Dynamic Analytical Model for Synchronous Homopolar Generators With Diode Rectifiers

Despite being a promising solution for applications requiring a reliable and robust electromechanical energy conversion system, synchronous homopolar machines (SHMs) are constrained by their low power density and complex three-dimensional magnetic behaviour, which requires computationally intense 3D FE for their analysis and design optimisation. This challenge becomes even more pronounced in SHMs with split winding configurations and in applications involving highly non-linear loads. To address these limitations, this paper proposes an analytical model aimed at bridging these gaps. The proposed model provides a computationally efficient alternative to 3D finite element analysis, addressing key challenges such as dynamic performance estimation and magnetic sleeve saturation, fully capturing the influence of both space and time harmonics. As a vessel to investigate such enhanced capability, a challenging case study is considered, encompassing an SHM with a split winding configuration where each winding set supplies a DC load via two series-connected three-phase diode rectifiers. After a thorough introduction of the analytical modelling framework, its dynamic numerical implementation is described. Its predictions are validated through comparisons with 3D FEA and experimental results carried out on a 1.2 kW demonstrator, under various operating conditions. The proposed analytical approach, demonstrated here for dynamic performance evaluation even under highly non-linear loads, provides a foundation for rapid design optimisation of SHMs.