Contactless energy transfer system for counter-rotating flywheels using an integrated dual-stator architecture

Abstract

Contactless energy transfer device for a rotating system, comprising: a) a rotor comprising a permanent magnet arrangement and acting as a flywheel; b) an inner stator coil assembly arranged radially inside the rotor; c) an outer stator coil assembly arranged radially outside the rotor; wherein the inner stator is primarily configured as a motor element and the outer stator is primarily configured as a generator element, enabling contactless energy transfer to and from the rotor.

Description

2. Technical field

[0001] The present invention relates to the field of energy supply systems for rotating assemblies. More precisely, it relates to a contactless system that utilizes a dual-stator, single-permanent-magnet rotor architecture to efficiently supply and control counter-rotating flywheels, particularly in gyroscopic systems for pulse control, and specifically energy supply systems for counter-rotating flywheels within such assemblies. 3. State of the art

[0002] In rotating systems, especially those with counter-rotating flywheels for applications such as spacecraft attitude control, supplying electrical energy to the rotating elements presents a significant technical challenge. Conventional solutions, such as slip rings and brushes, lead to mechanical wear, friction, particle emissions, and potential weak points, rendering them inadequate for the high-reliability and long-term requirements of space missions. Alternative methods, such as wireless inductive power transmission, introduce complexity, thermal management problems, and efficiency losses, particularly at the high power levels required for rapid pulse changes.A highly reliable and efficient system for powering rotating, especially counter-rotating, flywheels is required, one that eliminates physical contact, minimizes losses, and seamlessly integrates with pulse storage and control functions. The present invention addresses this unmet need. 4. Summary of the invention

[0003] The present invention offers a solution to the limitations of energy transmission in systems such as that described in the concurrently pending application entitled "System for multi-axis gyroscopic pulse control". It describes a contactless energy transmission device that eliminates the need for slip rings or complex wiring to the rotating flywheels. The invention comprises a single rotor, which functions as both a flywheel and a permanent magnet assembly, and is electromagnetically coupled between an inner and an outer stator coil assembly. The entire system is suspended by magnetic bearings and is designed for operation within a vacuum enclosure to minimize losses.

[0004] Key innovations include: • Providing an integrated dual-stator architecture that enables simultaneous motor and generator functions without physical electrical connections to the rotor. • Use of the inner stator primarily as a motor element to apply torque and supply kinetic energy to the rotor. • Use of the outer stator primarily as a generator element to extract electrical energy and regulate the rotational speed. • Use of the magnetic field of the permanent magnet rotor for both motor / generator functions and the floating bearing, thus eliminating the need for separate excitation power for the rotor. • Enabling highly efficient, contactless energy transfer within a counter-rotating gyroscopic system by applying the dual-stator principle to each flywheel, thereby solving the energy transfer problem inherent in these configurations. • Use of superconducting materials for stator coils and / or bearing electromagnets to minimize electrical losses, making the system particularly advantageous for cryogenic environments such as space.

[0005] In a preferred embodiment, the system is used to supply energy to the counter-rotating flywheels in a multi-axis gyroscopic impulse control system. 5. Brief description of the drawings • Fig.A schematic sectional view of the overall system, showing the vacuum housing, the dual-stator array, the permanent magnet rotor, and the magnetic bearings. The rotor with its array of permanent magnets (north / south poles indicated) is shown in the center. The inner stator is depicted as a ring of wire coils inside the rotor. The outer stator is shown as a ring of wire coils outside the rotor. Magnetic bearing electromagnets are visible at the axial ends of the rotor. Arrows indicate the rotation of the rotor. • Fig.An exploded isometric view detailing the core components: inner stator, rotor assembly (showing the permanent magnet arrangement), and outer stator. The inner stator is a hollow cylinder with visible slots for coils. The rotor is a larger cylinder with embedded magnet blocks. The outer stator is a larger hollow cylinder with internal slots for coils. All parts are aligned on a common central axis. • Fig.A system block diagram illustrating the power and control flow, including the power electronics, magnetic bearing control, and connection paths between the inner and outer stators. Boxes contain "External Power Source" connected to "Power Electronics," which is connected to "Inner Stator (Motor)." "Rotor" is in the center. "Outer Stator (Generator)" is connected to "Power Electronics" and then to "External Load." A separate box labeled "Bearing Control" connects to "Magnetic Bearing" and receives input from "Position Sensors." • Fig.Application diagram showing the integration of the invention into a gyroscopic attitude control system with two counter-rotating flywheels on a common axis. Two of the invented flywheel systems are mounted on a single shaft and rotate in opposite directions (indicated by curved arrows). Power and data cables connected to a central spacecraft bus are shown, but cables connected to the rotating parts themselves are not shown. 6. Detailed Description 6.1 Core Components Table number component Description Material & Main Feature 10 rotor The central rotating mass, which also acts as a flywheel, has permanent magnets (e.g., BNdFeB) embedded or attached to its structure. Composite core (e.g., carbon fiber) with high-strength permanent magnets. Provides the magnetic field for operation. 20 Magnetic bearing A set of electromagnets and position sensors that actively levitate the rotor and maintain its position. Superconducting electromagnets. Offers contactless suspension. 30 Inner stator A stationary coil assembly arranged radially inside the rotor. Superconducting (e.g., MgB2, REBCO) or high-purity copper windings. Primarily functions as a motor. 40 Outer stator A stationary coil assembly that is arranged radially outside the rotor. Superconducting (e.g., MgB2, REBCO) or high-purity copper windings. Functions primarily as a generator. Rigid material (e.g., aluminum alloy, titanium). 50 Vacuum housing A sealed chamber that houses the core components. Maintains a high vacuum to eliminate aerodynamic drag. 60 External power source The primary source of electrical energy for the system (e.g., solar cells, battery). Standard aerospace power generation or storage systems. Interface to the power supply system. 70 Power control system The power electronics and control logic that regulates the energy flow between the stators and manages the charging / discharging state. Includes converter, inverter and a digital processor. 80 External Load Any device or system outside the invention that consumes electrical energy generated by the device (e.g., on-board computer, radio, engine). Defined by the application. Represents the usable working output of the system. 90 Electromagnetic motor torque The rotational force exerted on the rotor, which results from the interaction of the current in the inner stator coils with the magnetic field of the rotor. A functional representation of the energy conversion process from electrical to kinetic. 100 Kinetic energy / rotation The stored energy and the state of motion of the rotating rotor. A functional representation of the energy storage medium and its main property (angular velocity). 110 Warehouse control A digital processor that regulates the power for the magnetic bearings. Receives data from position sensors and calculates stabilizing currents for the bearings. 120 Generated EMF / current The electromotive force (voltage) and the resulting electric current induced in the outer stator coils due to the rotation of the rotor. A functional representation of the energy conversion process from kinetic back to electrical. 130 Position sensors Sensors that provide real-time data on the rotor's position to the bearing control system. High-precision optical or inductive sensors. 140 Spacecraft bus interface The interface for power and data processing when used in a space application. Standard aerospace avionics and power supply modules. 150 Common mounting axis The rotating structural backbone on which the flywheel rotors are mounted. High-strength, lightweight material (e.g., titanium alloy, carbon composite). Designed for high speeds and minimal dynamic imbalance. 160 Flywheel assembly 1 A single instance of the invention (components 10, 20, 30, 40, 50, 110, 130). Rotates clockwise. See corresponding components. 170 Flywheel assembly 2 A single instance of the invention (components 10, 20, 30, 40, 50, 110, 130). Rotates counterclockwise. See corresponding components. 6.2 Operating principle 1. Contactless motor operation (energy supply to the flywheel): The system is configured to supply electric current to the inner stator

[30] . This current generates a magnetic field that interacts with the permanent magnet field of the rotor

[10] and produces a Lorentz force that exerts a torque and accelerates the rotor. Kinetic energy is stored in the rotating mass. 2. Contactless Generation (Current Extraction & Control): The system is configured to convert the kinetic energy of the rotating rotor

[10] back into electrical energy. The rotating permanent magnets induce an electromotive force (EMF) in the coils of the outer stator

[40] . Drawing current from this stator generates a counter-torque (by Lenz's law) that slows down the rotor and converts the kinetic energy back into electrical energy that can be used for other systems. 3. Integrated Application: In a system with two counter-rotating flywheels [160, 170], each is an instance of this invention. The integrated dual-stator architecture enables different operating modes for precise, contactless management of impulse and power: • Acceleration and deceleration via separate units: The inner stator of one flywheel can be powered to accelerate it, while the outer stator of the other can be used to generate power and decelerate it. • Torque control within a single unit: The outer and inner stators of the same flywheel assembly can be operated simultaneously. The outer stator

[40] can operate as a generator to produce a braking torque, while the inner stator

[30] operates as a motor to provide a driving torque. By adjusting the power flow between these stators, the net torque exerted by the flywheel assembly on the support frame can be precisely varied without necessarily altering the rotor speed significantly. 4. Integrated control function: The power switching assembly

[90] is configured to manage the flow of electrical energy. It is configured to selectively direct current generated by an outer stator

[40] to an inner stator

[30] , whether that of a counter-rotating unit or that of the same unit, thus enabling the operating modes described in point 3.

[0006] This architecture fundamentally decouples the functions of the motor and generator operation to separate, stationary coil sets, thus enabling precise and efficient bidirectional energy transfer with the rotating element without any physical electrical contact. 6.3 Technical Advantages • Elimination of wear-prone contacts: Completely removes reliability concerns associated with slip rings and brushes. • Highly efficient energy transfer: Minimization of losses through superconducting components (3, 4), magnetic bearings

[20] and a vacuum housing

[50] enables highly efficient energy conversion. • Dual functionality: The architecture offers independent ports for supplying and extracting energy, thus enabling sophisticated control strategies for simultaneous energy and impulse management. • Native suitability for aerospace applications: The system utilizes the space environment (vacuum, cryogenic temperatures) to enhance its performance and reliability. • Simplified system architecture: By solving the problem of energy transfer at the component level, it enables a simpler and more reliable overall design of the gyroscopic system.

[0007] Legend for Fig. : 10 Rotor / flywheel with permanent magnets 20 magnetic bearing electromagnets (axial) 30 Inner stator coil assembly 40 Outer stator coil assembly 50 Vacuum Housing Legend for Fig. : 10 Rotor with embedded permanent magnets 30 Inner stator coil assembly 40 Outer stator coil assembly Legend for Fig. : 10 Rotor / Flywheel 30 Inner stator coil assembly 40 Outer stator coil assembly 60 External power source 70 Power Electronics & Control System 80 External Load 90 Electromagnetic motor torque 100 Kinetic energy / Rotation 110 Magnetic bearing control 120 EMF generated / current 130 Position Sensors Legend for Fig. : 30 Inner stator coil assembly (per flywheel) 40 Outer stator coil assembly (per flywheel) 140 Spacecraft bus (power & data processing) 150 Common assembly axis 160 Flywheel assembly 1 (clockwise rotation) 170 Flywheel assembly 2 (counter-clockwise rotation)

Claims

[1] Contactless energy transfer device for a rotating system, comprising: a) a rotor comprising a permanent magnet arrangement and acting as a flywheel; b) an inner stator coil assembly arranged radially inside the rotor; c) an outer stator coil assembly arranged radially outside the rotor; wherein the inner stator is primarily configured as a motor element and the outer stator is primarily configured as a generator element, enabling contactless energy transfer to and from the rotor. [2] Device according to claim 1, further comprising a magnetic bearing system configured to levitate the rotor without physical contact. [3] Device according to claim 1, wherein at least one of the inner stator coils, the outer stator coils or the coils of the magnetic bearing system is made of a superconducting material. [4] Device according to claim 1, further comprising a sealed vacuum housing containing the rotor, the inner stator and the outer stator. [5] Device according to claim 1, wherein the device is integrated into a gyroscopic position control system having two counter-rotating flywheels on a common axis. [6] Device according to claim 5, further comprising a power switching assembly configured to transfer electrical energy between the outer stator of the first flywheel assembly and the inner stator of the second flywheel assembly to enable position control maneuvers and power management without the use of slip rings. [7] Device according to claim 6, wherein the power switching assembly is further configured to transfer electrical energy between at least one of the inner stators or outer stators and a stator of a central hub motor. [8] Device according to claim 7, further comprising a slip ring arrangement arranged on the stator of the central hub motor, wherein the slip ring arrangement is electrically connected to the power switching assembly [90] and configured to communicate with a spacecraft power supply bus. [9] Device according to claim 1, wherein the device is configured as a highly efficient energy storage device that stores kinetic energy in the rotor and recovers it as electrical energy via the outer stator when required. [10] Device according to claim 2, wherein the magnetic bearing system comprises a bearing controller and position sensors, wherein the bearing controller is configured to calculate stabilizing currents for the magnetic bearings based on data from the position sensors. [11] Device according to claim 6, wherein the current control system is configured to condition the current generated by the outer stator of a flywheel assembly and to provide it to the power switching assembly for transfer.

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