BACKGROUND

Embodiments of the present specification generally relate to a magnetic unit and method of operation of the magnetic unit, and more particularly, to a gapped magnetic unit having reduced winding losses for high frequency power conversion applications.

As be appreciated, power conversion applications, such as, motor drives, backup electrical power supplies, and the like use magnetic units, such as inductors/transformers and pulse width modulated (PWM) inverters/conveners. The PWM inverters/converters typically generate high frequency switching signals. In order to attenuate the high frequency switching signals generated by the PWM inverter/converter, gapped magnetic units are employed instead of solid core magnetic units. The gapped magnetic unit includes a magnetic core having an air gap and copper wire windings wound on the magnetic core. The gapped magnetic units are prone to fringing flux at air gaps. The fringing flux at the air gap induces eddy currents in the copper wire windings. Accordingly, the copper wire windings are subjected to higher thermal losses.

In recent times, use of litz wire as windings instead of copper wires has been proposed. The litz wire reduces copper losses caused due to fringing flux. However, the litz wire has many insulation layers, which increases physical size of the wire itself. As a result, footprint of the magnetic core increases in order to accommodate the litz wire windings.

Also, recently, use of magnetic core having distributed air gaps have been proposed to reduce copper losses resulting due to fringing flux. However, cost of manufacture of the magnetic core having distributed air gaps is relatively high.

Therefore, there is a need for an enhanced gapped magnetic unit for reducing winding losses for high frequency power conversion applications.

BRIEF DESCRIPTION

In accordance with one aspect of the present specification, a magnetic unit is presented. The magnetic unit includes a magnetic core. The magnetic core includes a first limb and a second limb disposed proximate to the first limb, where a gap is formed between the first limb and the second limb. The magnetic unit further includes a first winding wound on the first limb. Moreover, the magnetic unit includes a conductive element disposed facing an outer periphery of the first winding, where the conductive element is configured to control a fringing flux generated at the gap. Further, the magnetic unit includes a heat sink operatively coupled to the conductive element, wherein the conductive element is further configured to transfer heat from at least one of the conductive element and the first winding to the heat sink.

In accordance with another aspect of the present specification, a high frequency power conversion system is presented. The high frequency power conversion system includes a converter. Further, the high frequency power conversion system includes a magnetic unit operatively coupled to the convener, where the magnetic unit includes a magnetic core. The magnetic core includes a first limb and a second limb disposed proximate to the first limb, where a gap is formed between the first limb and the second limb. Furthermore, the magnetic unit includes a first winding wound on the first limb. Moreover, the magnetic unit includes a conductive element disposed facing an outer periphery of the first winding, where the conductive element is configured to control a fringing flux generated at the gap. Further, the magnetic unit includes a heat sink operatively coupled to the conductive element, wherein the conductive element is further configured to transfer heat from at least one of the conductive element and the first winding to the heat sink.

In accordance with yet another aspect of the present specification, a method of operation of a magnetic unit is presented. The method includes generating a fringing flux at a gap formed between a first limb and a second limb. The method further includes inducing a current in a conductive element disposed dicing an outer periphery of the first winding, based on the fringing flux. Moreover, the method includes generating a cancelation flux at the gap based on the current in the conductive element to control the fringing flux. Further, the method includes transferring heat from at least one of the conductive element and the lint winding to a heat sink.

