Electric stabilizer

Abstract

To provide an electric stabilizer to stabilize floating structure.SOLUTION: An electric stabilizer 1 includes: a track 2 for guiding a movable stabilizing mass 3 along the track direction; and at least one of linear motors 6, 7 that include planar stators 8, 12 extending along the track, and planar rotors 9, 13 adapted to move back and forth along the track together with the movable stabilizing mass. The stator includes multi-phase windings 10, 14, and the rotor includes a plurality of permanent motor magnets 15 facing the multi-phase stator windings that define a plurality of rotor poles of alternating polarity along the track direction. The electric stabilizer includes: at least one of line electromagnets 21, 22 for selectively attracting the movable stabilizing mass away from the track; and at least one of stoppers 29, 30 for controlling the movement of the movable stabilizing mass toward the electromagnets.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electric stabilizer, and more particularly to an electric stabilizer for stabilizing a floating structure.

[0002] The term "floating structure" is intended to cover any structure that is floating and requires stabilization when in use, such as, inter alia, a civil or military vessel, a floating platform or oil storage facility, a floating power generator, an offshore wind turbine, or others. [Background technology]

[0003] Stabilizers can be used on floating structures, such as ships, to reduce pitch and / or roll in rough seas and help maintain speed while reducing fuel consumption.

[0004] As used herein, "pitch" refers to the up and down movement of a vessel's bow and stern, or rotation about its transverse or port-starboard axis, and "roll" refers to the side-to-side movement of a vessel, or rotation about its longitudinal or fore-stern axis. In more general terms, "pitch" and "roll" can refer to the rotation of a floating structure about any two perpendicular axes.

[0005] Known stabilizers for ships and other floating structures include passive and active ballast, passive bilge keels, active fins, active gyroscopes, mechanical linear systems optionally including electrical dampers, and moving mass systems that may be electrically controlled.

[0006] For example, patent application EP 4292918 discloses a moving mass system that can include at least one planar linear electric motor configured as follows: a stator is fixed to a base, and a rotor is a moving mass guided relative to the stator. The rotor is electromagnetically levitated by active magnetic bearings and moved relative to the stator by the action of a motor region. Each active magnetic bearing includes an electromagnet fixed to the stator and a permanent magnet fixed to the rotor. The electromagnetic levitation of the rotor cooperates with both the electromagnet and the permanent magnet, and the rotor is fixed when the electromagnet is not powered. The rotor's movement is achieved by the action of other electromagnets in the stator and other permanent magnets in the rotor within the motor region. Dynamic positioning of the rotor is achieved very accurately. The motor has high torque. The electrical control system according to EP 4292918 has advantages such as compactness and unparalleled response time. Friction between moving and fixed parts is very low. Vibration and emitted noise are very low. The mass of the system can be adapted by selecting an appropriate number of subassemblies secured together. The components of the system are easy to find commercially or to manufacture. The system requires little maintenance. Due to its performance, the system allows for the elimination of stabilizing fins on ships.

[0007] In summary, moving mass systems including planar linear electric motors are advantageous for stabilizing floating structures.

[0008] Nevertheless, some points deserve improvement, especially considering certain conditions of intense use.

[0009] In particular, the air gap between the electromagnets and permanent magnets of an active magnetic bearing can be unstable, fluctuating even when programmed to a constant value. This can also cause instability in other air gaps in the motor region between the stator electromagnets and the rotor permanent magnets. Controlling the air gap between the stator and rotor can be difficult, as implementing electromagnetic levitation can be complex. Therefore, depending on the load and mechanical inertia, parasitic mechanical moments can be exerted on the moving mass, and air gap fluctuations can result in excessive consumption of electrical energy.

[0010] Furthermore, a high average current consumption of the system can be observed for a limited levitation force due to the fact that the electromagnets of the active magnetic bearings, which enable the rotor to levitate, act on the flow of the rotor's permanent magnets, which attract the rotor towards the stator to improve the braking effect when the electromagnets are not activated. More precisely, the magnetic flux generated by the electromagnets of the active magnetic bearings passes through the permanent magnets in a direction opposite to the magnetic flux present in the permanent magnets. Each electromagnet acts against the action of the permanent magnets to cancel the braking effect and obtain levitation of the mobile mass. In doing so, a high consumption of electrical energy is required.

[0011] In the case of levitation, control of the rotor is delicate because the moving mass system is mounted on a moving frame that is subject to random external accelerations.

[0012] Finally, due to the action of the electromagnets of each active magnetic bearing, a reduction in functional capacity may be observed, leading to the risk of loss of magnetic force of the permanent magnets, reducing the rotor's levitation capacity and the braking effect of said rotor. Summary of the Invention

[0013] One object of the present invention is to mitigate or overcome the aforementioned drawbacks and has the general object of improving electric ballasts. One object of the present invention is, in particular, to provide better control of the air gap between the stator and rotor of an electric motor in a ballast, thereby improving rotor stability. Another object is to reduce the average current consumption of the ballast system. A further object is to improve reliability and reduce maintenance costs.

[0014] According to the present invention, an electric ballast includes a track for guiding a mobile stabilizing mass along a track direction, at least one linear motor including a planar stator extending along the track (i.e., in the track direction) and a planar rotor adapted to move back and forth along the track with the mobile stabilizing mass, the stator including multi-phase stator windings, and the rotor including a plurality of permanent motor magnets facing the multi-phase stator windings defining a plurality of rotor poles of alternating polarity (i.e., north and south poles) along the track direction, and at least one line of electromagnets for selectively attracting the mobile stabilizing mass in a direction away from the track (i.e., perpendicular to the track), and at least one stopper for limiting movement of the mobile stabilizing mass toward the electromagnet.

[0015] When a sufficient number of electromagnets are powered, the movable stabilizing mass can contact each stop. Therefore, each air gap between the stator and rotor maintains a nominal value, which is a stable value related to the dimensions of the stabilizer's components. Therefore, each air gap between the stator and rotor can be stabilized. The geometry of the air gap can be constant and precise. The attractive force of each electromagnet can be adjusted to limit the mechanical force associated with the movable stabilizing mass contacting each stop. This ensures regular and stable operation of the stabilizer. One resulting advantage is the absence of parasitic mechanical loads and moments on both the movable stabilizing mass and each stop. Another resulting advantage is the rational consumption of electrical energy.

[0016] Additionally, each electromagnet can attract the movable stabilizing mass away from the orbit such that a moderate attractive force is sufficient to limit the electrical energy consumption of the ballast.

[0017] A further advantage is the simplicity of the ballast construction, whose components retain their properties and functional capabilities over time, which helps to improve reliability and makes maintenance simpler and more economical.

[0018] Preferably, the track is defined by first and second rails parallel to one another, the movable stabilizing mass occurs between the rails, the movable stabilizing mass has the general shape of a plate extending a length between a first end and a second end, a width between a first surface and a second surface, and a thickness between a lower surface and an upper surface, the first stop is a first tab protruding from the first rail and extending into a first groove in the first surface of the movable stabilizing mass, and the second stop is a second tab protruding from the second rail and extending into a second groove in the second surface of the movable stabilizing mass.

[0019] Advantageously, the length of the mobile stabilising mass is at most 11 metres, the width of the mobile stabilising mass is at most 8 metres and the thickness of the mobile stabilising mass is at most 1 meter.

[0020] Preferably, the first tab and the second tab are each parallel to the lower surface of the movable stabilizing mass.

[0021] Preferably, the first tab has a lower surface and the second tab has a lower surface.

[0022] Advantageously, the lower surface of the first tab has a first low coefficient of friction, and the lower surface of the second tab has a second low coefficient of friction, the first low coefficient of friction and the second low coefficient of friction being between 0.05 and 0.1.

[0023] Preferably, the center of gravity of the movable stabilizing mass, the contact surface between the lower surface of the first tab and the first groove, and the contact surface between the lower surface of the second tab and the second groove lie in the same plane.

[0024] Preferably, the first line of electromagnets is located above the movable stabilizing mass near the first rail, and the second line of electromagnets is located above the movable stabilizing mass near the second rail.

[0025] Advantageously, for each of the first and second lines of electromagnets, the air gap is greater than 8 mm when the first and second lines of electromagnets are not powered and is less than 8 mm when the first and second lines of electromagnets are powered.

[0026] Preferably, a first linear motor is located at the center and bottom of the plate, and a second linear motor is located at the center and top of the plate.

[0027] Advantageously, the mobile stabilising mass has a lower longitudinal groove in which the first motor is mounted and an upper longitudinal edge in which the second motor is mounted.

[0028] Preferably, the air gap of the first motor is 8 mm or less when the electromagnets of the first and second lines are not powered and is 8 mm or more when the electromagnets of the first and second lines are powered, and the air gap of the second motor is 8 mm or more when the electromagnets of the first and second lines are not powered and is 8 mm or less when the electromagnets of the first and second lines are powered.

[0029] The difference between the air gaps of the first and second motors is 3 to 7 mm.

[0030] Each linear motor is a direct current motor.

[0031] The movable stabilizing mass is provided with friction pads.

[0032] A first line of friction pads is located near the first rail and below the movable stabilizing mass, and a second line of friction pads is located near the second rail and below the movable stabilizing mass.

[0033] The movable stabilizing mass is made of a material having a high magnetic permeability.

[0034] The present invention also relates to a floating structure equipped with the electric ballast described above.

[0035] Other objects, features and advantages of the present invention will become apparent from a reading of the following description, given by way of non-limiting example only, and made with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a cross-sectional view of an electric ballast according to a proposed embodiment for carrying out the present invention; [Figure 2] FIG. 2 is a perspective view of a movable stabilizing mass of the electric ballast of FIG. 1. [Figure 3] FIG. 2 is a perspective view of a part that allows guiding the mobile stabilizing mass of the stabilizer of FIG. 1. [Figure 4] FIG. 2 is a partial view of [FIG. 1] showing the electromagnet when the electric ballast is stationary. [Figure 5] 1A is a partial view of FIG. 1A showing a portion of the first motor and a portion of the second motor when the electric ballast is stationary. [Figure 6] This is a diagram similar to [Figure 1] when the electric ballast is stationary. [Figure 7] This is a similar view to [Figure 4] when the electric stabilizer is in operation. [Figure 8] This is a similar view to [Figure 5] when the electric ballast is in operation. [Figure 9] This is a similar view to [Figure 6] when the electric ballast is in operation. [Figure 10] FIG. 1 is a diagram illustrating the rotation of a ship due to the action of swells. [Figure 11]FIG. 2 is a perspective view of the electric ballast according to FIG. [Figure 12] 1A and 1B are diagrams illustrating the movement of a movable stabilizing mass of an electric ballast. DETAILED DESCRIPTION OF THE INVENTION

[0037] 1, 2, and 3, an electric ballast 1 includes a track 2 for guiding a movable stabilizing mass 3 along a track direction. The track 2 is defined by a first rail 4 and a second rail 5 that are parallel to each other. Although not limiting, each rail 4, 5 has a general square shape.

[0038] The electric ballast 1 includes a first linear motor 6 and a second linear motor 7 extending along the track 2. The first linear motor 6 includes a planar stator 8 extending along the track 2 and a planar rotor 9 adapted to move back and forth along the track 2 together with the movable stabilizing mass 3. The stator 8 includes a multi-phase stator winding 10, and the rotor 9 includes a plurality of permanent motor magnets 11 facing the multi-phase stator winding 10, which define a plurality of rotor poles of alternating polarity along the track direction. Similarly, the second linear motor 7 includes a planar stator 12 extending along the track 2 and a planar rotor 13 adapted to move back and forth along the track 2 together with the movable stabilizing mass 3. The stator 12 includes a multi-phase stator winding 14, and the rotor 13 includes a plurality of permanent motor magnets 15 facing the multi-phase stator winding 14, which define a plurality of rotor poles of alternating polarity along the track direction.

[0039] The electric ballast 1 comprises a first line of electromagnets 21 located above the movable stabilizing mass 3 near the first rail 4 and a second line of electromagnets 22 located above the movable stabilizing mass 3 near the second rail 5 for selectively attracting the movable stabilizing mass 3 away from the track 2. The movable stabilizing mass 3 arising between the rails 4, 5 has the general shape of a plate extending a length between a first end 23 and a second end 24, a width between a first face 25 and a second face 26, and a thickness between a lower face 27 and an upper face 28.

[0040] The length of the movable stabilising mass 3 may be up to 11 metres, the width of the movable stabilising mass 3 may be up to 8 metres, and the thickness of the movable stabilising mass 3 may be up to 1 meter.

[0041] To limit movement of the movable stabilizing mass 3 toward the electromagnets 21 and 22, the stabilizer 1 includes a first stopper 29 and a second stopper 30. By way of example, the first stopper 29 is a first tab that protrudes from the first rail 4 and extends into a first groove 31 in the first surface 25 of the movable stabilizing mass 3, and the second stopper 30 is a second tab that protrudes from the second rail 5 and extends into a second groove 32 in the second surface 26 of the movable stabilizing mass 3. The first tab 29 has a lower surface 33 with a first low coefficient of friction, and the second tab 30 has a lower surface 34 with a second low coefficient of friction. The first and second low coefficients of friction are between 0.05 and 0.1.

[0042] The center of gravity G of the movable stabilizing mass 3, the contact surface between the lower surface 33 of the first tab 29 and the first groove 31, and the contact surface between the lower surface 34 of the second tab 30 and the second groove 32 may be in the same plane P1.

[0043] The placement of the center of gravity G of the mobile stabilizing mass 3 in the same plane P1 as the contact surface between the lower surface 33 of the first tab 29 and the first groove 31 and the contact surface between the lower surface 34 of the second tab 30 and the second groove 32 makes it possible to reduce the overturning moment generated by the inertial forces on the mobile stabilizing mass.

[0044] To facilitate the installation of the motors 6, 7 and the line electromagnets 21, 22, the movable stabilizing mass 3 has a lower longitudinal groove 35 in which the first motor 6 is mounted and an upper longitudinal edge 36 in which the second motor 7 is mounted.

[0045] To fix the movable stabilizing mass 3 when the electromagnets 21, 22 of the lines are not powered, the friction pads 41 of the first line are located under the movable stabilizing mass 3 near the first rail 4, and the friction pads 42 of the second line are located under the movable stabilizing mass 3 near the second rail 5.

[0046] The rest situation of the ballast 1 is presented in FIGS.

[0047] The line electromagnets 21, 22 are not supplied with power when the ballast 1 is in a rest state.

[0048] In the stationary state, the air gaps A1 between the movable stabilizing mass 3 and the electromagnets 21, 22 of each line, the air gap A6 of the first linear motor 6 between the planar stator 8 and the planar rotor 9, and the air gap A7 of the second linear motor 7 between the planar stator 12 and the planar rotor 13 may vary between 0.5 mm and 25 mm, for example between 1 and 15 mm, more preferably between 5 and 10 mm.

[0049] In the static state, the air gap A6 and the air gap A7 may be different, for example, the air gap A6 is equal to a ratio of 1 / 3 to 2 / 3 of the air gap A7, and the air gap A7 varies between 5 mm and 10 mm, for example.

[0050] During operation, when the first line of electromagnets 21 and the second line of electromagnets 22 attract the movable stabilizing mass 3, the air gaps A6 and A7 may be identical, e.g., 7.5 mm during operation, to simplify the control of the electromagnets 21, 22, or may be different.

[0051] At rest, the air gap A6 is smaller than the air gap A7. The magnetic force F exerted downward by the motor 6 is M2 is the magnetic force F exerted upward by the motor 7 M1 Stronger than F M2 and F M1The difference between the load and the load is applied to the weight P to generate a downward force pushing the movable stabilizing mass 3 downward. The result is the reaction F of the friction pads at lines 41 and 42. S1 and F S2 In relation to this, the mechanical clearances A29 and A30 between the lower surfaces 33, 34 of the stops 29, 30 and the grooves 31, 32, respectively, have a value of a few millimeters, for example at least 3.

[0052] The situation of the ballast 1 in the operating position is presented in FIGS.

[0053] In the operating position, the electromagnets 21, 22 of the line are powered.

[0054] The air gap A1 between the movable stabilizing mass 3 and the electromagnets 21, 22 of each line is, for example, 8 mm or less. The air gap A6 of the first linear motor 6 between the planar stator 8 and the planar rotor 9 is, for example, 8 mm or more. The air gap A7 of the second linear motor 7 between the planar stator 12 and the planar rotor 13 is, for example, 8 mm or less. In the operating position, the air gap A6 is larger than the air gap A7. The magnetic force F exerted downward by the motor 6 is M2 is the magnetic force F exerted upward by the motor 7 M1 Lower than F M2 and F M1 The difference between these forces generates an upward force that opposes the weight P. Furthermore, the forces Fg1 and Fg2 from the stops 29, 30 on the movable stabilizing mass 3 increase the magnetic force F of the electromagnets 21, 22. E1 , F E2 In relation to this, the mechanical clearances A29 and A30 between the lower surfaces 33, 34 of the stops 29, 30 and the grooves 31, 32, respectively, have a value equal to zero.

[0055] Since the lower surfaces 33, 34 of the stoppers 29, 30 have the first and second low friction coefficients, the driving force F of the motors 6, 7 ML1 , F ML2 can move the movable stabilizing mass along the trajectory 2.

[0056] The effect produced by the ballast is presented using Figures 10, 11 and 12.

[0057] A diagram illustrating the rotation of a vessel 43 due to the action of a swell is shown in FIG. 10. Time is shown in seconds on the x-axis X1, and amplitude is shown on the y-axis Y1. By way of non-limiting example, the swell cycle here is approximately 9 seconds. The movable stabilizing mass 3 moves laterally to counterbalance the heeling of the vessel 43 caused by the swell. For example, as shown in FIG. 11, the length of the rails 4, 5 is, for example, approximately three times the length of the movable stabilizing mass 3.

[0058] An example of the variation in the amplitude of the movement of the movable stabilizing mass 3 along the rails 4, 5 is given in Figure 12. The horizontal axis X2 is time and the vertical axis Y2 is the amplitude of the movement of the movable stabilizing mass 3. From one period of 9 seconds to the next, the amplitude of the movement of the movable stabilizing mass 3 increases until an appropriate compensation is achieved.

[0059] The present invention is not limited to the described embodiments, but includes all equivalents that may be included within the scope of the following claims.

[0060] In particular, various systems for motor management can be provided, either by supplying the motor with electrical power or by using the motor as a generator to recover the energy provided by the swell.In contrast to moving mass systems, the electric ballast 1 does not comprise a floating mass, and the mobile stabilizing mass 3 is guided by first and second stops 29, 30, ensuring simplified control of the mobile stabilizing mass 3 and the air gap. [Explanation of symbols]

[0061] 1. Electric ballast 2 orbits 3 Movable stabilizing masses / plates 4. The First Rail 5 Second Rail 6. First Linear Motor 7 Second Linear Motor 8 Planar Stator 9 Planar rotor 10 Polyphase Stator Windings 11 Permanent motor magnet 12 Planar stator 13 Planar rotor 14 Polyphase Stator Windings 15 Permanent motor magnets 21 First line electromagnet 22 Second line electromagnet 23 First end 24 Second end 25 First Surface 26 Second Surface 27 Bottom side 28 Top 29 First stopper / first tab 30 Second stopper / second tab 31 First Groove 32 Second Groove 33 Bottom side 34 Bottom side 35 Lower longitudinal groove 36 upper longitudinal edge 41 First Line Friction Pad 42 Second Line Friction Pads 43 Ship

Claims

1. An electric ballast (1) comprising: a track (2) for guiding a movable stabilizing mass (3) along a track direction; and at least one linear motor (6, 7) comprising a planar stator (8, 12) extending along the track (2) and a planar rotor (9, 13) adapted to move back and forth along the track (2) together with the movable stabilizing mass (3), the stator (8, 12) comprising multi-phase stator windings (10, 14), the rotor (9, 13) moving back and forth along the track (2) along the track direction. the electric ballast (1) comprising a plurality of permanent motor magnets (11, 15) facing the multi-phase stator windings (10, 14) defining a plurality of rotor poles of alternating polarity, the electric ballast (1) comprising at least one line electromagnet (21, 22) for selectively attracting the movable stabilizing mass (3) in a direction away from the track (2), and at least one stopper (29, 30) for limiting movement of the movable stabilizing mass (3) toward the electromagnet (21, 22).

2. The track (2) is defined by a first rail (4) and a second rail (5) that are parallel to one another, and the mobile stabilizing mass (3) occurs between the rails (4, 5), the mobile stabilizing mass (3) having the general shape of a plate extending in length between a first end (23) and a second end (24), in width between a first surface (25) and a second surface (26), and in thickness between a lower surface (27) and an upper surface (28).

2. The electric ballast (1) of claim 1, wherein the first stopper (29) is a first tab (29) protruding from the first rail (4) and extending into a first groove (31) in the first surface (25) of the movable stabilizing mass (3), and the second stopper (30) is a second tab (30) protruding from the second rail (5) and extending into a second groove (32) in the second surface (26) of the movable stabilizing mass (3).

3. 3. The electric ballast (1) of claim 2, wherein the length of the movable stabilizing mass (3) is at most 11 meters, the width of the movable stabilizing mass (3) is at most 8 meters, and the thickness of the movable stabilizing mass (3) is at most 1 meter.

4. 4. The electric ballast (1) according to claim 2 or 3, wherein the first tab (29) and the second tab (30) are each parallel to the lower surface (27) of the movable stabilizing mass (3).

5. 5. The electrical ballast (1) of any one of claims 2 to 4, wherein the first tab (29) has a lower surface (33) and the second tab (30) has a lower surface (34).

6. The electric ballast (1) of claim 5, wherein the lower surface (33) of the first tab (29) has a first low coefficient of friction, and the lower surface (34) of the second tab (30) has a second low coefficient of friction, and the first low coefficient of friction and the second low coefficient of friction are between 0.05 and 0.

1.

7. 7. The electric ballast (1) according to claim 5 or 6, wherein the center of gravity (G) of the movable stabilizing mass (3), the contact surface between the lower surface (33) of the first tab (29) and the first groove (31), and the contact surface between the lower surface (34) of the second tab (30) and the second groove (32) are in the same plane (P1).

8. 8. The electric ballast (1) according to claim 1, wherein a first line of electromagnets (21) is located above the movable stabilizing mass (3) near the first rail (4), and a second line of electromagnets (22) is located above the movable stabilizing mass (3) near the second rail (5).

9. 9. The electric ballast (1) of claim 8, wherein for each of the first (21) and second (22) line electromagnets, the air gap (A1) is greater than 8 mm when the first (21) and second (22) line electromagnets are not powered and is less than 8 mm when the first (21) and second (22) line electromagnets are powered.

10. 10. The electric ballast (1) according to any one of claims 2 to 9, wherein a first linear motor (6) is located at the center and bottom of the plate (3) and a second linear motor (7) is located at the center and top of the plate (3).

11. 11. The electric ballast (1) according to claim 10, wherein the movable stabilizing mass (3) has a lower longitudinal groove (35) in which the first motor (6) is mounted and an upper longitudinal edge (36) in which the second motor (7) is mounted.

12. 12. The electric ballast (1) according to claim 10 or 11, wherein the air gap (A6) of the first motor (6) is 8 mm or less when no power is supplied to the electromagnets of the first (21) and second (22) lines, and is 8 mm or more when power is supplied to the electromagnets of the first (21) and second (22) lines, and the air gap (A7) of the second motor (7) is 8 mm or more when no power is supplied to the electromagnets of the first (21) and second (22) lines, and is 8 mm or less when power is supplied to the electromagnets of the first (21) and second (22) lines.

13. The electric ballast (1) according to any one of claims 10 to 12, wherein the difference between the air gaps (A6, A7) of the first motor (6) and the second motor (7) is between 3 and 7 mm.

14. 14. An electrical ballast (1) according to any one of claims 1 to 13, wherein each linear motor (6, 7) is direct current.

15. 15. The electric ballast (1) according to any one of the preceding claims, wherein the movable stabilizing mass (3) is provided with friction pads (41, 42).

16. 16. The electric ballast (1) of claim 15, wherein a first line of friction pads (41) is located below the movable stabilizing mass (3) near the first rail (4), and a second line of friction pads (42) is located below the movable stabilizing mass (3) near the second rail (5).

17. 17. The electrical ballast (1) according to any one of the preceding claims, wherein the movable stabilising mass (3) is made of a material with high magnetic permeability.

Images