BR102017011470A2 - electromechanical battery with electrodynamic magnetic bearing - Google Patents

Abstract

electromechanical battery comprising a capsule-enclosed motor / generator (11) with a rotor (6) positioned coaxially and surrounding the stator (8) and has permanent magnets (12) located near the inner cylindrical surface of the rotor body (6), and has copper rings (1) positioned at the top and bottom of the inner cylindrical surface of the rotor body (6), and has magnet-shaped support bearing (5) positioned at the base of the rotor (6) forming pairs with the magnets (5) attached to the stator support structure (13), and the stator (8) formed by axially aligned cylinder trunks has ring magnets (2) and ferromagnetic material (3) attached to the cylindrical surface stator (8) and radially aligned with the copper rings (1), and the stator (8) has brushless windings (4) radially aligned with the permanent magnets (12), and the stator (8) has on the upper base angular position sensor (7), and the stator (8) has, along the axis, passage channel (10), and the inner cylindrical surface of the rotor (6) is spaced from the outer cylindrical surface of the stator (8) by bearings (9).

Description

ELECTROMECHANICAL BATTERY WITH ELECTRODYNAMIC MAGNETIC BEARING [001] The proposed innovation belongs to the area of energy, particularly energy storage and recovery equipment, which enables energy management between the electrical system and a flywheel. It has a system of levitation and guidance of the rotor, obtained by electrodynamic levitation effect, through magnetic strut bearings.

State of the art analysis [002] The growing use of clean and renewable energy demands a flexible energy storage system. Currently, the systems that manage the electrical system do not have a good availability of equipment that performs this type of paper, particularly compact equipment that has a high energy density per occupied volume. It is clear that different devices have been developed in different configurations to manage energy efficiently. The following describes works that to some extent have similarities to that described in this report.

[003] The reference WO96 / 24981, Flywheel Based Energy Storage System deposited by Jack G Bitterly and Steven E Bitterly on February 6, 1995, describes a compact system for energy storage with a high speed rotary flywheel and a motor unit /generator. The rotating components are under vacuum to reduce energy losses due to the action of air. The rotor profile is axial to maximize the energy density and the volume of system efficiency. The rotor configuration features

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2/15 hollow regions at each axial end to allow the fitting of magnetic bearings. The motor / generator is located at one end of the rotor, after the set of magnetic bearings. The stator is mounted on a translation set to allow axial movement. For normal operation, this stator will be aligned with the rotor axis of the flywheel. However, if no operation is required, either as a motor or generator, the stator can be placed in a position where it would be decoupled from the rotor. A magnetic shield is mounted around the rotor, being able to maintain the magnetic flux in this space, minimizing energy losses that could decrease the flywheel's speed in idle periods.

[004] The reference US006806605B1, Permanent Magnetic Bearings deposited by Christopher W Gabrys on October 19, 2004, describes a system of magnetic bearings to support rotating bodies with a vertical rotation radius through the center of mass - the text mentions a possible application example (flywheel) for energy storage. The bearing system would include a rotating part and a stationary part on each side of the rotating center of mass. At least two concentric axial pole rings are placed on an axial surface of the rotating body. These rings are arranged within a compartment at the base of the rotor with adjacent rings having inverse magnetic polarities. Regarding the stationary part, at least two permanent magnet rings concentrically magnetized interact with the rotating rings in order to produce an axial attraction force and a radial centrifugal force.

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3/15 [005] The reference US005398571A, Flywheel Storage System With Improved Magnetic Bearings deposited by David W. Lewis on March 21, 1995 describes a flywheel energy storage system designed to run in horizontal orientation. Such a system is assembled from a motor / generator set with the rotor external to the stator, the rotor being supported by magnetic bearings at each end. Each of these magnetic bearings compresses a single main actuator capable of supporting 80 to 99% of the gravity load at the ends of the rotor. The rest of the load must be supported by smaller actuators. The flywheel is built with high density material in the shape of radially connected hoops, so the flywheel can be positioned to rotate on a horizontal axis. The laminated part of this rotor with good magnetibility is placed on the central axis of rotation in order to decrease the centrifugal force during rotation. The energy storage capacity of this flywheel is associated with a constructive characteristic that allows more material to be placed in areas with a higher probability of stress and high speeds [006] The reference US005703423, “Energy Storage Flywheel System”, deposited by Fukao, Matsukazedai et al, on December 30, 1997, shows a flywheel that is a rotor that rotates around the stator. The object of this invention is capable of having high speeds of rotation and small losses of energy in a reduced structure. The energy storage system consists of a stator and an external rotor that acts as the flywheel for energy storage. The stator has a set of windings responsible for propelling the rotor. A second set of

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4/15 windings, with a different number of poles, are installed. The power supply will be the current supply for the first set of windings to make the rotor rotate, and the control will be made by the currents in the second winding that produce radial forces that act on the rotor to avoid contact with the stator. The control eliminates disturbances on the steering wheel. The invention can also be used with two rotors and stators connected in a three-phase system, so that one of the phases is inverted and a power converter is used to deliver the current to the windings. With the chains in the opposite direction, the rotors rotate in the opposite direction and cancel the turning moment vectors produced in the flywheel.

[007] The reference US005124605, “Flywheel Based - Energy Storage Methods and Apparatus”, deposited by Jack G Bitterly and Steven E Bitterly., On June 23, 1992, shows an energy storage system and its manufacturing methods. The invention provides a high density energy storage device designed to rotate at speeds above 200,000 RPM, depending on its radial size. They are preferably supplied with magnetic bearings and lubricating liquids and act within a vacuum chamber. The set of axes is contained within the chamber and preferably comprises a set of electromagnetic bearings around the axis. The device is provided with a shaft, a set of tubes and an edge. The shaft can be made of a rigid and light material, being a magnetic bearing sleeve opposite the set of bearings. Preferably the shaft has a channel containing liquid which, together with a series of shoulders in the chamber, provides a self-restoration system for the bearings. THE

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The 5/15 edge is made of a high-strength fiber, which is usually made to have a smaller interstice volume. The embodiments for storing and releasing energy are through the interaction between permanent magnets or magnetizable materials such as the magnetic sleeve with the electromagnetic stator as the bearing axis.

[008] The reference WO2016 / 107934 A1, “Flywheel Energy Storage System”, deposited by Julio Roca Moncada., On July 7, 2016, shows a flywheel system. The system comprises a flywheel that rotates around an axis in a chamber under vacuum conditions. The system is characterized by a flywheel composed of a set of permanent magnets and a flywheel driving system, rotating around the same axis, outside the chamber, but adjacent to it, provided with a set of suitable permanent magnets to cause the flywheel to rotate by magnetic coupling with the flywheel magnets. An electric motor for driving the driving element through a multiplier mechanical transmission. The multiplication and reduction of the angular velocity achieved through the reduction and multiplier mechanical transmissions allow the flywheel to be able to store greater kinetic energy and therefore, it has more capacity to neutralize the speed fluctuations of the whole system. An application of the system, the electric motor supply means comprise a fan device, integral with or driven by a driving element, and a series of wind rotors coupled to the respective auxiliary electric generators, propelled by the air current generated by the fan device.

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6/15 [009] Reference WO2004 / 068677 A1, “Energy Storage Flywheel with minimum power magnetic bearing and motor / generator”, deposited by McMullen, Patrick, T; Huynh, Co., Si., On August 12, 2004, shows an energy storage system. The invention provides an optimized energy storage system, using magnetic bearings, a permanent magnet motor / generator and a high-resistance disc, preferably constructed using a steel disc for kinetic energy storage, magnetic bearings configured as double thrust and an active combination between magnetic bearings and a permanent radial magnet, and a permanent magnet motor / generator.

[010] The reference “US 8,633,625 B2”, “Shaft-Less Energy Storage Flywheel”, consists of registering a kinetic energy storage system (flywheel) for different applications, but without the shaft for the transmission of mechanical energy common in flywheels conventional. There are several constructions presented for the system, such as a circular rotating mass with permanent magnets arranged externally or internally around (rotor), which can be positioned radially or axially, external windings in the stator or internal made with thin strips, both cases aligned with the magnets, possibility of magnetic bearings that stabilize the system so that there is no friction due to contact in the axial, radial and / or inclination directions and reserve bearings that act physically when the magnetic bearings do not stabilize the system. The author also considers the use of fixed or mobile poles distributed radially along the rotor and the stator with the function of magnetic bearing, a situation that the stator is unique, another in which the set

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7/15 stator-rotor does not promote primary magnetic levitation with effect on the rotating mass or even whose rotation of the mass occurs only due to the interaction of the magnetic field of the stator with that of the magnets in the rotor.

[011] The reference “US 2012/0175985 A1”, “Passive Magnetic Bearing System”, is a uniquely axial stabilizer for the rotor of a magnetic bearing with permanent magnets in a ring shape for levitation and external rigidity control through the switching of inductances of fixed windings positioned between two Halbach matrices coupled to the rotor. The external control allows its use in passive and active magnetic bearings and does not require an external power source or position sensors, since it can operate by detecting the voltages generated by the windings and switching them. The stabilizer for deviations transverse to the axis of rotation requires only a Halbach matrix for operation, eliminating the problem of mechanical compensation of the centrifugal forces for the magnets. The variation of the magnetic field of the magnets with the temperature is compensated by a bimetallic set coupled to the matrices under levitation that maintains the alignment of the system and prevents losses. The system is part of a project under study related to flywheels and energy storage from intermittent sources and for automotive purposes.

[012] The reference “US 2011/0298293 A1”, “Flywheel Energy System”, consists of a stationary kinetic energy storage system for the purpose of supplying electricity. The system deals with a flywheel, which consists of a magnetic bearing with the coupling of a ferromagnetic cylinder on a portion of its rotating axis and a permanent circular magnet

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8/15 is fixed to the stator in order to attract this cylinder and the rotor mass coupled to the shaft, without the use of electromagnetic devices. One or two low-friction bearings are used to maintain the radial positioning of the shaft and limit the axial movement already supported, in whole or in part, by the magnet assembly and ferromagnetic cylinder. The fixation of the permanent magnet still has a polar piece to provide a return path for the magnetic flux maintaining the balance of the ferromagnetic cylinder in the rotor. Among the different construction possibilities presented by the author, are the use of different compositions for permanent magnets, the use of non-magnetic materials for the composition of the rotor mass, different support values for the magnetic bearing, different motor / generator sets for coupling to the system, the use of vacuum, a cooling system, speed, mass and power specifications, etc.

[013] Nowadays, there is a need to develop clean energy storage systems. One way to store this energy is through Electromechanical Batteries.

[014] The working principle of Electromechanical Batteries can be described as follows: a rotating mass is placed in situations where it is not subject to any frictional force or any other external action. Mechanical energy is converted into electrical energy and vice versa, using an electric motor / generator. For the same mass, the higher the speed of rotation, the greater the stored energy. The first systems were developed using mechanical bearings, but the loss of energy due to mechanical bearings and the difficulty to deal with rotations

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High 9/15, in the order of 150,000 rpm, made this type of technological solution unfeasible. Mechanical bearings are not feasible for this rotation, as they cause losses and do not support the great physical stresses that are submitted. The recent development of magnetic bearings allows the mass to rotate at high speeds, in the order of 150,000 rpm, enabling Electromechanical Batteries.

[015] The electromechanical battery with magnetic bearing can be applied as an alternative for storing energy in a clean way and with less environmental impact. It is considered the need for energy storage for later use in cases of emergency and when generation is impossible. In the case of a solar panel, energy is only produced during the hours of the day. In the case of wind energy only in the presence of wind. Nowadays there is a debate about the problem of storing energy in a fast, efficient way, which is not harmful to the environment and which meets the peak demand. Industries can store energy during the night, when it is cheaper. Nowadays chemical accumulators are used, but the energy density ratio per unit weight is far from the necessary objectives. In addition, they are aggressive to the environment due to the substances that compose them (zinc, lead, cadmium, mercury, acids, bases, etc.) and also lose their load over time (even without being in use). To solve these inconveniences, the Electromechanical Battery can be used. This device has an energy density per unit weight many times higher than the density available in lead / acid type batteries and its performance can reach values close to 96%. The electromechanical battery has

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10/15 a huge field of application. Among them: emergency installations, industrial installations, electric power plants and hybrid vehicles.

[016] The Electromechanical Battery comprises mechanical, electrical and software parts necessary for the functioning of the system. Control is performed through a digital controller with central processing unit - CPU and analog and digital input and output modules.

[017] Considering the patent documents previously presented, there is a lack of a system consisting of a motor generator based on brushless machines (“brushless”) coupled to a rotating mass suspended through electrodynamic magnetic bearings, being the control the motor-generator implemented in digital devices called programmable logic devices (FPGA - “Field-Programmable Gate Array”) associated with a microprocessor system, ensuring great flexibility in the development of the machine control system.

[018] The electromechanical battery, described in this report, consists of an Electromechanical Battery that fulfills the need for an efficient, low cost and reliable system for energy storage. It comprises a high-efficiency Electromechanical Battery that can be used as an alternative for storing energy in a clean way and with less environmental impact. In order to have a system with high performance, the rotating mass that makes up the system must execute the rotation movement at high speed, in the order of 150,000 rpm. In this way, as a solution, there are the magnetic bearings which, due to the almost zero friction, allow high rotations. Inside the magnetic bearings there is the magnetic bearing

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11/15 homopolar electrodynamic applied to the battery, object of the patent. This has the advantage of being a passive and stable bearing at high speeds, consisting of one of the components that differentiate the motor-generator from the Electromechanical Battery, described in this report.

[019] The Electromechanical Battery with Electrodynamic Magnetic Bearing consists of an external rotor that is located on the outside of the equipment, surrounding the stator, and has only passive components in its structure. Non-ferromagnetic metal rings are responsible for conducting the induced current that should generate the guiding and stabilizing forces of the rotating structure. The rotor is the element that will store the electrical energy supplied by the brushless motor, and the energy is stored in the form of kinetic energy, which is proportional to the square of the scalar speed. The stator structure is fixed in the central part of the device, thus the rotor mass will be positioned in the region with the largest radius of the system, ensuring greater energy storage capacity. This configuration also allows access to the stator coils for cooling.

[020] The rotor is automatically stabilized on its axis of rotation by means of electrodynamic levitation forces generated by two low loss homopolyric electrodynamic bearings, without mechanical contact between the stator support structure and the rotor structure. These forces are induced when the metal conductive rings move at a certain speed in relation to the permanent magnets. Rotor suspension is implemented through the use of permanent magnets.

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12/15 [021] The structure will have propulsion based on a brushless motor driven by a programmable logic device (FPGA - “Field-Programmable Gate Array”) and power circuit. The programmable logic device allows parallel processing and rapid reconfiguration of the system's control parameters, acting in order to guarantee a performance with superior performance to those obtained in devices based on microcontrollers and microprocessors.

[022] The motor-generator system is based on brushless electrical machines (brushless) with permanent magnets without ferromagnetic core, and the current and power flow control is performed by the algorithms implemented in the programmable logic device.

[023] Figure 1 shows in longitudinal section the schematic of the Electromechanical Battery engine.

[024] Figure 2 shows the block diagram of the system.

[025] As shown in figure 1, the stator (8) is formed by axially aligned cylinders and the rotor (6) is positioned coaxial and surrounding the stator (8). The rotor (6) has copper rings (1) positioned at the top and bottom of the internal cylindrical wall of the rotor (6). The ring magnets (2) and ferromagnetic material (3), which are the items that form the electrodynamic magnetic bearing for the radial support of the rotor (6), are fixed on the stator (8) and aligned with the copper rings (1). Brushless windings (4) are present in the stator body (8) of the motor / generator. The permanent magnets (12) of the motor / generator are located next to the internal cylindrical surface of the rotor body (6). The position of the motor / generator windings (4)

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13/15 is provided by the angular position sensor (7). The bearings (9) have the function of ensuring the positioning of the rotor (6), and act as a retaining bearing for the system. Set of magnets (5) form the rotor support bearing (6) and are positioned at the base of the rotor (6) forming pairs with the magnets (5) fixed on the stator support structure (13) (8). The windings (4) of the motor / generator are connected to the power circuit by wiring that passes through the passage channel (10), positioned along the axis of the stator (8). The engine / generator is enclosed in a capsule (11). The friction due to the detachment of the rotor is attenuated by the vacuum chamber formed by the bell (11).

[026] At low speeds, the rotor is supported by the support bearing (5) and the retaining bearing (9). After a certain rotation and with the induced currents, the radial bearing (1,2 and 3) starts to act through radial levitation forces to control the movement of the rotor (6) without the need for an external control system . Increasing the speed of rotation leads to an increase in bearing stiffness and thus greater stability. The proper activation of the currents applied to the coils (4) of the brushless motor (brushless) can be carried out precisely because the position of the rotor (6) is measured through the sensor (7) placed on the top of the stator (8). The proposed system has two important additional characteristics: the coils (4) of the brushless machine have an air core, which allows an efficiency gain of the system, in addition the stator (8) has a hollow core, comprised by the passage channel (10) which, in addition to allowing

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14/15 of the coil wire wiring (4) and the rotor angular position sensor (7), also allows the addition of a coil cooling system (4).

[027] Figure 2 shows the block diagram of the system. The control system implemented in the programmable logic device (FPGA) sends signals to the electronic power system, which is responsible for controlling the flow of energy. Depending on the activations made in the power circuit, the electric energy will be transformed into kinetic energy, associated with the rotation speed of the rotor (6), which acts as a flywheel. The power circuit controls the currents applied to the high efficiency brushless motor generator. The activation of the motor-generator accelerates or reduces the speed of the rotor (6), delivering energy to it or converting kinetic energy into electrical energy.

[028] Considering the descriptions above, it is noted that the inventive step is characterized by obtaining a device with high efficiency thanks to the intrinsic constructive dispositions of the proposed solution. The electronic systems used allow a quick reconfiguration of the system, consisting of a tool that allows the implementation of algorithms that can be executed in parallel. The processing speed of the configurable electronic system allows ample flexibility in the use of new drive techniques. Likewise, the electrical machine proposed in this system converts electrical energy into kinetic energy and vice versa with high efficiency. The technologies of magnets with high magnetic energy that can be constructed in different formats, allow the construction of the bearings that support and guide the rotor (6) at high speeds, almost without friction.

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15/15 [029] The main market to be interested in the technology developed is the one in which the energy systems is intermittent. This is because in this type of system it is necessary to store the energy produced so that it can later be returned to the system, keeping the network powered. The developed technology could be applied in this type of situation, improving the efficiency of the system's energy use. The association of electromechanical batteries with alternative energy generation systems, such as solar and wind, allows the permanent supply of energy to the system, as the energy eventually produced in excess during the day in a solar panel system can be stored and reused through storage in these electromechanical batteries. From an environmental point of view, it is worth mentioning that these batteries do not present damage to the environment, as they do not need chemical reactions for the storage and reuse of energy, having a longer useful life for the system.

[030] Finally, it is understood that innovation is not limited to the specific form presented, and that modifications and other forms are understood to be included within the scope of the attached claims. Although specific terms are used here, they are used only in a generic and descriptive manner and not as a limiting purpose.

Claims (1)

CLAIM 1. ELECTROMECHANICAL BATTERY WITH ELECTRODYNAMIC MAGNETIC BEARING comprised of a motor / generator enclosed in a capsule (11), characterized by the rotor (6) positioned coaxially and involving the stator (8) having permanent magnets (12) located next to the internal cylindrical surface of the body rotor (6), and have copper rings (1) positioned at the top and bottom of the internal cylindrical surface of the rotor body (6), and have a bearing in the form of magnets (5) positioned at the base of the rotor (6) forming pairs with magnets (5) attached to the stator support structure (13) (8), and the stator (8) formed by axially aligned cylinder trunks has ring magnets (2) and ferromagnetic material ( 3) fixed on the external cylindrical surface of the stator (8) and radially aligned with the copper rings (1), and the stator (8) has windings (4) brushless aligned radially with the permanent magnets (12), and the stator ( 8) possess on the upper base the angular position sensor (7), and the stator (8) has, along the axis, a passage channel (10), and the internal cylindrical surface of the rotor (6) is spaced from the external cylindrical surface of the stator (8) by bearings (9).