AU758503B2

AU758503B2 - Boat or vessel with electric drive

Info

Publication number: AU758503B2
Application number: AU52638/99A
Authority: AU
Inventors: Christian Bouly
Original assignee: Alternatives Energies
Current assignee: Alternatives Energies
Priority date: 1998-07-29
Filing date: 1999-07-13
Publication date: 2003-03-20
Anticipated expiration: 2019-07-13
Also published as: DE69906086D1; EP1100717B1; FR2781755B1; ATE234757T1; FR2781755A1; CA2338163A1; EP1100717A1; AU5263899A; WO2000006450A1

Abstract

The invention concerns a boat or vessel with electric drive comprising at least an electric motor mounted in a sealed submersible and adjustable casing (22), the electric motor being of the alternating current type and with high rotating speed and housed in the casing (22) with a power inverter powered by on-board batteries, and a reduction gear for driving a propeller (26) mounted on an output shaft of the casing (22). The invention is particularly useful for electrically driving small or medium sized boats and vessels.

Description

PCT

ORGANISATION MONDIALE DE LA PROPRIETE INTELLECTUELLE Bureau international DEMANDE INTERNATIONALE PUBLIEE EN VERTU DU TRAITE DE COOPERATION EN MATIERE DE BREVETS (PCT') (51) Classification internationale des brevets 7 B63H 23/24

I

(11) Numd~ro de publication internationale: WO 00/06450 Al (43) Date de publication internationale: 10 f6vrier 2000 (10.02.00) (21) Numdro de la demande internationale: PCTIFR99/01 710 (81) Etats d~signds: AU, CA, JP, US, brevet europ6en (AT, BE, CH, CY, DE, DK, ES, Fl, FR, GB, GR, TE, IT, LU, MC, NL, PT, SE).

(22) Date de d~p6t international: 13 juillet 1999 (13.07.99) Donn~es relatives il la priorit&: 98/09683 29 juillet 1998 (29.07.98) FR (71) Ddposant (pour tous les Etats d~sign~s sauf US): ALTERNA- TIVES ENERGIES [FRIER]; 7, rue du Plessis, F-17000 La Rochelle (FR).

(72) Inveateur; et; InventeurID)6posant (US seulement): BOULY, Christian [FR/FR]; Capitainerie du Vieux Port, F-17000 La Rochelle

(FR).

(74) Mandataires: DOIREAU, Marc etc.; Cabinet Ores, 6 Avenue de Messine, F-75008 Paris (FR).

Publi~e Avec rapport de recherche internationale.

(54) Title: BOAT OR VESSEL WITH ELECTRIC DRIVE (54) Titre: BATEAU OU NAVIRE A PROPULSION ELECTRIQUE (57) Abstract The invention concerns a boat or vessel with electric drive compris- 3 ing at least an electric motor mounted in a sealed submersible and adjustable casing the electric motor being of the alternating current type and )XrP with high rotating speed and housed in the casing (22) with a power. in- 4 verter powered by on-board batter -3' ies, and a reduction gear for driving a3 propeller (26) mounted on an output 3 shaft of the casing The invention is particularly useful for electri-6 cally driving small or medium sized boats and vessels. ,2 (57) Abr~g6 Bateau ou navire k propulsion2602 6lectrique, comprenant au momns un moteur 6lectrique montd dans un boitier 6tanche (22) qui est immergeable et orientable, le moteur 6lectrique 6tant du type A courant alternatif et A vitesse de rotation 6]evde et 6tant log6 dans le boitier (22) avec un convertisseur de Puissance continu-alternatif alimentd A partir de batteries embarqu6es, et avec un r~iucteur A engrenage pour l'entrainement d'une h6lice (26) mont~e sur un arbre de sortie du boitier L'invention s'applique notamment A la propulsion dlectrique de bateaux et navires de petite ou moyenne taille.

AN ELECTRICALLY-PROPELLED BOAT OR VESSEL The invention relates to an electrically-propelled boat or vessel, in particular a boat or vessel of small or medium size suitable for leisure use, transporting passengers and/or goods, etc., at sea or on water courses or stretches of water such as rivers, canals, or lakes, for example.

For reasons of profitability and preserving the environment, proposals have already been made to replace the internal combustion engines that are used for propelling boats or vessels by means of electric motors that are fed with energy from electric batteries associated with charger means.

Electric motors can be placed on board boats or vessels so that they replace conventional internal combustion engines, however it is more advantageous to house them in leakproof housings that can be immersed and possibly also steered, which housings are fixed beneath the hulls of boats or vessels or are carried by systems for mounting outboard engines, said housings having an outlet shaft carrying a propeller that is driven in rotation. This makes it possible to eliminate conventional transmissions between propellers and motors mounted on board, and also to omit cooling systems for the motors, while simultaneously benefiting from propulsion that is silent and non-polluting.

Nevertheless, those known propulsion systems have been developed for vessels of large size and they are fitted with electric motors of a special type that is sophisticated and expensive, delivering powers of megawatt or greater order, and they are generally themselves powered by alternators driven by turbines or diesel engines. At present, no electrical propulsion systems exist that provide worthwhile performance at acceptable cost and that are suitable for fitting to boats of small and medium size (typically of length lying in the range about 3 meters to about 50 m) and 2 powered by electric batteries of weight and size that are compatible with such boats of small and medium size.

It is therefore an object of the present invention to provide an alternative electrically propelled boat or vessel.

To this end, the invention provides an electrically propelled boat or vessel having at least one electric motor placed in an immersible leakproof housing that is optionally steerable, a propeller mounted on an outlet shaft of the housing to be rotated by the abovementioned motor, electric batteries for powering the motor, battery charger means, and a DC/AC converter for supplying AC driving power from the electric batteries to the motor, wherein the motor is an AC motor connected to 15 the propeller via stepdown gearing placed inside the above-mentioned housing to be cooled together with the motor by exchanging heat with the water outside the housing, the battery charger means including means for providing an induction link to electricity distribution mains.

An embodiment of a propulsion system of the invention presents multiple advantages: the stator of the AC motor carries the windings and can be cooled effectively merely by contact with the 25 wall of the housing; the use of stepdown gearing between the electric motor and the propeller enables a motor to be used which rotates at relatively high speed, delivering sufficient power when of relatively small dimensions (reducing the H:\Maria\Keep\52638.99.doc 2/01/03 dimensions of the motor gives rise to a reduction in drag given that the motor is immersed); the gearing makes it possible to use a propeller of large diameter and relatively low rotation speed, providing good efficiency; the gearing is cooled by exchanging heat with the surrounding water and can therefore be used at a high speed of rotation without that giving rise to a loss of lubrication, so its lifetime can be long; the propulsion assembly (motor-gearing-propeller) requires very little maintenance and has a very long lifetime; the propulsion assembly generates very little noise or vibration and does not cause any heat to be given off inside the boat or vessel; and optimizing the motor-gearing-propulsion assembly enables electricity consumption to be kept down, thereby increasing the range of the propulsion system when operating from on-board batteries. For given range, this makes it possible to reduce the quantity of batteries required, and thus to reduce the overall weight and size of the batteries.

According to another characteristics of the invention which is particularly advantageous, the electrical power supply means of the above-mentioned motor comprise a DC/AC power converter which is housed in the leakproof housing so as to be cooled by exchanging heat with the water outside the housing.

This cooling of the DC/AC power converter makes it possible to eliminate the heavy and bulky radiators that would normally be associated with the electronic components of such a converter. This reduces the Weight, the size, and the cost of the power converter and considerably increases its longevity and reliability.

In a preferred embodiment of the motor, the abovementioned electric motor is a self-excited three-phase synchronous motor having a rotor with permanent magnets, and the above-mentioned gearing is a planetary gear unit.

In a variant, it is possible to use a propulsion assembly including a turbine which is driven directly by an electric motor of the above-mentioned type.

According to yet another characteristic of the invention, the means for charging the on-board batteries include means for making a connection by induction with the electricity distribution mains.

This serves in particular to enable the batteries to be charged automatically or quasi-automatically without requiring manual intervention to connect a charger to the electricity mains. This avoids risks of short circuits and bad contacts due to faulty electrical connections.

Furthermore, this type of charging is particularly advantageous when the boat or vessel is a "shuttle" that performs regular go-and-return trips between two points or that follows a predetermined course, with battery recharging taking place automatically each time the boat or vessel stops at a determined point on its course to pick up and put down passengers and/or goods, for example.

Advantageously, the battery charging means can also include photovoltaic solar panels, e.g. disposed on the roof of the boat or vessel, thereby considerably increasing range at low speeds and reducing running costs.

Solar panels can also be installed on land to participate in charging the batteries of the boat or vessel when it is at the quay side, and to inject energy into the electricity mains at other times.

According to another characteristic of the invention, the propulsion assembly is carried by a support structure that extends inside a well formed in the hull of the boat or vessel, said well having transverse dimensions that allow the motor-gearing- 5 propeller assembly to pass along the inside of the well for mounting on the boat or vessel and for dismounting.

This characteristic of the invention makes it possible to take action on the propulsion assembly while the boat or vessel is afloat, without it being necessary to take it to a dockyard and remove it from the water.

This greatly facilitates maintenance and repair of the propulsion assembly and reduces the cost thereof and also shortens down time of the boat or vessel very significantly, which is most advantageous for the owners or operators of such a boat or vessel.

The invention will be better understood and other characteristics, details, and advantages thereof will appear more clearly on reading the following description 15 given by way of example and with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of a vessel of a preferred embodiment of the present invention; Figure 2 is a diagram showing means for mounting a propulsion assembly on one of the hulls of the vessel; Figure 3 is a block diagram of the electrical power supply means of the propulsion system of the preferred embodiment of the present invention; Figure 4 is a fragmentary diagrammatic plan view of an automatic docking system that also serves to charge the batteries by induction; and Figure 5 is a fragmentary diagrammatic view showing a variant of the preferred embodiment of the present invention.

Reference is made initially to Figure 1 which is a diagram showing an example of a vessel of the preferred H:\Maria\Keep\52638.99.doc 2/01/03 5a embodiment of the present invention for carrying passengers on a predetermined course, e.g. within a port, in an estuary or on a lake, on a river, on a canal, etc.

The vessel is of the catamaran type and comprises two parallel hulls 10, a deck 14 having rows of passenger seats installed thereon, a roof 16 providing protection H:\Maria\Keep\52638.99.doc 2/01/03 against rain and sun, and a cockpit 18 from which a single person can control and maneuver the vessel.

The two hulls 10 are interconnected by cross-beams of a length that is determined as a function of the number of passengers the vessel is to carry. It is also possible, using the same molds, to manufacture hulls of greater or shorter length depending on the desired transportation capacity.

Each hull 10 of the vessel is fitted (Figure 2) with a propulsion assembly 20 for outboard mounting, said assembly comprising a leakproof cylindrical housing 22 containing a DC/AC power converter placed in the forward portion 24 of the housing, an electric motor placed in the housing immediately behind the power converter, a gearing unit having an axial inlet and an axial outlet placed inside the housing on the outlet shaft of the electric motor, and a propeller 26 mounted on the outlet shaft of the gearing, at the rear end of the housing 22, with a line cutting system integrated in the housing at its junction with the propeller.

In a variant, the propeller 26 can be at the forward end of the housing 22, and then the electric motor would be at the rear end thereof.

Optionally the cases of the engine and of the gearing can themselves constitute the above-mentioned leakproof housing.

This leakproof housing advantageously contains a thermal grease or other heat-conducting fluid to improve cooling of the motor, of the gearing, and of the components of the converter by exchanging heat with the surrounding water, with it being most important for this cooling to be effective (for example it makes it possible to double the power that can be delivered by the electric motor).

The propulsion assembly 20 is fixed on a rudder plate 28 carried by a lifting device in the form of a deformable trapezium-shaped linkage enabling the 7 propulsion assembly 20 to be lifted from its position shown in continuous lines so as to bring it into an outof-service position shown in chain-dotted lines, with the assembly moving initially in vertical translation and then tilting about a horizontal transverse axis.

More precisely, this device comprises a tube 32 extending in line with the rudder plate and connected by two articulated arms 34 and 36 of different lengths to two horizontal transverse shafts 38 and 40 carried by the rear portion of the hull 10, the top shaft 38 being suitable for connection to drive means to rotate it so as to provide motorized lifting and lowering of the propulsion assembly By raising the propulsion unit 20 in 15 substantially vertical translation from the position shown in continuous lines in Figure 2, it is possible to adapt the vertical position of the propulsion assembly relative to the hull 10 as a function of the depth of water beneath the hull and to reduce draught, e.g. for docking or for traveling at low tide.

A radial arm 42 is mounted at the top end of the tube 32 connected to the rudder plate 32 and enables the S•propulsion assembly to be turned about the axis 44 of the tube 32.

Cables connecting the batteries to the propulsion assembly can pass along the tube 32 and the rudder plate 28.

The electrical power supply means for the motors of the vessel of the preferred embodiment of the present invention are shown diagrammatically in Figure 3 and comprise a set of electric batteries 46 mounted on board the vessel and connected firstly to solar panels 48 mounted on the roof of the vessel, and secondly to charger H:\Maria\Keep\52638.99.doc 2/01/03 7a means 50 for charging from external electricity distribution mains 52, and also, for each electric motor 54, to a variable frequency DC/AC power converter 56 associated with a system 58 for controlling the speed of rotation of the motor 54 and a sensor 60 for o H:\Maria\Keep\52638.99.doc 2/01/03 sensing the exact angular position of the rotor of the motor 54.

Each motor 54 is preferably a self-excited threephase synchronous motor whose rotor is fitted with permanent magnets, and the mains supply 52 is preferably also three-phase.

In the invention, the charger means 50 comprise a first charging circuit 62 associated with means for linking to the electricity mains 52 by induction and a second charging circuit 64 connected in parallel with the first and suitable for being connected to the mains 52 by conventional pluggable connection means 66, and the charging capacities of these two circuits can be similar or different.

The means for linking the first charging circuit 62 to the mains 52 by induction comprise a three-winding primary 68 connected to the electricity mains 52 and a three-winding secondary 70 connected to the charging circuit 62 optionally with a switch (not shown) in the connection between the mains 52 and the primary 68 and/or in the connection between the secondary 70 and the charging circuit 62.

To charge the batteries 46 from the mains 52 via the charging circuit 62, it suffices to place the primary and secondary windings 68, 70 in a determined relative position such that a closed magnetic circuit is established between the windings which then operate as a three-phase inductive transformer.

This relative disposition of the windings can be provided, in accordance with the invention, by a docking system of the kind shown diagrammatically in Figure 4.

In this figure, the front portion of a hull 10 of the vessel is fitted with a docking finger 72 that projects outwards, and that is designed to co-operate by mutual engagement or interfitting with a docking block 74 mounted on a quay or a pontoon 76 alongside which the vessel is to be docked. The secondary 70 is mounted on 9 the docking finger 72 and the primary 68 is carried by a mechanism 78 which enables it to be placed against the secondary for charging the batteries and to be lifted away therefrom to allow the vessel to depart, the mechanism being designed to accommodate relative movement between the boat or vessel and the pontoon, e.g. under the effect of waves.

In the preferred embodiment of the present invention, the batteries 46 are of the nickel-cadmium type for reasons of longevity. They are also better adapted to intensive use of the motors 54. The batteries can be constituted by a plurality of cells connected in series °o 200 1.2 volt cells suitable for delivering 240 V) for the purpose of powering two DC/AC converters 56 15 connected in parallel and each connected to a motor 54 having nominal power of about 6 kilowatts (kW) In this example, the batteries have a capacity of ampere hours (Ah) and they are charged at a current of amps by the first charging circuit 62. The second charging circuit 64 can act, e.g. at night or during periods when the vessel is not in use, to perform overcharging using one-tenth of the current, said •overcharging serving to avoid battery memory effects.

The solar panels 48 mounted on board comprise a 25 plurality of cells connected in series, e.g. enabling the o001 batteries 46 to be charged via a circuit comprising diodes and a charging regulator and/or to power the motors 24 with a maximum current of about 4 A.

When the vessel 10 is used for following a predetermined course in a regular manner, the batteries can be recharged sufficiently to compensate for the quantity of energy that has just been consumed whenever H:\Maria\Keep\52638.99.doc 2/01/03 10 the vessel is docked for a certain length of time at a quay or a pontoon that is fitted with the inductioncharging means described with reference to Figures 3 and 4. For example, a two-minute stop at the pontoon 76 enables the batteries to be recharged sufficiently to compensate for the amount of energy that is consumed during a four-minute trip.

By way of non-limiting example, it is specified that a vessel of the kind shown in Figure 1 having a length of about 10 meters and capable of carrying 30 to passengers at a speed of about 5 knots is fitted with two propulsion assemblies 20 of the kind shown in Figure 2, each having an electric motor with nominal power of about 6 kW, each assembly 20 having an outside diameter of about 15 160 millimeters (mm) and being fitted with a propeller 26 having a diameter of 560 mm. The weight of the batteries :fitted to the vessel is about 650 kilograms (kg) and it can operate for a period of about 7 hours without recharging the batteries.

Naturally, it is possible for a propulsion system of the preferred embodiment of the present invention to S•use electric motors that are much more powerful without excessively increasing the diameter of the propulsion assembly (a motor having nominal power of 100kW has a 25 diameter of about 250 mm to 300 mm, for example).

Numerous modifications can be made to the means described and shown without going beyond the ambit of the invention. For example, the propulsion assemblies 20 need not be steerable, in which case differential control of the speed of the motors 54 can be used for steering the boat or vessel.

The motors 54 can be three-phase asynchronous motors. The battery charging circuits can be on board the H:\Maria\Keep\52638.99.doc 2/01/03 10a boats or vessels or they can be on land. Optionally, one charging circuit (with the induction link) can be on board while another charging circuit having a conventional connection can be provided on a quay or a pontoon.

Similarly, photovoltaic solar panels can be installed on board and/or on land.

In some cases traveling on a stretch of water where it is necessary to protect the flora), it can be H:\Maria\Keep\52638.99.doc 2/01/03 advantageous to use a propulsion assembly comprising a turbine which is driven directly by an electric motor.

For vessels of medium and large size having a length of about 50 m or more), it is advantageous to power the electric motors from alternators themselves driven by on-board diesel engines thus making a large amount of electrical power available while conserving the advantages of having electric motors that are immersed, which advantages apply both in terms of use and in terms of the structure of the boats and vessels.

Furthermore, when the boats or vessels are of relatively large size, the propulsion assemblies are no longer mounted as outboards as shown Figure 2, but are fixed beneath the hull, advantageously as shown in Figure In this figure, the hull 80 of the boat or vessel has a well 82 which extends vertically inside the boat or vessel over sufficient height to ensure that its top end is always above the water line 84 of the boat or vessel even when fully laden. The transverse dimensions of the well 82 are greater than the dimensions of the propulsion assembly 86 and the rudder plate 88 so as to enable them to be lowered and raised via the inside of the well, e.g.

by means of a crane The well 82 is substantially filled and closed by a leakproof caisson 92 whose cover 94 closes the top end of the well and is releasably fixed thereto, e.g. by means of bolts, and whose bottom 96 forms a surface that is continuous or quasi-continuous with the hull The propulsion assembly 86 and the rudder plate 88 are carried by a vertical post 98 which extends in a vertical duct 100 in the caisson and which is supported and guided in the duct by bearings 102. The top end of the post 98 is connected to means 104 for controlling swiveling of the propulsion assembly 86 about a vertical axis 106.

12 A hatch in the deck of the boat or vessel that is closed by a removable panel 108 gives vertical access to the caisson 92.

In the event of the propulsion assembly 86 breaking down or being damaged, or if maintenance is necessary, the panel 108 is withdrawn, the cover 94 is unbolted, a sling is secured thereto, and the propulsion assembly 86 is extracted from the well 82 by means of the crane 90, which crane can either be on the quay side or on board the boat or vessel (a small crane that can be dismounted and removed).

Advantageously, and whenever possible, a .o replacement propulsion assembly 86 is exchanged for the assembly removed.

15 The invention thus makes it possible to change the propulsion assembly of a boat or vessel in a relatively short period of time without the boat or vessel being immobilized for long and without it being necessary to take the boat or vessel to a dockyard and to take it out of the water.

is to be understood that, if any prior art publication is referred to herein, such reference does not S•constitute an admission that the publication forms a part "o of the common general knowledge in the art, in Australia or in any other country.

For the purposes of this specification it will be clearly understood that the word "comprising" means "including but not limited to", and that the word "comprises" has a corresponding meaning.

H:\Maria\Keep\52638 .99.doc 2/01/03

Claims

1. An electrically propelled boat or vessel having at least one electric motor placed in an immersible leakproof housing that is optionally steerable, a propeller mounted on an outlet shaft of the housing to be rotated by the above-mentioned motor, electric batteries for powering the motor, battery charger means and an DC/AC converter for supplying AC driving power from the electric batteries to the motor, wherein the motor is an AC motor connected to the propeller via stepdown gearing placed inside the above-mentioned housing to be cooled together with the motor by exchanging heat with the water outside the housing, the battery charger means including means for 15 providing an induction link to electricity distribution mains. *0

2. The boat or vessel according to claim 1, wherein the DC/AC power converter is housed in the above-mentioned housing to be cooled by exchanging heat with the water outside the housing.

3. The boat or vessel according to claim 1 or 2, 0 wherein the motor is a self-excited three-phase •0 25 synchronous motor with a permanent magnet rotor, or is a *000 three-phase asynchronous motor.

4. The boat or vessel according to any one of the preceding claims, wherein the above-mentioned gearing is a planetary gearing unit.

The boat or vessel according to claim 4, wherein the link means comprise a primary winding connected to the H:\Maria\Keep\52638.99.doc 2/01/03 1) Y oo oO ooa OoOO 11 ooooo oooo *ooo oo oooo oooo 14 distribution mains and a secondary winding connected to a battery charging circuit, said two windings being integrated in means that are formed in two parts: one mounted on the boat or vessel; and the other mounted on a quay, a pontoon or the like, and including a mechanism enabling the two parts to be moved close together in order to charge the batteries.

6. The boat or vessel according to claim 5, wherein the charger means include a second charging circuit connected in parallel with the first charging circuit and means for connecting the second charging circuit to the electricity distribution mains by mutual engagement, the two charging circuits having charging capacities that are similar or different.

7. The boat or vessel according to any one of the preceding claims, wherein the charger means also include photovoltaic solar panels connected to the above-mentioned 20 batteries.

8. The boat or vessel according to any one of the preceding claims, wherein the batteries comprise a plurality of nickel-cadmium cells connected in series.

9. The boat or vessel according to any one of the preceding claims, wherein the housing is mounted on the hull of the boat or vessel by a system of arms forming a hinged trapezium-shaped linkage and enabling the housing to be moved upwards initially substantially in translation from a bottom position, and then in tilting about a horizontal transverse axis to take it out of the water.

H:\Maria\Keep\52638 .99.doc 2/01/03 15 The boat or vessel according to any one of the preceding claims, wherein the boat or vessel is of the catamaran type and is fitted with two electric motor propulsion systems of the above-mentioned type, each connected to one of the hulls of the boat or vessel.

11. The boat or vessel according to any one of claims 1 to 3 and 5 to 8, wherein said propeller is replaced by a turbine which is driven directly by the electric motor.

12. The boat or vessel according to any one of claims 1 to 7, wherein the motor-gearing-propeller assembly or "propulsion" assembly is carried by a support structure extending inside a well formed in the hull of the boat or vessel, said well having transverse dimensions enabling o the propulsion assembly to pass inside the well for coo• mounting on the boat or vessel, and for removal therefrom.

13. The boat or vessel according to any one of the preceding claims, wherein said support structure comprises a caisson substantially filling the well and removably fixed thereto, and a post secured to the propulsion assembly and passing through the caisson, being supported and guided therein. o

14. An electrically propelled boat or vessel as claimed in claim 1, and substantially as herein described with reference.to the accompanying figures. Dated this 2nd day of January 2003 ALTERNATIVES ENERGIES By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and S 5 Trade Mark Attorneys of Australia H\Maria\Keep\52638 .99.doc 2/01/03