Direct Power Control for Dual Active Bridge Converter with Parabolic Carrier

The wide-bandgap (WBG) devices feature a highspeed switching. This requires a faster and simpler controller for WBG embedded DAB system so that the converter can benefit most from the fast switching of WBG devices. The power transfer of DAB is proportional to D(1-D), where D is the phase shift between two active bridges. When the DAB converter received the power command from the upper controller, the phase shift need to be either derived by solving the binary equation (online calculation) or looked up from a table (offline calculation). The online-calculation method is computational inefficient. This may slow down the control speed. The offline-calculation method has only discrete operating points. This may lead to inaccuracy especially in scenarios that requires seamless transition of load. Thus, this paper proposed the direct power control with parabolic carrier. The proposed method eliminates the online calculation of the binary equation of phase shift by introducing a parabolic carrier. The phase-shift is generated by comparing the power reference with the parabolic carrier. The proposed method holds the computational efficiency and accuracy at the same time. The proposed method is evaluated on a single-phase single-stage bidirectional DAB ac-dc converter simulation.