Investigation on the Method for Reducing the Time Constant of Exciting Winding of Homopolar Inductor Machine

The change rate of the exciting current of the homopolar inductor machine (HIM) would be affected by the time constant of exciting winding (EW). The smaller the time constant is, the faster the exciting current changes, which is help to build or eliminate the excitation magnetic field of HIM quickly. To reduce the time constant of EW, some methods are proposed and investigated in this article. First, the mathematical model of the time constant of EW is established based on the equivalent circuit method. Afterward, the factors affecting the time constant of the EW, including the resistivity of the winding, the equivalent air-gap length of the HIM, and the cross-sectional area of the winding, are investigated. Moreover, several methods are proposed and analyzed to reduce the time constant of the EW. Finally, the theoretical analyses are verified by simulations and experiments.