Design of a Three Phase AC-Side Common-mode Inductor

Avyay Sah, Purdue University

Abstract

In recent years, switch-mode power electronic converters have gained considerable popularity because of their compact size and high switching frequencies. This makes them suitable for power processing in various applications, including photovoltaic systems and electric vehicles. However, their high switching frequency capabilities have a drawback. A high-frequency common-mode voltage coupled with the switching of the power converters excites the parasitic capacitances of the system. It leads to the flow of common-mode current. Since the common-mode current flows through an unintended path, it can potentially interfere with the performance of system components. Passive filters can be used to mitigate common-mode currents. Using a common-mode inductor in conjunction with strategically placed capacitors makes it possible to limit the flow of common-mode current.As part of this work, passive mitigation of common-mode current will be investigated in a variable frequency drive system. In this regard, the process of designing a three-phase ac common-mode inductor is explained. As a first step, a mitigation strategy is proposed and described. Next, the issue of self-capacitance of the inductor is discussed. Afterwards, the ac common-mode inductor is designed using a multi-objective optimization-based approach. Following this are the design results, concluding the dissertation.

Degree

M.Sc.

Advisors

Sudhoff, Purdue University.

Subject Area

Design|Electrical engineering|Transportation

COinS