Different buried permanent magnet arrangements in rotors are compared based on electrical machines found in literature regarding high-speed capability. An analytical approach is presented to analytically calculate mechanical stresses in the bilateral and central bridge of V arrangements in order to determine the achievable circumferential velocity of a rotor geometry. The mechanical model is coupled to an analytical model which can determine the flux density in the main air gap under consideration of flux leakage within the rotor. The multi-domain model enables the analytical design of high-speed rotors with buried permanent magnets in V-arrangement.

The publication addresses the dynamic state challenges encountered during development of a Dual Active Bridge (DAB) converter within DC microgrid systems. The conventional startup method is identified as instigating a cascade of unfavorable outcomes, encompassing elevated starting current, transformer current asymmetry, DC voltage distortions, EMI and heightened thermal stress on semiconductor components. Additionally, it necessitates precise calibration of magnetic components and diodes. A proposed remedy to these issues is introduced, involving a control method based on an additional phase shift to modulate the current of the primary H bridge. This novel control methodology is posited as a means to mitigate the aforementioned undesirable effects associated with traditional converter initiation techniques. The research also delves into considerations of proper design procedure for the converter. Emphasis is placed on integrating the novel control methodology into the design framework to effectively address challenges arising during transient states. Validation of the proposed solution is substantiated through a series of laboratory tests, the results of which are comprehensively presented in the article. These tests affirm the efficiency of the system when incorporating the novel control methodology, thereby substantiating its practical utility in mitigating the identified issues during the initiation phase of the DAB converter in DC microgrid systems.