V.R.S. COLLEGE OF ENGINEERING AND TECHNOLOGY, VILLUPURAM AEROSPACE FLYWHEEL

DEVELOPMENT

PRESENTED BY: G.JAYASEELAN (FINAL

MECH)., V.VIGNESH (FINAL

MECH).,

AGENDAINTRODUCTIONWHAT IS FLYWHEEL?COMPONENTS OF FLYWHEEL SYSTEMPRINCIPLE OF OPERATIONEXPERIMENTAL SETUPFLYWHEEL CONTROLTECHNICAL CHARACTERISTICSAEROSPACE FLYWHEEL CHALLANGESFLYWHEEL ENERGY STORAGEADVANTAGESAPLLICATIONSCONCLUSION AND FUTURE WORK

INTRODUCTION

• Presently, energy storage on the space station and satellites are held by chemical batteries (nickel cadmium or nickel hydrogen)

• A flywheel energy storage system is an alternative technology for future space mission.

WHAT IS FLYWHEEL?A flywheel used in machines act as a

reservoir of energy storage It stores energy during higher supply and

release during demand.A flywheel control the speed variation caused

by the fluctuation of the engine turning moment during each cycle of operation.

PRINCIPLE OF OPERATIONThe law of conservation of energy is a law

of physics. It states that the total amount of energy in a

system remains constant over time . A consequence of this law is that energy can

neither be created nor be destroyed: it can only be transformed from one state to another. The only thing that can happen to energy in a system is that it can change form.

EXPERIMENTAL SETUP

Experimental facility consists of: Power Supply, Power Electronics, Electric Motor, Flywheel, Amperemeter, Voltmeter

COMPONENTS OF FLYWHEEL SYSTEMComposite rotorMagnetic bearingsMotor/Generator Power electronicsControl and instrumentationVacuum housing

ROTORa spinning mass that stores energy in the

form of momentum BEARINGSpivots on which the rotor restsThe bearings support the flywheel rotor and

keep it in position to freely rotate. The bearings must constrain five of the six

degrees of freedom for rigid bodies, allowing only rotation around the axis of the rotor.

MOTOR –GENERATOR a device that converts stored mechanical

energy into electrical energy, or vice versa

Motors convert electrical energy into the rotational mechanical energy stored in the flywheel rotor during charge, and generators reverse the process during discharge

POWER ELECTRONICS An inverter and rectifier that convert the

raw electrical power output of the motor/generator into conditioned electrical power with the appropriate voltage and frequency

CONTROLS AND INSTRUMENTATION Electronics which monitor and control the

flywheel to ensure that the system operates within design parameters

HOUSING Containment around the flywheel system,

used to protect against hazardous failure modes. It is sometimes also used to maintain a vacuum around the rotor to reduce atmospheric friction.

FLYWHEEL CONTROL

There are three modes of operation for the flywheel in a spacecraft power system

ChargeCharge reductionDischarge

CHARGINGDuring charging, an electric current flows

through an electromagnetic coil and creates a magnetic field that interacts with the magnets loaded on the rotor, causing it to spin.

DISCHARGING AND CHARGE REDUCTION During this modes,the spinning magnets on

the rotor induce a current in the electromagnet and generate current flow out of the system

Technical characteristicsIn Rotor technologyThe kinetic energy stored in a rotating mass

is:E=1/2 J ω2 ……………(1)where J is the moment of inertia, and ω is the

angular velocityThe moment of inertia is a function of the

mass and shape of the flywheel :J=∫x2 dmx ………….(2)where x is the distance of the differential mass

dmx from the axis of rotation.

In the case of a flywheel where the mass m is concentrated in the rim at radius r, then the moment of inertia is given by:

J=mr2 …………….(3)Substituting equation (3) in (1) gives:E=1/2mr2ω2

which shows that high angular velocity is more important than mass to achieve high stored energy.

Materials Density[kg.m-3]

Strength[MN.m-2]

Theoretical maximum specific energy[Wh.kg-1]

Steel(AISI 4340)

7800 1800 32

Alloy(AlMnMg)

2700 600 31

Titanium(TiAl6Zr5)

4500 1200 37

GFRP Glass fibre reinforced polymer(60 vol% E-glass)

2000 1600 111

CFRP Carbon fibre reinforced polymer(60 vol% HT Carbon)

1500 2400 222

(Material properties taken from Aspes Engineering AG website)

AEROSPACE FLYWHEEL CHALLENGESThe important factor which preventing the use

of flywheels for long term energy storage is loss in the bearings.

The above problem is prevented by using non-contact active magnetic bearings.

Superconducting magnetic bearings have losses of 10⁻2 to 10⁻3 watts per kg for a 2,000

rpm rotor. This translates an efficiency of 84%

FLYWHEEL ENERGY STORAGE(FES)It works by accelerating a rotor to a very

high speed and the energy in the system as inertial energy.

Advanced flywheel are made of high strength carbon-composite filament that spins at the speed of 20,000-1,00,000 rpm in a vacuum enclosure.

Quick charging is done in less than 15 minutes.

It has high energy density (~130 wh/kg) and large maximum power output.

The energy efficiency of flywheel can be as high as 90%.since FES can store and release energy power quickly, they found as pulsed power.

ENERGY STORING OF FLYWHEEL

ADVANTAGESHigh power output, long life.Not affected by temperature changes.Does not suffered by memory effect.Less potential to damage the environment.Possible to know the exact amount of energy

stored.Simple measurement of the rotational speed.

APPLICATIONSIn 1950s flywheel-powered buses, known as

gyro buses were used in yverdon ,switzerland.

It is hope that flywheel systems can replace conventional chemical batteries for mobile applications such as for electric vehicles.

Flywheel system have also been used experimentally in small electric locomotives for shunting or switching.

CONCLUSION AND FUTURE WORKThis paper has presented a new algorithm for

regulating the charge and discharge mode of a FES system.

Experimental and stimulation results shows the successful control of the flywheel system in all modes of operation.

A future application of flywheel technology is used to combine the energy storage and the altitude control function on spacecraft

REFERENCES

Anand, D.K., kirk, J.A., Bangham, M.L., “Simulation,Design, and construction of a flywheel magnetic bearing”, ASME paper 86-DET-41,1986.

Kirk, J.A., and Anand, D.K., “satellite power using a magnetically suspended flywheel stack”, journal of space power , vol-22, issue-3&4, mar/apr-1988.

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