Jlg Jeroen Janssen

Design Aspects of an Active Electromagnetic Suspension System for Automotive Applications

This paper is concerned with the design aspects of an active electromagnet suspension system for automotive applications which combines a brushless tubular permanent-magnet actuator with a passive spring. This system provides for additional stability and safety by performing active roll and pitch control during cornering and braking. Furthermore, elimination of the road irregularities is possible, hence, passenger drive comfort is increased. Based upon measurements, static and dynamic specifications of the actuator are derived. The electromagnetic suspension is installed on a quarter-car test setup, and the improved performance using roll control is measured and compared with a commercial passive system. An alternative design using a slotless external-magnet tubular actuator is proposed which fulfills the thermal and volume specifications.

Active electromagnetic suspension system for improved vehicle dynamics

This paper offers motivations for an electromagnetic active suspension system that provides both additional stability and maneuverability by performing active roll and pitch control during cornering and braking, as well as eliminating road irregularities, hence increasing both vehicle and passenger safety and drive comfort. Various technologies are compared with the proposed electromagnetic suspension system that uses a tubular permanent-magnet actuator (TPMA) with a passive spring. Based on on-road measurements and results from the literature, several specifications for the design of an electromagnetic suspension system are derived. The measured on-road movement of the passive suspension system is reproduced by electromagnetic actuation on a quarter car setup, proving the dynamic capabilities of an electromagnetic suspension system.

Three-Dimensional Analytical Calculation of the Torque Between Permanent Magnets in Magnetic Bearings

In the high-precision industry, accurate vibration isolation and magnetic levitation are extremely important. As a result, high-performance vibration isolation and magnetic bearings based on permanent magnets are increasingly considered. This paper proposes improved analytical expressions for the torque on cuboidal permanent magnets applied to a magnetic bearing. These novel expressions are valid for any relative magnet position, especially when surfaces of the different magnets are in the same plane. Further, the torque can be obtained with respect to any reference point. Although these equations seem rather complicated, they enable an extremely fast and accurate calculation of the torque on a permanent magnet in the presence of a magnetic field of another permanent magnet. These properties enable a fast design and optimization process of such bearings using fully analytical expressions.

Relative Permeability in a 3D Analytical Surface Charge Model of Permanent Magnets

The analytical surface charge model is used to calculate the magnetic field of magnets in 3D in an unbounded domain. The method combines high accuracy with a short calculation time. However, in the classical method the relative permeability of the magnet is assumed to be equal to air. This introduces an error in the resulting magnetic field strength. In this paper the permeability of the magnet is taken into account in the form of a redistribution of magnetic surface charge. As such, an exact solution for the magnetic field at low relative permeability is obtained. The interaction force between two magnets is calculated using the newly obtained expressions for the magnetic field and compared with FEM and measurements.

Study of magnetic gravity compensator topologies using an abstraction in the analytical interaction equations

This paper identifles an abstraction that is found in the equations that describe the 3D interaction between cuboidal permanent magnets and applies this to the magnetic design of a gravity compensator. It shows how the force between magnets and its position-sensitivity, important design parameters for magnetically levitated 6-DoF gravity compensators, may be translated into the magnetic domain and verifles this with 3D analytical models. With this information, a number of basic gravity compensator topologies is derived. These topologies are subsequently investigated in more detail, with speciflc focus on combining a high force with low position sensitivity.

Analytical flux linkage and EMF calculation of a Transverse Flux Machine

Transverse Flux Machines (TFM) exhibit 3-D flux patterns. Their analysis and design are generally based on 3-D Finite Element Methods (FEM). Previous analytical models were mostly limited to Magnetic Equivalent Circuits (MEC). The analytical model presented in this paper is used to perform extremely fast calculation of the flux linkage and EMF of a TFM. The analytical model uses a combination of the magnetic charge and magnetic imaging techniques to represent magnetic flux distribution within the air gap of a TFM. Furthermore, a suitable method to calculate the flux linkage of the TFM had to be determined to allow EMF calculation. This resulted in an analytical model which obtains a magnetic flux distribution with less than 10% error in the air gap. The calculated EMF, and therefore the flux linkage, is within 15% accuracy compared to the EMF measured for two prototypes.

Design Considerations for Coreless Linear Actuators

Linear permanent magnet synchronous motors are often used in applications where a high accuracy is needed. This paper investigates the influence of the key design parameters on the performance of a linear actuator with vertically magnetized magnets and a magnet array with quasi-Halbach magnetization. The performance is modeled by means of analytical expressions of the three-dimensional magnetic field components and optimal design ratios and guidelines are established.

3-D Analytical Calculation of the Torque Between Perpendicular Magnetized Magnets in Magnetic Suspensions

This paper presents novel equations that enable the direct analytical calculation of the interaction torque between perpendicularly magnetized cuboidal permanent magnets in free space. These expressions complement the expressions for the interaction force and stiffness that are already available in literature and are computationally inexpensive due to their analytical nature. They are suitable in the design and analysis of ironless structures such as certain types of magnetic bearings or for obtaining the peeling torque on the magnets in devices such as voice coil actuators or electron beam focusing devices.

Three-Dimensional Analytical Field Calculation of Pyramidal-Frustum Shaped Permanent Magnets

This paper presents a novel method to obtain fully analytical expressions of the magnetic field created by a pyramidal-frustum shaped permanent magnet. Conventional analytical tools only provide expressions for cuboidal permanent magnets and this paper extends these tools to more complex shapes. A novel analytical model for the magnetic field induced by triangular charged surfaces is combined with the field expressions for rectangular charged surfaces. This provides a fully analytical expression for the magnetic field of a pyramidal-frustum shaped permanent magnet. Field and force obtained using this model are validated with Finite Element Modeling.

Modeling and control of a 6-DOF contactless electromagnetic suspension system with passive gravity compensation

A contactless Electro-Magnetic Isolator (EMI) is designed for gravity compensation of a heavy payload by passive Permanent Magnetic (PM) force and control by active Lorentz force. The theoretically calculated PM force and torque produced by this EMI are presented. To characterize the EMI and to evaluate the vibration isolation performance, the Single EMI System (SEMIS) is designed by adding three horizontal and three vertical Lorentz actuators for control. It is a six Degrees-of-Freedom (DOF) contactless electromagnetic suspension system possessing the properties of inherent instability, nonlinearity, no mechanical contact, passive gravity compensation. The physical SEMIS model is developed based on reasonable assumptions and approximations. It is subsequently linearized for control design. The vibration isolation performance of the two control strategies, decoupled control and decentralized control, are simulated and compared. The results show that decentralized control has more significant coupling than the decoupled control for only two DOF-pairs.