Magnetic circuit

About: Magnetic circuit is a research topic. Over the lifetime, 15707 publications have been published within this topic receiving 118099 citations.

Electromagnetically actuated rotating machine unbalance compensator

Abstract: An electromagnetically actuated machine balancer (110) including a plurality of peripherally placed magnetic circuits and a power driver which selectively interrupts the magnetic flux (1210) through the circuits, thereby moving unbalanced rotors (350-351) in a desired manner to compensate for machine unbalance. The balancer assembly (110) includes a remote stationary microprocessor based controller (140), operating under stored computer program control and adapted to control assembly (110) in a manner which is specified by the stored program and certain environmental and measured parameters.

Design of a Novel Parallel-Hybrid-Excited Dual-PM Machine Based on Armature Harmonics Diversity for Electric Vehicle Propulsion

Abstract: A novel parallel-hybrid dual permanent magnet (PM) machine topology with both enhanced torque density and improved flux weakening capability is proposed for electric vehicle propulsion in this paper. The key is to artificially construct the harmonics diversity with a single-layer concentrated armature winding in the stator and thus simultaneously couple the armature field with the excitation field produced by slot PM, rotor PM, and stator dc source, respectively. Enhanced torque density is obtained in this new topology due to the symmetrical flux-modulation effect between dual PM sources. Moreover, benefiting from a parallel excitation characteristic of hybrid magnetic circuit, the demagnetization risk is significantly mitigated for slot PM source and thus an extended flux weakening range is obtained. In this paper, the proposed new topology and its design mechanism are investigated, along with its electromagnetic performance evaluated based on finite-element analysis. Further, some leading design parameters are analyzed and determined to provide a design guideline for the proposed new topology. Finally, a prototype is built and fully tested. Relevant experimental results agree well with the finite-element predication.

Combined Radial-Axial Magnetic Bearing for a 1 kW, 500,000 rpm Permanent Magnet Machine

Abstract: Ultra-high-speed and high-power-density drives are attracting much interest in today's industry. For instance, there are several investigations into mesoscale gas turbine generator systems and turbocompressors for fuel cells. In all ultra-high-speed machinery the bearing is a key technology. Therefore, this paper focuses on the design of a 500,000 rpm active magnetic bearing suitable for use in a 1 kW PM machine to complete an ultra-high-speed electrical drive system. The design procedure selects the suitable magnetic bearing type to keep the system compact and small. The electromagnetic characteristics are determined, the results for the rotor dynamic analysis are presented and the air friction losses caused by the high frequency operation are evaluated. The final design is a combined radial-axial magnetic bearing with a volume of 50 cm3.

Solenoid actuator having a magnetic flux sensor

Abstract: A solenoid actuator comprising a coil or coils of electrical wire and a plugnut and movable core within the coil(s). A magnetic yoke surrounds the coil(s), the axis of the latter extending across the magnetic circuit defined by the yoke. Relatively large and small permanent magnets are associated with the yoke on opposite sides of the axis, the magnets producing flux in opposite directions. A flux sensor, closer to the small magnet, senses changes in direction of the flux. When the core and plugnut are separated, the large magnet flux predominates throughout the yoke. When the core engages the plugnut, the small magnet flux predominates in its portion of the yoke, this change in flux direction being detected by the sensor. Thus, the sensor can be used to indicate the position of the core with respect to the plugnut.

Design and Analysis of a Stator-Doubly-Fed Doubly-Salient Permanent-Magnet Machine for Automotive Engines

Abstract: This paper presents a new outer-rotor stator-doubly-fed doubly-salient permanent-magnet (SDF-DSPM) machine, which can be used as the integrated starter-generator for modern automobiles and mild hybrid electric vehicles. The key of the proposed machine is to incorporate both dc field windings and PMs in the inner stator, hence, offering a compact arrangement of hybrid field excitations. While armature windings are located in salient poles of the outer stator, the outer rotor is simply composed of salient poles without windings or PMs. In addition, an air bridge is purposely created in shunt with each PM in the inner stator, hence, providing an amplification effect for flux regulation. With this idea, the air-gap flux can be strengthened or weakened with a small dc field current so that the electromagnetic torque and induced electromotive force (EMF) can be effectively regulated. The newly designed SDF-DSPM machine is analyzed by using both the magnetic circuit model and finite element method, and assessed by performance simulation