A.J.A. Vandenput

Modeling of Magnetically Levitated Planar Actuators With Moving Magnets

This paper presents three types of magnetostatic models of ironless planar actuators with moving magnets. The models predict the force and torque exerted on the translator of the actuator, which can be positioned in six degrees-of-freedom with respect to the stator coils. The force and torque are calculated with the Lorentz force law. The analytical and numerical models can be used for the design of large planar actuators, for the fast comparison of actuator topologies, and in the decoupling and commutation algorithm. The models have been verified with experiments

Sensorless direct field orientation at zero flux frequency

Nowadays field orientation of three phase AC machines is carried out without using flux sensors but only using easily measurable stator voltages and stator currents. In this paper, a measuring method is described that makes sensorless field orientation possible down to zero flux frequency. The method takes profit of particular phenomena in AC machines that occur under saturated operating conditions. Measurements have proven the applicability of the proposed method.

Magnetically Levitated Planar Actuator With Moving Magnets

This paper concerns the design, optimization, and commutation of a six-degree-of-freedom planar actuator with an active magnetic bearing. The planar motor has a stationary coil array and a translator with a Halbach magnet array. During movements in the plane, the set of energized coils changes with the position of the translator. In this paper, a method for the electromagnetic design of this type of actuator is discussed, and several topologies are compared. The best performing topology in terms of power dissipation and force and torque ripples has been manufactured and successfully tested.

Modeling Ironless Permanent-Magnet Planar Actuator Structures

This paper describes an analytical model that includes end effects for ironless synchronous permanent-magnet planar actuators. Because of its flexibility, the model can be used to predict the performance of various permanent-magnet array and coil array topologies and commutation schemes. Moreover, since control currents have to be nonsinusoidal, it allows analysis of the motor performance without specifying a commutation scheme by directly dealing with the motor-coupling matrix that links the coil currents to the forces or accelerations acting on the translator

Magnetically Levitated Planar Actuator with Moving Magnets

This paper concerns the design, optimization and commutation of a six degree-of-freedom planar actuator with active magnetic bearing. The planar motor has a stationary coils array and a translator with a Halbach magnet array. During movements in the xy-plane, the set of energized coils changes with the position of the translator. In this paper a method for the electromagnetic design of this type of actuator is discussed and several topologies are compared.

Model-Based Commutation of a Long-Stroke Magnetically Levitated Linear Actuator

This paper concerns a commutation and switching algorithm for multi-degree-of-freedom moving-magnet actuators with permanent magnets and integrated active magnetic bearing. Because of the integration of long-stroke actuation and an active magnetic bearing, DQ-decomposition cannot be applied. Therefore, these actuators are a special class of synchronous machines. A newly developed model-based commutation algorithm for linear and planar actuators enables long-stroke motion by switching between different sets of coils. Moreover, the ohmic losses in the coils are minimized. Three different versions of the algorithm are compared and successfully implemented on a 3-DOF magnetically levitated linear actuator

Development of an improved electrically assisted bicycle

The paper discusses the comprehensive mechanical, electromechanical, electromagnetic, control design and test approaches leading to the system integration, design solutions and physical implementation of electrically assisted bicycle as a result of the cooperative research work done by the Dutch Company-ID Bike and Technical University of Eindhoven.

Ironless magnetically levitated planar actuator

This paper describes a magnetically levitated planar actuator with moving magnets. This ironless actuator has a stationary coil array above which a translator with a permanent-magnet array is levitated and propelled in the xy plane. During the movements in the xy plane, the set of active coils is switched, as a result of which the stroke in the xy plane can be made, in principle, infinitely long. Measurements on the realized planar actuator show the feasibility of this concept.

Cogging Force Reduction in Tubular Permanent Magnet Actuators

This paper describes a method to reduce cogging force in the design of a tubular slotted PM actuator for industrial applications. A comprehensive analysis is undertaken by considering a pre-established design in coherence with extended 2D finite element analysis, which enables the determination of the cogging force associated both with the stator slotting and finite length of the ferromagnetic armature core of a 3-phase slotted tubular brushless permanent-magnet actuator. In order to reduce the total cogging force, sinusoidal skewing is implemented on the tubular structure. This paper investigates the validity of the cogging force predictions and the effectiveness of skewing techniques using a representation of the tubular structure in a 2D axial rotating finite element model.

Contactless Energy Transfer to a Moving Actuator

In this paper a new topology for contactless energy transfer is proposed and tested that can transfer energy to a moving actuator using inductive coupling. The proposed topology provides long-stroke contactless energy transfer capability in a plane and a short-stroke movement of a few millimeters perpendicular to the plane. In addition, it is tolerant to small rotations. The experimental setup consists of a platform with one secondary coil, which is attached to a linear actuator and a 3-phase brushless electromotor. Underneath the platform is an array of primary coils, which are each connected to a half-bridge square wave power supply. The energy transfer to the electromotor is measured while the platform is moved over the array of primary coils by the linear actuator. The secondary coil moves with a stroke of 18 cm at speeds over 1 m/s, while up to 33 W power is transferred with 90% efficiency