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Brushless wound-rotor doubly-fed electric machine

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The brushless wound-rotor [synchronous] doubly-fed electric machine (i.e., electric motor or electric generator) is a proprietary technology that incorporates the most optimum electromagnetic core structure of any electric machine, which is the core structure of the wound-rotor doubly-fed electric machine, but without the Achilles' Heel of the wound-rotor doubly-fed electric machine, which is the multiphase slip ring assembly with control instability. Development of the brushless wound-rotor [synchronous] doubly-fed electric machine seems to be limited to one company, Best Electric Machines (http://www.bestelectricmachine.com).

How it works

The brushless wound-rotor [synchronous] doubly-fed electric machine (i.e., electric motor or electric generator) incorporates a proprietary multiphase electromagnetic commutator that instantaneously emulates the speed dependent electrical excitation requirements of the electric motor or electric generator under control, regardless of speed. Simultaneously, the electromagnetic commutator exchanges virtually pure sinusoidal multiphase electrical power between the rotor (or stator) multiphase active winding set(s) and the electrical power grid without electrical-mechanical contact of any kind (i.e., brushless).

Unique attributes of brushless wound-rotor doubly-fed technology

Only as convenience for operational illustration, the electromagnetic commutator can be considered akin to the electromechanical commutator but with substantially more resolution of servo-like control and without brushes or sliprings. Because the excitation waveform is instantaneously produced precisely to any speed, there is no opportunity for instability that is common to all other means of control, such as Field Oriented Control, which iteratively calculate speed variant to speed invariant transformations and synthesize the excitation waveform by functionally remote electronic processing. Further, the electrical power grid and the winding sets of the electric motor or generator under control are isolated from any high frequency harmonics, which dramatically improves insulation and bearing life. The unique attributes of the brushless wound-rotor doubly-fed technology incrementally improve efficiency, improve reliability and lower system cost.

See also