Abstract:
A tunable inductor has a first magnetic core and a second magnetic core wound with a direct current (DC) winding and an alternating current (AC) winding. A first portion of the AC winding is wound around a first portion of the first magnetic core, and a second portion of the AC winding is wound around a first portion of the second magnetic core. The DC winding is wound simultaneously around the first magnetic core and the second magnetic core in a second portion that does not overlap the first portion of the first magnetic core and the second magnetic core. The DC winding is connected to a DC control circuit that applies a DC voltage to control permeability of the first magnetic core and the second magnetic core, which allows inductance value of the tunable inductor to be adjusted.
Abstract:
Enhanced common mode current reduction in three-phase inductors, transformers, and motor drive systems. A motor drive system includes an iron core transformer, a common-mode transformer coupled to a three-phase motor, and a variable speed drive providing a three-phase power signal to drive the three-phase motor, and coupled to the iron core transformer and the common mode transformer. The system includes a DC bus having a DC bus midpoint. The common-mode transformer includes a toroidal ferrite core, a first choke winding, a second choke winding, a third choke winding, a first coupling winding collocated with the first choke winding, a second coupling winding collocated with the second choke winding, and a third coupling winding collocated with the third choke winding. The first, second, and third coupling windings are coupled in parallel to one another. The coupled windings couple a neutral point of the iron core transformer to the DC bus midpoint.
Abstract:
A combination capacitor and inductor employ a common volume of high permeability material for energy-storing electrical and magnetic fields thereby reducing the bulk of these components with respect to separate components of comparable value. Capacitor conductors are arranged so that while proximate to the high permeability material they provide countervailing current flows to minimize parasitic inductance exacerbated by the high permeability material.