Study of unified power unit based on combined voltage converter

Nowadays, there is a stable tendency to reduce weight and size of a spacecraft and, as a result, power supply systems, which are the main service systems. That is why current developments and applications in power systems of power modules with high-performance (weight and size, power, etc.) are essential. This paper discusses the construction of a modular spacecraft power system that provides stable output parameters at the time of its operation both in stationary and in emergency modes. Particular attention is paid to the study of nonlinear dynamic characteristics of the combined voltage converter on the basis of which such a unit can be configured. The bottom line of this study is reduced to find the permissible range of parameters of circuit components, providing a stable single-cycle mode of operation of the device, as well as boundary points of bifurcation, which are points of transition from the single-cycle to high cycle regimes. Thus obtained verifiable mathematical model of the combined converter, based on the switching-discontinuous functions and takes into account the non-linear parameters such as capacitance of input and output filters, as well as the inductance of the storage inductor. The results of a mathematical simulation and experimental study of the combined converter, in particular the bifurcation diagrams of output parameters, dependence of ripples on the load current and gain feedback loop, the output voltage waveform are given. The calculations are checked on a model of such a device, recommendations for practical application of the combined converter in real power system.