right hand sides of
the differential equations describing their dynamics feature discontinuities with respect
to the current process state. The sliding mode control approach is recognized as one of
the efficient tools to design robust controllers for complex high-order nonlinear
dynamic plant operating under uncertainty conditions.
The major advantage of sliding mode is low sensitivity to plant parameter
variations and disturbances which eliminates the necessity of exact modelling. Sliding
mode control enables the decoupling of the overall system motion into independent
partial components of lower dimension and, as a result, reduces the complexity of
feedback design. Sliding mode control implies that control actions are discontinuous
state functions which may easily be implemented by conventional power converters
with “on-off ” as the only admissible operation mode sliding mode control has been
proved to be applicable to a wide range of problems in robotics, electric drives and
generators, process control, vehicle and motion control.
The output of the inverter can be variable/ fixed AC voltage with variable/fixed
frequency. This conversion from DC to AC along with variable supply is produced by
varying the triggering angle to the thyristors. Most of the thyristors used in inverters are
employed with forced commutation technique. These can be single phase or three phase
inverter depending on the supply voltage. These converters are mainly divided into two
groups. One is PWM based inverters and other multilevel inverters. Further, these are
Department of EEE 27 GNIT
Modeling and Simulation of Micro Controller Based MPPT Method Using FPGA
classified voltage source inverter and current source inverter. Each type is subdivided
into different types such as PWM, SVPWM, etc. Multilevel inverters are more popular
in industrial applications.
4.2.7 DC to DC Converters
These converters can converter a fixed DC input voltage into variable DC voltage or
vice versa. The DC output voltage is controlled by varying of duty cycle.
Figure.4.14: Single and dual stage inverter topology with coupling capacitances
Single-stage topology
Figure represents the most reliable and cost effective solution but with the
operational limitation of minimum PV voltage being larger than the peak ac grid
voltage in order to avoid the over-modulation operation resulting in the large series
connection of PV panels which is unwanted from the optimal operation point ofview
and can be attenuated by connecting to a line frequency transformer. However this
topology is bulky and less efficient.
Meanwhile the AC output power ripple which has double fundamental frequency
oscillation unavoidably introduces the double-line-frequency voltage ripple unlike the
CHAPTER 5
MATLAB SIMULATION AND RESULT
5.1 INTRODUCTION
The realization of controller was done by simulation in MATLAB program. The
controller was designed which is based on the mathematical modelling as discussed in
Chapter 4. The grid-connected inverter system has two major parts which are the grid
and a power conversion system. Fig. 1 shows a configuration of the proposed grid-
connected inverter system. The FPGA controller consists of a soft-core processor, a
dedicated current controller and other peripherals. The processor performs the higher
level control and gives a current command to the dedicated current controller. The
dedicated current controller is implemented by Hardware Description Language (HDL).
It samples the inverter output current, the grid current and the grid voltage through
Analog-to-Digital (AD) converters and executes the control algorithm. Then, it sends
out the inverter gating signal to the full-bridge inverter. When a satisfactory result is
obtained via simulation, implement their design using SIMULINK to allow the user to
view the response plot.
Figure 5.5 Shows irradiance levels that are incident on the surface of 80 W modules at
constant temperature equal to 25°C.
Figure 5-6. shows I-V and P-V Characteristics of one module at 250C and Figure 5.7
shows the I-V and P-V Characteristics of array at 250C depends on the solar radiation.
Figure 5.8(b)
Figure 5.8 (a) Grid Voltage Waveforms and (b) Grid Current Waveforms
Fig.5.8 shows the 3-phase output current & voltage response at grid side. The peak
value ofvoltage is 380 V and peak value of current is 0.4 A under grid connected mode
The above plot shows that the regulated output voltage is tracking the given reference
voltage i.e, 450 V and the output ripple of the voltage is 1.21%. Figure 5.8 shows the
plot of the Source current and Source voltage, from these plot it is observed that current
is sinusoidal and in phase with the source voltage.
amplitude voltage of 311+10%. The transformer turns ratio should be (1/18) to satisfy
synchronism with utility grid.
CHAPTER 6
CONCLUSION AND FUTUR SCOPE
6.1 CONCLUSION
In this Project attempts have been applied to apply the sliding mode control concept for
the Boost converter using MATLAB/SIMULINK based on FPGA The Grid connected
PV module of 80W, MPP P&O tracker, half bridge inverter, series-resonance and high-
pass filters, step-up transformer, coupling inductor, and an ideal switch to feed
residential load with utility connected grid. To satisfy the results, the PV Module is
simulated under the following conditions:
• Large uniform change of irradiance at constant 25°C temperature.
• Linear and step change of temperature at constant irradiance.
• Combined of irradiance and temperature change.
• Residential load change.
The conversion topology has been proposed without transformer in PV system and
verified its results in MA TLAB Simulink which is interfaced with FPGA based Xilinx
system generator. In this topology no common mode voltage is generated, thus changes
in the behavior of the inverter in terms of high efficiency and insures that no DC will be
injected into the load. The FPGA based control logic for single stage grid connected
photovoltaic system has been implemented.
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