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The three-phase dual active bridge (3p-DAB) converter is widely addressed in emerging power systems applications such as solid-state transformer and dc microgrids. Its successful integration requires accurate modeling of its small-signal characteristics. Due to its dc–ac–dc structure, the DAB converter brings many challenges to small-signal modeling. The state-space averaging (SSA) has been the first proposed methodology to approximate the control-to-output and line-to-output transfer functions of the 3p-DAB. However, as shown in this paper, SSA is not precise for the stability analysis of 3p-DAB converters. A generalized state-space averaging (GSSA) model based on the dynamic phasor concept is developed in this paper for the Y-Δ 3p-DAB. A hybrid SSA and GSSA model representation is then proposed for the evaluation of all the converter transfer functions. The developed models are validated with detailed time-domain switch-level simulations in an electromagnetic transient-type (EMT-type) program. They are also used for the accelerated stability prediction in an EMT-type program. [ABSTRACT FROM PUBLISHER]

During the operation of dc rapid transit systems, the rail passenger vehicles are subjected to surge transient events that can damage the on-board equipment and cause service interruption. During the testing phase, vehicle manufacturers must demonstrate the performance of the vehicles under the specified transients. However, system testing is generally not available during design. Engineering analysis must be performed to ensure that the design will meet the transient requirements, and that the overvoltage and overcurrent protective devices are coordinated on a system level. In response to these design challenges, detailed time-domain simulation models of a switching surge transient generator and the vehicle equipment have been developed and validated experimentally. These models are used to evaluate vehicle system parameters sensitivity, as well as to provide design guidelines for increased vehicle power system safety, reliability, and availability. [ABSTRACT FROM AUTHOR]