Eddy Current Brake Research Articles

Braking Torque Analysis and Control Method of a New Motor with Eddy-Current Braking and Heating System for Electric Vehicle

Braking Torque Analysis and Control Method of a New Motor with Eddy-Current Braking and Heating System for Electric Vehicle

The Effect of Temperature on the Braking Force Experienced by Magnet Falling Through a Copper Pipe

The braking experienced by a magnet falling through a conductive pipe is often shown in laboratories, as it is highly intriguing and captures the imagination of students. The Eddy current is the physical phenomenon behind Eddy current braking, which has a lot of utility as Eddy current brakes do not utilise friction and hence do not wear. Linear eddy current brakes, often used on rail vehicles, use the rail as a conductor. Consequently, it is important to address the impact of the rail's properties. Previous papers have explored the significance of thickness and material however temperature has yet to be considered.
 Here, coils were wrung around a copper pipe and an oscilloscope was used to determine the position of a neodymium magnet falling through pipe at various temperatures in order to determine the magnet’s terminal velocity. This data was then used to determine the braking force exerted by the pipe on the magnet. The experimental findings were compared to a theoretical model for the braking force. Graphing the inverse of the dragging constant and temperature showed a positive linear relationship suggesting that increasing the temperature reduces the braking force experienced by the magnet, which is in line with pre-existing theory that increasing the temperature will reduce conductivity, in turn reducing the eddy currents that cause the braking force.
 Finally, this study establishes that temperature, and hence the weather plays a significant role and needs to be considered when designing eddy current based machines, such as magnetic brakes in high-speed trains.

Equivalent subdomain method for performance prediction of permanent magnet eddy current brakes

Equivalent subdomain method for performance prediction of permanent magnet eddy current brakes

Modeling the Impact on Wheel Sensor Readouts by Eddy Current Brakes Installed in High-Speed Trains

This paper presents a model to anticipate the impact of Eddy Current Brakes (ECBs) installed in high-speed trains on the readouts of rail-side wheel sensors. The purpose is to anticipate false positive readouts of train wheels when traversing, one of the main obstacles for full ECB deployment. The ECB type EWB 154 from Knorr-Bremse and Wheel Sensor types RSR180 and RSR123 from Frauscher Sensor Technology are represented in a comprehensive model, integrating LTSpice and CST Microwave Studio. The wheel sensor predicted readout error is 4% compared to measurements when DC current is not applied to the ECB (passive case). It is demonstrated that the RSR180 is not compatible with ECBs, whereas the RSR123 is. The impact of active (DC current fed) brakes is analyzed when performing running tests with a high-speed ICE 3 train equipped with ECBs. The model is adjusted to study the saturation of the rail and ECB pole cores. The extra damping of the wheel sensor fingerprint is modeled by an extra 6% drop that may well be applicable to passive tests in a laboratory setting to shift to active tests without actually performing them. In this way, cost and time would be saved. Based on the model outcomes, a test bench is recommended for laboratory tests to emulate active behavior.

Analysis of linear eddy current brakes for maglev train using an equivalent circuit method

An equivalent circuit method (ECM) is developed to analyse the linear eddy current braking system (ECBS) of the maglev train. The distribution of eddy current in the rail is represented by dividing the rail into a series of small segments in which the current is assumed to be uniform. Each segment is described as an equivalent circuit with parameters of resistance and inductance. The circuit parameters, such as self-inductance and mutual inductance, are evaluated from the geometry parameters using an analytic method. The state equation derived from the circuit equations and the Newton's equations is solved using the Runge–Kutta method, from which the dynamic performance of the linear ECBS can be obtained. The accuracy and efficiency of the proposed ECM are verified by comparing the results with the one obtained from the finite element method. By adopting the developed ECM, the influence of parameters, such as speed, the exciting current and air gap of the linear ECBS, are analysed. The variation law of the linear ECBS with parameters is roughly grasped.

Mini Review on Eddy Current Brakes Parameter

The need for braking systems has increased. The widely used braking system is a friction brake. The use of friction brakes has a problem in maintenance intervals and the risk of failure due to heat generation. Research and the development of the braking system have carried out. Eddy Current Brake (ECB) is an alternative braking system. ECB is braking that uses eddy currents as a source of braking force. Many parameters need to consider in implementing the ECB. There have been many studies on the working parameters of the ECB. However, the previous research has researched the effects of parameters by make experiments or mathematical models. This article provides an analysis of the recent research about the ECB performance parameters. From the review of the previous study, it conducted that better performance of ECB is affected by the density of the use of magnetic flux.

Design of eddy current brake for electric motorcycle braking system

Braking systems in motor vehicles generally use a braking system that utilizes friction. The braking performance will decrease caused by using friction rapidly. To overcome this, as an alternative, an electromagnetic braking system can be used by utilizing eddy currents, such as eddy current brakes (ECB). Eddy currents are generated when the rotor pass the magnetic field of the electromagnet. The research aim is to design an ECB system. The performance of the disk design will be determined in this study. The study is about the tendency of the ECB properties. The finite element (FEM) method is used by modeling ECB performance. The experimental results were used to validate the result. The test showed the results of braking using aluminum disk showed the best performance in 12.03 Nm. From these results, the combination of the disks is needed by an appropriate disk design.

Non-Propellant Eddy Current Brake and Traction in Space Using Magnetic Pulses

The safety of on-orbit satellites is threatened by space debris with large residual angular velocity and the space debris removal is becoming more challenging than before. This paper explores the non-contact despinning and traction problem of high-speed rotating targets and proposes an eddy current brake and traction technology for space targets without any propellant consumption. The principle of the conventional eddy current brake is analyzed in this article and the concept of eddy current brake and traction without propellant is put forward for the first time. Secondly, according to the key technical requirements, a brand-new structure of a satellite generating artificial magnetic field is designed accordingly. Then the control mechanism of eddy current brake and traction without propellant is analyzed qualitatively by simplifying the model and conditions. Then, the magnetic pulse control method is proposed and analyzed quantitatively. Finally, the feasibility of the technology is verified by the numerical simulation method. According to the simulation results, the eddy current brake and traction technology based on magnetic pulses can make the angular speed of target decrease linearly without propellant during the process. This technology has huge advantages compared with conventional eddy current brake technology in terms of efficiency and reduced propellant consumption.

Characteristic and Thermal Analysis of Permanent Magnet Eddy Current Brake

In this paper, the subdomain analysis model of the eddy current brake (ECB) is established. By comparing with the finite element method, the accuracies of the subdomain model and the finite element model are verified. Furthermore, the resistance characteristics of radial, axial, and Halbach arrays under impact load are calculated and compared. The axial array has a large braking force coefficient but low critical velocity. The radial array has a low braking force coefficient but high critical velocity. The Halbach array has the advantages of the first two arrays. Not only the braking force coefficient is large, but also the critical speed is high. The parameter analysis of the Halbach array is further carried out. The inner tube thickness and air gap length are the sensitive factors of resistance characteristics. The demagnetization effect is significantly enhanced by the increase of the inner tube thickness. In order to ensure that the ECB does not overheat, the electromagnetic-thermal coupling model is established based on the heat transfer theory. The temperature rise of the inner tube is obvious while that of the permanent magnet is small. The temperature rise of the inner tube is more than 20 K each time, and that of the permanent magnet is less than 1 K each time.

Design of adaptive sliding mode controller for ant-lock braking system using eddy current

When vehicle speed increases, stable and powerful brake system is required to ensure the safety of the vehicle and passengers. For high speed braking of vehicle, contactless eddy current brake (ECB) is developed and applied to antilock brake system (ABS). An adaptive sliding mode controller for ABS using eddy current is presented with a sliding mode observer (SMO). Using vehicle acceleration, wheel speeds, and braking torque, the vehicle velocity estimated by SMO. To control the system based on wheel slip, half-car model is developed by considering uncertainty of the road slope and aerodynamic drag force. According to the controller, the vehicle ABS model is built with MATLAB Simulink. The response of controller is compared in terms of braking time and stopping distance. The results indicate proposed controller algorithm achieves minimum braking time and minimum stopping distance on selected roads.

Design of adaptive sliding mode controller for ant-lock braking system using eddy current

When vehicle speed increases, stable and powerful brake system is required to ensure the safety of the vehicle and passengers. For high speed braking of vehicle, contactless eddy current brake (ECB) is developed and applied to antilock brake system (ABS). An adaptive sliding mode controller for ABS using eddy current is presented with a sliding mode observer (SMO). Using vehicle acceleration, wheel speeds, and braking torque, the vehicle velocity estimated by SMO. To control the system based on wheel slip, half-car model is developed by considering uncertainty of the road slope and aerodynamic drag force. According to the controller, the vehicle ABS model is built with MATLAB Simulink. The response of controller is compared in terms of braking time and stopping distance. The results indicate proposed controller algorithm achieves minimum braking time and minimum stopping distance on selected roads.

Research on Temperature and Braking Performance of Water-Cooled Eddy Current Retarder

Trucks have the problems of frequent braking and long-term braking during long-slope transportation. As the temperature of the traditional eddy current retarder is as high as 500 °C during braking, the braking torque of the retarder is seriously degraded. According to the principle of eddy current braking and current thermal effect, this paper proposes an eddy current retarder in which both the stator and the excitation coil are water-cooled. The multi-field coupling and bidirectional data transmission model of stator temperature field, coil temperature field and transient electromagnetic field are established. The relationship between the braking torque and the working time is analyzed under continuous braking conditions, considering the stator temperature and the temperature of the excitation coil. It provides theoretical support for the optimal design of the retarder. A test prototype of a water-cooled eddy current retarder was manufactured, and a bench drag test was carried out. The calculation results show that the numerical simulation method of coupling between the stator temperature field, the coil temperature field and the transient electromagnetic field is adopted, and the simulation values of the braking torque is in good agreement with the experimental values.

Brake Torque of Three-phase AC Excited Eddy Current Brakes Using Cu/SPCC Composite Material Disc

Brake Torque of Three-phase AC Excited Eddy Current Brakes Using Cu/SPCC Composite Material Disc

Cost Minimization of a Permanent Magnet Eddy Current Brake by Multiobjective Particle Swarm Optimization Based on Nonlinear Reluctance Network Modeling

Design optimization of a permanent magnet eddy current brake (PM-ECB) is performed by applying multiobjective particle swarm optimization (MO-PSO) for cost minimization. A previously designed and patented PM-ECB is used as a reference model in the study. A quasi-3-dimensional (3D) analytical modeling approach based on a reluctance network considering the actual structure of the reference PM-ECB is proposed and verified. The Gauss–Seidel method is used as a nonlinear solver for the reluctance network modeling, and the braking torque is calculated considering both the skin effect and the armature reaction. Multiobjective optimization is developed by applying a particle swarm algorithm, and a 3D Pareto front is provided to demonstrate all non-dominating design points. Three cost functions, viz. rated braking torque, magnet mass, and magnetic flux density of the yoke, are selected as the objectives for the optimization problem, and the optimum design point is addressed in detail. The optimized design is validated by 3D-FEA and experiments. The results indicate that a 40% reduction in the magnet volume could be brought about by the optimized PM-ECB design with practically the same braking torque. Further, a 40% cost reduction in the optimized brake could be achieved compared with the reference one.

ИССЛЕДОВАНИЕ РАБОТЫ ТОРМОЗНЫХ МАГНИТНЫХ РОЛИКОВ ГРАВИТАЦИОННЫХ РОЛИКОВЫХ КОНВЕЙЕРОВ

One of the main elements of safe operation of gravity conveyors used in gravity racks for pallets is the brake roller. The most promising design is a brake roller of magnetic (eddy current) type. A mathematical model of the process of moving pallets on a magnetic brake roller is developed. The equation of the speed of movement of the pallets on the brake magnetic roller obtained. The main parameter that determines the braking functions of the brake magnetic roller, and therefore the speed of movement of the pallet on the gravity roller conveyor is the coefficient of magnetic viscosity. A comparative experimental evaluation of the magnetic viscosity coefficient of eddy-current brakes of two designs - disk and centrifugal - has been carried out. It has been established that the coefficient of magnetic viscosity for both designs of brakes decreases with an increase in the air gap between the conductive body and the magnets when the magnets are placed on one and on both sides of the conductive body, and this dependence is exponential; for a disc brake, when magnets are placed on both sides of a conductive body, 2.5-3 times more than with a magnet located on one side of the disc; for a centrifugal brake when magnets are placed on both sides of a conducting body, 4-4.5 times less compared to a conducting body in the form of a disc with magnets on both sides and 1.5-2 times less than a conducting body in the form of a disc with a magnet one side.

A Timesaving Transient Magneto-Thermal Coupling Model for the Eddy Current Brake

Eddy current brakes (ECB) are widely installed on heavy-duty vehicles to improve driving safety and economy. When the ECB works, the mechanical energy of the vehicle is converted into thermal energy under the action of the electromagnetic field, which is a process of mutual influence between the electromagnetic field and temperature field, and this process can be simulated by establishing a transient Magneto-thermal coupling model with bidirectional data transmission. However, due to the long calculation time required for accurate 3D electromagnetic analysis, the above model must be simplified. The parameter sensitivity analysis of the ECB shows that the temperature of the eddy current generating location directly affects the braking torque. Through the 3D electromagnetic field numerical analysis, the mapping relationship between the temperature of the eddy current generating layer and the braking torque is established and brought into the transient heat transfer model. The finite difference method is used to calculate the heat transfer model. The calculation results can predict and analyze the braking performance of the ECB during its working process.

Unsteady flow and aerodynamic behavior of high-speed train braking plates with and without crosswinds

Owing to continuous improvement in train running speeds, braking safety has become increasingly important, challenging braking approaches such as adhesion, eddy current, and electric magnet wheel brakes. Aerodynamic braking is an effective braking supplement whose braking effect is particularly outstanding in trains running at high speed. However, the flow field around the train can be significantly changed with the aerodynamic plate opening, degrading the aerodynamic performance of the train and even causing the train to sway violently. In this study, the unsteady aerodynamic characteristics of the full course of the braking plate, with and without crosswinds, were simulated and analyzed. The results show that pulse aerodynamic forces appear during the plate motion process, especially in the opening stage, and crosswinds increase the maximum values of these forces. Aerodynamic forces on the plate in the opening process are greater than those on the plate in the same position in the closing process. The difference in the flow field behind the plate in these processes is aggravated by crosswinds. Therefore, aerodynamic braking devices should be designed very carefully to minimize the impact of plate motion on the catenary and pantograph.

Research on Heat Dissipation Optimization of a Novel Liquid-Cooling Eddy Current Brake

As an auxiliary brake element, the eddy current brake is widely used to ensure safe driving in heavy vehicles due to its noncontact braking characteristics. It is important to increase the power density of the eddy current brake and suppress the thermal derating of its braking performance. According to the principle of the eddy current braking and current skin effect, a decline in temperature can greatly increase the eddy current density of the low-frequency electromagnetic device. In this paper, a new heat dissipation method is proposed to cool the heating surface of the eddy current brake directly. The electromagnetic field model and the flow-heat coupling model are established to predict and analyze the steady-state temperature distribution and braking torque. A new type of internal liquid cooling eddy current brake prototype was manufactured for a bench test. The experimental data prove that the computational model is effective. The calculation results show that the new internal liquid cooling eddy current brake has improved heat dissipation advantages.

Application of Multiple Unipolar Axial Eddy Current Brakes for Lightweight Electric Vehicle Braking

The braking system in a vehicle has the main role of slowing down the speed or stopping the moving vehicle. Compared to mechanical braking, which utilizes friction, non-contact braking has several advantages, including longer lifetime and less maintenance. One form of non-contact braking systems is the eddy current brake (ECB), an electric braking system that employs eddy currents to operate. This research focuses on the impact of magnetic field sources used in the ECB. In addition, the number of magnetic field sources is also observed. In order to achieve an ECB design that can be easily applied in any types of vehicles, including motorcycles and compact cars, a compact ECB design with an excellent braking torque is required. In this study, a compact design of the ECB is obtained by distributing the required braking torque from the disc brake into multiple electromagnets. Finite element method-based modeling has been performed to study ECB parameters, including the number of coil winding, the number of electromagnets, and the electric current. The results of this study show that the developed compact ECB could produce 93.66% of the torque required for braking.

Designing an Eddy Current Brake for Engine Testing

An Eddy Current Brake (ECB) has several advantages making it suitable for using in a dynamometer for testing engines. In this paper, a model is presented which considers the electromagnet’s core saturation to predict the performance of an ECB. A design is then proposed for a dual coil, single rotor ECB that meets the design requirement to dissipate a power of 30 kW at 3000 rpm. A comparison between the results obtained for a few different materials considered to be used in the rotating disc are also presented.
 Keywords: Antimagnetic force, Dynamometer, Eddy current brake, MATLAB Model