Winding Design that Balances Asymmetric Three-Phase Coupled Inductors

Technology #16353

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Shuo Wang
Le Yang
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Richard Croley
Assistant Director 352-392-8929

Reduces Signal Noise in the Voltage Conversion Process

These compensation winding structures achieve balanced three-phase impedance on asymmetric E cores, widening the E core selection range for three-phase coupled inductors and transformers. Most U.S. commercial buildings use three-phase power applications of AC electric power generation, transmission and distribution because of its power density and flexibility. Three-phase power applications can supply more power without increasing the thickness of wires or provide the same power at a lower current, reducing costs for construction and energy. Voltage conversion is a fundamental component in proper electronic functionality. Likewise, inductors are essential in voltage conversion, being integral in the engineering of the voltage converter’s filter. Inductors have a wide range of applications and technological uses, and the inductor market is expected to reach $3.94 billion by 2022. Although inductors are fundamental to proper voltage conversion, certain challenges in inductor design remain. For example, a sudden increase in voltage can cause electronic noise in the voltage conversion process. This sudden voltage increase can ruin electronics and cause signal noise that interferes with the proper functioning of a device. Conventional inductor designs for three-phase power applications require EE or EI magnetic cores with the same cross section area on each limb. Sometimes three separated toroidal cores are adopted in three-phase inductor design that will largely increase the total volume of the three-phase inductor.

Researchers at the University of Florida have developed winding structures that when added to an asymmetric E core can achieve balance and quiet signal noise in the voltage conversion process by narrowing the range of incoming power to the inductor. This design broadens the types of E cores that can be used in three-phase power or three-phase transformer systems.


Winding design that increases range of E core selection for three-phase coupled inductors and transformers


  • Narrows the range of incoming power, protecting devices against sudden voltage increases
  • Simple and cheap technological solution, providing an efficient method of reducing signal noise
  • Flexible structure for various applications, allowing the design to be applied in three-phase transformer systems


This inductor design improves the voltage conversion process of electronic devices by providing a winding structure of the inducting coils. Inductors are widely used in design of voltage converter filters. Usually construction of these inductors involves separate magnetic cores; however, conventional three-phase coupled inductor design has a strict requirement on the shape of magnetic cores. The design is a winding structure that can apply to three-phase coupled inductors. By adding two additional compensation windings, the coupled inductor can achieve balanced three-phase impedance on an asymmetrical E core, providing protective measures against signal noise from voltage conversion. This structure also applies to three-phase transformer systems.