Research Article

Modeling of solar/wind hybrid energy system using

MTALAB simulink
SHWETA GOYAL *1 , SACHIN MISHRA 2 , ANAMIKA BHATIA 3
1
Department of Electrical Engineering Graphic Era University, Dehradun - 248002, Uttarakhand, India,
2
Associate Professor, School of Electronics & Electrical, Lovely Professional University, Phagwara, India.
E-mail: shwetugoyal@gmail.com, (M) - 9410777617, E-mail: smishra28281@gmail.com, (M) – 9411754414.

ABSTRACT
non conventional sources like solar and wind are presented everywhere, cheap or freely available, and they are used to
generate power or electricity in remote area also where transmission or grid connection are not possible. In this paper
a smart PV/Wind hybrid system developed with any grid connection.A complete hybrid model of wind, solar PV array,
with battery system is designed so as to ensure uninterruptible power supply across the load. Due to depletion of fossil
fuels, a move towards clean energy has emerged from the last few decades. A basic understanding of different sources
and a battery as an emergency can be employed in an isolated area/village where transmission of electricity is quite
costly can be overcome using any of these sources. MATLAB simulink software used to design this model. To maximize
the power generation Perturb and observe (P&O) algorithm is used maximum power point tracker (MPPT). The
dynamic behavior of the proposed model is examined under different operating conditions. The solar PV system is
designed to generate approx 45-50kW, the wind system is basically designed for 147kW approx The efficiency of the
wind system is maximum 40-45% at the peak wind speed practically so it is considered for higher rating. The model is
basically designed in the discrete mode with the sample time 20 μs. To maintain the unidirectional transmission a diode
is connected across each source and an ideal switch which maintains the switching of the respective sources.

Keywords: Solar Energy System, Wind Turbine System

INTRODUCTION

Energy is a basic requirement for economic Proposed Hybrid Energy System

development. Every sector of the national economy configuration structure for hybrid energy system
like agriculture, industry, transport, commercial and (HES)based solar and wind energy systems shown in
domestic are needs the inputs of energy. The figure 1. A complete hybrid model of wind, solar PV
economic development plans implemented since array, and battery system is designed so as to ensure
independence have necessarily required increasing uninterruptible power supply across the load. Due to
amounts of energy. As a result, consumption of depletion of fossil fuels, a move towards clean
energy in all forms has been steadily rising all over energy has emerged from the last few decades. A
the country. Now a days different combinations of basic understanding of different sources and a
renewable sources with battery used for energy battery as an emergency can be employed in an
generation to uphold the consistency of power. isolated area/village where transmission of electricity
Renewable energy resources are very useful for rural is quite costly can be overcome using any of these
areas where electric grid cannot reach easily. There sources. From the last few decades scientists are
are some difficulties which can be fulfilled by the working towards biodiesel which can be made using
renewable energy resources a) It decreases gap the vegetable oils is also replacing the present
between supply & demand, b) Helpful for decrease available diesel.
the environment pollution, c) It gives solution for Wind Energy system
rural electrification, d) It gives voltage stability at the Turbine block: A wind energy system is generally
time of fluctuation. The main drawback to used to employed where the speed of wind is more than
renewable sources is that they doesn’t generate 10m/s. Thus to describe the operation of Wind
continues energy to overcome this problem Turbine system, a matlab block of WIND Turbine is
maximum power point tracking is used. Performance used .In the block the general equation of
in different condition is checked. There are many mechanical power(Pmec) generated is given as
works upon hybrid energy system modeling and Pmec=ρACp(λ,β)v3
optimization is done previously. In this paper a Where ρ=Air density
simple control method tracks the maximum power A=Area swept by blades
from the wind/solar energy source to achieve much Cp=Coefficient parameters which are constant
higher generating capacity factors and simulation λ,β=Tip ratio and pitch angle
results proved the feasibility and reliability of the Tip Ratio=Velocity of wind striking the tip of
system blade/Total velocity of the wind

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 Shweta et al / Modeling of solar/wind hybrid energy system

Pitch Angle=The pitch angle is the angle at which the rotor in rad/sec) we get the required Mechanical
blade surface contacts the wind. It is often variable to torque(Tm).The mechanical torque or load torque is
ensure optimum operation of the turbine in varying basically used with asynchronous generator so as to
wind conditions.Is used to design the wind turbine bring the rotor into motion. All the quantities in this
block.The block is designed using the basic Simulink block are considered in pu.
blocks.Whem Pmec is divided by ω(angular speed of

Fig 1: configuration of HRES

tuned using the PI controller blocks.Also some of the
initial parameters which are required in the machine
or generator block is calculated using the machine
initialization tab in POWERGUI block of simpower
systems. Also along with the DC link capacitor in
wind system , a small resistor is also connected so to
discharge the capacitor. Otherwise the capacitor will
hold the voltage while the current will drop down
thus causing the problems in the switching.

Fig 2: equivalent circuit of PV cell

Asynchronous machine block

The MATLAB has an option of different kinds of
machines block which can be used in any of the
mode either generating or motoring. In this wind
energy system three phase asynchronous machine
block(pu) is used .Although the induction generator is
used for 149kVA so as to run a 30kW load. The
efficiency of wind energy system is not more than 45- Fig:3 Output voltage of Solar model
50% in real scenario and moreover when imparting
an asynchronous machine a separate capacitor Solar PV array: A solar PV array consists of solar
banks used to provide the reactive power, which is modules which are connected in some series or
another drawback of this system. parallel combinations. A module consists of solar
Transformer cells shown in figure 2. To design a solar module a
A three phase three winding transformer is used so to block modeling of characteristics equation is done
convert AC to DC through two different rectifiers. The using the basic Simulink blocks. For solar PV array
purpose of using two different rectifier is to get one of the important parameters are irradiance and
controllable dc output voltage, by tuning the firing temperature. To calculate the irradiance a data is
angle (α) of the 12-pulse synchronized PWM considered of one of the location through which
generator, and the narrowed commutation periods, irradiance is calculated using the parabolic reflector.
which causes less harmonic distortioneffects on the The photovoltaic current can be presented as
source side. In this model a three-phase two winding
transformer is used to obtain six input ports with
appropriate phase angles for the double-bridge
rectifier. The purpose of converting AC/DC is to
maintain a common voltage on the DC bus
irrespective of the source supplying it. The pulses for Where Igc is the light generated current, Io is the
synchronised 12 pulse generator and pitch angle is dark saturation current dependant on the cell
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 Shweta et al / Modeling of solar/wind hybrid energy system

temperature, e is the electric charge = 1.6 x 10-19 filtered using the LC filter.The PWM is synchronised
Coulombs, K is Boltzmann’s constant = 1.38 x 10- with the load voltage so as to maintain the
23 J/K, F is the cell idealizing factor, Tc is the cell’s modulation index. All the respective waveforms are
absolute temperature, vd is the diode voltage, and shown in different scopes.
Rp is the parallel resistance. The photocurrent (Igc)
mainly depends on the solar irradiation and cell Simulation Results
temperature, as The complete system design i.e hybrid energy system
is simulated using SIMULINK. A 30-kW
wind/PV/battery. The complete model is made to run
in discrete mode so as to have faster simulation.
Where μsc is the temperature coefficient of the cell’s Generally continuous mode is implemented when the
short circuit current, Tref is the cell’s reference models are small. The complete model is run for 1.2
temperature, Isc is the cell’s short circuit current at a sec which will be scaled to time from 0-24 hours. The
25oC and 1kW/m2, and G is the solar irradiation in ideal switch are implemented so as to switch different
kW/m2. Furthermore, the cell’s saturation current (Io) sources at different intervals of duration during the
varies with the cell temperature day.Output from different section of HRES are shown
in figure 3 to figure 5 showing the graphical
representation output. The main objective of the work
to observe the behavior of the model in different time
during night and day time also.

Fig:4 Output form WT model Wind voltage

Boost Convertor
The output voltage generated by the solar PV array is
not enough to run a three phase load. As a result
before supplying this voltage on the DC Bus, the
voltage is boosting up upto 450V so as to maintain
400-415V on DC bus apart from charging a battery.
Since a boost convertor involves a switch (say
Fig: 5 Battery output
IGBT/GTO), the triggering/pulses of boost converter
is provided through MPPT. The MPPT (maximum
Conclusion
power point tracking) tracks the direction of sun at
Output from solar and a wind system is converted
which power is maximum, so that maximum output
into AC power output by using inverter. In the given
can be extracted from the solar. Once we get the
time additional load of 30 KW is connected by using
DC, a dc link capacitor is connected so to make the
Circuit Breaker. Under all operating conditions to
output as uniform with little distortions.
meet the load the hybrid system is controlled to give
Battery: A battery is connected in parallel with the
maximum output power. Battery is supporting to wind
overall hybrid system so as to provide the emergency
or solar system to meet the load and Also,
backup when none of the system works especially
simultaneous operation for the same load, almost
during the night time, Although the standard battery
uniform voltage, current, irrespective of the source
available is generally 12/24V, but to avoid number
with some spikes but its mainly due to discrete
of batteries in series or parallel, a single battery
simulation
block available in MATLAB is used. The rating are
considered with respect to load. The initial charging
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