77 results about "Magnetic energy" patented technology

The invention belongs to the field of magnetic materials. The invention provides a preparation method of a rare earth permanent magnet, which comprises the following steps: weighing rare earth magnetic powder, adding a binder solution, uniformly mixing, and drying until a solvent is completely volatilized to obtain bonded magnetic powder; the bonded magnetic powder is placed in a die cavity of a constant-temperature die for heat preservation and preheating; an inner cavity of the constant-temperature mold is vacuumized to form a vacuum environment, and gas adhering to gaps of the magnetic powder is exhausted; applying a magnetic field to the mold, forming an oriented magnetic field in the mold cavity, arranging easy magnetization axes of the magnetic powder along the direction of the oriented magnetic field, and applying pressing force to obtain a mold pressing blank; and heating and curing the molded green body to obtain the rare earth permanent magnet. The rare earth permanent magnet prepared through the preparation method has high compactness, the residual magnetism and the maximum magnetic energy product capacity of the permanent magnet are improved, rare earth magnetic powder is prevented from being oxidized, and the coercive force of the permanent magnet is remarkably improved.

The invention discloses a magnetic-mechanical-electric coupling amplitude-change pole simulation method based on finite element analysis, and relates to the technical field of magnetoelectric antenna simulation. The magnetic-mechanical-electric coupling amplitude-change pole simulation method based on finite element analysis comprises the steps that parametric modeling is carried out, and a multi-physical field environment is imported; defining material attributes; solid mechanics, an electrostatic field and a magnetic field are coupled, and piezoelectric and piezomagnetic effects are started; dividing grids and configuring a solver; executing simulation calculation; and evaluating displacement and stress results and performing iterative optimization. According to the magnetic-mechanical-electric coupling amplitude-change pole simulation method based on finite element analysis, through multi-physics field coupling simulation, electric-mechanical-magnetic energy conversion is accurately simulated, the problem of traditional simulation distortion is solved, a high-performance amplitude-change pole capable of amplifying the amplitude of a permanent magnet sheet to 9 micrometers is guided to be designed, and the radiation capacity and reliability are remarkably improved.

The invention relates to a transformer leakage inductance calculation method and device and computer equipment. The method comprises the following steps: acquiring magnetic induction intensity and vector magnetic potential of any point in an iron core window; obtaining magnetic field energy in an iron core window area based on the magnetic induction intensity and geometric parameters of the iron core window; based on the vector magnetic potential and the cross section size of the winding area, obtaining interaction energy of the current and the vector magnetic potential in the winding area; on the basis of the interaction energy and the magnetic field energy, magnetic leakage energy stored by a unit length winding is obtained; the leakage inductance of the transformer is obtained based on the total leakage flux energy of the winding and the winding current of the low-frequency equivalent circuit, and the total leakage flux energy is obtained through calculation based on the leakage flux energy stored by the winding per unit length and the winding length.

The present invention discloses a large current measurement device based on a magnetic coupling mutual inductance voltage divider structure, comprising an incoming line shunt, a multi-coupled mutual inductance voltage divider coil, a magnetic energy detection unit, a magnetic energy storage unit and a control module. By setting a plurality of magnetic energy detection units, it is determined whether the current voltage signal exceeds a measurement threshold. If so, unactivated windings and corresponding magnetic energy detection units are continuously connected to ensure that the multi-coupled mutual inductance voltage divider coil does not reach the magnetic saturation in the nonlinear region, thereby achieving high-precision and wide-range current detection. Moreover, if the total voltage signal is still greater than the measurement threshold after all magnetic energy detection units are loaded, the electric energy in the energy storage element is discharged through the magnetic energy storage unit, thereby ensuring that the multi-coupled mutual inductance voltage divider coil does not reach the magnetic saturation in the nonlinear region.

This application belongs to the field of metal electromagnetic high-speed forming manufacturing technology, specifically disclosing a method and system for obtaining an electromagnetic forming actuator. The method includes: determining the basic structural parameters of the electromagnetic forming actuator with the goal of maximizing the magnetic energy utilization efficiency and the electromagnetic force impulse on the workpiece; obtaining the bottom morphology function of the electromagnetic forming actuator based on the electromagnetic forming force field requirements, and determining the parameters to be optimized and their value ranges in the bottom morphology function; determining a typical deformable workpiece configuration based on the workpiece deformation process and the target forming shape; calculating the weighted average of the magnetic field distribution uniformity index and magnetic energy efficiency of the electromagnetic forming actuator with different bottom morphology parameters on the typical deformable workpiece configuration; and selecting the optimal bottom morphology parameters based on a multi-objective optimization model with the goal of improving the magnetic field uniformity and magnetic energy efficiency. This application fundamentally solves the problem of uneven electromagnetic force caused by the structure of the electromagnetic forming actuator.

The invention discloses a permanent magnet-magnetizer magnetic control type electric kinetic energy synchronous output device, relates to the crossing field of permanent magnet power and power generation equipment, and discloses the permanent magnet-magnetizer magnetic control type electric kinetic energy synchronous output device to overcome the defects that an existing device is low in magnetic energy utilization rate and single in function and depends on external energy. The device forms a'starting-regulating-driving-power generating-self-sufficiency 'closed-loop system through the supporting system, the core energy conversion system and other four units. The core unit adopts a neodymium iron boron N52 permanent magnet and a high magnetizer, and the air gap is 0.4-1.5 mm; the intelligent regulation and control system realizes millisecond-level switching of magnetic field polarity through a Hall sensor and a driving module; the power generation coil and the power coil are complementary in magnetic field, and the characteristics of load increasing and torque synchronous increasing are achieved. The magnetic energy conversion efficiency of the device reaches 88%, the service life exceeds 150000 hours, the device is completely separated from external energy after initial starting, and the device can be applied to the fields of industry, aerospace and the like through power expansion.

The invention relates to the technical field of magnetic element modeling and control, in particular to a multi-factor magnetic core loss prediction method based on machine learning. The method comprises the following steps: firstly, acquiring magnetic flux density data of a magnetic element, extracting distribution characteristics and shape characteristics of the magnetic element, and realizing excitation waveform identification by constructing a classification model; secondly, introducing a temperature index correction term based on a Steinmetz equation, and establishing a temperature sensitive loss model; further performing importance evaluation on multiple factors by using an entropy weight method and statistical analysis; constructing a magnetic core loss prediction model by adopting an integrated learning model of a random forest and LightGBM; and with minimum loss and maximum magnetic energy transmission as targets, a single-target optimization model is established by fusing differential evolution and a simulated annealing algorithm. According to the method, the generalization ability and prediction precision of the model are improved, the magnetic core loss modeling requirements under the conditions of multiple materials, multiple waveforms and multiple working conditions can be met, and the method is suitable for application scenes such as high-frequency magnetic element design and power electronic system optimization.

The invention provides a non-intrusive magnetic field energy collection device capable of self-adapting to magnetic field fluctuation, and belongs to the technical field of magnetic energy collection, the device comprises a magnetic energy collection module, a compensation module, a rectifier bridge and a magnetic field fluctuation self-adjusting module, and the compensation module comprises a first capacitor, a first relay, a second capacitor and a second relay; dividing voltage is generated according to the direct current output voltage through a magnetic field fluctuation self-adjusting module, and the dividing voltage is compared with preset reference voltage; when the divided voltage is larger than the reference voltage, the first relay and the second relay are disconnected, the first capacitor is connected in series with the magnetic energy collection module, and the second capacitor is disconnected. And when the divided voltage is not greater than the reference voltage, the first relay and the second relay are conducted, the first capacitor is short-circuited, and the second capacitor and the magnetic energy collection module are connected in parallel, so that the defect that an existing non-intrusive magnetic field energy collection device cannot adapt to wide-range fluctuation of a magnetic field is overcome.

The present application relates to the technical field of magnetic element modeling and control, and particularly relates to a multi-factor magnetic core loss prediction method based on machine learning. The method first acquires the magnetic flux density data of the magnetic element, extracts its distribution characteristics and shape characteristics, and realizes excitation waveform recognition by constructing a classification model; secondly, a temperature index correction term is introduced based on the Steinmetz equation to establish a temperature-sensitive loss model; further, the entropy weight method and statistical analysis are used to evaluate the importance of multiple factors; an integrated learning model of random forest and LightGBM is used to construct a magnetic core loss prediction model; and a single-objective optimization model is established by combining differential evolution and simulated annealing algorithm with the objectives of minimum loss and maximum magnetic energy transmission. The method improves the generalization ability and prediction accuracy of the model, can adapt to the modeling needs of magnetic core loss under multiple material, multiple waveform and multiple working condition conditions, and is suitable for application scenarios such as high-frequency magnetic element design and power electronic system optimization.

The invention discloses a conversion device capable of generating power by repulsion of same magnetic poles. The conversion device is composed of two different steering rings. The conversion device is composed of a first circle and a second circle. According to the magnetic kinetic energy conversion principle, a magnetic energy material is subjected to two different force steering circles under the same-pole repulsion steering physical action. The first ring or the second ring turns physical effects in two different directions to one direction, and the power is transmitted to the generator to generate electricity.

A device for providing a magnetic treatment by evoking muscle contraction by a time-varying magnetic field and providing a RF treatment by heating biological structure. The device includes an applicator having an RF electrode and a magnetic field generating device. The device may also include a main unit, a human machine interface, and a control unit. The control unit adjusts a signal provided to the RF electrode and creates an RF circuit, and also adjusts the signal provided to the magnetic field generating device and creates a magnetic circuit electrically insulated from the RF circuit. The RF circuit may include a power source and a power amplifier, and the magnetic circuit may include an energy storage to supply the magnetic field generating device with electric current.

The present invention relates to a dryer using dielectric heating and a control method thereof. The dryer of the present invention comprises: a body; a drum provided inside the body and accommodating an object therein; a fan for circulating air in the drum; a motor for circulating at least one of the drum and the fan; an energy harvester for collecting magnetic energy from a magnetic field formed in the motor; a plurality of electrodes provided in the body to be spaced apart from each other and forming a magnetic field in the drum; a first power controller connected to a commercial power source and the plurality of electrodes; and a second power controller for generating a driving signal by using power supplied from the energy harvester and transmitting the generated driving signal to the first power controller. The first power controller of the dryer according to one aspect converts power supplied from the commercial power source into power having a preset frequency and a preset magnitude on the basis of a driving signal received from the second power controller, and applies the converted power to the plurality of electrodes.

The present invention relates to the technical field of magnetic-coupled wireless power transmission, and specifically discloses a full-space magnetic-coupled wireless local power transmission system and a magnetic energy regulation method thereof. The power transmission system includes N ≥ 3 three-dimensional orthogonal solid coils; each three-dimensional orthogonal solid coil includes an X-plane orthogonal coil, a Y-plane orthogonal coil, and a Z-plane orthogonal coil that are respectively distributed on the X, Y, and Z coordinate planes and whose geometric centers coincide with the origin of coordinates; any combination of an X-plane orthogonal coil, a Y-plane orthogonal coil, and a Z-plane orthogonal coil forms a transmitting mechanism for full-space electromagnetic transmission. The magnetic energy regulation method selects the optimal transmitting mechanism according to the position of the receiving coil, the magnitude and direction of the desired magnetic field. After determining the optimal transmitting mechanism, the amplitudes of the three excitation currents are set according to the solutions of the non-linear programming equation, and the phases of the three excitation currents are set to be in the same phase, which can dynamically regulate the spatial distribution of magnetic energy with the position and orientation of the terminal within the effective power transmission range, eliminate the influence brought by the dead zone space, achieve omnidirectional and full-angle power transmission, and minimize magnetic leakage.

When the distance between the magnetic slider and the fixed magnetic pole block in the first and second magnetic energy storage components of the laser direct-write imaging device provided in this application is compressed, the magnetic slider promotes the acceleration or deceleration of the scanning component under the action of the magnetic force applied by the fixed magnetic pole block. The first and second magnetic energy storage components can convert the kinetic energy of the scanning component during the deceleration phase into potential energy, and then release the potential energy during the reverse movement to accelerate the scanning component in the opposite direction. This improves the scanning speed of the emitted light array without changing the motor power and the weight of the device itself, thereby improving the production efficiency of the laser direct-write imaging device. Secondly, the laser direct-write imaging device in this application uses the force between the non-directly connected magnetic slider and the fixed magnetic pole to promote the acceleration or deceleration of the scanning component, avoiding mechanical vibration caused by direct contact and improving the stability of the laser direct-write imaging device.

The utility model provides a wireless power supply vacuum cup, which relates to the field of wireless power supply, and is characterized in that a nanocrystalline layer, a first ferrite and an electromagnetic induction receiving coil are sequentially overlaid at the bottom of a vacuum cup body, so that the vacuum cup as a power supply object of a power supply base can effectively restrain and concentrate an alternating magnetic field generated by a transmitting coil of the power supply base; loss of magnetic energy in the transmission process is reduced, and efficient interception and conversion of the receiving coil to the magnetic field are achieved; wherein the nanocrystalline layer inhibits ineffective divergence of a magnetic field by virtue of the property of high magnetic conductivity of nanocrystalline, so that the magnetic field of the coil is more focused, and loss in an electromagnetic conversion process is reduced; and the first ferrite forms magnetic circuit shielding on the back surface of the receiving coil, so that eddy-current loss generated by the cup body of the vacuum cup is reduced, the overall coupling efficiency is improved, the loss in the electromagnetic conversion process is further reduced, and the energy use efficiency of the wireless power supply vacuum cup is improved.

1. Name of the design product: inductor. 2. Use of the design product: electronic component for converting electric energy into magnetic energy and storing magnetic energy. 3. Design points of the design product: in shape. 4. Picture or photo best indicating the design points: perspective view 1. 5. The right view is the same as the left view, and the right view is omitted.

To provide an amplifying device that uses power of a magnet to generate electrical energy output with a small rotational input to convert the energy stored in the magnetic field during magnetic attraction and repulsion into other energy sources, and extracts continuous energy.SOLUTION: A reciprocating magnet is attached to an elastic body, a ring-shaped rotating magnet with magnets of opposite polarity spaced evenly is rotated directly below the reciprocating magnet, and magnetic energy is converted into electrical energy, and the magnetic energy contained in the magnet is repeatedly extracted by attracting the magnet attached to the elastic body with the attractive force acting between the ring-shaped rotating magnet and the reciprocating magnet, while the repulsive force pulls them apart, and reciprocating the magnet attached to the elastic body near an electromagnetic coil.SELECTED DRAWING: Figure 1

A secondary circuit device including a secondary coil for transmitting and / or receiving magnetic energy of a magnetic field and converting the magnetic energy into electrical energy; a rectifier for rectifying the electrical energy; and a detection unit; wherein the secondary coil is connected to the rectifier via a conducting unit, the conducting unit for transmitting electrical active energy and an electrical reactive energy; the conducting unit connected to an input of the rectifier; the rectifier having an output for providing the electrical active energy as voltage and / or current; the detection unit connected to the input and / or the output of the rectifier to detect an overvoltage at the input and / or the output of the rectifier and / or an external magnetic field; and, when the overvoltage is detected, the detection unit is designed such that it influences the conducting unit and / or the magnetic field to limit the transmission of the electrical active energy.

The invention relates to the technical field of heat treatment of welding seams, and discloses an electric-magnetic coupling energy field time-sharing loading type circumferential welding seam strengthening process and device, and the process comprises the following steps: (1) welding seam positioning; (2) tool positioning; (3) high-frequency large-current treatment; (4) coupling treatment of medium and low frequency strong electric pulse-strong alternating magnetic field; (5) low-frequency medium-strong electric pulse-medium-strong alternating magnetic field coupling treatment; and (6) the tool is unloaded. According to the method, a multi-stage multi-directional magnetic field and a wide-frequency-domain controllable pulse current field are actively constructed, the space-time action domain of an electric-magnetic energy field is accurately matched, micro defects and solute atoms are driven to directionally migrate and evolve, precipitated phase size distribution is regulated and controlled in a targeted mode, local obdurability and heat-conducting property of a non-uniform body of a welded workpiece are cooperatively improved, and the welding quality is improved. The method has the characteristics of high flexibility, high efficiency, short process, high space-time integration in the manufacturing process and the like.

The invention relates to the technical field of thermal diffusion pumps, in particular to a thermal diffusion pump heating structure and a diffusion pump, and the thermal diffusion pump heating structure comprises a controller which is used for converting alternating current into superaudio current; the heating coil is connected with the controller and used for converting the ultrasonic frequency current into a magnetic field; the vortex plate is connected with the diffusion pump and used for converting the magnetic energy into heat energy to heat an oil pan at the bottom of the diffusion pump. According to the electromagnetic induction principle, the controller is used for generating ultrasonic frequency current to drive the heating coil to generate a high-speed alternating magnetic field, so that heat is directly and quickly generated in the vortex plate due to the vortex effect, and the vortex heat effect is generated in the extremely thin skin depth of the surface of the vortex plate, so that the thermal inertia is extremely small; and the system can quickly start heating.

The invention discloses a low-field permanent magnet type MRI magnetic circuit design method and a magnet system thereof, and belongs to the technical field of magnetic resonance imaging. A sintered neodymium-iron-boron magnet with a high magnetic energy product and a sintered samarium-cobalt magnet with an excellent temperature characteristic are utilized to form the annular hybrid magnetic pole disc, the sintered samarium-cobalt magnet is located in the center area of the hybrid magnetic pole disc, and the sintered neodymium-iron-boron magnet is located in the edge area of the hybrid magnetic pole disc. And finally, the low-field MRI magnet system with light weight and excellent uniformity and temperature stability of the magnetic field is realized. The total weight of the magnet system is less than 400kg, and the central magnetic field intensity of the magnet system reaches 0.07 T; meanwhile, in a sphere space with the diameter of 200 mm and with the center of the magnet system as the sphere center, the magnetic field non-uniformity at the boundary is smaller than 100 ppm, and the fluctuation of the magnetic field non-uniformity at the boundary along with the temperature is also smaller than 100 ppm / DEG C.

The present disclosure relates to a sintered neodymium-iron-boron magnet and a method for preparing the same, the magnet comprising a main phase and a grain boundary phase, a ratio of an average grain size of a surface layer of the magnet to an average grain size of a central region of the magnet being 1.05-1.35; wherein the surface layer of the magnet refers to a region at a distance of 35 μm or less from a surface of the magnet; and the central region of the magnet refers to a region at a distance of 500 μm or more from the surface of the magnet. The sintered neodymium-iron-boron magnet has a sum of a maximum magnetic energy product (BH)max and an intrinsic coercivity HcJ of greater than 80; and a remanence Br of greater than 13 KGs; the maximum magnetic energy product (BH)max has a unit of MGOe, and the intrinsic coercivity HcJ has a unit of KOe.

To solve a problem in which conventionally, a method of controlling a radiation ray so as no to affect a human body and the like controls using a function of a substance having a shielding action such as a metal and the like, but to provide a method different from a way of thinking so far, and to enhance effectiveness of the radiation-ray control.SOLUTION: Magnetic force (magnetic energy) has a characteristic that shields many areas of a radiation-ray. A ferromagnetic body such as a neodymium magnet and the like, a high-conductivity metal such as a material copper of an electro magnet such as a pure iron and the like, and a carbon system good conductor such as a carbon allotrope and the like are processed to be powder or liquid solution to be mixed. The mixture has a mutual conversion action of the magnetic energy and electric energy, and generates quite strong magnetic force. Utilizing the mixture solves the problems by a method of controlling the radiation-ray using a function of energy, not a function of the substance.SELECTED DRAWING: None

The invention relates to a bidirectional carrier rocket launching and recycling device based on ground-rocket magnetic field coupling, a launching method and a recycling method, and belongs to the field of aerospace ground support equipment. Comprising an integrated ring and an active magnetic energy base. The integrated ring is connected to the tail end of a rocket through a flange and comprises an aluminum silicon carbide structure base body, an aluminum-coated steel coil, a cooling channel and a crushable honeycomb module, and the periphery of the integrated ring is coated with a carbon fiber outer wrapping layer and a carbon / silicon carbide shielding layer. The top of the active magnetic energy base is provided with a Halbach magnet array and a driving coil, and the bottom is provided with a moving mechanism. During launching, the driving coil is electrified to generate a traveling wave magnetic field which acts with the integrated ring to generate electromagnetic repulsive force to boost takeoff; during recovery, the integrated ring cuts into a static magnetic field to generate eddy current damping deceleration, the cooling channel dissipates heat through phase change of a propellant, and the honeycomb module absorbs residual kinetic energy to achieve soft landing. Bidirectional energy reuse of launching boosting and damping recovery is achieved, and the rocket carrying efficiency and recovery reliability are remarkably improved.

The present invention relates to a field coil stable power system for generating and stabilizing electrical output. The system includes a ferromagnetic core, preferably made of iron, that interacts with a field coil. The field coil generates a magnetic field when current flows through it, and this magnetic field interacts with the magnetic field of a permanent magnet, producing attraction or repulsion forces on the ferromagnetic core. The ferromagnetic core absorbs magnetic energy and dissipates the magnetic energy gradually, preventing abrupt changes in current. The system is capable of stabilizing electrical output by balancing fluctuations in current and is applicable to various electronic devices, including audio equipment and medical devices.

The invention provides a grooved axial surface local induction quenching device and an induction quenching heat treatment method. The device comprises a reinforcing structure, an inductor main body and a water sprayer, and the inductor main body and the water sprayer are combined into an integral structure of the local induction quenching device through the reinforcing structure; the inductor main body is used for rapidly heating the grooved axial surface of the crank arm by heat energy converted from magnetic energy, so that the surface of the crank arm is subjected to structure transformation; the water sprayer is used for spraying water to cool the crank arm. According to the magnetic induction principle of a high-energy magnetic line of force at the output end of medium-frequency induction equipment, the grooved axial surface of the crank arm is rapidly heated by heat energy converted from magnetic energy in magnetic circulating current formed under the guidance of an inductor, and quenching and tempering of the grooved axial surface of the crank arm are completed by controlling parameters such as working voltage and heating time; and the hardness, the hardening layer depth and the structure meeting the design requirements are obtained.

The present invention relates to a dryer using dielectric heating and a control method thereof. The dryer of the present invention comprises: a body; a drum provided inside the body and accommodating an object therein; a fan for circulating air in the drum; a motor for circulating at least one of the drum and the fan; an energy harvester for collecting magnetic energy from a magnetic field formed in the motor; a plurality of electrodes provided in the body to be spaced apart from each other and forming a magnetic field in the drum; a first power controller connected to a commercial power source and the plurality of electrodes; and a second power controller for generating a driving signal by using power supplied from the energy harvester and transmitting the generated driving signal to the first power controller. The first power controller of the dryer according to one aspect converts power supplied from the commercial power source into power having a preset frequency and a preset magnitude on the basis of a driving signal received from the second power controller, and applies the converted power to the plurality of electrodes.

The invention belongs to the technical field of metal electromagnetic high-speed forming manufacturing, and particularly discloses a method and system for obtaining an electromagnetic forming driver, and the method comprises the steps: taking the magnetic energy utilization efficiency of the electromagnetic forming driver and the maximum electromagnetic force impulse on a workpiece as targets, and determining basic structure parameters of the electromagnetic forming driver; based on the electromagnetic forming force field requirement, a bottom morphology function of an electromagnetic forming driver is obtained, and to-be-optimized parameters and a value range in the bottom morphology function are determined; determining a typical deformation workpiece configuration based on the deformation process of the workpiece and the target forming shape; and calculating a weighted mean value of the magnetic field distribution uniformity index and the magnetic energy efficiency of the electromagnetic forming drivers with different bottom morphology parameters on the typical deformation workpiece configuration, and selecting the optimal bottom morphology parameter based on a multi-target optimization model by taking improvement of the magnetic field uniformity degree and the magnetic energy efficiency as a target. The problem that electromagnetic force is not uniform due to an electromagnetic forming driver structure and the like is fundamentally solved.

An ion-permeation energy conversion device and its control method based on light and magnetic energy regulation are disclosed. When the ion-permeation energy conversion device is in working condition, the magnetic field strength of the permanent magnet is adjusted to disperse the magnetic nanoparticles, and the concentrator is adjusted to heat the ion-permeation energy conversion device body with photothermal magnetic nanoparticles to improve power generation performance. When the ion-permeation energy conversion device is in non-working condition, the magnetic field strength of the permanent magnet is adjusted to distribute the magnetic nanoparticles at the interface between the nanoselective membrane and the low-concentration reservoir to prevent ion transport, and the concentrator is adjusted to make the light intensity on the nanoselective membrane exceed the threshold to form a reverse driving force, further hindering ion diffusion and synergistically solving the self-discharge problem of the ion-permeation energy conversion device body.

A dual-rotor machine comprising a dual rotor support structure rotatably connected to a frame. A stationary stator is disposed between the rotors and is fixed to the frame. An inner rotor and outer rotor, each comprising a permanent magnet Halbach array, are coaxially disposed with the stator and are rotable about the stator. In this configuration, the inner rotor channels its magnetic flux to its outside, while the outer rotor channels its magnetic flux to its inside. The magnetic flux density at the stator for the dual-rotor machine can be as high as 2 Tesla or higher for high-grade neodymium-iron-boron permanent magnet material, and the stored magnetic energy for conversion to mechanical or electrical energy available to the stator may be at least 0.5 KJ / m. The rotor Halbach arrays may comprise monolithic permanent magnets with continuously variable magnetic field direction.