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The brushless doubly-fed generator (BDFG) has the advantages of brushless structure, variable-speed constant-frequency operation, flexibly controllable active and reactive powers, low converter capacity and cost, and so on, which is very suitable for the wind power generation, especially the large wind turbines and offshore wind farm [1].
Contra-rotating double-rotor disc-type PM motor is suitable to directly drive contra-rotating propeller of torpedo, due to avoid yawing and spinning. In this paper, the electromagnetic design scheme for different pole numbers are compared, and design method of permanent magnet size and stator winding are searched, then the effect of magnetic isolation material used in stator is analyzed. Finally,...
In this paper, the express test feasibility of the fiber optic gyroscope (FOG) coil winding symmetry quality using periodic variation temperature excitation is confirmed in theory by using the 3D fiber coil model that we proposed early. Then experiments are conducted to see how a FOG coil responds to periodic variation temperature excitation when its symmetry properties are purposely changed, which...
A criterion to describe the turn-to-turn discharge of the secondary winding in Tesla transformers is presented. Factors which have influences on the turn-to-turn insulation of the winding such as the wire diameter, the wire distance, the void size, the purity of transformer oil and the insulation strength of the wire are researched based on this criterion. By theoretical calculation, the electric...
An experimental scale-down model of UHVDC converter transformer is designed and manufactured to study the wave process in the winding under impulse voltage. Nine outgoing lines are set up on the different winding coil of the scale-down model. The voltage waveforms of different outgoing lines are obtained by lightning impulse test. The simulation model of scale-down transformer is established to calculate...
Traditional direct-drive permanent magnet synchronous machine (PMSM) suffers from large bulk and complex topology structure [1], which extremely limits its industrial applications. As a novel embranchment of PMSM, PM vernier machine (PMVM) incorporates the magnetic gear effects into conventional PMSM producing high torque at a relatively low speed, which is desirable for direct-drive applications...
Pole-changing permanent magnet (PM) machines, which can offer wide operating speed range, have attracted global attention in industry application [1-3]. However, the previous pole-changing PM machines adopting distributed winding, suffer from lengthy end winding and relatively low efficiency. Therefore, this paper presents a new variable flux pole-changing PM memory machine (VF-PCPMMM) employing fractional...
Wound rotor synchronous generators are widely used for diesel-generating sets (gen-sets) and wind power generation. For the former, they are designed for operation at only one speed and their operating conditions are dictated by the load. The gen-sets are a standard power supply in islanded power systems as a back-up power supply in remote locations [1]-[3]. For the latter, the wind turbine needs...
A simplified approach to choosing number and diameter of strands in litz wire is presented. Compared to previous analyses, the method is easier to use. The parameters needed are only the skin depth at the frequency of operation, the number of turns, the breadth of the core window, and a constant from a table provided in the paper. In addition, guidance is provided on litz wire construction — how many...
This paper investigates the controllability of a 6-phase single winding bearingless permanent magnet (PM) slice machine drive system under a variety of power electronic short-circuit conditions and the proper control algorithms to accomplish the successful rotor levitation under these short-circuit faults. Analysis shows that the bearingless PM slice machine drive system is only controllable under...
This paper presents an effective method of power generation from the multi-mode and multi-axis vibration of a vehicle. First, road tests considering the mass and velocity variation are conducted and analyzed. Next, in order to select an optimal lead zirconate titanate (PZT) device for the power generation, no-load and load tests are performed. Based on the characteristic results of the vehicle's vibration,...
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