Simulation and operational protection of three-phase/twelve-phase hybrid AC-DC supply generator system

The hybrid AC-DC supply has been applied to various situations. It provides simultaneous AC and DC power with least weight, volume and cost to meet the special requirement of mobile power networks. In this paper, a mathematical model, based on the multiloop method, including speed regulator and excitation regulator, is established to reflect the system operation aspect. The simulation results of voltage harmonics are compared with experiments to verify the validity of the mathematical model. The DC side power oscillation and short circuit may result in system breakdown. The simulation program provides the guideline for system operation and protection. The simulation results showed the factors that affect the amplitude and frequency of the DC side power oscillation. The q-axis winding and feedback control of the DC load current on the excitation voltage can increase system stability. The DC side short circuit currents are also calculated for the tuning of the relays.