This paper presents a novel magnetic levitation gravity compensator and its design philosophy by which the nearly constant levitation force performance within a relatively large vertical displacement can be easily obtained. Generally, the absolute levitation is desired in many ultraprecision positioning systems, because the vibration disturbance can be effectively isolated. However, it is very difficult to obtain the low stiffness performance due to the serious nonlinearity of the passive force between two permanent magnets. The proposed magnetic levitation gravity compensator is combined with two passive magnetic levitation units owning the opposite levitation force characteristics. Based on the design principle of stiffness counteraction, the two levitation forces from the two units are superimposed but the resultant levitation force variation is very low. The stiffness counteraction effect is finally verified by experiments. The prototype testing data shows that the maximum levitation force variation of the proposed magnetic levitation gravity compensator within ±5 mm is only 0.72 N, which is 2.4% of the rated passive levitation force 30 N.

Transverse flux machines (TFMs) can achieve high force density by the reducing the pole pitch because of the decoupling of electric and magnetic loadings. But the main flux linkage interlinking with the armature coils will decrease as the pole pitch reducing, resulting in motor performance degradation. Unlike the approaches adopted by many literatures to suppress the leakage flux, this paper proposes a novel dual-consequent-pole transverse flux linear machine by adopting dual-PM structure. Without increasing the occupied volume, the coil flux linkage is enhanced and the force density can be further improved. At first, the basic configuration and operation principle are introduced at first. Then the leading parameter influence on the force density are investigated. The electromagnetic performance of the proposed machine is investigated by three-dimensional finite element analysis and is compared with its counterparts. The field distribution, winding flux linkage, back EMF, detent force and thrust force are emphasized as well as the efficiency and power factor. Finally, a prototype machine is constructed and tested to validate the theoretical analysis.

In this paper, a novel dual-consequent-pole transverse flux motor and its analytical model are proposed. Differ from existed transverse flux machines, the proposed motor owns core-tooth-to-magnet types of consequent-pole configuration on both stator and rotor. This unique motor configuration improves the no-load permanent magnet flux linkage interlinking with armature winding, thus leading to an enhanced torque density. The structure and working principle of the proposed motor are introduced as the first half part. Then, based on the combination of equivalent magnetic circuit method and subdomain method, an analytical modeling method is proposed to estimate the electromagnetic performance of the proposed motor. The parameters of the equivalent magnetic circuit model, e.g., the magnetomotive forces and reluctances are calculated based on subdomain model technique, considering the influence of the cores' saturation and the axial end effect during calculation. Based on the magnetic field distribution result, the electromagnetic performance is estimated. The analytical results are verified by both finite element method and prototype experiment.

In this paper, a dual-consequent-pole transverse flux motor and its electromagnetic design method are proposed. Both stator and rotor of the proposed motor are designed to own the consequent-pole configurations. The unique motor structure improves the space utilization and the torque density. Firstly, the detailed structure and principle are introduced, and the development of the torque density of the proposed motor is discussed. Secondly, the electromagnetic design method's theory, considerations and flow process are listed. Then, the selections of some main structure parameters are proposed, e.g. pole-pitch, thickness of PMs and pole-arc coefficients of PMs. The electromagnetic performances of proposed motor are compared with the existed transverse flux machines. At last, a prototype is manufactured and some primary experiments are done to verify and evaluate the proposed motor topology.

In this paper, a novel hybrid excitation linear eddy current brake is presented as a braking system for high-speed road and rail vehicles. The presence of the permanent magnets (PMs), whose flux lines in the primary core are oppositely directed with respect to the flux lines by the excitation windings, has the effect of mitigating the saturation of the iron in the teeth of the primary core. This allows the brake to be fed with more intense currents, improving the braking force. First, using the magnetic equivalent circuit method and the layer theory approach, the analytical model of the hybrid excitation linear eddy current brake was developed, which can account for the saturation effects occurring in the iron parts. The saturation effects make the design and control of eddy current brakes more difficult. Second, the relationship between the braking force characteristics and the design parameters were analyzed to provide useful information to the designers of eddy current brakes. Then, the controller of the hybrid excitation linear eddy current brake was designed to control the amplitude of the braking force. Finally, experimental measurements were conducted to verify the validity of the theoretical analysis.

In the nanopositioning system, such as the wafer stage in a lithography machine, vibration isolation is applied to decrease the influence of the lower basic frame on the upper positioning system. At present, the combination of passive gravity compensation with magnetic force and active stabilization control using linear actuators is a potential solution for vibration isolation. In this paper, an opposite stiffness cancellation method which can be used to decrease the vertical stiffness of a passive gravity compensation system is proposed. By comparison, the new passive gravity compensation system has less stiffness than that of the conventional structure. Lastly, a prototype is manufactured and tested.