книги / Innovative power engineering

THE DESIGN OF A NEW SOLAR-POWERED

UNMANNED AIRCRAFT

Li Songqi, Yu Tianning, Wang xuchen, Li Haoran

Northwestern Polytechnic University, Xi’an, P.R.China

The ability to fly an unmanned aircraft under solar power has been demonstrated. The uniqueness of a solar powered aircraft, compared to a conventionally powered aircraft, lends its use to equally unique applications both military and civilian. Most of these applications involve subsonic flight at either high altitudes or for long durations or both. The advantages of solar power over conventionally powered fuel burning propulsion systems, for these types of applications, is that a solar power system does not require the use of the atmosphere in the generation of power. This eliminates the need for multiple stage compressors that are necessary for high altitude combustion driven aircraft. Also since the power for flight comes from the sun, no fuel supply is needed. If this solar system is coupled to a regenerative fuel cell system or rechargeable battery system of sufficient energy density (approximately 400 Wh/kg or greater) then long endurance flight on the order of weeks to months can be achieved depending on the flight location.

However, traditional solar powered aircrafts have inherent disadvantages. The traditional solar powered aircrafts are large, which means qualified run ways that are long and wide enough are needed for taking off and landing, and such rigorous demands of runway lead to great reduction of its application. On the other hand, though multi-axle aircrafts can overcome these drawbacks and can basically achieve vertical taking-off and landing on any sorts of terrain, its inherent structural problems make it impossible to use solar energy as driving power.

We aim to design a solar-powered unmanned aircraft with rotated wings that can achieve vertical taking-off and landing. It use solar energy as propulsion power, use high efficiency, light weighted

181

lithium-ion polymer battery as energy storage devices, use DC motor with high torque as drive force, use high-efficient propeller in the propelling system. Compared with taking-off and landing process of traditional solar-powered aircraft, aircrafts with rotated wings can takeoff and land vertically on all kinds of land and water surfaces, overcoming the inherent flaw of traditional solar aircrafts that a long and wide run way is indispensable. Compared with multi-axis aircrafts, our new production utilizes solar energy as power source and enables long-period and long-distance flight missions.

Key techniques:

On the basis of fixed wings aircraft, accomplish vertical taking-off and landing of the solar-powered unmanned aircraft without a runway

(1)Reasonably arrange the solar energy input-storage-output process, and ensure that the power allocation of the aircraft is reasonable when flying for long periods.

(2)Solve balance problems of the aircraft when it flies into flat state from vertical take-off state, which means flight control system is needed.

(3)In order to realize rotation of wings, the strength of the internal structure, and the matching of rotating parts need to be tested.

182

EXPERIMENTAL AND CALCULATED STUDYING FOR THE EFFECT OF THE ORIENTATION ON PHOTOVOLTAIC EFFECTIVENESS

A.T. Jailany 1, S.E. Shcheklein 2, Y.E. Nemikhin 2, D.A. Nemkov 2

1Alexandria University (Egypt)

2Ural Federal University

Solar radiation which comes onto an oriented surface is the sum of the direct radiation from the sun from the sky diffuse and reflected from the surface of the earth. Direct radiation Rdir is the main source of energy for photovoltaic installations (PVI). The value of the direct solar radiation can be calculated by the following formula:

where i – angle between the surface normal and the direction of the solar panel on the sun; RCH – measured solar radiation comes on a perpendicular surface.

where h – the angle between the surface and the horizon; h – the height of the Sun position; A – the difference between azimuth of the Sun and the surface normal projection onto the horizontal plane [1]. Due to the fact that the sun changes its position in the sky the value of cos i is constantly changing. As a result the value of the direct solar radiation reaching the PVI changes. Therefore, the maximum efficiency cannot be achieved with a rigid fixing PVI constructs. One possible solution to this problem is the automatic orientation of the PVI in the sun. Today, there are many different ways of automatic orientation PMT in the sun. Most of them react to deviations of solar panels on the direction of the Sun, using the visible range of solar radiation, current sensors with solar cells solar panels, temperature sensors. In other words, these systems are oriented to the sun in terms of its direct impact on the bodies of data tracking systems that may entail certain difficulties associated with atmospheric and climatic conditions [6].

183

At the department of nuclear power plants and renewable energy sources in the Ural Federal University (hereinafter Department NPRES) propose a method for automatic orientation of the PMT in the sun, namely, the orientation of the PMT on a predetermined path of movement of the sun across the sky. The following equipment is used to allow for the orientation of the PMT in the sun: the rotator azimuthelevation Radant AZ1000V for satellite and parabolic antennas (Fig. 1) [2] and the antenna rotator controller AZV (Fig. 2) [3].

The controller controls the antenna rotator supports connection to a PC via the serial port. PC control is performed on the interface Yaesu GS-232 and its own team of developing MS-232 provides precision installation to 0.1°.

The protocol supports the following set of commands:

Team Aaa.a (-) eeee <CR> sets the position on the azimuth angle and the angle of elevation aaa.a eee.e. The minus sign is placed in the case, if the value of the angle of elevation is negative.

Y command requests the current value of the azimuth angles and elevation.

The S command immediately stops the plant [4].

184

Also, at the department NPRES software enabling automatic orientation of the sun with a PC was developed. The program reads from a file of a particular sequence of dates, time intervals and azimuth angles and elevation, wherein the predetermined value of the azimuth and elevation for each point in time. The sequence is made automatically on the basis of statistical data on the movement of the sun across the sky. Next the program requests the current values of the azimuth and elevation angles from the installation and according to the read sequence sets are the azimuth and elevation angles, which correspond to the maximum efficiency of the PMT.

The use of such automated systems orientation to the sun can increase the coefficient of performance in the PMT tracking the sun by 25 %. Further steps on the way to improve the system and the software will: support for multiple PVI and synchronize their rotation with each other, automation generation rotary sequence based on the statistical data on the movement of the sun and the geographical position of installation, creating a common base for monitoring such systems for the collection of statistical data and their subsequent analysis.

References

1.9 . ( % 9 ‹ 0' & / &5. – L: m&. /$:&@ ' &4.($% * J– J

2.The azimuth-elevation rotator Radant AZ1000V [Site] //

1F1 1D90 H= 6 + 8 ( «(.(». – URL: http=;;7 '( I;produkciya/povorotnye_ustroystva/povorotnoe_ustrojstvo _az1000v_maloe; .( ( 3 (Œ &5= CO O C.

3.The antenna rotator controller AZV [Site• ;; 1F1 1D90 H:

6 + 8 («(.(». – URL: http=;;7 '( I;produkciya/

kontrollery_upravleniya_dlya_povorotnyh_ustrojstv/kontroller_upravleniya_ povorotnym_ustrojstvom_AZV; .( ( 3 (Π&5= CO O C.

4. Controller protocol commands [Site] // 1F1 1D90 H:

6 + 8 ( «(.(». – URL: http://7 '(.I/data/ documents/Radant_Port_Exchange.txt (.( ( 3 (Œ &5: 23.03.2015).

185

DEVELOPMENT OF POWER SUPPLY SYSTEM

OF AUTONOMOUS MARINE RESEARCH BUOY

D.V. Vorotintcev, N.D. Karpov, Y.L. Muravitsky

National Research University «Moscow Power Engineering Institute», Dept. of Hydro Power Engineering and Renewable Energy Sources

The studying of sea surface currents is very important for understanding processes, which take places in Russians seas. One method of studying surface currents is by using drifting buoy. It has several problems. One of them is a small time of Autonomous operation due to insufficient supply capacity of the batteries. That work suggests the way to solve this problem – to use sun batteries to charge battery of drifting buoy. The result of work we have increased the time of autonomous work from 2 days up to 3 months.

Keywords: sun batteries, surface currents, autonomous work, buoy.

One method of studying surface currents is the method of floats. It implements the approach suggested by the Lagrange in the framework of classical fluid mechanics, and involves monitoring the movement of each particle. [1, 2] The location of the particles is fixed at certain intervals of time, which allows to reconstruct the trajectory and speed of its movement and then to draw up the schematic circulation of surface waters. In practice, the observed particles used drifting buoy – drifter [3].

The picture 1 shows the structure of the drifting buoy. Developed drifter is a structure consisting of a float with a fixed GNSS receiver and a GSM module for data transfer, underwater sails and cargo [3].

The problem with this drifter is a small time of Autonomous operation due to insufficient supply capacity of the batteries, and the electrical connection is impossible, and installation of large batteries impractical for a number of reasons (the weighting structure, the price of batteries, size, etc.). Table shows the main characteristics of the battery used in the drifter.

When analyzing possible solutions to the problem identified several areas for producing electricity to charge the battery:

1.Solar photoelectric converter;

2.The electromechanical generator.

186

Main characteristics of the battery [4]

Fig. 1. The construction of drifting buoy

1. The Electromechanical generator

The proposed principle of operation of the Electromechanical transducer of wave energy into electrical is the following. The excitement of the surface of the water creates oscillatory motion, resulting in the drifter and the system of linear generators placed inside of its body, changes its position. Permanent magnets, arbitrarily moving under the action of gravity inside the windings of the generator, generate induction current. Due to the stochasticity of the directions of oscillation of the drifter proposed installation of several linear generators located in different planes, to ensure a constant supply [5].

187

For power tests was made prototype linear generator [6]. As a body, were used polypropylene sanitary pipe diameter of 20 mm, an inner diameter of 12.5 mm, length – 200 mm. As the rotor of the generator used 5 permanent magnets of cylindrical shape 12x20 mm. On the surface of the body evenly installed 4 of the stator winding of the wire diameter 0.6 mm, each for 100 turns. The contacts of the windings are derived for various possible connections. The experiments investigated the effectiveness of a linear generator with parallel and series connection of windings, resulting in what has been achievedcircuit voltage in 0.2 V, short circuit current is 10 mA.

Taking into account the required values of current and voltage, providing a battery life of drifter, this design is deemed not capable of providing power to the sensor even with a larger number of generators due to the limited size of the buoy. However, research on the applicability of a similar design of the Electromechanical generator, the authors will continue. Among the possible reasons of low efficiency of the generator can be assumed: insufficient number of turns and thickness of wire of the stator winding, a large thickness of the shell.

2. Solar photovoltaic Converter

Fig. 2 shows the current – voltage characteristic (CVC) of this solar cell. Based on the calculation [6], it was found that to achieve the desired operation time of need 36 solar cells. The size of the solar cell

is 3503 mm2.

To determine the power generated by the solar module required for recharging the battery, used data from [7]:

a)Evpatoria (Republic of Crimea. 45° n, 33° e.);

b)Sochi (Krasnodar Krai. 43° n, 39° e).

The current value stored in the battery power can be represented as [8]:

where <0 – the initial state of the battery; S<i – changing the content of

energy in the battery for the time interval i.

188

Fig. 2. I–V curves of the solar cell

In turn, the change in the energy stored in the battery, for the time interval i can be represented as [8]:

where <Ži – monthly average hourly amounts of total solar radiation on

a horizontal surface under average conditions of cloudiness, for the i-th

interval, W·h/m2 [9]; N<L – the number of solar cells, piece; –

efficiency of the solar cell.; S – area of the solar cell, m2; <i – drifter

consumed by the energy for the i-th interval, WH.

The average values of <Ž = 0,27 kWh/m2 obtained for June –

August [10], the battery life of a drifter is 2–3 months when the number of solar cells N<L = 36 and the scheme of their connection in 3 parallel

chains of 12 solar cells.

References

1.Chygaev R.R. Fluid mechanics (technical fluid mechanics): textbook for hydrotechnical line university.

2.Loyanski L.G. Fluid mechanics and gas: textbook for university on specialty “Mechanical”. – M.: Fizmatlit.

3.Malenkov S.A., Samsonov I.E.The study of currents on the shelf of the

Black sea using GNSS – monitoring / MSU M.V. Lomonosov Moscow state University; Khiterer M.J., Ovchinnikov I.E. 0 Synchronous electric machine of the reciprocating movement. – SPb.: Crown print, 2004. – 368 .

4.Battery specification Panasonic NCR18650BD Li-Ion 3.7V 3200mAh

189

5.Korobkov V.0. Energy conversion ocean. – M.: Shipping, 1986.

6.Sichkarev V.I.The basics of research and developmentof wave power stations. – Vladivostok: DVNC AN USSR, 1987.

7.Scientific applied reference book on climate of the USSR. – S.Petersburg: Gidrometeoizdat, 1992.

8.Germanovich V. Alternative energy sources and energy saving. – M.: Science and technique, 2014.

9.Alhasov 0.B. Renewable energy. – M.: Publisher: Fizmatlit, 2010.

10.Myagkih D. The development of renewable energy sources in Russia: Opportunities and practice. – Greenpeace Council, 2006.

190