25-10-2016, 04:36 PM
1461160604-VENUSOLARCARAD.docx (Size: 3.92 MB / Downloads: 6)
ABSTRACT
The transport needs of our ever growing and evolving society is becoming increasingly stringent and more demanding. In order to combat this, more efficient transportation vehicles need to be developed which are faster and cleaner. As the human race starts to realize the real extent to which the internal combustion engine has gradually polluted the atmosphere, more research is being concentrated on alternative forms of propulsion.
Solar power is in the forefront of many renewable energy related discussions. The reason is simple. Solar power has enormous potential to be the most dominant energy source this century and at the rate at which it is being tapped into this possibility maybe realized sooner than we predict.
THE DESIGN
The roof of the car is fitted with 650mm solar panels that are readily exposed to sunlight while it’s available.
Two 150W batteries are also on board that take a total of 8 hours to fully charge. These batteries are of course responsible for the conversion of energy which moves through the transmission chain to the wheels to put the car in motion
A WORD ON THE PERFORMANCE…
This solar car can travel 40 km on a single battery charge at a maximum speed of 30 km/h.
WHAT’S MORE IMPRESSIVE…
Is that it’s powered exclusively by solar energy and as such the vehicle is not
RESPONSIBLE FOR NOISE OR POLLUTION OF ANY KIND.
In a setting where motor scooters and motorcycles are still the most dominant form of transportation in Vietnam, this nifty looking vehicle underlines yet again the fact that going green doesn’t necessarily have to be revolutionary or exceedingly expensive…
ADVANTAGES
Advantages of solar powered cars include: they produce no emissions, they require less service as they have few moving parts and there are no fuel costs. The drawback is that they can only run when the sun is shining unless they have another power source and they are very expensive to purchase.
DESCRIPTION OF PROJECT
The renewable energy is vital for today’s world as in near future the non renewable sources that we are using are going to get exhausted. The solar vehicle is a step in saving these non renewable sources of energy. The basic principle of solar car is to use energy that is stored in a battery during and after charging it from a solar panel. The charged batteries are used to drive the motor which serves here as an engine and moves the vehicle in reverse or forward direction. The electrical tapping rheostat is provided so as to control the motor speed. This avoids excess flow of current when the vehicle is supposed to be stopped suddenly as it is in normal cars with regards to fuel. This idea, in future, may help protect our fuels from getting extinguished.
All recent electric vehicles present drive on AC power supplied motor. The setup requires an inverter set connected to battery through which DC power is converted to AC power. During this conversion many losses take place and hence the net output is very less and lasts for shorter duration of time. Although this is cheaper the setup and maintenance required is much more in AC drive than DC drive. The vehicle designed is controlled by ELECTRICAL means and not by ELECTRONIC means
INTRODUCTION
Energy is one of the most vital needs for human survival on earth. We are dependent on one form of energy or the
Other for fulfilling our needs. One such form of energy is the energy from FOSSIL FUELS. We use energy from these sources for generating electricity, running automobiles etc. But the main disadvantages of these FOSSIL FUELS are that they are not environmental friendly and they are exhaustible. To deal with these problems of FOSSIL FUELS, we need to look at the NON-CONVENTIONAL SOURCES of energy. With regard to this idea we have designed an Electrical vehicle that runs on solar energy. The vehicle designed is a four wheel drive and can be used for shuttle and short distances. As these vehicles form the future of the automotive industry, we need to concentrate on improving their design and making them cost effective. This vehicle is an initiative in this direction.
The above diagram gives an overview of the working of solar vehicle. Sun is the main source of energy for the vehicle. Energy from Sun is captured by the solar panels and is converted to electrical energy. The electrical energy thus formed is being fed to the batteries that get charged and is used to run 24 V DC high torques DC series motor. The shaft of the motor is connected to the rear wheel of the vehicle through chain sprocket. The batteries are initially fully charged and thereafter they are charged by panels. This helps in completing the charging-discharging cycle of the batteries, which is very important for proper working of batteries.
BASIC CIRCUIT DIAGRAM
The fig 2 shown below represents the connections of the motor for forward and backward motion. The connections are made from battery to motor via switch, controller unit and the solar panel. As stated before, the motor used in this vehicle is24 V dc series motor. There are four terminals on motor, namely A1, A2, F1, F2, as A1, A2 are the armature terminals and they are internally shorted. All the connections are made keeping the DPDT switch at the centre. The either connections on DPDT switch are made for forward direction motion of motor and the next side of DPDT switch is made for reverse direction of motor. The motor will work as the switch is kept in either of the directions as per requirements. The A2 is directly taken from battery to the positive side of DPDT switch and F2 is taken via controller unit to the negative terminal of switch. For the DPDT the centre terminals are given the upper side as positive from battery and the lower as the negative from battery. The controller unit used here is a high resistance setup box which can with stand up to the current of 60amps. Now the A1, A2 are he internally shorted terminals of the motor. Thus either of the one is the main and another one is the dummy. In case of our motor the A1 terminal is dummy and A2 is the main terminal. Thus all connections are made keeping A2 as the main terminal. In the switch the A2 and F1 are the terminals that are responsible for the reverse motion of motor. All the connections are directly to switch, A2 is given to positive and given to the negative of switch.
COMPONENTS USED
Various types of electrical components were used for making the solar powered vehicle. A list of these components used with their range and the specific quantities that were required for making the solar vehicle is given in the following table. Apart from the above listed components the main component that is responsible for speed control of the motor is the speed control switch. It is defined as follows:-
SPEED CONTROL SWITCH
The speed control of the DC motor is the essential part of the vehicle. For controlling speed of the motor, a switch was designed with 8 tapping, giving different values of resistance at each tapping, hence limiting the current that flows in the motor. The switch uses pure Nichrome wire for resistances. It uses a 8 tapping DC switch.
The switch has been provided with two terminals; one for the motor connections and the other for the battery connections. The arrangement of the switch is more or less like a rheostat. The different tapping act as resistance points. With each increase in the tapping value the value of resistance decrease, thus at the last tapping the motor will run at the highest speed as the limiting resistance will be minimum whereas the high torque condition of the motor will arise when the minimum tapping will be used, since the limiting resistance will be maximum. The picture showing the view of the tapings is shown below in fig. It can be easily concluded that two coils are connected in a series to give one taping hence increasing the resistance.
SOLAR PANEL DETAILS
Solar cars have been developed in the last twenty years and are powered by energy from the sun. Although they are not a practical or economic form of transportation at present, in the future they may play a part in reducing our reliance on burning fossil fuels such as petrol and diesel.
A solar powered racing car is shown above. These are expensive to produce and usually seat only one or two people. The main cost is due to the large number of expensive and delicate photovoltaic solar panels that are needed to power the vehicle. Also, many of the solar powered cars used in races today are composed of expensive, lightweight materials such as titanium composites. These materials are normally used to manufacture fighter jets. Carbon fiber and fiber glass are also used for much of the bodywork. Most of the cars used in races are hand made by specialist teams and this adds to the expense.
A solar powered vehicle can only run efficiently when the sun shines, although most vehicles of this type have a battery backup. Electricity is stored in the batteries when the sun is shining and this power can be used when sun light is restricted (cloudy). The batteries are normally nickel-metal hydride batteries (NiMH), Nickel-Cadmium batteries (NiCd), Lithium ion batteries or Lithium polymer batteries. Common lead acid batteries of the type used in the average family car are too heavy. Solar powered cars normally operate in a range of 80 to 170 volts. To reduce friction with the ground the wheels are extremely narrow and there are usually only three.
One of the more realistic ways in which that solar powered cars could become practical is to charge up their batteries when they are parked, during the day. Imagine driving the short distance to work and plugging the car into a set of photovoltaic solar panels. Whilst you are working the batteries charge up ready for use for the journey home. The same procedure could be carried out when the car is parked at home. A combination of solar power and wind power may prove to be a method of charging the batteries of ‘electric cars’.
WORKING OF THE VEHICLE
The solar module mounted on the top of car is used to charge the batteries via charge controller. A 140 WP solar module is used with output ranging from 24V to 25V at STC. The batteries are initially fully charged and then they are connected to solar module for charging. This helps to keep the battery charged always. This is also done as the efficiency of solar module is only 15%.Thus under this condition the battery gets fully charged again within 3hrs-3.5hrs. Thus to keep the full sine wave of charging this time lap is made. The maximum solar radiations are obtained between morning10am to evening 3:30pm. Hence the panel is so mounted that maximum output may be obtained. As the supply is given through DPDT switch the motor takes a high starting current to propel the wheel to move in forward direction. On start the load on motor is nearly 250kg including the weight of person driving it. The motor after start acquires the maximum speed of 20kmph to 30kmph. The batteries get charged always from the solar panel and so it provides the continuous run for the vehicle. Motor must be started on top most gear so as to get maximum torque and speed to lift the full load. The speed may be varied later according to the driver’s requirements. As the speed varies the load current also varies. So the speed variation must be low to keep battery alive for maximum duration of time. For stopping the motor, the speed control switch should be brought to minimum gear and then switch should be open; thereafter the mechanical brakes should be applied. The mechanical brakes can be applied instantly during emergency but this should be avoided as this could damage the motor and also produce unnecessary back emf. The average battery back-up is around four hours. The batteries are continuously charged by the solar panel but to increase their rate of charging three dynamos each of 24 V can be connected to the wheels of the vehicle. As the vehicle moves these dynamos will generate EMF and will charge the batteries. Hence the chagrining and discharging cycle of the batteries will be complete.
How A Photovoltaic Cell Works
The "photovoltaic effect" is the basic physical process through which a PV cell converts sunlight into electricity. Sunlight is composed of photons, or particles of solar energy. These photons contain various amounts of energy corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell, they may be reflected or absorbed, or they may pass right through. Only the absorbed photons generate electricity. When this happens, the energy of the photon is transferred to an electron in an atom of the cell (which is actually a semiconductor). With its newfound energy, the electron is able to escape from its normal position associated with that atom to become part of the current in an electrical circuit. By leaving this position, the electron causes a "hole" to form. Special electrical properties of the PV cell—a built-in electric field—provide the voltage needed to drive the current through an external load (such as a light bulb).