Performance Analysis of Rapid Capacitor Charging System Based on Differential Modulated Brushless Doubly Fed Alternator With Low-Frequency AC Excitation

The brushless doubly fed alternator (BDFA) based on differential modulation shows promising potential as an application in pulsed capacitor charging power supply (CCPS) systems, due to its high reliability and flexible excitation method. Unlike the previous study that only focused on the impact of BDFA on the charging performance of capacitors under dc excitation, this article focuses on analysing the transient characteristics of differential modulated BDFA on capacitor charging under low-frequency ac excitation in order to achieve better charging performance and fully utilise the advantages of BDFA ac excitation. Also, the system is classified into different operating modes according to the changing state of the charging current. The voltage and current equations in both modes are analysed to determine the impact of alternator parameters, particularly the excitation frequency, on charging performance. Finally, on the basis of the theoretical analysis, the system is simulated and the test of the actual device is completed. Both simulation and experiment verify the correctness of the transient characteristic analysis in the article, which provides an important reference for the subsequent research of pulsed CCPS system based on differential modulated BDFA.