GB2477442A - Generator braking compensator - Google Patents

Abstract

A generator braking compensator comprises one or more rotors 2 mounted on the shaft of a generator 1 that is driven by a prime mover 8. The compensator rotor has flux sources 5 that are magnetically repulsed by flux pulses produced in stationary compensating coils 3 that are in series between the output of the generator 1 and its load, producing pulsed force vectors to compensate for pulsed braking experienced by the generator rotor. Two compensator coils 3 can be in series, producing two pulses per generated half-wave and be positioned such that the force vectors produced are synchronised with and oppose generator braking force vectors. The prime mover can be a wind, steam or water turbine but in a test rig it can be a motor 8. The compensator can be retrofitted to an existing generator and the invention aims to reduce the torque required to turn a generator shaft when supplying current to a load due to the Lenz effect.

Description

GENERATOR BRAKING COMPENSATOR

Reduction in Energy Input Requirement for Electricity Generation

BACKGROUND

In the recent past there have been attempts to reach agreement on reductions in global C02 emissions; this has proven complex with very few real solutions forthcoming.

A recent development is the proposal to build more coal fired generation plants; these are deals made possible with the advent of the carbon credit market and the involvement of the World Bank. In the meantime, subsidies fund renewable projects which have little chance of replacing hydrocarbons and appear as yet another drain on the public purse.

A common thread in virtually all electrical power generation is the electrical generator. If it were possible to drastically reduce the input energy required to turn the shafts of those generators at the time when they are supplying optimum power, the results could both improve the worldwide efficiency of electrical power generation and start to reduce C02 emissions to the benefit of the on-going process of ameliorating AGW.

Reducing the input energy required to produce a given magnitude of electrical power has another connotation. The process of producing an otherwise prohibitively expensive energy storage medium such as hydrogen gas becomes cost effective.

In addition, the domestic market has been touted as a means to supplement the centralized supply of electrical power. To date, the options available have been intermittent, mainly wind and solar and perhaps hydro, where geographically appropriate.

The principles of this invention have been tested with the use of low grade ferrite magnets which are a factor of eleven times less energy dense compared to Neodymium Iron Boron "rare earth" magnets. Without compensation for the Lenz effect (this invention), the use of such flux sources would simply increase the braking effect and the advantage of using them would be minimal. This is the predominant reason for the huge size of modern wind turbines; high torque is required to offset the braking.

STATRMENT OF INVENTION

This invention takes the form of a device having a physical connection to the drivesbaft of a generator and electrical connections to the output of that same generator. After utilizing the output current to compensate for the natural braking effect of the generator, the device routes the output to the original intended target There is negligible effect on the output The effect of the device is that it allows electiical current to be generated with a much reduced input work requirement Up to the present day, the effect of what the experimental physicist Lenz discovered has been countered with high torque. What he found reflects the situation where if a generator is terminated with a fixed load and its shaft angular velocity increases then the increase in EMF causes an increase incurrent but also an increase in the braking effect Lenz recognized a natural reaction in the process of electrical induction. The reaction is not a linear brake action but is a pulsed effect where the associated force vector matches the shape of the generated current sinusoid.

By diverting the output and arranging that the magnetic polarity of pulses derived from that output are incident upon and in synchronism with flux sources having an identical flux density the braking effect can be minimised.

For the rig described herein, the flux sources (in that case permanent magnets) are smaller in area than the generation coils. This is true for most generators. There is a sequence of repulsion followed by attraction as the flux sources move over the coils to the centre position. Following this there is an identical sequence as the flux sources move out of scope of the coils.

Theoretically, the invention could be thought of as a motor being driven by a generator, regardless of the number of phases involved. Physically they are connected together on a single shaft whereas electrically they are connected aback to back" with the generator stator feeding the motor's stator. In this sense, the modifications to the motor are part of the subject of this

specification.

Using this analogy, an appreciation of the possibilities of this invention can be made which supports the comments included in the background chapter. There have been advances in the efficiency of electric motors in recent years. In Japan there is a verified instance of a particular electric motor achieving 96% efficiency. As the compensator could be considered a modified electric motor then the implication is that 96% of the output of the associated generator could be used to offset the braking effect experienced by it It follows that the generation of electrical current experiences a revolutionary increase in efficiency. The test results (below) support this view, which shows that, for the test rig, it is possible to reduce the braking due to current induction by at least 70%.

Accordingly the invention provides for a generator braking compensator as defined in the accompanying claims.

ADVANTAGES

Has the advantage of facilitating the re-use of generated electrical current, prior to dissipation in a load, in order to reduce the mechanical braking known as the Lenz Effect hence reducing the input mechanical power required to generate a given magnitude of electrical power.

Has the potential advantage of reducing the raw material requirement and/or preparation costs in any electricity generating station.

Has the advantage of facilitating a new renewable energy source, that is, the harvesting of the high flux density of rare earth magnets.

Hasthe advantage of allowing otherwise restrictedenergy related commodities to be produced cost effectively, for example reducing the production cost of hydrogen by electrolysis to a level where it competes favourably with hydrocarbon derivatives. This would go some way to bringing the scientific recommendations on emissions into focus.

There is an associated advantage when the cost of an energy storage medium is reduced. As an alternative to battery storage, it allows renewable sources to contribute "off-line" thereby removing a current problem, that is, the costly element of national grid extensions.

Has the advantage of being a catalyst for the mass production of industrial and domestic devices Has the advantage of increasing the justification for the deployment of existing renewable energy sources; specifically, in the wind turbine case, of reducing the required blade swept area (reduced torque requirement), reducing the physical size of the device, reducing the required separation and improving responsiveness to low wind speeds.

Has the advantage of relative simplicity implying low cost and rapid implementation and deployment.

INTRODUCTION TO DRAWINGS

Figure 1 shows a simplified side elevation and plan of the test rig. Note that the plan view is partial to avoid clutter.

Figure 2 illustrates the test rig physical generating flux source and coil interaction.

Figure 3 shows the compensation circuitry for the test rig and that for a single phase of a conventional generator.

Figure 4 shows the per-phase compensation sequencing for a rotary flux generator.

Figure 5 outhnes a device based on this invention that has the potential to be a new renewable energy device based on magnetic flux surpluses.

Figure 6 illustrates the test rig layout.

Figure 7 shows a graph of the test results.

Figure 8 illustrates the braking scenario for a rotary flux generator.

Figure 9 shows precise detail relating to how and why the compensation process works.

Figure 10 illustrates the movement capability of flux sources in general.

Figure 11 is the first part of a sequence diagram detailing test rig movement specifics.

Figure 12 is the second part of 11.

Figure 13 is the fIrst part of an improved sequence diagram.

Figure 14 is the second part of 13.

DETAILED DESCRIPTION

Note that in the following description the term "flux source" can represent either a permanent magnet or an electromagnet All induction machines experience energy losses in the form of friction which increases with angular velocity and rotating component weight The effect of this type of loss may be thought of as linear braking.

The electrical generator also suffers a second type of loss due to the effect of the interaction between the flux bearing components and any affected coils. This loss can be thought of as variable braking and is proportional to the induced current which in turn is dependent on the magnitude of the generated EMF and the value of the connected load. It is otherwise known as the Lenz effect. To eliminate this is the target of this invention.

This secondary braking is non-linear in that it manifests itself as a set of pulsed force vectors, the shape of each vector being sinusoidal. The vector shape matches precisely the generated EMF and induced current Therefore to nullify the retardation we require a set of reciprocal force vectors.

Classical electrical theory demonstrates that if a loaded coil experiences a pulsed EMF across it then that pulse will be converted to a flux field for the pulse duration with negligible loss.

Several of these conversions are used to produce the reciprocal vectors, which repel compensation flux sources rotating in synchronism with the generator rotors, in order to nulJifr the retardation.

The repulsion also ensures that the compensation flux source does not contribute to the output of the generator itself, thereby preventing the compensating flux source and coil from contributing to the retardation. The flux lines disperse each other.

To substantiate the claims of the content of this specification, a test rig has been built in the general form of a device which could be the basis of a non-intermittent domestic facility.

The test rig consists of two types of component, the generator component (1) and the compensation component (2). In any implementation there may be several generation and compensation components, also referred to as "rotors".

The generator component consists of a single set of eight stationary coils (3) sandwiched between two sets of eight moving flux sources, which for the test rig are permanent magnets(4).

All components are equally spaced in a circular manner such that the flux sources can move completely over the coils and then are able to completely clear them. The polarities of the poles of the flux sources are opposite (attracting) such as to maximize the density of the flux cutting the coils.

The compensation component consists of any number of sets of flux sources (5), similarly configured to the generation flux sources, together with sets of stationary compensation coils (6) the diameter of which allows positioning of two per flux source (i.e. one pair of compensation coils per compensation / generating flux source).

All flux sources in both components rotate in synchronism as they are connected by rods (11) on the same shaft (7). Note that any final implementation of a device similar to the test rig would be assumed to be fitted with a bearing consisting of industrial diamond tips/cups. The test rig runs metal to metal.

The compensation coils (6) are fixed in position where the magnetic effect on the compensation rotors is maximized.

Regardless of the application to which the principles are applied, the objective is to arrange that flux pulses derived from the product of the individual generation coils are fed to the respective compensation coils and are then delivered in an appropriate manner to affect the compensation flux sources.

To achieve this, several compensating coils-are required to be wired in series with the generating coil(s). Each coil causes a 90 degree phase shift which limits the number of coils in series to a maximum of three. After this, electrical interference occurs and the output is affected.

The reason for this requirement is two-fold. Firstly the flux density with regard to the compensation action must be equivalent to the generator pole areas that overlap the coils. See figure 2. Secondly, the compensation action is per-quadrant which necessitates the quadrant-orientated synchronization of force vectors to overcome the physical braking. This is accomplished by utilizing the 900 and 180° phase lag of two compensation coils wired in series.

See the section entitled Precise Explanation of Compensator Mechanism" below for more information.

For the test rig, each compensation coil pair is wired in series to one leg of a full wave rectifier (17) composed of 4 low forward voltage rectifiers (21).

The test rig makes use of a 12V DC motor (8) controlled by a PWM (16). The input power can therefore be measured directly.

The test rig currently runs in suboptimal mode. There are several reasons for this as detailed in the section "An overview of the test rig" below.

Figure 2 is included for completeness in understanding the relationship between a single coil and its associated flux sources as implemented for the test rig.

As the two magnetically opposite pole flux sources move over the coil they experience a physical braking effect confined to the area of overlap. The braking effect is due to the coil's reaction to the rate of change of flux as discovered by Lenz. The magnetic consequence is a sequence of repulsions and attractions during the supply of output current, labeled "R" and "A" in the figure. The physical consequence is the application of the brake vector shown.

To serve as a comparison with rotating flux devices, figure 8 illustrates the pole of a salient pole generator moving close to a coil with the corresponding output noted as Q1/Q3 and Q2/Q4 showing the physical resultant brake vector with respect to the output The maxima of the generated EMF is marked "x". The movements of the north and south poles are illustrated in three states.

State 1 sees the flux lines in-line with the coiL The rate of change of flux is zero (beginning of Q1/Q3). State 2 sees the flux lines perpendicular to the coils. The rate of change of flux is maximal i.e. fSXIP arrived at, beginning of Q2/Q4. State 3 sees the end of Q2/Q4. From the start of Q1/Q3to "x" there is repulsion. From the start of Q2/Q4 there is attraction.

The physical brake vector can be compensated for with flux magnetic repulsion in a similar manner to the test rig.

AN OVERVIEW OF THE TEST RIG FOLLOWS: There are several deficiencies due to the build quality, mainly caused by budget constraints.

They are listed here: 1. The flux source and coil rotors are fabricated using MDF which is far from a perfect solution due to the material's pliability and lack of strength. This means that the rotation of the flux source rotors is not ideal therefore the gap between the flux sources and the coils is large and variable (for both compensation and generation).

2. The base point bearing consists of a conical tip ground at the end of a bright steel shaft sitting in a mild steel cone. It is anticipated that the two parts would be replaced in their final form with something approaching diamond hardness.

3. All coils are hand wound.

4. Ideally, the surface area and shape of the compensation components should be equivalent.

The test rig only approximates to this; the flux sources are square in section whereas the coils are circular. Some loss of compensation does occur.

5. The compensation seen is reduced by losses in the method of supplying the pulse train for the compensation (FWR). On a larger scale, these losses would be negligible but for the test rig it means approximately 15% loss of compensation.

Overall, the test rig is crude but providing all measurements are relative to an initial known state then relative offsets from that state can be observed.

TESTING AND OBSERVATIONS

Notes.

1. The speed and voltage out are expressed as nn/nn...@n.nV, where the speed is lower/upper (stated / 8llzx6Orpm).

2. The volts are peak (half wave) reduced due to FWR losses.

3. An identical load is used in tests 2,3 and 4.

In the current test rig configuration, each coil exhibits near identical output in terms of phase and amplitude.

Currently, the generating flux sources' surface areas are approximately half the surface areas of the coils. This is not part of the design but a factor of component re-use.

The test rig is illustrated in figure 6. The motor is fed by a PWM module (16) fed from a 12V battery (15). Total current consumed can be monitored on the DVM (17). The output from a photo-transistor/diode combination (18) is fed to a frequency meter (19) to enable monitoring of the angular velocity. An oscilloscope (20) monitors the waveform out.

Testing has occurred on several separate coils and it has been observed that the results are a simple aggregate of those of a single coil. To that end, the test results stated here are for a single generating coil only.

Test 1 was carried out in order to establish the unloaded perfonnance of the rig. Graphs were generated of the input current.vs. angular velocity at individual stages of the rig build. The final graph illustrates the performance with two generating flux source rotors and one compensation flux source rotor installed on the driveshaft. See Fig.7.

Test 2 was to establish the performance of the rig when the coil under test was loaded with a simple FWR circuit terminated with a 2.211 resistor. This was plotted on the graph (point A) for an input current of 3.4A. The result was 37/38@2.7V.

Note that measurement and motor control electronics consume 0.3A, therefore the applied total current was 3.7A.

Next, the compensation coils were positioned on the rig and connected as shown in Fig.3. This diagram emphasizes the lateral positioning of the compensation coils. The coils are wired in series. In test 3 the rig was spun up and the compensation coils adjusted with the intention to attain the maximum speed possible with the same input current and load as test 2. The average result was 55@3.OV. (Graph point B).

The result of the test represents an increase in speed of 44%+(17/38) w.r.t the overall speed in test 2 but given that the unloaded losses consume 2.4A (Test 1), the total possible variable loss open to compensation is 1A(span C). Converting the variable loss to speed (span D), the total speed increment possible is 23, that is from 38 to 61(see graph). Taking the speed increment of 17 with compensation and deriving a percentage w.r.t 23 yields an improvement of 70%+ (17/23), span E. This of course might be dismissed as a pure effect, but a further test is now possible.

If this is a true improvement, then the speed increase must translate directly to an input current reduction. The maximum possible reduction is 1A. So it should be possible to reduce the input current by 70% of what is possible i.e. to 3A (including measurement electronics) and be able to match the performance of test 2.

Test 4 consisted of a reduction in input current to 3A and a re-adjustment of the compensating coils. The results were 43@2.7V, proving that the speed increment matches the input current reduction.

A note is applicable here regarding the re-adjustment of the test rig compensating coils. As the frequency reduces, the wavelength increases and the peaks of the waveform (including the pulsed braking vector) move. This necessitates re-positioning. No such adjustment is necessary in the rotary flux case.

Note also that as well as a reduction in input energy to produce a given magnitude of electrical power, the converse is true i.e. if the input energy is maintained at the same level for a prime mover I generator combination, the yield of that combination will increase, albeit that the output power AND frequency will increase proportionally with the net effectiveness of the compensation.

PRECISE EXPLANATION OF COMPENSATOR MECHANISM

The number of compensator coils acting on compensator flux sources is two per active generator pole. Two poles, the most common, equivalent to the test rig case, require 4 compensator coils.

The granularity of compensation is per-quadrant.

Sets of two compensator coils, wired in series, are energized by each generated half-wave.

The natural phase lag induced by the compensator coils results in two pulses of flux, due to the natural operation of current flowing through inductors, these being 90 and 180 degrees distant from the original generated pulse.

Only the very first generated quadrant is not compensated for.

The compensation process is a loop (following) whereby the second quadrant of any generated pulse fall is compensated for by that same pulse's previous rise in the first compensator coil and the next generated pulse quadrant rise is compensated for by the 180 degree pulse produced by the now previous generation pulse in the second compensator coil.

Starting at the peak (90 degree) of generated EMF (current in phase) or Q2 For each half-wave (At the start of each half-wave the pairs of compensation coils are effectively swapped, one set replacing the other to ensure repulsion of the compensation flux sources) The 90 degree pulse compensates for the braking due to the generated quadrant ("second") EMF fall to 0. The braking is due to the flux magnetic attraction of the generator rotor by the generator coils.

The 180 degree pulse compensates for the braking due to the generator next ("third") quadrant EMF rise to its maximum value (i.e. the start of the next generated pulse). The braking is due to the flux magnetic repulsion of the generator rotor by the generator coils.

End For Figure 9 illustrates this process.

APPLICATION OF THE GBC PRINCIPLES

FLUX HARVESTER

An outline for such a device is outlined in Figure 5, modeled on the test rig. To ensure the minimum friction contribution, a BLDC motor would be used where the rotating flux source component of the motor (14) is an integral part of the shaft.

The compensation (2) and generating (1) rotors would be similar to the test rig. The size and number of rotors is only limited by what is a practical maximum.

Any such device would naturally incur frictional losses on the bearings proportional to the weight of the supporting infrastructure. The main component of the infrastructure weight is that of the flux sources. If it were possible to reduce the flux source weight whilst retaining or even increasing the generation energy density then the fixed bearing losses reduce proportionally.

This is reflected in basic comparisons between the test rig components and technical detail freely available. The test rig uses recycled components, namely grade 3 ferrite magnet blocks.

These have a BHmax (a measure of energy density) of 3.5. In comparison, NdFeB magnets (also known as "rare earth" magnets) have a BHmax of 40, which is >11 times that of ferrite.

Having compensated for the natural braking effect between the generating flux sources and coils, the only negative aspect remaining is frictional loss from either bearings or air turbulence.

Using documentation available freely on the web, it is possible to paint a scenario where these negative aspects are nullified.

Carbon Fibre Reinforced Polymer (CFRP) is extremely strong and lightweight Other materials and techniques (for instance, honeycomb structuring) also exist which could provide a basis for the rotor.

Additionally, the Flywheel Energy Storage (FES) project at NASA demonstrates the feasibility of using permanent flux source bearings with perfect diamagnetic guides formed from high temperature superconductors. This is feasible because of the known low cost means (nitrogen) to supply the energy necessary to produce superconductors. Although the project itself removes the air turbulence aspect by operating the flywheel within a vacuum, probably an unwanted aspect in any domestic implementation of the GBC, the fact that the frictional bearing losses are virtually eliminated could be an additional aspect to a harvester implementation.

The availability of a domestic system which had a guaranteed payback for either local use or feed-in tariff purposes would have a world-wide audience and would be a key part in any real moves towards a hydrogen economy.

Ex!sTING GENERA TORS The test rig approximates to a permanent magnet alternator and as such is a rotating flux domain machine unlike most generators in the field which are based on the principle of rotating flux. The basic magnetic and electrical principles are similar however in most respects.

The components required for compensation in any rotating flux generator are outlined in figure 4 (one phase; 2 pole rotor). Note that the stator coils are wired in series. Because the coils are reverse wound, the EMF from each winding is cumulative. Similar to the test rig, the voltage and current are in phase. Regardless of the number of windings and the generator configuration, the points of maximum braking are singular per phase but may be at a mean point which is a cumulative maximum of several individual braking points.

Existing AC generators can be used to supply DC or AC current. In the DC case, rectification is implemented in a manner not unlike the test rig, accepting that several phases will be included.

The AC case is similar, see figures 3 and 4. The number of compensation coils is always twice the number of active poles (this also applies to the test rig). In the given example, this is 4(2x2).

Notice that the rotor flux sources replace the permanent magnets of the test rig. They are shown to have identical flux magnetic polarity and to be repelled the compensation coils have to match that polarity. Note that for a 3 phase generator, only 2 rotors are necessary as both ends of the flux sources mounted on the rotors can be used. A four phase machine (if it existed) would also require only 2 compensation rotors. See also the base of figure 3 for compensation coil positional information per-phase for the conventional generator.

In the field there are many variations in existing generator designs but, ignoring the method of excitation, all fall into three categories. These are non-salient pole (NSP), salient pole (SP) and permanent magnet (PM).

There are two scenarios applicable to NSP generators. The first is to attempt to apply a retrofit GBC. The second is to replace the NSP generator with a cluster of smaller SP generators.

Non Salient Pole generators are those used mostly in electricity generating stations where the prime mover is usually high pressure steam i.e. the "fired" generation types. The huge physical size of these generators is such as to render a very efficient generator, in the order of 98%. That said, to get the required mechanical power to the generator shaft requires raw material processing which reduces the overall plant efficiency to around 45%.

The rotor in the NSP case is cylindrical, usually having 2 poles and an integral exciter generator.

The mechanical and electrical stresses on the rotor are high which necessitates cooling, often in the form of hydrogen gas. The application of the GBC to such a large generator would cause the GBC itself to be large but given the prevalence of fired stations it is here that the C02 reductions would be greatest. If the GBC could be built as a retrofit unit for the world's bulk electricity generators, regardless of the input energy medium, then it becomes a viable export product.

There is also the potential to affect the number of electricity generating stations required to be built in the future and be complementary to CCS.

To be a viable retrofit candidate, the number of constraints on existing kit must be minimal. To this end it is suggested that only one exist, that of a simple shaft coupling from the generator to the GBC. Most large existing generators are self exciting so the GBC has to be also. For the GBC to work successfully on all phases, usually three, the compensation components have to be separate per-phase. Mutual inductance is an unwanted side-effect for the GBC.

As one of the proven constraints for correct operation of the GBC, the active areas and flux densities of the compensator and generator have to be equivalent The GBC exciter current would be considerably less than that required for the generator rotor, requiring only air cooling. This is because the flux is only required to be equivalent in the gap between the stationary and moving components of the compensator. In comparison, the generator rotor is required to project its flux component throughout the three huge windings of the stator.

The other option is replacement of the NSP. The GBC changes the landscape of system efficiencies. Before the GBC there was only one way to increase the yield of a generator at a fixed frequency i.e. by increasing the torque at the same time as increasing the physical size. With the prospect of the GBC the situation now is that an NSP generator could be replaced by several SP generators each equipped with a GBC. As the generators could run on the same shaft, the output would be perfectly in-phase and the generated EMF could be aggregated in the same way as in multi-coil phase generation. The energy consumed in any prior NSP cooling scenario would be saved and if the steam pressure could be reduced the rankine losses would be reduced in proportion.

OVERALL ELECTRICAL CoNsIDERATIoNS In any generator implementation, consideration has to be given to the intended types of load.

The NSP generator is likely to be terminated by a transformer on the way to providing HVAC to destination distribution systems. In all other cases the load scenario is mixed.

Connecting inductors in series with the individual generator phases comprises part of the general implementation of a compensator.

The effect of adding an inductor is to introduce a 90 degree phase shift between the generated EMF and the induced current The current lags the voltage but if terminated by a resistive load the current and voltage across the resistance is in-phase. The lag only exists between the source voltage and current and the resultant across the inductor. Up to the frequencies of 50 to 60 Hz the effect of the introduced inductive reactance due to the compensator coils is minimal so unless the resistive element of the circuit is high the effect of the reactance is low. Where a sink is highly reactive i.e. the generator is directly terminated by a reactive load, the standard means i.e. introducing a compensating capacitive reactance would be implemented to avoid apparent power effects.

COMPENSATIONADJUSTMENTS DUE TO SPEED VARIATIONS IN FLUX DOMAIN MACHINES

Where a permanent magnet generator is compensated, i.e. generators embodying the principles of the test rig, small adjustments of the compensator coils are necessary when the speed of the prime mover changes. The adjustments are small but necessary to position the compensation vector at the time of the next brake point. There is no such need in the rotary flux generator case.

A running scenario for this case might be as follows. At the start, the generating device is unloaded; the device speeds up then, at a certain speed, the load and compensator are switched in. At this point, two complimentary effects occur: 1. The load will draw current which will cause a braking effect and the generator will slow down 2. The compensator will compensate for the braking and the generator speed will increase Electronics on the compensator would determine the angular velocity.

Small adjustments would be made electronically by physical adjustment of the compensator fixed coils with, for instance, a stepper motor until (for a particular load) the maximum speed is obtained.

The speed is controlled by the load with the compensator in circuit The load can increase i.e. resistive value decreases, knowing that less torque is required due to compensation.

ADVANTAGES AND APPLICATION GUIDE FOR EXISTING RENEWABLE DEVICES

HYDRO

The output from any hydro system depends chiefly on water flow rate and head height Water, hitting vanes or cups connected to one or more generators, provides the torque required to overcome the natural braking effect of the generating components. To date, the classical means of providing this environment has been to build dams which over time are anything but environmentally friendly.

There have been, at the time of writing, suggestions that classical water wheels and other historical means of electricity generation be resurrected to contribute to what is perceived as a potential major shortfall in future power provision. Although much has been reported regarding this, all of the known problems that caused hydro solutions to languish in the background are still there. High head and flow rate only occur in certain circumstances. Additionally, "Pelton" wheel devices still affect the water downstream due to the removal of kinetic energy to satisfy the requirement for high operating torque.

This could all change with the application of the GBC. In a particular situation, the flow rate of water is fiuirly constant Removing the dependency on high torque removes the reliance on high head and at the same time reduces the downstream effect A Pelton wheel would be able to rotate at speeds which do not impede the prevailing flow rate.

The GBC might be regarded as the means to commandeer any water flow for purposes of power generation, regardless of its disposition. For instance, although a weir has been suggested as a means to provide a supplement to the general electricity supply, in all practical respects the yield to date would have precluded its use. The flow rate may be acceptable but the head height questionable given existing technology constraints.

WIND

Wind turbines are promoted as the saviour to achieving perceived safe levels of C02 emissions at some later date. The promotion is usually advocated by groups who both know that those who are supposed to know do not understand the science and who are at the same time intent on reaping the benefits of subsidies.

There are certain situations that benefit from wind turbines but in their present form they will never replace hydrocarbons for base load. Anyone without a biased agenda will understand that However, the GBC may be of use to existing turbines, necessitating some modifications to the turbines. The major effect of GBC implementation would be to shrink the size of the blades thus allowing greater speed. One problem would probably be that the effect of a far lighter blade structure and a heavier generator assembly (which included the GBC) would render the tower unstable. However, the nacelle could be modified to mount the generator above rather than below the low speed shaft, reverse its physical emplacement, move it closer to the tower(improving its CG) then mounting the GBC such thatthe CG is rendered perfect, balancing the weight of the generator and GBC combination across the top of the tower.

Wind turbines built in the future could be far smaller hence less costly to manufacture with the inclusion of the GBC.

The generator types used in wind turbines vary; logically this implies the types will either be SP or PM. The compensation requirements for these generators are covered elsewhere in this

specification.

One interesting fact regarding the deployment of offshore wind turbines is the necessity to recti1y their output in order to overcome capacitive losses in the cables to shore. Undersea cables cannot successfully carry AC. The generators are of the permanent magnet type. The components to implement a GBC are probably already there. A related aspect is the subject of long-distance DC supply which in the same manner already incorporates most of the components required for the implementation of the GBC.

From an observer's viewpoint, the take-up to date of domestic wind turbines has been patchy. It appears to have been accepted that to reap the benefits of wind incurs constraints that cannot easily be overcome in every case. The GBC has the potential to change this. As with hydro systems, the wind turbine converts naturally occurring kinetic energy to torque. If the torque requirement is reduced then the turbine rotates faster which implies that the blade diameter can be reduced. This reduces the weight hence the bearing losses. If the torque requirement can be effectively eliminated, as has been implied during the testing of the GBC prototype, then the blades present very little drag on the prevailing wind so are more sensitive to lower wind-speeds.

It is also possible that alternative turbine designs, made possible by the reduction in the requirement for high torque, may be able to reap the high kinetic energies available from the effects of wind swirl e.g. around tall buildings. This is an area for future experimentation.

HYDROGEN

The consideration of hydrogen as a global storage medium is relevant for several reasons. The main reason is the fact that the power yield of the gas dissipation has only one side effect, that is, the production of pure H20.

In the renewable energy scenario, energy storage is a major problem. Hydrogen itself has a major problem in that to split it from water is extremely costly. There are projects that aspire to generate hydrogen from the power yield of renewable energy but these are relegated to also-rans due to this inherent conversion ineffIciency.

The GBC could change this. By increasing the electrical productivity of generators relying for their prime movement on natural intermittent energy variations, the increased volume of electrical current could ensure the maximal volume of hydrogen and therefore justify the conversion effort. The cumulative effect of hydrogen generation projects then serves to allay any intermittency concerns.

There is work ongoing that has its target the replacement of hydrocarbon based power provision. The applications are diverse, ranging from transport to human survival.

The GBC offers a range of options for the efficient generation of hydrogen. The efficiency of the best gas turbines is of the order of 60%. This is considerably better than the overall efficiency of plant relying on steam production.

The GBC can obviously not improve the efficiency (watt for watt) of individual turbines but what it can do is increase the overall production yield when those turbines are used to generate electricity.

Gas turbines are also capable of burning hydrogen. There is an apparent flaw in the implication that hydrocarbons need to be burned, albeit more efficiently, to produce the hydrogen in the first place. There is an advantage though when the concept of CCS becomes viable. The CCS would only be needed in the small number of sites where the conversion took place, rather than at every power station in existence.

Regarding domestic generation, a guaranteed feed-in from many contributors suggests that a physical storage mechanism for those contributions would be necessary. To this end, it would be unlikely that individual households would be deemed responsible enough to manage this.

More likely, an area-centric hydrogen generation and storage facility would be powered with aggregated electrical contributions.

Another facility could then be accommodated, that is, an area-centric generation which could incorporate CHP. Alternatively, the accumulated gas could be transported to a central generation point (e.g. an existing power generation site).

Such scenarios are not a "big bang" approach but rather are implementable over time. Costs are thus absorbed by the consumer / implementer during the time in which distributed networks of power systems are built. This has the desirable effect of introducing the concept of redundancy i.e. one failed branch will not affect connected branches.

RELATED PROCESSES POTENTIALLYAFFECTED BY IMPLEMENTATION OF THE GBC

An area of waste management, namely the gasification of material otherwise destined for landfills has to date been impeded by the end-to-end process efficiency where more energy is used than can be recovered. By reducing the input work requirement of say, a gas turbine, this inefficiency recedes.

ANALYSIS OF THE GBC TEST RIG

The test rig for the GBC was assembled from pre-used components and as such it was a surprise to the implementer that it worked. The theory of the principles was reverse-analyzed for this

specification (detailed above).

It will be appreciated that if the precise practical mechanism of the rig could be understood and documented then there would be a good chance of improving the compensation percentage by design rather than chance. That is the purpose of this analysis.

As part of the analysis it is necessary to understand what happens when two flux sources come into close proximity to one another. Dependent upon the direction and magnetic polarity the resultant mechanical forces vary considerably.

MOVEMENT CAPABILITY OF FLUX SOURCES

See figure 10.

The effects represented in the figure may have been documented elsewhere; if so the terminology is with respect to this specification only.

In terms of physical movement capability of related magnetic force, the writer has decided to refer to these as "modes". In this regard there are 3 modes, movement enhancement mode (m-e mode), movement retardation mode (m-r mode) and movement neutral mode (rn-n mode).

Specifically, m-e mode is used in the GBC to counteract m-r mode in an associated electrical generator. rn-n mode represents the state existing in the transition between m-r mode and m-e mode.

The first example (1) illustrates movement retardation. This is where as the flux sources approach each other then due to their same magnetic polarity they retard movement. This is also known as type 1 m-r mode.

The second example (2) illustrates movement enhancement. This is where as the flux sources approach each other then due to their opposite magnetic polarity they enhance movement. This is also known as type 1 rn-e mode.

The third example (3) illustrates movement enhancement This is where as the flux sources move away from each other then due to their same magnetic polarity they enhance movement.

This is also known as type 2 m-e mode.

The fourth example (4) illustrates movement retardation. This is where as the flux sources move away from each other then due to their opposite magnetic polarity they retard movement.

This is also known as type 2 m-r mode.

The fifth example (5) illustrates movement neutral mode. In the case of two same-pole magnetic surfaces where the flux lines are perpendicular there is a finely defined balance of neutrality when those surfaces are exactly in-line. As the surfaces move away from each other there is (always) a repulsive force but this does not result in 100% physical horizontal movement until the surfaces are very near to being precisely out-of-line i.e. at the point where the switch to m-e mode results. This applies to any build up of flux in a related coil as the diagram illustrates.

When the flux due to the current ramping up reaches its pealc the interaction between the compensating coil(6) and magnet(5) changes to m-e mode.

In the GBC therefore the 900 and 180° coils pulses build first of all in rn-n mode then when the coils are precisely out-of-line with respect to the compensating flux sources the force vector is applied due to the natural change to m-e mode.

At the base of figure 10, a generator coil (3) and magnet (4) are shown. It can be seen that the overlapping areas are approximately equal which explains why (accidentally) parity can be demonstrated between the test results and the analysis presented here.

TEST RIG

Figures 11 and 12 are sequence diagrams of the test rig components; see also the key sheets.

The percentage of compensation seen in the test rig test results is reflected in the positional detail presented.

It should be noted that the test rig was originally tested with one generation coil and just two compensation coils. The second set of compensation components was added purely in the belief that the areas needed to match the effective flux application areas of the generator with no regard to the phase effect of two coils in series. This discovery became apparent after those tests. In this sense the test rig is a simulation of the final requirements of the GBC i.e. it is now known that 4 compensating coils are required to compensate two poles of a generator rotor on a per-quadrant basis.

Figures 13 and 14 are sequence diagrams of the same generator configuration as the above but with the addition of another compensator rotor with repositioned compensating coils to ensure that all 4 compensating quadrant vectors arrive at the correct time. This is likely to maximize the braking compensation.

Claims (6)

1. CLAIMS1. A generator braking compensator which arranges to compensate for the braking effect recognized by Lenz, the braking exhibiting itself as pulsed force vectors resulting in the physical retardation of the rotational movement of an associated electrical generator driven by a prime mover, the braking being proportional to the power required to be delivered to a load, the compensation being derived from an arrangement redirecting the generator output to pairs of fixed coils wired in series with the load in order to create flux pulses having a known phase relationship with respect to both the generated current and between themselves, the pulses being arranged to affect flux sources on one or more rotors mounted on the shaft of the generator, the rotor flux sources being of the same magnetic polarity resulting in synchronized physical pulsed force vectors implemented byrepulsion, the result being compensation for the pulsed braking experienced by the generator rotor, the consequence of which causes an increase in the angular velocity of the generator rotor and subsequent increase in output power which jointly can be offset by the reduction in input energy supplied to the prime mover.
2. 2. A generator braking compensator according to claim 1 utilizing the natural effect of momentary zero-loss energy storage in the form of magnetic flux resulting from current flowing in fixed electrical coils, the magnetic effect being used to repel flux sources in order to compensate for the per-quadrant pulsed braking, two coils in series causing two pulses per generated half-wave being ninety degrees and one hundred and eighty degrees offset from the generated half-wave, the sequencing and position of the pulses being arranged to force the generator poles over the "next" quadrant braking force vectors experienced by the generator rotor, the three hundred and sIxty degree single cycle quadrant braking being the sequence of repel-attract-repel-attract corresponding to the generation sequence of per-quadrant generation electrical wave transitions of rise-fall-rise-fall, compensated by the generator braking compensator sequence of repel-repel-repel-repel.
3. 3. A generator braking compensator according to claim 1 where the positions of the fixed coils are such that the rise of the current pulses occur at points in time where the effect of the repulsions by fixed coils on rotor flux sources are least, in preparation for the points in time at which the repulsions have a maximal effect in compensating for the uflextl? quadrant braking vectors, the "next quadrant braking vectors being those which occur after the compensation repulsions.
4. 4. A generator braking compensator according to claim 1 that can be attached retrospectively as a physical unit to support the operation of any electrical generator in the field thereby facilitating the reduction in applied torque required by a prime mover in order to generate electrical power, the generator being either of a type where a magnetic rotor rotates within stator coils, known as a rotary flux generator, or alternatively one where magnetic sources move over coils in close proximity, known generally as a permanent magnet alternator or rotating magnetic domain machine.
5. 5. A generator braking compensator according to claim 1 that facilitates a significant reduction in the energy required to be supplied to a prime mover in order to turn a generator shaft for the purposes of generating electrical current, the reduction made possible by the application of compensating force vectors which act in an opposing direction to the braking force vectors.
6. 6. A generator braking compensator according to claim 1 which, as the converse of claim 5, results in a significant increase in speed and power output when the input energy to the prime mover remains at the level before the compensation mechanism was applied to the generator.Amendments to the claims have been filed as followsCLAIMSL A generator braking compensator for an electilcal generator that delivers power to a lap A A.p.b.a..a rk.A. n A4 k.. -e.,a *ka e.nn.pnpnbztr 13. A generator braking compensator according to claim I where the prime mover is a turbine converting any naturally occurring kinetic energy resource to rotational speed and torque.S*0**S*S S * *05*5S S * *0 * 0 0 55.5 * 5* 0 * 0**5