Study of Operation Principle of a Split‐Cascaded Multiphase AC Brushless Excitation Pulsed Alternator

ABSTRACT Traditional pulsed alternators adopt a brush excitation mode. Although this can improve the power and energy density of the machine, the high‐speed and high‐voltage sliding electrical contact between the brush and slip ring greatly reduces service life and reliability. To address this issue, a split‐cascaded multiphase AC brushless excitation pulsed alternator has been proposed. First, the basic structure of this machine is described, and its pulse discharge system is analyzed in detail. Then, the electromagnetic coupling process between the exciter and pulsed alternator is deeply discussed. The relationship between the rotor winding connection phase sequence and the output voltage is deduced, highlighting the advantage of AC excitation. Based on this, an electromagnetic analytical model for calculating the no‐load magnetic density of the AC excitation pulsed alternator is established, and its magnetic field distribution characteristics are analyzed. Finally, the field coupling finite element method is employed to analyze and verify the no‐load and load characteristics of the pulse discharge system, with preliminary experimental studies conducted on an existing platform. Research shows that the adoption of a multiphase structure can effectively reduce the current stress in each phase. The split‐type design makes it easy to achieve the parameter matching between the pulsed alternator and the exciter. This structure reduces the difficulty of system design and manufacturing and offers greater flexibility and reliability.